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eHam Forums => Software Defined Radio => Topic started by: KA4POL on April 25, 2012, 11:16:10 AM



Title: DVB-T Stick as SDR
Post by: KA4POL on April 25, 2012, 11:16:10 AM
Similar to the well known Funcube a simple USB DVB-T receiver can be used as SDR. It must contain either the E4000 or the RTL2832U chip. Software can be WinRad or HDSDR for example. See http://www.youtube.com/watch?v=-Fh4EB0sX2w
This is a simple and really inexpensive solution but nice for experimenting.


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on April 25, 2012, 04:06:32 PM
Similar to the well known Funcube a simple USB DVB-T receiver can be used as SDR. It must contain either the E4000 or the RTL2832U chip. Software can be WinRad or HDSDR for example. See http://www.youtube.com/watch?v=-Fh4EB0sX2w
This is a simple and really inexpensive solution but nice for experimenting.

"The RTL2832U outputs 8-bit I/Q-samples, and the highest theoretically possible sample-rate is 3.2 MS/s, however, the highest sample-rate without lost samples that has been tested so far is 2.8 MS/s. The frequency range is highly dependent of the used tuner, dongles that use the Elonics E4000 offer the widest possible range (64 - 1700 MHz)."

8 bit samples is going to severely limit dynamic range even with process gain.  It is not going to be much more than a toy.

Gene


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on April 25, 2012, 09:50:47 PM
Funcube uses the E4000. At a cost of about 20$ you can't expect a perfect SDR from a DVB-T stick.
A compatibility listing can be found here: http://www.reddit.com/r/RTLSDR/comments/s6ddo/rtlsdr_compatibility_list_v2_work_in_progress/


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on April 26, 2012, 05:24:08 AM
Funcube uses the E4000. At a cost of about 20$ you can't expect a perfect SDR from a DVB-T stick.
A compatibility listing can be found here: http://www.reddit.com/r/RTLSDR/comments/s6ddo/rtlsdr_compatibility_list_v2_work_in_progress/

I am sure it is fun to play with and for that price for the hardware its not bad.  But people should be aware that 8 bit samples are really going to limit the dynamic range of this receiver.  It may be OK for DVB-T where the signals are strong you don't need great dynamic range, but for general purpose receiving use it will disappoint.

For informational purposes, those  in the USA who might think they can pick up and demodulate digital TV on one of these devices, the DVB-T system is not used in the USA.

Gene


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on April 26, 2012, 08:31:01 AM
For those traveling to Europe, however, the main use of those sticks is to receive terrestrial video. There is no more analog TV available. And, by the way, beginning on April 30th even Satellite TV will be purely digital in Europe.


Title: RE: DVB-T Stick as SDR
Post by: W0ARN on August 16, 2012, 02:58:33 PM
There's lots of free software to use with this ultra-cheap SDR dongle with more coming daily.  Many people are playing with it in a number of very interesting comm. (not necessary amateur comm.) projects, so I wouldn't overlook this off if you're into comm. generically.  Free software + ultra cheap hardware + computer you already have = something fun to play with:

Search youtube.com for RTL2832 and you'll find 112 videos.  Here are a few:

$20 ultra-cheap Software Defined Radio with RTL2832 DVB-T USB stick

https://www.youtube.com/watch?v=Z0hEquzLsWU

RTL-SDR APCO Project 25 (P25) receiver (DVB-T)

http://dangerousprototypes.com/2012/04/06/rtl-sdr-apco-project-25-p25-receiver/

World's cheapest INMARSAT reception system using DVB-T USB dongle (RTL SDR)

https://www.youtube.com/watch?v=zuyHpx1tnWI

World's cheapest aviation RADAR Mode S ADS-B receiver: AvMap + $20 RTL2832 Dongle

https://www.youtube.com/watch?v=bKzii5K3AqA

RTL2832 SDR + WRPLUS : WFM test

https://www.youtube.com/watch?v=BX9cLj1nMjQ

Google Group Ultra Cheap SDR:

https://groups.google.com/forum/#!forum/ultra-cheap-sdr


Title: RE: DVB-T Stick as SDR
Post by: N9RO on August 16, 2012, 09:41:14 PM
I have a Funcube and performance radio's these are NOT.  For playing around with they are cheap and fun.  I quickly glued together some apps, thru up a CMS system and uploaded the recorded Funcube GUI to the web site so some of the local repeater owners could go to the web and see their signal (for entertainment purposes).  The legacy hams at this point in time would probably have no use for these but for low cost experimenting they are fine.

Tim


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on December 15, 2012, 12:41:31 AM
There is a detailed description in QST 01/2013. It even includes a proposal for an up-converter. Seems interesting for those inclined to experiment and DIY.


Title: RE: DVB-T Stick as SDR
Post by: WD5GWY on December 15, 2012, 10:03:28 AM
Looks like a fun and cheap setup to play with. And I am very tempted to order
one. Plus that would give me a reason to get back into programming again!
C# is not one of my favorite languages, (love VB.net) but, I can do some things
with it.
  I read the article in QST and found it quite interesting.
Guess, I'll have to go and spend some money now!!   ;D
james
WD5GWY


Title: RE: DVB-T Stick as SDR
Post by: N3DT on December 15, 2012, 12:43:47 PM
So the limitation is the 8 bit sample rate.  Exactly what does that mean to my analog brain?  As a disappointment, in what area?  For $20 and some time spent playing is it worth it or is it just going to be like the old original 2fer's, or worse.


Title: RE: DVB-T Stick as SDR
Post by: WD5GWY on December 15, 2012, 03:06:16 PM
So the limitation is the 8 bit sample rate.  Exactly what does that mean to my analog brain?  As a disappointment, in what area?  For $20 and some time spent playing is it worth it or is it just going to be like the old original 2fer's, or worse.

The sampling rate has to do with the Analog to Digital converter(s) and Digital to Analog converters in a device. Here are a couple of articles from Wikipedia that might help:

http://en.wikipedia.org/wiki/Analog-to-digital_converter#Sampling_rate (http://en.wikipedia.org/wiki/Analog-to-digital_converter#Sampling_rate)
And here is one that lists various SDR radio's specs along with their sampling rates:

http://en.wikipedia.org/wiki/List_of_software-defined_radios (http://en.wikipedia.org/wiki/List_of_software-defined_radios)

 In the above list, the DVB-T dongle from RealTec, seems to sample  from 1 Mhz to
3 Mhz. But, tends to not be reliable at the top end. Still, for $20 or so, that is not too
shabby! And building an upconverter for HF reception is cheap as well. If you get QST
read the January 2013 issue and there is a good article there covering this pretty well.
james
WD5GWY
 
 


Title: RE: DVB-T Stick as SDR
Post by: N3DT on December 15, 2012, 06:03:10 PM
I read the qst article, that's why I'm here.  But it sounds like the guy is listening to P25 stuff, which is cool and way more than anything I have available otherwise.  But what is it like on ssb and cw, or even AM?

I got involved in the P25 with the Motorola Astro radios before I quit work, but our agency was encrypted and I know this thing is not going to do that, but it would be nice to hear the P25 local stuff.

It might be a worthwhile project for the bad winter days when I can't get outside and I'm sure any decent SDR would be at least 10 times that price, no?


Title: RE: DVB-T Stick as SDR
Post by: WD5GWY on December 15, 2012, 06:53:07 PM
Do a search on YouTube for "DVB-T" and you'll find a ton of
videos showing AM, FM, SSB and other modes using the DVB-T
dongle with and without, an HF up-converter. The audio on most
of the videos is not great. But, then again, they are probably recorded
with cellphone cameras that have pretty poor microphones.
There is even a few demos of HF being tuned in without using an up-converter.
But,image rejection is poor. There is a company on Amazon.com that sells
the DVB-T dongles and also  sells an HF up-converter. For less than $90 total,
you can get an entire setup if you don't want to build your own converter.
james
WD5GWY
 


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on December 15, 2012, 10:02:16 PM
So the limitation is the 8 bit sample rate.  Exactly what does that mean to my analog brain?  As a disappointment, in what area?  For $20 and some time spent playing is it worth it or is it just going to be like the old original 2fer's, or worse.
You are combining two things, the sample rate and the the data bit length.
The sampling rate determines how often a data conversion takes place. This usually limits the upper frequency (Nyquist Criterion). You need at least two samples to read a signal. This means at a sampling rate of 125 MHz you can read signals up to 62.5 MHz.
The dynamic range can roughly be calculated by multiplying the bit length by 6: 8 bit times 6 is 48 dB. This is not much but good in relation to the cost.The dynamic range can be regarded as the ratio between the highest number and the smallest number that it can represent expressed as a dB value.


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on December 16, 2012, 07:28:32 AM
So the limitation is the 8 bit sample rate.  Exactly what does that mean to my analog brain?  As a disappointment, in what area?  For $20 and some time spent playing is it worth it or is it just going to be like the old original 2fer's, or worse.

It is something to play with, but you'll soon grow tired of the poor dynamic range and the image problems.

Gene


Title: RE: DVB-T Stick as SDR
Post by: N3DT on December 16, 2012, 11:58:54 AM
Yeah, the old Heathkit super regens on 6 and 2 were sort of effective with AM, but certainly left a lot to be desired.  I got a VX-7 from HRO years ago and was so disappointed with the image problems I took it back.  But we're not talking $300 here.  There were digital spurs all over the ham bands and strong too.  I actually measured the image rejection and it was like 30db, not within spec.

Dynamic range, I take it you mean it overloads easily and then get a lot of extraneous signals?  I live in the boonies, so there's not much in the way of strong signals here.  But it's probably not very sensitive either and adding a pre-amp would probably overload it and make the DR worse.


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on December 16, 2012, 09:44:23 PM
I started this thread with experimenting in mind. If you want the perfect SDR you can select from expensive ready made units on the market. That's experimenting using your wallet.


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on December 17, 2012, 02:59:24 AM
I started this thread with experimenting in mind. If you want the perfect SDR you can select from expensive ready made units on the market. That's experimenting using your wallet.

That's OK if you are into wasting your time playing with silly toys or *maybe as a first introduction to SDR.   There are many other options out there to experiment with, such as the SoftRock Ensemble or the UHFSDR, that are much higher performance than these silly DVB-T dongles.  And they are not expensive.

Gene

*maybe, because it will turn some off to SDR when they see how bad the DVB-T performance is when compared to even a conventional analog receiver.


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on December 17, 2012, 03:35:21 AM
Your destructive comments are really not helpful at all. If you want to be pessimistic, return your license.


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on December 17, 2012, 03:41:55 AM
Your destructive comments are really not helpful at all. If you want to be pessimistic, return your license.

It has nothing to do with being pessimistic.  Encouraging people to buy into these DVB-T dongles and use them as a SDR is not doing anyone a favor.  These were made for decoding digital television where there is no need for great dynamic range. Using them as a general purpose SDR is another story.  You just don't like opposing opinions backed up with fact.

I gave other much better examples of simple SDRs to experiment with, so your comment about being destructive is also not true.

Gene


Title: RE: DVB-T Stick as SDR
Post by: K9AQ on December 22, 2012, 07:15:00 AM
I can speak from experience that the DVB-T stick works very well on HF SSB.  I am using an upconverter from Opendous, which can be purchased through Amazon or Ebay.  Look up "ham it up" converter.  I am using HDSDR software and linked it with HRD using DDE.  This only allows the SDR to track my Kenwood TS-480 so that can compare the sensitivity of the DVB-T/upconverter versus my Kenwood. (HDSDR also supports a CAT interface to HRD, but I haven't set this up yet.)

It works!  I won't use it as my primary receiver but for a second receiver to provide a panadapter display it works very well.  It is a real pleasure to be able to quickly see if a band is open and to visually see the activity on the band.   As I am writing this, I am listening to a DX station on 15 meters that doesn't register on my TS-480 S-meter but I can still hear him on the DVB-T.  If I can comfortably hear a station on the TS-480 I can also hear it on the DVB-T.

For a total investment of less than $100, with the upconverter, this is much more than a "toy"!  Don't let the negative postings from hams that have no real experience with the DVB-T discourage you from experimenting with it.

Don, K9AQ


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on December 22, 2012, 07:48:37 AM
I can speak from experience that the DVB-T stick works very well on HF SSB.  I am using an upconverter from Opendous, which can be purchased through Amazon or Ebay.  Look up "ham it up" converter.  I am using HDSDR software and linked it with HRD using DDE.  This only allows the SDR to track my Kenwood TS-480 so that can compare the sensitivity of the DVB-T/upconverter versus my Kenwood. (HDSDR also supports a CAT interface to HRD, but I haven't set this up yet.)

It works!  I won't use it as my primary receiver but for a second receiver to provide a panadapter display it works very well.  It is a real pleasure to be able to quickly see if a band is open and to visually see the activity on the band.   As I am writing this, I am listening to a DX station on 15 meters that doesn't register on my TS-480 S-meter but I can still hear him on the DVB-T.  If I can comfortably hear a station on the TS-480 I can also hear it on the DVB-T.

For a total investment of less than $100, with the upconverter, this is much more than a "toy"!  Don't let the negative postings from hams that have no real experience with the DVB-T discourage you from experimenting with it.

Don, K9AQ

Yeah, the 48 dB theoretical dynamic range sure qualifies it to be more than a 'toy' alright.   ::)  Maybe compared to a very poor receiver it is better.  However, I doubt that those who consider this a serious SDR receiver even know what dynamic range is anyhow...

Gene


Title: RE: DVB-T Stick as SDR
Post by: KS4JU on December 22, 2012, 10:45:33 AM
K9AQ, you are quite correct! I have been using a RTL2832U / Ham It Up coverter for HF reception also. It easily out does my more expensive commercial receivers. When it come to SDR, it isn't always about the numbers. Unfortunately, there are apparently folks that have no real clue about what they are talking about when it comes to RTL2832U devices or SDR for that matter. There are two components to consider, the hardware and the software. Often the software can make a bigger difference than the hardware. For under $100 you can put together a very nice HF receiver with a 2.5MHz spectrum display. It's almost embarrassing that such an inexpensive system can outperform receivers costing 6 time more.


