Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: Prev 1 2 3 4 5 6 [7] 8 9 10 11 Next   Go Down
  Print  
Author Topic: DVB-T Stick as SDR  (Read 132556 times)
HAMMYGUY
Member

Posts: 87




Ignore
« Reply #90 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. 
Logged
N9RO
Member

Posts: 124


WWW

Ignore
« Reply #91 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
Logged

Real techies don't use knobs.
W4HIJ
Member

Posts: 367




Ignore
« Reply #92 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
Logged
KE5JPP
Member

Posts: 0




Ignore
« Reply #93 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.
Logged
HAMMYGUY
Member

Posts: 87




Ignore
« Reply #94 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.
Logged
PJ2BVU
Member

Posts: 115




Ignore
« Reply #95 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
Logged
KE5JPP
Member

Posts: 0




Ignore
« Reply #96 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.
Logged
W4HIJ
Member

Posts: 367




Ignore
« Reply #97 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
Logged
KD7RDZI2
Member

Posts: 73




Ignore
« Reply #98 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.
Logged
KK4MRN
Member

Posts: 95




Ignore
« Reply #99 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.
Logged
OH6I
Member

Posts: 26




Ignore
« Reply #100 on: February 22, 2013, 12:36:12 AM »

Daniel,
this SDR kit SMD components are already fitted:
http://o28.sischa.net/fifisdr/trac
http://www.box73.com/

Jari
OH6I
Logged
K4AX
Member

Posts: 34




Ignore
« Reply #101 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
Logged
W4HIJ
Member

Posts: 367




Ignore
« Reply #102 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
Logged
K4AX
Member

Posts: 34




Ignore
« Reply #103 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
Logged
W4HIJ
Member

Posts: 367




Ignore
« Reply #104 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. Cheesy 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
Logged
Pages: Prev 1 2 3 4 5 6 [7] 8 9 10 11 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!