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Author Topic: DVB-T Stick as SDR  (Read 136774 times)
WD5GWY
Member

Posts: 406




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« Reply #60 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
 
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WD5GWY
Member

Posts: 406




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« Reply #61 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
 
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KA4POL
Member

Posts: 2125




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« Reply #62 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.
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KA4POL
Member

Posts: 2125




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« Reply #63 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.
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W0VP
Member

Posts: 6




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« Reply #64 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
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KA4POL
Member

Posts: 2125




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« Reply #65 on: January 28, 2013, 10:29:02 AM »

Hey, you could have known that already on April 25, 2012, 11:16:10 AM  Grin
That's when I started that thread  Cool
I just pity those people you mentioned.
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KN0CK
Member

Posts: 22




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« Reply #66 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 
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KN0CK
Member

Posts: 22




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« Reply #67 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
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W0VP
Member

Posts: 6




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« Reply #68 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  Cry 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
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KN0CK
Member

Posts: 22




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« Reply #69 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
« Last Edit: February 02, 2013, 07:37:44 AM by KN0CK » Logged
W0VP
Member

Posts: 6




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« Reply #70 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

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

73,
KC, W0VP
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KN0CK
Member

Posts: 22




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« Reply #71 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
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KE5JPP
Member

Posts: 0




Ignore
« Reply #72 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.
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W4HIJ
Member

Posts: 367




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« Reply #73 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
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KA4POL
Member

Posts: 2125




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« Reply #74 on: February 04, 2013, 09:32:58 AM »

Would you be doing Amazon?
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