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on December 22, 2012, 12:00:06 PM
K9AQ, you are quite correct! I have been using a RTL2832U / Ham It Up coverter for HF reception also. It easily out does my more expensive commercial receivers. When it come to SDR, it isn't always about the numbers. Unfortunately, there are apparently folks that have no real clue about what they are talking about when it comes to RTL2832U devices or SDR for that matter. There are two components to consider, the hardware and the software. Often the software can make a bigger difference than the hardware. For under $100 you can put together a very nice HF receiver with a 2.5MHz spectrum display. It's almost embarrassing that such an inexpensive system can outperform receivers costing 6 time more.

You must have some real junky commercial receivers!  No, it is more like guys who think that the performance of these 8 bit DVB-T sticks is great have probably not used a real high performance SDR receiver before.   They are just dazzled by the pretty spectrum display.  Anyone with even a fundamental understanding of SDRs will know why 8 bits is hot going to get you high receive performance.

Gene


Title: RE: DVB-T Stick as SDR
Post by: KS4JU on December 22, 2012, 01:26:22 PM
I think that most folks consider Yaesu HF receivers to be too junky and yes I have used a higher end SDR. The point is that it doesn't matter and the end of the day about the bits, just the results. What does matter is that at the end of the day for less than $100 you can get a pretty darn good HF SDR radio out of a RTL2832U and the Ham it Up HF converter (Opendous). I don't think anybody here was ever comparing the RTL2832U sticks to $800 SDR radios. However in my opinion a well set up RTL2832U / Ham it Converter offers a lot of bang for the buck.

Plus, the popularity of the $20 RTL2832U based SDR receivers have exploded over the past year. This has allowed a lot of people to experiment with SDR that may not have done so if it weren't for the cheap entry to the hobby. Hopefully, this will spur more interest in the hobby and some will move on to more sophisticated gear down the road. The other advantage of the RTL2832U sticks is that a lot of clever applications have been developed around them. Applications that we have not seen developed with the pretty much stagnated gear thats been around for several years for SDR. The RTL2832Us are now pretty well regarded as entry level ADSB receivers. There are other projects using the RTL2832U as AIS receivers, GSM receivers, GPS applications, Pocsag decoders, trunking receivers, and APO25 receivers. You can even couple a RTL2832U to a Raspberry Pi for a cheap ethernet SDR server. I understand that since the response to cheap SDR has been so hugely successful, that some vendors are working on higher quality devices. One vendor that I know of is currently working on a cheap SDR with a touchscreen interface. So in the long run the SDR hobby is getting a long needed "shot in the arm".

So, the discovery of the hacked RTL2832U SDR receiver has been a good thing, inspiring more innovation than we have seen in SDR in years. So, I would say to folks who are interested in the RTL2832U SDR to spend $20 bucks and learn more about SDR radio in general and look into all the interesting things you can do with a RTL2832U. Its good cheap radio fun!


Title: RE: DVB-T Stick as SDR
Post by: WD5GWY on December 22, 2012, 02:44:28 PM
I can speak from experience that the DVB-T stick works very well on HF SSB.  I am using an upconverter from Opendous, which can be purchased through Amazon or Ebay.  Look up "ham it up" converter.  I am using HDSDR software and linked it with HRD using DDE.  This only allows the SDR to track my Kenwood TS-480 so that can compare the sensitivity of the DVB-T/upconverter versus my Kenwood. (HDSDR also supports a CAT interface to HRD, but I haven't set this up yet.)

It works!  I won't use it as my primary receiver but for a second receiver to provide a panadapter display it works very well.  It is a real pleasure to be able to quickly see if a band is open and to visually see the activity on the band.   As I am writing this, I am listening to a DX station on 15 meters that doesn't register on my TS-480 S-meter but I can still hear him on the DVB-T.  If I can comfortably hear a station on the TS-480 I can also hear it on the DVB-T.

For a total investment of less than $100, with the upconverter, this is much more than a "toy"!  Don't let the negative postings from hams that have no real experience with the DVB-T discourage you from experimenting with it.

Don, K9AQ

 My setup just arrived in today's mail!! Including the up converter. (same one as yours)
I also have dug up enough parts to build another up converter for it. The Ham It UP converter
seems like it might be a good deal.
Now I need to go to Radio Shack and see if they have any of the SMA connectors and MCX
connectors. I thought I had some of those around here someplace. I'll probably find them
once I go buy new ones!
  Personally, I don't see any reason to discourage anyone from playing around with the
DVB-T dongles and up converters. It's not like buying a dongle and building/buying an
up converter are going to break the bank!  Dynamic Range etc. at that price point
($20 for my dongle) is not a big issue. Testing it, building things for it (additional HF
up converter) and doing some C# programming for SDR Sharp, is what I am interested
in.  To me, it's just another way to have some enjoyment in life and learn some new
and interesting things.
I hope more people give them a try and share their experiences using them here.
If some of the naysayers here would go to You Tube and do a search for "DVB-T"
they might be surprised at what some people have managed to do with such inferior
hardware!
james
WD5GWY
   


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on December 22, 2012, 04:23:32 PM
I can speak from experience that the DVB-T stick works very well on HF SSB.  I am using an upconverter from Opendous, which can be purchased through Amazon or Ebay.  Look up "ham it up" converter.  I am using HDSDR software and linked it with HRD using DDE.  This only allows the SDR to track my Kenwood TS-480 so that can compare the sensitivity of the DVB-T/upconverter versus my Kenwood. (HDSDR also supports a CAT interface to HRD, but I haven't set this up yet.)

It works!  I won't use it as my primary receiver but for a second receiver to provide a panadapter display it works very well.  It is a real pleasure to be able to quickly see if a band is open and to visually see the activity on the band.   As I am writing this, I am listening to a DX station on 15 meters that doesn't register on my TS-480 S-meter but I can still hear him on the DVB-T.  If I can comfortably hear a station on the TS-480 I can also hear it on the DVB-T.

For a total investment of less than $100, with the upconverter, this is much more than a "toy"!  Don't let the negative postings from hams that have no real experience with the DVB-T discourage you from experimenting with it.

Don, K9AQ

 My setup just arrived in today's mail!! Including the up converter. (same one as yours)
I also have dug up enough parts to build another up converter for it. The Ham It UP converter
seems like it might be a good deal.
Now I need to go to Radio Shack and see if they have any of the SMA connectors and MCX
connectors. I thought I had some of those around here someplace. I'll probably find them
once I go buy new ones!
  Personally, I don't see any reason to discourage anyone from playing around with the
DVB-T dongles and up converters. It's not like buying a dongle and building/buying an
up converter are going to break the bank!  Dynamic Range etc. at that price point
($20 for my dongle) is not a big issue. Testing it, building things for it (additional HF
up converter) and doing some C# programming for SDR Sharp, is what I am interested
in.  To me, it's just another way to have some enjoyment in life and learn some new
and interesting things.
I hope more people give them a try and share their experiences using them here.
If some of the naysayers here would go to You Tube and do a search for "DVB-T"
they might be surprised at what some people have managed to do with such inferior
hardware!
james
WD5GWY
   

I am not trying to discourage others from experimenting with them.  I have one of the dongles and converters myself.  Just please don't exaggerate their performance.  They are no where in the league of the more sophisticated SDRs on the market.  In relation to them, they are just a 'toy'.

Gene


Title: RE: DVB-T Stick as SDR
Post by: WD5GWY on December 22, 2012, 06:40:41 PM
Well, other than looking at the videos on You Tube, and hearing the
results, that is the limit of my experience with them. I have not had
time to set mine up yet. Been busy playing with my Flex 1500 and
the latest version of PowerSDR!
  I'm sure that most, if not all, of the people that are wanting to use
or experiment with the Dongles and upconverters understand that
they are not as good as real SDR receiver. After all, the dongles were
never intended for that sort of usage. That someone found that the
hardware instruction set included commands that make it possible to
use them as SDR receivers, is interesting to me. (and others)
  Toys or not, it really doesn't matter in the long run. Experimenting and
learning does matter.  I plan to get one of the RxTx Ensemble kits and play
around with one of those as well. I would even like to get a Genesis G59
transceiver kit too. But, those are very expensive for a one watt radio.
And they use a sound card for the I/Q processing.
Lots of possibilities out there!
james
WD5GWY
 



Title: RE: DVB-T Stick as SDR
Post by: WD5GWY on December 23, 2012, 01:39:11 PM
Just a quick update. Installed SDR# and got it going with my $20 toy!
Works much easier than HDSDR. But, then again, it has a much simpler
interface. Just playing around with the software, I am surprised at how
well it does work. I live quite some distance from a lot of FM radio stations
and i was surprised that it receives stations in the Dallas/Ft.Worth area as
well as it does. Especially since I just used the provided antenna, which is
about 5" long at the most. I'm going to dig out an old Radio Shack scanner
antenna I have had for years and see what happens with that one.
Also downloaded the source code as well. Think I'll fire up Visual Studio and
see what kind of mischief I can get into with that!!!
james
WD5GWY
 


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on December 23, 2012, 09:46:41 PM
If you compare quality and price with one of those commercially available SDRs you are getting much more per dollar.

Merry Christmas!


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on December 24, 2012, 08:08:33 AM
If you compare quality and price with one of those commercially available SDRs you are getting much more per dollar.

Merry Christmas!

For $20 you getting about $20 of performance.  Glad that you are satisfied with such low performance.

Gene


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on December 24, 2012, 09:52:19 PM
Amen!


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on December 28, 2012, 10:01:31 AM
You know, in life you're going to find A LOT of differing opinions - and everybody has one.  Given that, I'll weigh-in on the performance of my RTL-2832U + 'Ham-it-Up' HF Upconverter:

By design, the RTL2832U won't exhibit great receiver dynamic range since it's relying on 8-bit architecture for it's receive functionality (so I've been told), so the best you can expect is between 48 - 60dB dynamic range given that bit weighting.  While that may - to the 'SDR-purist' out there - be a nonstarter, for those who want to have a secondary receiver that can tune the bands and do an admirable job for what you DO get, I'm not complaining about not getting that extra 30 or more dB of dynamic range.  Using the same longwire antenna (I live in restrictive covenants - so don't get me started there), I can tell you that I have receivers that do a better job of pulling signals out of the noise because they have proper filtering and definitely better signal dynamic range performance according to what you pay for.  Spend low, you get marginal 'consumer product' performance.  Spend high (within reason) and you get professional quality receiver performance.  But if you're just looking to have fun with a wideband radio that can detect strong SWL signals and a few strong-signal hams while listening to nets, AND be able to tune the VHF band at the same time, this dongle+upconverter combination (for $60.00) does an ADMIRABLE job!  No kidding, I'd put it against any of my radios for casual tuning of the SWL band and it has comparable performance for stronger shortwave signals.  It undoubtedly falls short of being perfect on the Amateur bands, but it's a GREAT receiver for CASUAL tuning and listening on the cheap. 

Where the HF upconverter falls REAL short is where they upconverted the HF band to - - The FM Radio Band.  By doing a straight 100 MHz upconversion from the expected HF tune frequency, it lands you pretty much from 101.8 MHz to 130 MHz - about the lower 1/3 of the HF tuning range for the RTL-2832U and HF Converter will be subject to A LOT of interference if you have strong FM signals that land anywhere in that range.  I cannot imagine anyone living in a major metropolitan area to have this receiver be useful in the 80m, 75m, 60m, and 40m bands.  I live in a somewhat metropolitan area and I know that strong FM stations at 103.3 MHz, 104.5 MHz, and 107.9 MHz practically destroy your ability to listen to anything that falls into the lower end of the 80m band and the top of the 40m band.  The elliptical low pass filter design that they used is not effective in cutting down those strong signals.  Adjusting the RF gain of the dongle improves it some, but not enough to pull any weak signals out of the residual noise.  I would think that upconverting to 120 MHz would have been a better solution since all you have to deal with there is aircraft and public service that are, by nature, narrowband intermittent services and with A LOT less power to interfere.  If nothing else, the elliptical filter will roll off even better if the signals were upconverted to 120 MHz.  But I can understand the reasoning behind doing a straight 100 MHz upconversion:  EASE OF USE WITH TUNING.  For me, I would have just dealt with that small issue of performing the math and took the better upconversion (and receiver) performance.

I cased my RTL-2832U dongle and HF converter in a cheap black plastic Radio Shack project box, added a long (about 6') shielded USB cable to it, and drilled a hole to allow the HF Antenna connection (SMA connector) to be exposed out of the box and attached a SMA to SO239 connector to it.  Once I connected everything up I purposely hid that box in my setup (what's to look at - it's a black box) and now I have a semi-pro receiver playing through by PC speakers while I have any of the other rigs tuned elsewhere and playing, too.  Frankly, I have an older military receiver that I used to turn on and listen to as my standby receiver.  From the day I pressed this cheap SDR into service, I haven't turned on that old receiver in about a week (and it was a week ago that I cobbled this SDR together).  It plays GREAT in my setup!!

So, the final grade I give this SDR is: B- (good effort, but needs a couple tweaks to be considered a truly great receiver).

73 - de Marty, KN0CK  


Title: RE: DVB-T Stick as SDR
Post by: K9AQ on December 28, 2012, 03:54:47 PM
I completely agree with Marty's observations. I am using the same up converter and while it does work for me on the lower bands, it would seem that it could be improved by replacing the 100 mhz oscillator with a 120 mhz one.  When I have some free time, I will give this a try.

I am really enjoying having a second reciever with the HDSDR display.  I don't know how I got along for so many years without it.  It may not be "perfect" but it is sure a lot better than not having one!  I am also really enjoying experiementing with SDR, which over time could lead me to a Flex.

Don
K9AQ


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on December 28, 2012, 04:46:37 PM
Don,

Thanks for the nod on the observations - it's nice to have positive responses to this thread...

Before you attempt to replace the 100 MHz oscillator with a 120 MHz version, I just tried replacing the oscillator with a comparable 125 MHz oscillator that I had out of one of those AD9850 programmable oscillators and the following observations were noted:

1.) Working the math with the new oscillator frequency, you can tune and listen to stations with A LOT less interference (see point #2 directly below).  I was able to tune WWV, CHU Canada (in the 20m band) and the ENTIRE AM band (.5 to 1.6 MHz) without ANY interference from nearby FM stations.  However, the I.F. filter kicks in and does decrease the I.F. drive to the RTL-2832U some (see point #3 below).

2.) The noise floor decreased SUBSTANTIALLY (which is a good thing) since we're fighting higher noise floor with the nearby FM stations with this HF Upconverter.  It flattened the entire noise floor at least 20 dB over what it was with the 100 MHz oscillator.

3.) The IF drive to the RTL-2832U was decreased because the filter arrangement in the I.F. path cuts the power of the by about 3dB (half the signal) because the range has been shifted into the upper part of the bandpass filter in the '2932U's input.  I need to do some analysis of the I.F. filter in CircuitLab (http://www.circuitlab.com) and emulate their filter to see what the response is when the 125 MHz oscillator is plugged in.  I'm banking that the bandpass filter they're using does have the ability to cut into the I.F. power to the RTL-2832U and that's causing the issue with lower receive.  Either removing one filter section (jumpering over it) or providing new values will solve this issue.  I'm planning on doing a simulation on their filter tomorrow (12/29/12) and report back on what I see.  No kidding, plugging-in that 125MHz oscillator in place of the supplied 100MHz oscillator made a BIG difference in the noise floor (and, in effect, the performance of the receiver).

So those are my observations - stay tuned for more info as I have that available once I do the circuitlab simulations tomorrow...

73 de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: WD5GWY on December 28, 2012, 07:05:14 PM
If you have access to the January 2013 issue of QST, there is an article there has an HF converter design that uses a 125Mhz oscillator just like you are talking about. And it moves the tuning range
to 125-155 Mhz, well away from the FM radio band. I have most of the parts to build that one.
Just cannot seem to get enough time away from work to start building it.
 james
WD5GWY

(oh, I also have the Ham it Up converter too. Waiting for the connectors I ordered to arrive)
 


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on December 28, 2012, 09:03:34 PM
James,

Thanks for the tip - I should have noticed that one, but didn't remember until you just mentioned it here.  I do have that issue at hand (I'm a yearly subscriber) and will definitely check that out.  But I'll also report back my findings on the CircuitLab analysis of the 'Ham it Up' I.F. filter - might be interesting to check the two filter designs and see if they're similar (albeit with different component values because of the difference in upconverter tuning).

More to follow on this - do stay tuned, and thanks again for the info, James..!

Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on December 29, 2012, 04:32:59 AM
James,

Reviewed the design in the January 2013 QST and was certainly surprised to see that the author used an NE602 active mixer and absolutely NO filtering at the I.F. output from the mixer to the DVB-T receiver.  While this ensures that there's no loss in that path (it's straight capacitive coupling) it also ensures that there's a possibility of aliasing that can occur.  I think the author took the tact that any aliasing that shows up in the mixer's I.F. port are far enough out from the desired signal that it doesn't play an active role in the performance.  However, that's a bad assumption because those mixed products DO have an overall effect in the receiver's performance that shows up as decreased dynamic range in the desired signal because no matter what happens the power in that undesired signal is at the front end of that DVB-T stick, too, raising noise against the desired signal that could be improved through filtering out those undesired products.  He probably balanced 'good enough' performance and simplicity in design against adding complexity (and losing some I.F. power) through filtering.  There's nothing inherently wrong with that design assumption if that's his objective, but it will have a definite effect on the receiver's small signal acquisition - large signals will perform well with, again, decreased dynamic range (which is also an inherent issue with the DVB-T right out of the chute).

That said, I like the NE602 mixer design in the article and would use it as-is, but would probably add a less complex bandpass filter (fewer poles than are in the 'Ham it Up' I.F. filter) to help reduce undesired signals and improve (as best it can be) the small signal capture performance and still keep it relatively cheap.

Again, thanks for passing along the article - it does give me a new perspective on this project that's still worth pursuing (I bought a second DVB-T and will probably 'roll my own' HF upconverter as a hybrid of the 'Ham it Up' and NE602 upconverters).

73 de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on December 29, 2012, 07:18:39 AM
All who own the 'Ham it Up' HF Upconverter board:

I did a circuit analysis of the HF Elliptical LPF and swept that filter from 2 to 200MHz in CircuitLab....I can assure you, THAT IS NO LPF..!  As it turns out (and I have the frequency response plots to prove it) there's a REAL GOOD reason that we're all seeing more FM in our receivers than expected: It's because the filter response has a 'pop-up' at 100MHz that doesn't REALLY roll-off at all.  About the only place that the filter does roll off is about 90MHz, but then immediately you get to 100MHz pop-up and then the filter 'sort of' rolls off at 160MHz but then again at 200MHz it's back up to the input level.  So you're going to see all sorts of FM stations in there no matter what.  The LPF needs to either have more poles to make it fall off sharper (and sooner than 90MHz), or the poles need to be retuned so the knee is more like 40 - 50MHz.

I'm going to use their existing design and tweak the poles to see if I can improve the performance and then report back.  But I have 'swept' the HF LPF and the I.F. Bandpass filter and the bandpass filter is fine - - it's capable of working properly as-designed.  But the LPF IS A MESS..!

Again - I'll tweak the values and let you know the outcome - Stay tuned...

73 de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on December 29, 2012, 10:36:36 AM
Is this the filter you are talking about?
http://www.george-smart.co.uk/wiki/FunCube_Upconverter#Low_Pass_Filter


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on December 29, 2012, 03:39:59 PM
Dieter (and other 'Ham it Up' board users),

No, that LPF for the FunCube is quite a bit different than the 'Ham it Up' filter.  The FunCube uses a standard LPF design, while the 'Ham it Up' filter uses a Elliptical (Cauer) filter.  However, I did some more research this afternoon and came up with an updated schematic package than was posted on the open source website (http://code.google.com/p/opendous/wiki/Upconverter) a few days ago when I started to look into this issue.  As it turns out, the new schematic package more closely aligns to the design of the board I have than I first thought.  I haven't had a chance to 'run the numbers' on this new elliptical filter design (has one more pole to it than the package I downloaded 3 days ago) but if the data on the website is accurate, then this new filter should  have acceptable performance.  Again, I'm planning to run CircuitLab on it this evening and check that the design appears to match the data on the website - should, I have no reason (now since there's a more accurate schematic in the design package) to question it.

More to follow - stay tuned,

de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on December 29, 2012, 09:57:10 PM
Thanks for the link. They obviously have measured the filter using the SDR-Kits VNWA. I know that analyzer. It is a very good ham solution that delivers trustworthy data if the calibration has been done well enough.


Title: RE: DVB-T Stick as SDR
Post by: K9AQ on December 30, 2012, 06:25:08 AM
Has any one had any experience with the upconverter from 9A4QV http://upconverterup-100.blogspot.it/ ?  I am currently using an RTL with the Ham it Up upconverter and while I am happy with it, there are some areas that could be improved.  9A4QV's upconverter has an LPF between the oscillator and the mixer and an LPF on the input.  It also has a build in preamplifer to compensate for the conversion losses.  It is supposed to have an overall conversion gain of 10 db.

I have ordered one and when I get it will run some comparison tests.

Don
K9AQ


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on December 30, 2012, 07:23:33 AM
Don,

I think I've seen these HF upconverters listed on EBay at one time and then they disappeared for awhile - haven't seen them in a few weeks.  The design looks REAL interesting against everything I've seen (the NE602 QST article upconverter, 'Ham-it-Up', and now this one), but the only drawback I see is that it requires an additional 9 - 12V supply to power it, as well as RF amps to recover conversion losses that often comes with added noise figure - - but then again we're not talking about high performance when the primary receiver (the dongle) has a 40 - 50dB dynamic range to work with.  The only advantage that the 'Ham-it-Up' and the NE602 HF upconverters have is that they can be powered from USB and makes for a pretty simple application to augment anyone's setup (USB and an antenna is all that's needed).  Other than that, they come with conversion losses that make for lesser receive sensitivity - which this UP-100 seems to have the leg-up over everything else out there.

Thanks for passing this one along and do check back with performance data and observations when you have it - I'd be particularly interested in knowing how it compares to the 'Ham-it-Up' board.

73 de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on December 30, 2012, 08:04:34 AM
I just did a circuit analysis this morning of the updated Elliptical LPF that's in the schematic of the 'Ham-it-Up' board.  It's a great improvement over an earlier schematic that I acquired off the open source website, and did an analysis on a few days ago.  I'm convinced that the LPF that's on the current 'Ham-it-Up' board is acceptable and should provide decent FM band rejection provided that you're not situated within line of sight of the commercial FM transmitter.

On the flip, I did a circuit analysis of the M1GEO LPF that's been applied to the FunCube dongle and can report that at 88MHz it provides 39dB of rejection and when at 108MHz it provides 52dB of rejection - - the rolloff is pretty sharp starting at 75MHz.  From 500kHz to over 30MHz it shows no perceptible loss and at a couple of points in its range (15MHz and 42MHz) it shows an some modest gain.  Frankly, I liked this filter design - A LOT.

With all the different methods of filtering and upconverting I've come to the conclusion that there's a hybrid design out there that employs the best of all three <known> upconverter designs out there.  I'm about to go apply them to my own HF upconverter design.  I'm planning to design it this week, 'run the numbers' on it in CircuitLab, and then I might set out to design a board for this if I have time (the prototype will be on perfboard).  My design criteria is pretty simple:

1.) Has to operate on USB power ONLY
2.) Has to be simple in design (nothing exotic)
3.) Two, or less, active components
4.) Passive filtering with no RF amps to recover losses
5.) Connectivity with wires to the board or easily found (and/or inexpensive) connectors
6.) Has to fit on a board no larger than 1.5" x 2.5"
7.) Uses readily available 'RTL' apps (HDSDR and Zadig)
8.) Price target of $20 or less (it's just my own personal objective)

I'll keep you posted with my progress - stay tuned...

73 de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: WA8RVD on January 02, 2013, 02:25:22 PM
It's FUN!   It is a low cost toy - lots of fun for very little money!


Title: RE: DVB-T Stick as SDR
Post by: WD5GWY on January 02, 2013, 05:29:17 PM
It's FUN!   It is a low cost toy - lots of fun for very little money!
Exactly !!
james
WD5GWY


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on January 02, 2013, 07:57:03 PM
Hi All,

Just a note since my last post - - I have a design in hand and have ordered parts from Digikey yesterday (1/1/13).  I expect to see those by this weekend.  My design is a different twist on the same upconversion, but puts it in a part of the spectrum that <now> should be pretty quiet these days.  I simplified the output bandpass filter, kept the same LPF <but adjusted the frequency to a new range>, and used the SA612 as the oscillator/mixer, too.  I'm also not using an outboard crystal oscillator to achieve the mix, I'm using the SA612's internal oscillator to make that happen (makes the design a lot easier and less expensive that way, too).  The only active device is the SA612 and it can be run off USB power directly.  The total cost on the parts to make this all happen was less than $15.00, too.  Based on the part selection, the whole thing should fit on a 0.75 x 1.5" circuit board.  Provided that the prototype build goes well, I'll spill the design within a few days after testing and successful final evaluation of the design data and test results occurs.  On the heels of that, a PCB design could be out there soon after - - Stay tuned...

TNX, de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on January 06, 2013, 08:05:04 PM
All,

Okay - so I set out with a design, assembled it from the parts that arrived on Friday from Digikey and then gave it a test....Final result:  Success!  I would say that the performance rivals the 'Ham-it-up' board, only requires a low pass filter along with the SA612 mixer, and does not need a output bandpass filter going to the DVB-T stick receiver (my new one is a EZ-CAP receiver).  The only drawback is that I have to use an external +5VDC supply because the oscillator requires it.  I tried an earlier experiment where the SA612 used its internal oscillator and I used a 60 MHz crystal and it was powered off of the USB port and it had decent performance, but there were also too many instances of images at even frequencies (60 MHz and 80MHz) that I ended up using a 125MHz 'can' oscillator off a programmable VFO (that you can buy off EBay for $6.00) and just upconverted using that.  The oscillator is a power hog (draws about 120mA) and will not power from the USB hub I used.  If you're using a powered hub, then the current draw may not affect it.  So, at this time, I'm using an external supply until I can come up with a 120MHz and lower power oscillator.

As I mentioned, upconverting to 125MHz and using the LPF design I'm using the performance of the DVB-T stick and my HF upconverter appears to be equal - if not slightly better - than the 'Ham-it-Up' board.  Also, the final size of my HF upconverter is 0.75" x 1.75" - - MUCH SMALLER than the 'Ham-it-Up' board.  Right now I have the receiver tuned to 75m and I'm listening to various hams yacking away on this Sunday night.  I'm also VERY surprised that it's pulling signals out of the noise pretty decently - something that the 'Ham-it-Up' board had more issues doing.  It's pretty 'self contained', too...The whole thing (DVB-T stick and my HF upconverter) is taking up less than 3" x 0.75" x 0.75".  I reused the PAL connector off the antenna by cutting the cable and attaching it to the output of the HF upconverter.  I have the antenna input just alligator clipped to the upconverter's input at the LPF.

Anyway - I spent the better part of the day playing with it and the design is pretty firm now.  It's a necessity to upconvert into 120MHz or better to avoid overlapping the FM band.  My LPF has a DEEP cutoff (past 70dB) at 88MHz, so as you go up the FM band it just keeps getting better and I'm not getting a lot of noise from FM stations.  At 125MHz it does make tuning a challenge, but I'm not done with the oscillator - - more to follow on that.

Design details - if anyone's interested - do exist.  Post here if you're interested in seeing the design thus far and I'll post that on my website.

73 de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: WD5GWY on January 08, 2013, 04:47:37 PM
Well, as has been mentioned, the DVB-T dongle is  fun and cheap to play with. I also got
a Ham it UP converter to go along with mine. Finally found the right adapters etc. to hook
the whole thing up. (two came from China in two weeks!!! NO shipping fees, came US Mail)
Using SDR#, I got the whole thing cobbled together and working. I had already been messing
with just the dongle waiting for the adapters to arrive. (my home built up converter, will NOT
have SMA connectors on it!) It is surprisingly sensitive considering how widebanded it is.
Just the dongle by itself was fun.
Adding the upconverter made it better. The toughest part was getting the offset correct so that
SDR#'s frequency readout would be correct on HF. Still not 100% there. But, pretty close.
 Is it as good as my Flex 1500? No, but it surprised me that it heard some things as well as it did.
All in all, I think it is a fun "toy" and having just a bit over $60 in it shipped, it's not bad at all.
(that's including the HamItUp converter too)
 james
WD5GWY
 


Title: RE: DVB-T Stick as SDR
Post by: AB1SO on January 09, 2013, 05:03:08 PM

Anyway - I spent the better part of the day playing with it and the design is pretty firm now.  It's a necessity to upconvert into 120MHz or better to avoid overlapping the FM band.  My LPF has a DEEP cutoff (past 70dB) at 88MHz, so as you go up the FM band it just keeps getting better and I'm not getting a lot of noise from FM stations.  At 125MHz it does make tuning a challenge, but I'm not done with the oscillator - - more to follow on that.

Design details - if anyone's interested - do exist.  Post here if you're interested in seeing the design thus far and I'll post that on my website.

73 de Marty, KN0CK


Marty - I would be interested is seeing additional design details or any other information you can post regarding your converter design.

Mark/ AB1SO


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on January 09, 2013, 05:28:46 PM
Mark,

Thanks for the post - I'm currently working on the circuitboard design right now and will be posting that as well.  I have the schematic saved in ExpressSCH and will post that along with the PCB design within the next few days once the whole package is done.  As well, I've considered having 10 prototypes made through either OSHPark or ExpressPCB - - right now it looks like OSHPark is probably the cheapest route to make that happen.  I may pull the trigger on that once the board design is done and will have some protos for sale on EBay within the month either integrated with the DVB-T stick (it can fit inside a EZCAP DVB-T radio), or as the stand-alone upconverter board.  Depending on how well that goes, other boards could be produced to keep that going.  Not sure yet - it's kinda early in the game.

The intent of the design was for the HF upconverter design I've come up with (and am listening to on 75m at this very moment - - WORKS EXCELLENT) was to enclose it into an EZCAP or similar DVB-T dongle so it's a complete HF radio in that small form factor.  So that's what inspired the board design I did until 1:00 AM last night (that is 0.75" x 1.75").  However, I did it in ExpressPCB and now need to take that same board design and re-do it in EagleCAD - - it's the only file format the OSHPark accepts.  So I'll have to redraft that board design... : /

Anyway - I'll post the entire package this weekend up on my website and allow you and others to see this, too, and let you know when it's up there...Stay tuned...

de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on January 13, 2013, 10:13:38 PM
Did you now post your converter circuit? I could not find it.


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on January 14, 2013, 08:57:44 PM
Dieter / All,

I've contained the schematic and the board layout to the following weblink:

http://www.kn0ck.com/HFUpconverter/

These pics were just posted in the size they are now - I just threw them up there to get them out so you can look them over.  I'll refine the size and make the overall presentation of the files 'prettier' over the next few days.  What you can do for now is to do a right-click on either image and save it to your desktop.  That way you can size it to anything you want.

Again, data is up there for your review now.  I want to remind everyone that the board layout and schematic are there for INDIVIDUAL HAMS to build from since this design has been verified - - You may use it for YOURSELF with no issue from me at all.  The board and schematic are under copyright to prevent any businesses, domestic or international, to mass-produce this design.  I have the rights to the design as I envisioned it (I realize there are MANY different spins of this out there in the Ham community that use the SA612 - but this is MY design with my component values and the technology I selected (SMD) that were NOT copied from anyone else's design), along with the board design that is ENTIRELY of my own making and vision.  Again, I want to make it abundantly clear that I am NOT preventing a INDIVIDUAL HAM to use the data I have to make his/her own HF Upconverter from my design -- I'm just preventing someone from mass producing them from my idea.

That said.....

I have circuit boards being made at this time and will have 12 of them sometime around the beginning of February.  I will be building 3 final prototypes of this HF Upconverter using the SMD design such that I can fit it into the EZCap DVB_T receiver.  Once I've proven that the final design works acceptably, I'll post the results and then let other Hams know where to buy the boards (may be me since I'll see what the interest is and then go from there).  I may offer a kit or assembled boards, but again, will depend greatly on the interest in the Ham community.

TNX es 73, de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: WV4I on January 25, 2013, 07:53:33 AM
I've been playing with a DVB-T using SDR# and Win 7 32 bit on FM BCB, AM aircraft, and 2M. Receivers designed for those freqs modes far outperform the DVB-T, but then they don't cost $23 plus shipping either. I think that if want HF, better off skipping up converters etc., and get an SDR designed for HF, around $67-$110 kit/built, far better performance, less wires (RFI magnets), etc..


Title: RE: DVB-T Stick as SDR
Post by: W0VP on January 26, 2013, 06:56:49 AM
Well, as has been mentioned, the DVB-T dongle is  fun and cheap to play with. I also got
a Ham it UP converter to go along with mine. Finally found the right adapters etc. to hook
the whole thing up. (two came from China in two weeks!!! NO shipping fees, came US Mail)
Using SDR#, I got the whole thing cobbled together and working. I had already been messing
with just the dongle waiting for the adapters to arrive. (my home built up converter, will NOT
have SMA connectors on it!) It is surprisingly sensitive considering how widebanded it is.
Just the dongle by itself was fun.
Adding the upconverter made it better. The toughest part was getting the offset correct so that
SDR#'s frequency readout would be correct on HF. Still not 100% there. But, pretty close.
 Is it as good as my Flex 1500? No, but it surprised me that it heard some things as well as it did.
All in all, I think it is a fun "toy" and having just a bit over $60 in it shipped, it's not bad at all.
(that's including the HamItUp converter too)
 james
WD5GWY
 

My experience is almost exactly the same as James'. I read the article in QST last month and immediately purchased a DVB-T dongle on eBay from China, which arrived in about 10 days I believe. I then ordered the Ham It Up converter and a couple of SMA adapters, which took a week to arrive. Then ordered the correct SMA adapter cables (again from China) to couple the DVB-T dongle to the converter, another two weeks. Finally got everything hooked together and the software downloaded - and by gosh it works! And it really is fun to play with. I haven't compared it yet with the receiver in my IC-706mkIIg or my Sony ICF-2010.

And now I'm starting to think about going to the next level of SDR. I'm not sure yet if I want to go with the Ensemble II receiver, or maybe something like the Ten-Tec 320D. But I am going to start doing some research. In any case just playing around with the dongle/converter combo has re-ignited my interest in amateur radio / SWL which started over 40 years ago with a battery-operated Sears shortwave receiver I received for Christmas. And it didn't take me long to upgrade from that one either!

73,

KC, W0VP


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on January 26, 2013, 08:41:53 AM
And now I'm starting to think about going to the next level of SDR. I'm not sure yet if I want to go with the Ensemble II receiver, or maybe something like the Ten-Tec 320D.

The Ten Tec 320D is not a SDR.  It is a PC controlled receiver.  Even Ten Tec does not call it a SDR.


Title: RE: DVB-T Stick as SDR
Post by: W0VP on January 26, 2013, 10:57:13 AM

The Ten Tec 320D is not a SDR.  It is a PC controlled receiver.  Even Ten Tec does not call it a SDR.


I just noticed that myself. From what I've read it looks like a pretty nice receiver, and a definite upgrade from the dongle/converter combo.

KC, W0VP


Title: RE: DVB-T Stick as SDR
Post by: K5TED on January 27, 2013, 08:03:00 AM
Last week I took out a second mortgage on my toaster oven, and was approved for over $50 in a loan, which I had planned to invest in one of these high-end DVB-T dongle setups. With this economy, one never knows, but I decided to take the leap and devote some serious resources in hopes it would pan out for me, possibly replacing every radio receiver in the shack...

However, what I've learned here is that if you already own a DVB-T dongle and software to run it, and you are actually having fun playing with it, then you must be doing something wrong. Very soon you will be face to face with the realization you've squandered that princely sum, it's a complete failure and waste of time, and worst, you will be disappointed with the performance. This revelation came just in time to save me from a sure road to skid row. Whew!..

Thank goodness for this venue where almost every little pastime project and casual fun radio endeavor can be vetted, scrutinized, dissected, and shown to be worthless and a waste of time, by our resident experts.


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on January 27, 2013, 09:09:58 AM
Last week I took out a second mortgage on my toaster oven, and was approved for over $50 in a loan, which I had planned to invest in one of these high-end DVB-T dongle setups. With this economy, one never knows, but I decided to take the leap and devote some serious resources in hopes it would pan out for me, possibly replacing every radio receiver in the shack...

However, what I've learned here is that if you already own a DVB-T dongle and software to run it, and you are actually having fun playing with it, then you must be doing something wrong. Very soon you will be face to face with the realization you've squandered that princely sum, it's a complete failure and waste of time, and worst, you will be disappointed with the performance. This revelation came just in time to save me from a sure road to skid row. Whew!..

Thank goodness for this venue where almost every little pastime project and casual fun radio endeavor can be vetted, scrutinized, dissected, and shown to be worthless and a waste of time, by our resident experts.

Yeah, I bet you feel like a real GOOF for spending that exorbitant amount on your Flex 1500 when a DVB-T would have done.  ::)


Title: RE: DVB-T Stick as SDR
Post by: WD5GWY on January 27, 2013, 09:19:46 AM
Wow!! This thread sure took a sudden turn...........
  In my case the Dongle/UpConverter combo does not compete with my
Flex 1500. But, I enjoy using both anyway.
james
WD5GWY
 


Title: RE: DVB-T Stick as SDR
Post by: WD5GWY on January 27, 2013, 05:26:45 PM
Tried the latest build of SDR Sharp earlier today and I am surprised at how much better
the DVB-T dongle & HamIt Up converter work with that version as compared to the earlier
version. (there is a "nightly build" available on the developer's website)
Not sure about all that he has upgraded. But, everything seemed to be working MUCH better.
And I finally got the setting right so that the frequency display is dead on! (amazing what poking
around in different menus will turn up!)
 I have got to say that this cheap setup would work as an inexpensive way for someone to get
into SDR radio and SWL. Still not as good as my 1500, but, not all that bad either!
james
WD5GWY
 


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on January 27, 2013, 10:13:07 PM
I have got to say that this cheap setup would work as an inexpensive way for someone to get
into SDR radio and SWL. Still not as good as my 1500, but, not all that bad either!
That's exactly the point. And after finding out what is possible you still can get one of the more expensive hardwares. And you also noticed the software is about 50% of the business.


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on January 28, 2013, 03:32:41 AM
I just came across another nice solution for the HF converter: http://www.ct1ffu.com/site/hf-converter.pdf
For those not much inclined towards PCB production etc there is even a kit available.


Title: RE: DVB-T Stick as SDR
Post by: W0VP on January 28, 2013, 07:27:42 AM
I have got to say that this cheap setup would work as an inexpensive way for someone to get
into SDR radio and SWL. Still not as good as my 1500, but, not all that bad either!
james
WD5GWY

I'm not sure why there are hams who get heartburn over someone who is actually having a good time with their inexpensive DVB-T dongle and downconverter. It is - IMO - an excellent gateway to better quality gear. As I stated in an earlier posting, 40 years ago I got my feet wet with a Unelco 1914 shortwave receiver from Sears, a little plastic battery-operated radio with interchangable coils for different bands. Was it as good a receiver as my neighbors Collins S-Line? Nope. But I can't count the number of times I stayed up all night with my headphones plugged into that receiver slowly tuning around the shortwave bands, and then eventually the ham bands. I had a blast! But the Unelco had no BFO, so I had to upgrade to a Hallicrafters S-120 receiver to copy SSB and CW. Next was a Swan 240 3-band transceiver. Then a Tempo One transceiver. Then a Drake TR-4. Then an Icom 706. Not to mentions all the accessories and other goodies that go along with those rigs. But it all started with that little plastic box so many years ago.

I've discovered that I enjoy SDR and I'm already planning to upgrade to something better. But I wouldn't have known that without that January 2013 QST article and my DVB-T dongle and Ham It Up converter.

KC, W0VP


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on January 28, 2013, 10:29:02 AM
Hey, you could have known that already on April 25, 2012, 11:16:10 AM  ;D
That's when I started that thread  8)
I just pity those people you mentioned.


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on January 28, 2013, 08:49:00 PM
Hi All,

Just a note that the first batch of circuit boards (QTY 12) from my design have been completed and I have populated the first board (with the exception of 4 capacitors that I have on order with Digikey).  I've tested the board for power (+5V and 3.3V) and the 120 MHz oscillator - All is well and working fine.  This board is small enough to fit inside and be powered from the USB of the EZCap E4000 DVB-T receiver (0.5" x 1.75") and will be assembled as such once I've completed the assembly of my first board.  When testing is completed, I'll post here again with the test data and let everyone know how it went.  I can tell you that I'll be modifying my circuit board design when this is all done - there are some things I would do differently now from assembling the first board (especially with circuit board pads for the oscillator - I will be making those larger).

73 de Marty, KN0CK 


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on February 01, 2013, 08:14:52 PM
All,

I'm pleased to report this evening that a new DVB-T dongle (EZCap, E4000) that I have that was outfitted with one of the HF Upconverter circuit boards I recently designed and built is working excellent and per design.  I am currently playing with it in the HF band using Zadig and HDSDR and it's playing fine with the 120 MHz oscillator that I selected for the design.  I'm not seeing any performance degradation based on the original prototype that I made about a month ago and the nice thing about it is that it's COMPLETELY self contained and my new circuit board fits PERFECTLY inside the EZCap dongle.  I also cut the PAL connector (center conductor) to allow the antenna to be connected directly to the USB dongle so the HF Upconverter splices into the DVB-T module like I intended, too.  About the only thing I may play with is decoupling the 3.3VDC supply a little because there is a little drift noticeable but once I decouple the supply it should stabilize - - I'll keep you advised of that.

Anyway, the first board is built, the proof of concept is complete, and I have a couple tweaks to the circuit.  It is - for all intent - the smallest 0.5 MHz to 40 MHz HF receiver you can buy right now...No bigger than a thumb drive.

73s for now....de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: W0VP on February 02, 2013, 04:43:06 AM

Anyway, the first board is built, the proof of concept is complete, and I have a couple tweaks to the circuit.  It is - for all intent - the smallest 0.5 MHz to 40 MHz HF receiver you can buy right now...No bigger than a thumb drive.

73s for now....de Marty, KN0CK

Congratulations Marty. Now I wish I hadn't spent all of my first (and only) year at Georgia Tech's EE school playing pinball and drinking beer instead of going to my classes  :'( Maybe then I could design and build my own HF converter instead of waiting for people like you to do it for me!

Anyway, pencil me in on your list of customers for your new HF receiver (a built one please, as my hands just aren't steady enough anymore for soldering those teensy components). And if you get the time, perhaps a YouTube video comparison of your converter with the 120 MHz oscillator vs. a converter with a 100 MHz oscillator.

Great job!

73,
KC, W0VP


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on February 02, 2013, 07:06:26 AM
Kevin,

Thanks for the congrats - It was a lot of fun building this up and I must say that the circuit analysis part in CircuitLab.com made me confident enough of the design in the early-go to build up the first prototype on perfboard.  Once that worked well enough that I felt I really had something, I sought out Oshpark.com to have boards cut for this project.  Again, while this 'cut' of the board design lacks anything fancy (like a lot of supply decoupling and all that), the performance of the design is every bit as good as the 'Ham it Up' HF Upconverter.  Since I built the first prototype and began using it, I completely stopped using the 'Ham it Up' setup altogether - my prototype worked even better and didn't have the image issues with the FM band stepping all over where I wanted to tune and listen in the 75m to 40m bands.  I upconverted to 120 MHz to avoid all that and I don't have any images that make it hard to tune and listen as a result.

I'm currently talking with a board house in San Diego to manufacture 25 completely assembled HF Upconverters, but the NRE for that is what's setting me on my heels.  It's an investment of nearly $600.00, but it will provide with the first set of boards where I don't have to use tweezers, a magnifying glass, bifocals, and patience to assemble 'em.  I'm weighing my options on that part of the project now if I should make that jump.  I'll keep the group advised if that happens, but right now I have a plan to build 2 more with the parts I have (both are already sold) and will be picking up 3 more receivers and parts to build 3 more radios.  One of those is already sold, and the other 2 are up for grabs.  You are penciled for one of those and I've already checked your QTH - you're not that far from my neck of the woods here in Iowa.  Once I build that batch I'm done - it's gonna depend heavily if I want to spend the NRE to have the larger batch made...I'm still pondering that...

Anyway, that's where it's at now....More to follow - stay tuned,

73 de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: W0VP on February 02, 2013, 08:13:09 AM
Kevin,

One of those is already sold, and the other 2 are up for grabs.  You are penciled for one of those and I've already checked your QTH - you're not that far from my neck of the woods here in Iowa.  Once I build that batch I'm done - it's gonna depend heavily if I want to spend the NRE to have the larger batch made...I'm still pondering that...

Anyway, that's where it's at now....More to follow - stay tuned,

73 de Marty, KN0CK

 ;D
Thanks Marty! I can't wait to give it a try. PM on the way to you!

73,
KC, W0VP


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on February 03, 2013, 05:08:29 PM
ALL,

I've had a number of inquiries for purchases of the HF Upconverter board that I've designed and thought it best to remind everyone of the quality of this design given that I'm keeping it 'low budget'.  The primary component of the design includes a 120 MHz oscillator that is specified at a jitter/drift rate of 10 PPM.  In 'laymans terms' that means that the oscillator output frequency can jitter or drift up to 1.2 kHz <peak> over the run time of the system.  In practice, I've noticed drift/jitter of around 100Hz on SSB and CW <and for other digital modes as well>.  A good example of the quality of this SDR can be heard on a session that I recently recorded on the 75m phone band this evening:

http://www.martywittrock.com/Hamwaves/index.html

As you can tell, there's a little perceptible jitter/drift of about 100 - 200 Hz in the voice on occasion, but not so distracting that it's not usable.  It's very similar on CW, too.  The only way this could be 'tightened-up' is to go to a 1 PPM oscillator that would cost - by itself - about $80.00 making the design impractical to make for a low cost.  But for casual listening and the size of the HF Upconverter (that fits inside the DVB-T case), you can't beat the performance of this SDR.  Again, on AM SWL stations, there is NO perceptible drift in the signal and you can listen for hours without hearing any anomalies.  On SSB and CW - where tuning is more critical, what you heard in the audio sample is what you can expect in performance.

Anyway, I thought it best to share an actual wavefile recorded from the SDR so everyone could get an idea of the performance of this design - you now know.

73s de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on February 04, 2013, 02:56:34 AM
ALL,

I've had a number of inquiries for purchases of the HF Upconverter board that I've designed and thought it best to remind everyone of the quality of this design given that I'm keeping it 'low budget'.  The primary component of the design includes a 120 MHz oscillator that is specified at a jitter/drift rate of 10 PPM.  In 'laymans terms' that means that the oscillator output frequency can jitter or drift up to 1.2 kHz <peak> over the run time of the system.  In practice, I've noticed drift/jitter of around 100Hz on SSB and CW <and for other digital modes as well>.  A good example of the quality of this SDR can be heard on a session that I recently recorded on the 75m phone band this evening:

http://www.martywittrock.com/Hamwaves/index.html

As you can tell, there's a little perceptible jitter/drift of about 100 - 200 Hz in the voice on occasion, but not so distracting that it's not usable.  It's very similar on CW, too.  The only way this could be 'tightened-up' is to go to a 1 PPM oscillator that would cost - by itself - about $80.00 making the design impractical to make for a low cost.  But for casual listening and the size of the HF Upconverter (that fits inside the DVB-T case), you can't beat the performance of this SDR.  Again, on AM SWL stations, there is NO perceptible drift in the signal and you can listen for hours without hearing any anomalies.  On SSB and CW - where tuning is more critical, what you heard in the audio sample is what you can expect in performance.

Anyway, I thought it best to share an actual wavefile recorded from the SDR so everyone could get an idea of the performance of this design - you now know.

73s de Marty, KN0CK

Jitter and drift of an oscillator are two different things.   You are talking about drift.  Jitter relates to phase noise when a clock oscillator is used an a LO in a receiver.


Title: RE: DVB-T Stick as SDR
Post by: W4HIJ on February 04, 2013, 06:50:44 AM
I have got to say that this cheap setup would work as an inexpensive way for someone to get
into SDR radio and SWL. Still not as good as my 1500, but, not all that bad either!
james
WD5GWY

I'm not sure why there are hams who get heartburn over someone who is actually having a good time with their inexpensive DVB-T dongle and downconverter. It is - IMO - an excellent gateway to better quality gear. As I stated in an earlier posting, 40 years ago I got my feet wet with a Unelco 1914 shortwave receiver from Sears, a little plastic battery-operated radio with interchangable coils for different bands. Was it as good a receiver as my neighbors Collins S-Line? Nope. But I can't count the number of times I stayed up all night with my headphones plugged into that receiver slowly tuning around the shortwave bands, and then eventually the ham bands. I had a blast! But the Unelco had no BFO, so I had to upgrade to a Hallicrafters S-120 receiver to copy SSB and CW. Next was a Swan 240 3-band transceiver. Then a Tempo One transceiver. Then a Drake TR-4. Then an Icom 706. Not to mentions all the accessories and other goodies that go along with those rigs. But it all started with that little plastic box so many years ago.

I've discovered that I enjoy SDR and I'm already planning to upgrade to something better. But I wouldn't have known that without that January 2013 QST article and my DVB-T dongle and Ham It Up converter.

KC, W0VP
Heck I own a Flex 1500 which has all the receiver I need for HF but I'm still considering experimenting with one of these DVB-T sticks for VHF/UHF satellite reception. Still wish someone would make a "turn key" kit for a 2m/70m all mode SDR! As far as the DVB-T sticks, can someone point me to a "non E-bay" source for the proper one? I don't do E-bay.
Michael, W4HIJ


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on February 04, 2013, 09:32:58 AM
Would you be doing Amazon?


Title: RE: DVB-T Stick as SDR
Post by: WD5GWY on February 04, 2013, 10:09:54 AM

Heck I own a Flex 1500 which has all the receiver I need for HF but I'm still considering experimenting with one of these DVB-T sticks for VHF/UHF satellite reception. Still wish someone would make a "turn key" kit for a 2m/70m all mode SDR! As far as the DVB-T sticks, can someone point me to a "non E-bay" source for the proper one? I don't do E-bay.
Michael, W4HIJ

How about this one:
http://www.nooelec.com/store/
They sell on Amazon (where I bought mine....from their online store) or directly from their
website. You can get a complete setup from them for less than $70 including shipping. Not
a bad deal for getting your feet wet. Or since you are currently only interested in VHF/UHF
reception, the price drops to $25. Not bad at all.
james
WD5GWY


Title: RE: DVB-T Stick as SDR
Post by: N3YZ on February 04, 2013, 05:24:07 PM
Concur with GWY on NooElec. I just received the dongle (VHF) and upconverter (HF). Works. The challenges were finding the connections (F to SMA, SMA to PL259 etc) and realizing to offset -100,006,000 in SDRSharp. Nice job.

John, Annapolis, MD


Title: RE: DVB-T Stick as SDR
Post by: KA4NMA on February 12, 2013, 04:23:02 PM
I am interested in trying out SDR (hf, vhf and uhf) as a beginner.  I am more interested in fun, experimenting and trying it out, than in high performance.  I am disabled and cannot do any circuit building.  Can anybody help me out with a SDR set?

Randy ka4nma

my email is pastor dot spaceboy (at) gmail


Title: RE: DVB-T Stick as SDR
Post by: K4AX on February 13, 2013, 07:01:36 AM
Randy, the RTL usb stick is the way to go, it's a painless software install if you use SDRsharp to install. For a antenna you can get adapters to go from MCX to whatever, even to SO239.  I've got two of them, the one I use most of the time I just cut off the antenna and made a loop from about 8 feet of wire, and put a coax stub filter right at the feed point to help cut down a blow torch FM radio station here in town.


Title: RE: DVB-T Stick as SDR
Post by: KA4NMA on February 13, 2013, 10:11:21 PM
Randy, the RTL usb stick is the way to go, it's a painless software install if you use SDRsharp to install. For a antenna you can get adapters to go from MCX to whatever, even to SO239.  I've got two of them, the one I use most of the time I just cut off the antenna and made a loop from about 8 feet of wire, and put a coax stub filter right at the feed point to help cut down a blow torch FM radio station here in town.

Where do I get the RTL usb stick?


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on February 13, 2013, 11:03:32 PM
Amazon sells them among others.


Title: RE: DVB-T Stick as SDR
Post by: NN4F on February 14, 2013, 10:07:09 AM
Randy, the RTL usb stick is the way to go, it's a painless software install if you use SDRsharp to install. For a antenna you can get adapters to go from MCX to whatever, even to SO239.  I've got two of them, the one I use most of the time I just cut off the antenna and made a loop from about 8 feet of wire, and put a coax stub filter right at the feed point to help cut down a blow torch FM radio station here in town.

Where do I get the RTL usb stick?

www.nooelec.com, get the TV28T, has the better R820T tuner.. works like a dream

Paul- NN4F


Title: RE: DVB-T Stick as SDR
Post by: W4HIJ on February 16, 2013, 04:44:40 PM
 As I said, my thought is to use something like this as a basic satellite receiving solution. Do any of the software packages which work with these, have any provisions for CAT? Or are they too experimental for that?
Michael, W4HIJ


Title: RE: DVB-T Stick as SDR
Post by: W4HIJ on February 16, 2013, 05:32:07 PM
Ahhh what the heck, I ordered one. You can spend twenty bucks easy on burgers and fries these days and it will be fun to mess with even if it doesn't satisfy some of the"know it alls" on here. ::) ::) I think I've even got an old discone lying around here that will suit it fine for experimentation. Meanwhile the Flex 1500 keeps me as happy as a wolf in a hen house as far as HF is concerned.
Michael, W4HIJ


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on February 16, 2013, 09:41:35 PM
As I said, my thought is to use something like this as a basic satellite receiving solution.
What are you planning to do concerning satellite receiving? Is it ham radio or else?


Title: RE: DVB-T Stick as SDR
Post by: W4HIJ on February 16, 2013, 10:04:44 PM
As I said, my thought is to use something like this as a basic satellite receiving solution.
What are you planning to do concerning satellite receiving? Is it ham radio or else?
2m/70cm FM ham sats. Maybe a linear bird. Would probably have an RX preamp in the 70cm side at least. I live "way out in the sticks" so I don't think there is anything around here that will just totally overload the thing and blot it out. I don't know how well it will handle when everyone keys up at once trying to get their call and grid out but hey it was 20 bucks right?
Michael


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on February 16, 2013, 10:18:37 PM
In comparison to your Flex the cost effectiveness is really super. A good antenna will be helpful. I actually can receive NOAA WX satellites with my Chinese HT and the rubber ducky.


Title: RE: DVB-T Stick as SDR
Post by: W4HIJ on February 16, 2013, 10:39:32 PM
In comparison to your Flex the cost effectiveness is really super. A good antenna will be helpful. I actually can receive NOAA WX satellites with my Chinese HT and the rubber ducky.
Well yeah, true enough. Then again the RX side of my  Flex cost effectiveness vs. the $2K and up XCVR's it outperforms is pretty super too! :D :D I'm not looking for miracles, I just would like to mess around with the new FM birds that are hopefully soon to be upcoming and I don't want to do it all with an HT, I'd like to do it from the comfort of my shack. I have a discone for experimentation and it's a simple matter for me to whip up a "cheap yagi" if I want something with a little gain. Heck I still have all my homebrew AZ/EL rotator stuff, there's just nothing up above my MA5B HF mini beam right now. I can easily put something there. I can get the signal down to the dongle with no problem, it's just whats it going to do with it when it get's there? That's my 20 buck gamble. My next step up would be a Funcube dongle but I don't have the funds right now.
Michael, W4HIJ


Title: RE: DVB-T Stick as SDR
Post by: NH7L on February 17, 2013, 06:27:21 AM
Between amazon.com and Quicksilver Radio  (qsradio.com), you can find every kind of connector, even made-up cables with connectors, you need for dongle funz. Qsradio will even custom-build cables for you if you're soldering-iron challenged.


Title: RE: DVB-T Stick as SDR
Post by: KD7RDZI2 on February 20, 2013, 02:34:51 PM
Hello, everybody. One simple question. How can I set the gain of the Realtek SDR stick to get about -120dbm noise floor using SDR#? I get no less than -70dbm nose floor!


Title: RE: DVB-T Stick as SDR
Post by: HAMMYGUY on February 20, 2013, 03:14:05 PM
I've got the same issue with mine.  The sensitivity is horrible.  Local FM stations barely come in on the included magnetic whip.

Since so many are having good results, there must be something in the setup that is being overlooked. 


Title: RE: DVB-T Stick as SDR
Post by: N9RO on February 20, 2013, 04:43:56 PM
I've got the same issue with mine.  The sensitivity is horrible.  Local FM stations barely come in on the included magnetic whip.

Since so many are having good results, there must be something in the setup that is being overlooked. 

I found this device very disappointing but then again it was only $25 I got what I paid for. 

Tim  N9RO


Title: RE: DVB-T Stick as SDR
Post by: W4HIJ on February 20, 2013, 05:28:02 PM
I've got the same issue with mine.  The sensitivity is horrible.  Local FM stations barely come in on the included magnetic whip.

Since so many are having good results, there must be something in the setup that is being overlooked. 
My first guess would be the antenna, even for local FM. I don't have mine yet but I'm not expecting it to have performance along the lines of a top of the line VHF/UHF radio. It's just something to play with at the above 50Mhz level without investing close to 200 bucks in a Funcube Dongle Pro.
Michael, W4HIJ


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on February 20, 2013, 05:49:18 PM
I've got the same issue with mine.  The sensitivity is horrible.  Local FM stations barely come in on the included magnetic whip.

Since so many are having good results, there must be something in the setup that is being overlooked.  
My first guess would be the antenna, even for local FM. I don't have mine yet but I'm not expecting it to have performance along the lines of a top of the line VHF/UHF radio. It's just something to play with at the above 50Mhz level without investing close to 200 bucks in a Funcube Dongle Pro.
Michael, W4HIJ

DVB-T users generally fall into two categories:  Those who have tried one only to be disappointed with the performance and those who don't know any better.


Title: RE: DVB-T Stick as SDR
Post by: HAMMYGUY on February 20, 2013, 06:50:56 PM
You're probably right Gene.  I tried the Funcube Dongle and sold it after the first day. It too was about as sensitive as a crystal radio hooked to a coat hanger.  This seems to be in the same class.  Maybe with enough preamp it might hear our local NOAA station.


Title: RE: DVB-T Stick as SDR
Post by: PJ2BVU on February 20, 2013, 07:37:57 PM
Do you really expect that a $25.00 radio will perform as well as a multi k$ one?
This is a toy. And I do not say it in a pejorative way, it is a wonderful toy to give you a taste of what SDR is all about. You will want more after playing with it.
For better performance:
Softrock RX Ensemble II HF receiver ($67.00 kit, $92.00 built). HF only.
Softrock 6m/4m/2m RX Ensemble receiver ($68.00 kit only). You build it for one band.
Softrock RXTX Ensemble Transceiver ($89.00 kit only). HF only.
These are also toys but much closer to the real thing.

Jean-Claude PJ2BVU


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on February 21, 2013, 03:33:39 AM
You're probably right Gene.  I tried the Funcube Dongle and sold it after the first day. It too was about as sensitive as a crystal radio hooked to a coat hanger.  This seems to be in the same class.  Maybe with enough preamp it might hear our local NOAA station.

These things were made to pick up digital TV signals so they do not need the dynamic range that a HF receiver needs.  On HF, you typically have signals that range from -130 dBm to over 0 dBm.  That requires a very large dynamic range, ideally over 120 dB.  Those DVB-T sticks have a window of about 42 dB dynamic range.  You can shift the window up and down with a preamp or attenuator, but increase the gain and you start overloading on strong HF signals. Decrease the gain and you start going deaf and can't hear the weaker ones.  The problem is a little less for general purpose (playing around) VHF/UHF use, but still 42 dB is not nearly enough.


Title: RE: DVB-T Stick as SDR
Post by: W4HIJ on February 21, 2013, 10:21:06 AM
You're probably right Gene.  I tried the Funcube Dongle and sold it after the first day. It too was about as sensitive as a crystal radio hooked to a coat hanger.  This seems to be in the same class.  Maybe with enough preamp it might hear our local NOAA station.
I wasn't implying the fun cube dongle was any great shakes either, I wouldn't know, never having owned one. My whole point was that for something just to play with, I'd rather invest 20 bucks than 200 bucks.
Michael, W4HIJ


Title: RE: DVB-T Stick as SDR
Post by: KD7RDZI2 on February 21, 2013, 11:47:53 AM
I have the Funcube Pro. It is not deaf at all. And I could set the noise floor at the level I wanted, usually -120dbm. But I am able to exploit the full capability of the Funcube because I use (reasonable priced) helical bandpass filters tht do a good job. The only issue I see is related to the dynamic range when signals are strong enough to artificially rise the noise floor. A strong point in favor of the Funcube is the software: SDR Console, is just fantastic, allowing to set the gain at each stage of the receiver.
The RTL seems different at least in the software. SDR# is nice but different. I activate the tuner AGC in configure and then I see signals close to 0 dbm and a high noise floor, usually -60-70dbm. The funny thing is that I use a notch FM broadcast filter rated at abt -50db and see FM broadcasts still close to 0 dbm. They are notched out so they should be much weaker. Indeed they are: using the Funcube and the same notch filter these signals are about at -50dbm. And this level is quite realistic. It seems to me that SDR# keeps the noise floor as variable, rising the noise floor when signals are low up to -60/70dbm and maybe lowering it when signals are strong. I am a bit puzzled by the software and I don't think the hardware is a toy. Surely the Funcube is not and I hope the RTL is not too.


Title: RE: DVB-T Stick as SDR
Post by: KK4MRN on February 21, 2013, 04:02:59 PM
I would love to get a SoftRoc SDR and build it, but I have no desire to solder surface mounted parts.  I am lucky enough to be able to solder through-hole parts.  I wish the surface mounted ICs were already soldered on the board.  I have a Weller WLC100 soldering iron which I don't think will work for surface mounted ICs.   However, it is very tempted to get the pre-built SDR receiver (when it's available), the pre-built sells out quickly.


Title: RE: DVB-T Stick as SDR
Post by: OH6I on February 22, 2013, 12:36:12 AM
Daniel,
this SDR kit SMD components are already fitted:
http://o28.sischa.net/fifisdr/trac (http://o28.sischa.net/fifisdr/trac)
http://www.box73.com/ (http://www.box73.com/)

Jari
OH6I


Title: RE: DVB-T Stick as SDR
Post by: K4AX on February 22, 2013, 08:57:28 PM
Here is a recording I made my stick with the r820t tuner on it the other day. https://www.youtube.com/watch?v=pZATpTrw9mc&feature=youtube_gdata_player


Title: RE: DVB-T Stick as SDR
Post by: W4HIJ on February 23, 2013, 09:14:04 AM
I wasn't expecting the tiny little antenna jack on the Noo Electric and apparently ordered the wrong adapter. No great problem though,after I play with the little antenna that came with it a bit, I'll cut that end off and wire it to a female F connector  that I found in my junk box from my satellite days.  Off to download software. We had about a twelve hour long internet/cable TV outage. Never know how used to having that stuff that you get till you don't have it.
Michael, W4HIJ


Title: RE: DVB-T Stick as SDR
Post by: K4AX on February 23, 2013, 03:01:57 PM
If anyone is interested, I picked up one of these, took a little over a week to get it from HK.  Works great. http://www.ebay.com/itm/160962314322?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649


Title: RE: DVB-T Stick as SDR
Post by: W4HIJ on February 23, 2013, 04:45:18 PM
Well I got mine working with HDSDR but I'm not getting much off the little antenna. Of course I didn't expect to. Out here in the boonies I live in you can barely get a NOAA weather station to come in with a handheld. It's the price I pay for no antenna restrictions and a lake in my backyard. :D Anyway I'm hoping to try and get something outdoors soon. The XYL has me on house arrest this weekend because it's cold and rainy out and I already have a really bad cold.
Michael, W4HIJ


Title: RE: DVB-T Stick as SDR
Post by: K9AQ on February 27, 2013, 01:56:08 PM
Don't judge the DVB-T based on its' performance with on FM with the "stubby" antenna.  When you have good quality upconverter and connect it to your regular HF antenna, you will find that it works quite well.  I am using this "toy" as a second receiver/panadapter with my Kenwood TS480.  I use HDSDR and have it linked to HRD so my SDR and my Kenwood track each other.

I don't use the SDR to listen to stations, only for the panadapter display and for point and click tuning of the Kenwood.  For that purpose it works extremely well.  I have been using mine for about a month and I don't know how I got a long with out.  I have been a ham for 51 years and have a degree in electronics.  I take exception to the posts on this forum that only people who don't know any better who be happy with the DVB-T dongle.

If anyone is seriously interested in doing what I have done, email be at dsolberg@wi.rr.com and I will send you some screen snapshots showing the SDR Panadapter is daily use.

Don
K9AQ


Title: RE: DVB-T Stick as SDR
Post by: W4HIJ on February 27, 2013, 02:33:51 PM
No, I'm not judging it by the tiny little antenna that came with it at all. I have a Flex 1500 so therefore don't need it for HF. My interest in it is to see how well it performs as a wide band VHF/UHF RX and also to see if it will "hear" the satellites. I just finished getting a piece of mast up in the air and I'm going to mount a "scanner antenna" I had laying around and feed it with some RG-6 Quad shield. Then I will get a better gauge on it's performance. And don't pay any attention to the "know it alls" on here, best thing to do is put e'm on ignore. That's what I did and it makes for a much more pleasant experience on e-ham, especially in this forum.
Michael, W4HIJ


Title: RE: DVB-T Stick as SDR
Post by: 9A4QV on February 28, 2013, 11:55:05 AM
Hello guy's,

Of course you will hear the satellites, if you have a decent antenna first of all  :o
Speaking about the cheap USB DVB-t dongle, one should be aware of the limitations that this kind of equipment have. If you accept the dynamic range, NF, MDS, saturation point figures already known then it is much easier to predict and expect the results of mentioned setup.

Of course, somebody using the Flex radio or Perseus will said that the DVB-t SDR is junk, but also somebody using Harris military SDR radio 0-500Mhz can say same for the Flex radio or Perseus. On the other side the Perseus owner will be still proud on his SDR no matter what Harris SDR owner said on that.
The same goes for the cheap DVB-t SDR dongle.

I am aware of all limitations, but I still have a lot of fun using this 20$ dongle with or without HF upconverter, attenuator, LNA, filters etc. It is great and most of all affordable peace of radio that can be entry for the young and most of all old hams in the world of SDR.
I sell a lot of upconverters and surprisingly mostly to older hams or the hams that a coming back to hobby after a long pause. They are all interested to try this new trend, SDR and for sure this is the easiest and cheap way.

Adam, 9A4QV

P.S. If you look for the satellites i suggest a good LNA (AD6IW have the nice LNA for all bands) and mounted close to the antenna / far from the USB dongle.
Simple notch filter made of simple L/4 section of coax cut for the 100MHz broadcast band can reduce the noise a lot and make the satellite reception more pleasant. At he same time this noch filter will kill some signals also in the TV band (200, 400, 800 MHz) 


Title: RE: DVB-T Stick as SDR
Post by: W4HIJ on February 28, 2013, 02:36:35 PM
Hi Adam,
Yes, I'll definitely be using a preamp eventually. I either will build or buy one. It's not my first foray into satellite communication so I know how to set everything up. I just want to see how far I can go with the inexpensive DVB-T dongle before I've pushed it to it's limitations.
Michael, W4HIJ


Title: RE: DVB-T Stick as SDR
Post by: 9A4QV on February 28, 2013, 03:20:22 PM
Hi Michael,

well then you will definitely have some fun chasing the birds on ham and out of the ham bands. Just to let you know that I saw DVB-T dongle receiving EME on 144mhz with and barefoot without LNA. More over I saw MAP-65 working very nice with the same dongle. It is amazing to watch screen full of decoded call signs. The antenna was 4x8 el yagi.

Have fun
Adam


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on March 01, 2013, 09:13:40 PM
At this time I've finished the first production of my SMD HF Upconverter that fits INSIDE the EZCap (E4000) RTL2832 dongle and have sold to 10 Hams - - 6 of those outside my state (Iowa).  For anyone interested in seeing this receiver, look here ----> http://blog.kf7lze.net/tag/up-converter/             
Look for the article called:  "KN0CK HF Upconverter Fits Inside the USB Tuner’s Enclosure"

The performance has been remarkable and I can tell you that while it may not have wide dynamic range, in the noisy HF band it performs just as well as some of my better receivers on my shelf.  I'm now on my second <and third> productions of this HF Upconverter for the EZCap receiver that I bought from Nooelec (on EBay) and my customers are also VERY happy with their purchases.  Again, this HF Upconverter fits INSIDE the receiver and looks the same as the VHF/UHF model you buy off EBay but it's a full-blown 10kHz to 30 MHz HF receiver.  I've even outfitted a couple of the receivers I sold with a HF/V-UHF switch so the user can still use it for listening to 2m, 70cm, and satellites operation and then switch to HF to listen there, too. 

So, for anyone that thinks that these RTL2832 receivers are junk or don't perform - I have no idea what you're talking about because there isn't anything that I can't hear with this receiver compared to equipment that I paid more than $700 to hear the same thing.

73 de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: 9A4QV on March 02, 2013, 02:05:57 PM

So, for anyone that thinks that these RTL2832 receivers are junk or don't perform - I have no idea what you're talking about because there isn't anything that I can't hear with this receiver compared to equipment that I paid more than $700 to hear the same thing.

73 de Marty, KN0CK

Well, maybe this is because you 700+$ radio is really bad. You should ask then money refund from your radio dealer :-)

There are only two things where the combination USB DVB-T + Upconverter can beat the standard radio setup: the price and the panoramic view. If you expect that DVB-T dongle will perform as the standard radio, then you better do not "invest" 20$ in DVB-T dongle. Here in the Europe we can still use the dongle to watch the local TV if we are not happy with the SDR performance, so at the end this is good investment.

Adam, 9A4QV


Title: RE: DVB-T Stick as SDR
Post by: W4HIJ on March 02, 2013, 07:25:21 PM
Participation in the contest this weekend plus my lingering cold has slowed my progress a bit.  The scanner antenna I had lying around here is now installed and had the RG-6 quad shield attached via F connector but the rest of the cable is lying on the roof. I find at 50 years old that I'm not as easily inclined as I used to be to crawl under the house and push the cable up through the floor. :D :D I'll get there though.  I am looking forward to seeing what the VHF/UHF performance actually is.
Michael, W4HIJ


Title: RE: DVB-T Stick as SDR
Post by: KN0CK on March 03, 2013, 05:03:21 AM
It always amazes me when certain people don't 'get it' with this technology...Adam, thanks for confirming that for all of us.

de Marty, KN0CK


Title: RE: DVB-T Stick as SDR
Post by: KE5JPP on March 03, 2013, 05:27:23 AM

So, for anyone that thinks that these RTL2832 receivers are junk or don't perform - I have no idea what you're talking about because there isn't anything that I can't hear with this receiver compared to equipment that I paid more than $700 to hear the same thing.

73 de Marty, KN0CK

Wow, confirms what I said earlier about not knowing any better.   ::)

It sounds like you have some real junk in your shack.


Title: RE: DVB-T Stick as SDR
Post by: KD7RDZI2 on March 11, 2013, 02:00:59 PM
I added HamItUp upconverter for HF reception... well... in front of that I use a good preselector and a 16db high IP3 preamplifier so I keep the gain of the RTL at very low level.  This setup excludes the saturation of the RTL stick and gives plenty of sensitivity. About the modest dynamic range... maybe that could be an issue during contests but with this setup I do not see a great need for better dynamic range. For me, the most important feature of SDR is image rejection, and the software SDR# essentially solved it. This upconverter is quite a nice addon. These days I used also an RX Ensemble which is good but the upconverter gives much more band to see... thumbs up!


Title: RE: DVB-T Stick as SDR
Post by: VE3TMT on June 18, 2013, 07:41:56 AM
I use one (R820T) as a panadapter on my Yaesu FT990 and it works amazing. The display on my 22" monitor is a lot more than you will see on any of the PRO series or some of the newer radios. When the radio is interfaced with Omni-Rig, I simply click and I'm there. Pretty slick for $20.

See the display on QRZ under my call.

73,
VE3TMT


Title: RE: DVB-T Stick as SDR
Post by: K4AX on June 18, 2013, 11:55:49 AM
I do the same with my FT-857, and though the receiver on the 857 is "OK" I prefer to listen to the rig on the dongle with HDSDR.   What setup do you have with yours? Is it buffered?


Title: RE: DVB-T Stick as SDR
Post by: VE3TMT on June 19, 2013, 06:18:05 AM
I tapped the RF board between T1005 and T1010 just before the 47 MHz filter. Tap was done only through a .01uf cap. Tested received signals on a known signal before and after the tap, no difference was noted.

I prefer the sound through the PC, I can adjust the IF response as wide or narrow as I need. I find it very comparable to the receiver on my old TS870S, even better in some cases.

73,
VE3TMT


Title: RE: DVB-T Stick as SDR
Post by: KF5TOR on July 27, 2013, 02:26:23 PM
The stick can be converted to HF with NO converter. Contact Thomas Hillard KC9QLE for a e-document to do this ($8). It works great! I have no association with Thomas but as a satisfied customer.
It took me about 1/2 hour to build the required components and do the soldering, download and install the software. My total cost was less than $30. My stick came from NooElec and is a R820T SDR & DVB-T (e-bay).
Thurmond


Title: RE: DVB-T Stick as SDR
Post by: VK4KL on August 01, 2013, 02:24:43 AM
Bought one of the Realtek DVB-T devices and its a waste of time. My 2 meter rig 5' away from the devices antenna and not a thing was heard no sign of signal on the screen at all get plenty of hash and nothing else.

Adrian


Title: RE: DVB-T Stick as SDR
Post by: VE3TMT on August 01, 2013, 07:03:37 AM
Hi Adrian,

Did you have the gain up on the device?

Mine will pick up repeaters out to 50 miles, as well as aircraft as far as New England from Ontario.

I have devoted mine to it's original purpose, SDR on the Yaesu FT990, which it works very well.

I have a second unit sitting in a drawer that I may experiment with, but I find it easier just to use my scanner for the VHF stuff.

Max


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on August 01, 2013, 08:26:31 AM
Bought one of the Realtek DVB-T devices and its a waste of time. My 2 meter rig 5' away from the devices antenna and not a thing was heard no sign of signal on the screen at all get plenty of hash and nothing else.
What do you mean by your rig being 5' away. Do you receive signals on the rig and not on the stick? do you switch the antenna between both?
Could it be a software issue?


Title: RE: DVB-T Stick as SDR
Post by: AE4RV on August 01, 2013, 11:39:39 AM
I'm with Max, check the gain. If using SDR# hit the configure button and turn on AGC.


Title: RE: DVB-T Stick as SDR
Post by: VE3TMT on August 01, 2013, 11:47:20 AM
While on the subject of the 990 and the dongle...

Does the unit need all 4 wire connections from the USB jack?

Just curious if it would be possible to mount the tuner inside the 990 and run a USB cable from the back of the 990 to the computer. The tuner could grab its power from the radio, so only the data lines would have to go to the USB port.

Not show how a computer detects something has been plugged into a USB port, is it the current draw or do the data lines trigger something?

Max


Title: RE: DVB-T Stick as SDR
Post by: VK4KL on August 01, 2013, 06:48:12 PM
I setup the USB device receiving on 147.000mhz used my handheld to transmit on 147.000 simplex and not a thing heard on the SDR. Was using HDSDR and AGC was turned on.
Thinking I might have a faulty unit

Adrian


Title: RE: DVB-T Stick as SDR
Post by: VK4KL on August 01, 2013, 08:50:23 PM
Update
I have a dud USB device. I borrowed a USB device and it worked perfectly although a bit noisy. Listening to police 170 km away in Rockhampton noisy but understandable next step buy a good USB device and build a decent antenna for it.

Adrian


Title: RE: DVB-T Stick as SDR
Post by: K1ZJH on August 02, 2013, 08:28:33 AM
I setup the USB device receiving on 147.000mhz used my handheld to transmit on 147.000 simplex and not a thing heard on the SDR. Was using HDSDR and AGC was turned on.
Thinking I might have a faulty unit

Adrian


My understanding is that these devices were intended for TV reception. I've read comments that a user has to adjust the tuning to compensate for frequency correction when used for narrow band reception.  Perhaps your receiver is set for 147.000, but it is actually receiving on another frequency?  Does your software have spectrum display features?  Just a WAG on my part.

Pete


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on August 02, 2013, 08:43:49 AM
Well, transmitting with about 5 W close to a receiver might do some harm to the first stage.


Title: RE: DVB-T Stick as SDR
Post by: VK4KL on August 02, 2013, 11:18:14 PM
Was only 0.1w from IC2A. Bought new device today and works well.

Tried to find a FunCube online and the best I can find is $313 inc post on eBay are they usually this price?


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on August 02, 2013, 11:28:25 PM
At https://funcubedongle.3dcartstores.com/checkout_one.asp the sell for 124 GBP which is around $ 200. That is the Pro.


Title: RE: DVB-T Stick as SDR
Post by: VK4KL on August 02, 2013, 11:59:49 PM
For now I'll stick with the $20 version.

Adrian


Title: RE: DVB-T Stick as SDR
Post by: WV4I on October 22, 2013, 05:28:40 AM
I can say that the $11 (Ebay) RTL2832/820T chipset USB sticks work great on 1090mhz with the supplied antenna even indoors. Aviation band with outdoor antenna for that band. Ditto FM broadcast and 2M. Except for 1090mhz, using SDR#. Of course your results may vary. The January 2013 QST had a nice article re how to get into this nearly free world of SDR receivers.


Title: RE: DVB-T Stick as SDR
Post by: WB8VLC on March 13, 2014, 10:44:43 AM
A Total waste of money is what all of these USB SDR so called receivers are.

 All the USB SDR packages suck, they typically cannot find the dongles especially if you are using win 7 or win 8.

 Don't waste your money they are to frustrating and certainly not plug and play, if you want to spend, no waste,  weekends trying to get the software to find the dongle, and I tried all of the software packages, then fine waste your money on this junk.

If you value your time then buy a bigger name SDR with discrete IQ outputs to a sound card I have never had a problem with the older models such as softrocks but stay away from these USB dongle nightmares. 


Title: RE: DVB-T Stick as SDR
Post by: VE3TMT on March 13, 2014, 12:52:11 PM
A Total waste of money is what all of these USB SDR so called receivers are.

 All the USB SDR packages suck, they typically cannot find the dongles especially if you are using win 7 or win 8.

 Don't waste your money they are to frustrating and certainly not plug and play, if you want to spend, no waste,  weekends trying to get the software to find the dongle, and I tried all of the software packages, then fine waste your money on this junk.

If you value your time then buy a bigger name SDR with discrete IQ outputs to a sound card I have never had a problem with the older models such as softrocks but stay away from these USB dongle nightmares. 

I've had no issue with any of the dongles I've purchased, except for one which the computer wouldn't recognize. I've used them with SDR#, HDSDR and RTL1090 all with good success. I have one devoted to my FT990 as a panadapter driver using HDSDR and it works great.

Sure they're are true SDR receivers, what do you expect for $10, but you get a lot of fun for the money. My panadapter works great, I click on a signal and the radio follows. I can use the dongle to monitor a second frequencies for true dual receive.

If anyone needs help setting one up in HDSDR, I'll be glad to help.

VE3TMT

 


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on March 13, 2014, 10:26:43 PM
20 bucks is much less waste of money than 800. I've seen a guy who was not able to manage his high end SDR, Most of the time it is a tiny problem that can be resolved. Actually this is what this forum is about. State your problem and very often someone will be found to help.


Title: RE: DVB-T Stick as SDR
Post by: K4AX on March 16, 2014, 11:13:40 AM
This has not been my experience at all, run the drivers, install the software, plug the stick in, turn the gain up, hit start and it generally works.  I've installed them on many windows 7 machines at this point. Plug and play? In my opinion it is.   

A Total waste of money is what all of these USB SDR so called receivers are.

 All the USB SDR packages suck, they typically cannot find the dongles especially if you are using win 7 or win 8.

 Don't waste your money they are to frustrating and certainly not plug and play, if you want to spend, no waste,  weekends trying to get the software to find the dongle, and I tried all of the software packages, then fine waste your money on this junk.

If you value your time then buy a bigger name SDR with discrete IQ outputs to a sound card I have never had a problem with the older models such as softrocks but stay away from these USB dongle nightmares. 


Title: RE: DVB-T Stick as SDR
Post by: G7MRV on March 19, 2014, 07:02:20 AM
A Total waste of money is what all of these USB SDR so called receivers are.

 All the USB SDR packages suck, they typically cannot find the dongles especially if you are using win 7 or win 8.

 Don't waste your money they are to frustrating and certainly not plug and play, if you want to spend, no waste,  weekends trying to get the software to find the dongle, and I tried all of the software packages, then fine waste your money on this junk.

If you value your time then buy a bigger name SDR with discrete IQ outputs to a sound card I have never had a problem with the older models such as softrocks but stay away from these USB dongle nightmares. 

I think you may be in a minority with that opinion!

I have two of these cheap dongles. Both work fine, so long as you take into account the lack of front end filtering and the limited dynamic range. I use mine for ADS-B, ACARS, POCSAG, UHF airband scanning, and all manner of other tricks. I have also set three other people (both non-hams but ex-radio technicians, or studio engineers) up with them with no problems.

The problems people have with these are usually down to a lack of research. I initially had troubles, all of which were due to me not reading up on them enough!

I also had NO problems installing them with Win 7. But the driver windows find is NOT the correct driver (again, well documented!)

Of course they wont compete with a multi-hundred dollar device, but for what they cost they are quite amazing.

As for them being just 'toys' - this is a hobby - spend what you want, £10 or £10,000 all your buying is your own 'toys'! If you need to spend thousands to have fun, thats your own choice!


Title: RE: DVB-T Stick as SDR
Post by: KD7RDZI2 on March 19, 2014, 10:47:03 AM
A Total waste of money is what all of these USB SDR so called receivers are.

 All the USB SDR packages suck, they typically cannot find the dongles especially if you are using win 7 or win 8.

 Don't waste your money they are to frustrating and certainly not plug and play, if you want to spend, no waste,  weekends trying to get the software to find the dongle, and I tried all of the software packages, then fine waste your money on this junk.

If you value your time then buy a bigger name SDR with discrete IQ outputs to a sound card I have never had a problem with the older models such as softrocks but stay away from these USB dongle nightmares. 

The USB dongles are the easiest to use. They are supported by the excellent SDRSharp. The Softrocks receivers are mainly for HF, the USB dongles mainly for above the HF. The USB dongle works very well under linux too. Not that easy the softrock. Not to say the softrock transceivers... a real nightmare to TX!!!!


Title: RE: DVB-T Stick as SDR
Post by: N5INP on March 19, 2014, 04:10:23 PM
A Total waste of money is what all of these USB SDR so called receivers are.

Ridiculous.

I use a cheap USB dongle every single day with HDSDR DXing and I wouldn't want to be without it. It works very well and is certainly not a waste of money.  ::)


Title: RE: DVB-T Stick as SDR
Post by: G7MRV on March 20, 2014, 04:16:38 AM

A Total waste of money is what all of these USB SDR so called receivers are.

Heres a thought for you - How much did you spend on snacks last time you went to a hamfest? My bet is it was far higher than the cost of one of these, and what you bought was far less healthy than if you'd taken your own snacks from home?

Heres what I did - I like a good cooked breakfast from my works canteen - about £3. I didnt have that two days in a row, and bought a RTL USB stick!

An im very surprised by what these things can do and be used for. They are a lot of fun, a very easy way to have a go at SDR and see if you like it


Title: RE: DVB-T Stick as SDR
Post by: K2NCC on March 21, 2014, 07:14:19 PM
An im very surprised by what these things can do and be used for. They are a lot of fun, a very easy way to have a go at SDR and see if you like it

No doubt!  Sold all my HF gear recently and thought I'd try a couple RTL-SDRs for something to experiment with for a while.  Now, until something better comes along, they're a permanent fixture of my shack.

Turns out I can do more with a $20 tv-tuner than I could with a $2000 Flex3000 SDR.  Granted, I can't TX, but more of a listener anyway.  I also don't get the quality of signal as I would from a more expensive rig, but the trade-offs are worth it if you hardly hear your radio anyway.

I never had 2M SSB (etc) but I do now.  I was once so impressed with the Flex huge waterfall, but now that's a sliver.  Back way out and voice looks like a JT9 signal so much fits on there.  I can now listen to six slices of RF across 3MHz.  Only 2 within a 100KHz slice on the Flex.

All thanks to a cheap device and some really really really smart people who share their skills.  Often for no cost to the user.

Check out some of the recent fun I've had with my dongle.  (which sounds bad out-of-context!)
http://www.youtube.com/user/k2nccvids/videos

If you're into amateur radio and haven't bought one of these yet (i recommend NooElec), you should try one out for a few days at least.  Worth the 20 bucks for what you'll learn and experience.


vy 73, de frank in Oregon, k2ncc


Title: RE: DVB-T Stick as SDR
Post by: KI6LZ on March 21, 2014, 08:15:41 PM
Maybe I missed something. I have a Funcube that I use for spectrum display of FT-1000 IF output. But I can only get about 192 KHz max spectrum using USB 2. I would love to see 1 or 3 Mhz for other uses, what am I missing?



Title: RE: DVB-T Stick as SDR
Post by: K2NCC on March 21, 2014, 09:23:39 PM
I have a Funcube that I use for spectrum display of FT-1000 IF output. But I can only get about 192 KHz... what am I missing?

I'm not familiar w/the Funcube, but the specs page say the max you can see is what you are.
http://www.funcubedongle.com/?page_id=1201


Title: RE: DVB-T Stick as SDR
Post by: WB8VLC on March 25, 2014, 11:22:04 PM
ok i'll admit that for 10 to 20 bucks they are ok to experiment with but for serious receiving they are only so so unless you have lots of time to experiment.

 But again the low price is the selling point and the potential to add your own external hardware to improve performance is another plus if you have the time.

The biggest negative for me was that you can't use them near any transmitter unless you add a bank of switched band pass filters which is what I do just to listen to 2 local PD's, one running DMR and the other NXDN96, but the price for mine being free was the reason why I have one.

And I'll admit that the software is free and they are certainly better than a uniden scanner at several digital demod schemes and at trunking but be prepared to spend a lot of time compiling code and experimenting with the numerous settings in the various plugin screens. 

If you can get past the frustrations of setting up all the numerous plugins, which are required to do the more interesting digital demodulation and trucking, then you actually may learn something but for me it was the darn frustration of getting the dongles working on one pc while it failed outright on another and the constant software tweaking of the plugins but of course it is free.


Title: RE: DVB-T Stick as SDR
Post by: K2NCC on March 25, 2014, 11:46:26 PM
If you can get past the frustrations of setting up all the numerous plugins... then you actually may learn something but for me it was the darn frustration... and the constant software tweaking of the plugins...

The setup and use of all these great tools is more fun than any conversation I've had in amateur radio.  Once it's all up and running, the fun part is about over!

Most of the places I listen I can't transmit anyway.

"Appliance operators" are often looked down upon and underestimated.  Next time someone that only likes to PTT or click a couple pieces of metal together gives me a hard time, I'll just hand them an RTL-SDR dongle and see what they can do with it. 8)


Oh, while I'm here... this is what I'm doing at the moment....
(https://dl.dropboxusercontent.com/u/42020338/rnzi_rtlsdr_sample004.jpg)
(be sure to check out my YOUTUBE page for dozens of samples)



Title: RE: DVB-T Stick as SDR
Post by: CHRISTOFERO on April 21, 2014, 10:16:25 PM
I probably have at least seven or eight of them. I use them for all sorts of things. I have even been able to use one for GPS. The most flexible environment for them is Gnuradio where you basically build your radio application using a flowchart metaphor.

I have to admit I've put a huge amount of time into it but I've finally figured out I think how to get optimal performance out of them in a great many situations that had me frustrated at the beginning. And I've learned a hell of a lot about a great many aspects of radio, about antennas, about propagation, about various aspects of the sciences.

I HIGHLY recommend them as gifts, especially for people who like to tinker. I can't imagine a better inexpensive gift for a technically oriented person.

If a ham wants to change the world of ham radio and bring THOUSANDS of new hams into the hobby, all they need to do is build some hardware project that for maybe $125 takes a system that already consists of an RTLSDR and a ham it up upconverter to the next level and lets it transmit as a slightly more than QRP (20 watts would do it for digital modes) all band SDR. The transmit chain I think is simpler than the receive.

I think an up-converter could be used in reverse to transmit, right? Use the mixer/oscillator in the other direction, filter the output? All in all a huge learning experience and lots of fun too.


Title: RE: DVB-T Stick as SDR
Post by: CHRISTOFERO on May 04, 2014, 08:33:41 PM
Hello,

If you have any problems with a USB SDR dongle you should visit the forum over at reddit: http://www.reddit.com/r/RTLSDR (http://www.reddit.com/r/RTLSDR).

The info you can find in the forum and wiki there should be able to give anybody all the info they need to have a great experience with them. And feel free to ask questions.

I have to say I have the complete opposite experience, I think my most recent USB dongle purchase - which cost a whopping $12, shipped, is hands down the best gadget deal I've ever found in my life, in terms of fun/value for money. The one I like is the white one with the IEC connector and the little curved row of ventilation holes. It has the flat SMT style crystal, which in my experience is slightly more stable.

The frequency is off by around 1.5 ppm. I can live with that, for the money.

I don't think they are all that accurate. I think I just lucked out on this one. (I have others that range up to 13ppm off)


Quote
A Total waste of money is what all of these USB SDR so called receivers are.
...  Don't waste your money they are to frustrating and certainly not plug and play, if you want to spend, no waste,  weekends trying to get the software to find the dongle, and I tried all of the software packages, then fine waste your money on this junk.

You probably were using it without a USB and some ferrites, and with the stock antenna.. People have to remember they are 8 bit SDRs, very susceptible to noise.   You need to use a USB extension to get it a bit of distance away from a PC, and its good to throw at least two ferrites on there , or more if possible.   Also, you need to use a better antenna, the antenna they come with may be connected with black wire but if you open that up you'll find a sorry, sorry ... 
Trust me on that.   

For VHF, here is a very good, almost instant broadband antenna you might even be able to use for transmitting in a pinch..

http://www.wa5vjb.com/references/PlanarDiskAntennas.pdf


But even if you can't make the dongle sing for you, keep it around for times when you need to listen to VHF/UHF for some reason.

A while ago we had a big storm here and it was really interesting to listen to the rescue operations all over the tri-state-area.

I'm using mine with an upconverter to listen to DX on 40 meters right now. It sounds great. I can hear all the weak signals, no problem.

One thing to get decent receive for HF, with an upconverter, I use a 9:1 "unun" - and make sure you have a good ground.

That makes all the difference.



Title: RE: DVB-T Stick as SDR
Post by: AC7CW on May 13, 2014, 07:14:28 PM
I plugged my NooElec R820T into a Lenovo laptop with SDR#. Once I found the place in SDR# to turn up the RF gain everything was fine. Essentially it's plug and play. Can hear a half dozen FM stations with the little supplied antenna. I have a lot of surplus cable from Dish Network, Cox, etc.. can put a discone on the roof and see what I can find. Pretty much fun really. I hope nobody is offended that I'm have fun here.. NOT!

Reminds me of when I was a teenager in the middle of cycle 23. I had a regen rx, 50watt xtal transmitter, a bug and a dipole. People with expensive rigs were surprised that I could work the world. I had fun, it's a hobby, that's what hobby is about afaik :)


Title: RE: DVB-T Stick as SDR
Post by: KC9QLE on June 19, 2014, 08:13:34 AM
HF SDR DIY Manual.

I've read through this thread and am very pleased to see how many have put this amazing RTL2832U dongle to good use.

For those who have been "frustrated" trying to get things working, I publish an eBook downloadable to your email.

The RTL SDR is amazing when used with HDSDR software. It has better filters and notch filtering then commercial rigs.
Amazing performance with CW Skimmer, EasyPal, PSKpal. Also does Olivia and other Digital Voice via software.

It works with any HF transceiver that has a "REC ANT" port, such as a KWM-2A or a Collins stand alone transmitter. I also use it with my Kenwood rigs. A fantastic Panadapter for <$20.

It is "PLUG N PLAY" if you have done the mod. and installed HDSDR.

No "up-convertor" please, they just add noise.

Google     HF SDR DIY







Title: RE: DVB-T Stick as SDR
Post by: HAMMYGUY on June 19, 2014, 09:22:44 AM
Add me to the extremely frustrated group.  The default drivers are included in Windows and installed quickly when they recognize the device.  That seems to be a real problem.  If I run "zadima" (sorry don't remember the name) the device is found but not under the right name.  Then that program is supposed to replace the Windows default driver then at least should work on VHF and above.  

Nope It doesn't.  

That has been my experience with a new dongle and a new Chinese device that includes an HF converter onboard.  

I know it's something I'm doing as so many are reporting good results.  Plus I've had extremely good results with the  FunCubePro plus.


Title: RE: DVB-T Stick as SDR
Post by: KA4POL on June 19, 2014, 10:07:09 AM
Do you have a better way to get on HF? There are many of us who would like to receive HF.


Title: RE: DVB-T Stick as SDR
Post by: K2NCC on June 19, 2014, 10:36:09 AM
I've never had any RTL-SDR dongle "auto install" the driver.  Methinks HAMMYGUY used the CD at some time.  Not really "plug and play", but almost as easy.

Yes, the upconverter does add noise, but the mod won't have the same performance as a complete board offering HF.  And you'll not get 14-28mhz w/o a band pass filter. Might also introduce an ESD problem, so keep spares handy.

As I mentioned, I'm just an appliance operator, and would rather not take a soldering iron to my gear. ;)
If you're one who is, some direct sampling mod info here: http://www.rtl-sdr.com/rtl-sdr-direct-sampling-mode/

But still, what a great "toy"!  Sure glad there are gurus out there feeding hungry minds with new things to try!

(https://dl.dropboxusercontent.com/u/42020338/pics/k2ncc2014RTLSDRhamshackpic0.jpg)






Title: RE: DVB-T Stick as SDR
Post by: HAMMYGUY on June 19, 2014, 12:52:50 PM

This is happening on an almost new computer.  The other SDR's that have plugged into it are a Fun cube pro plus, an Anan 10, and a FiFi sdr.    Nothing else that I can think of.  Yet the machine continues to auto install some kind of driver even after the dongle has been deleted in device manager. 



Title: RE: DVB-T Stick as SDR
Post by: HAMMYGUY on June 21, 2014, 09:40:25 PM
It turned out the issue was having an older version of zadig.exe and attempting to use it on a Windows 8.1 machine.  After downloading the newest file the dongle finally began to work.  Windows had some type of driver that placed the dongle when first plugged in under the sound, video, and game controller directory.