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I'll help you if you want to stand up an iGate

Stable iGate with Raspberry Pi and SDR

Over the past year I've received a few private messages and email asking if I had a working solution for an iGate build with one of the USB SDR dongles (that's a 'software defined radio').

I can now say - with reasonable confidence - yes.

I am completing final performance tests on reception and will have statistical data in another 48 hours.

I will be replacing the iGate at Hopalong (because Bill reported the last one overheated :mad:). I also hope to get one installed at an undisclosed location in New Hampshire to take care of a big void up there. I will replace the one at 53VG with this new version as a continuous test platform.

Power usage is around 5W and it is tolerant of power failures.

For anyone who wants to build one, I will write a short blog post with the shopping list, a downloadable image and instructions.

The cost of parts will be around $60. (Buying knock-off hardware from the Pacific Rim could cut the cost in half.)


There's no need for a picture. It looks just like a Raspberry Pi with a USB stick on the end :rolleyes:
 
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RPi+SDR test results

I ran a set of comparative benchmarks for the mew iGate design.

I installed a splitter on my existing antenna. While the splitter does attenuate the signal, it does so equally so it was a valid test.

One feel went to the Kenwood on my old iGate and the other feed went to the SDR.

After 1 hour, the SDR had successfully received and processed approximately 10% less than the radio. After 3 hours, it had settled in and the SDR was successfully processing 6%-8% fewer messages.

The data format was sufficiently gorpy that I did not bother to determine which messages were missed. I also did not attempt extensive tuning on the gain setting of the SDR because reducing the gain was losing weak signals and increasing the gain was blowing out stronger signals.

I'll make one more post with the link to a shopping list, instructions, and downloads.

Beyond that, the new iGate is now on-line at 53VG and will remain so.
 
I will be replacing the iGate at Hopalong (because Bill reported the last one overheated :mad:).

Yeah, from the looks of the gun safe, I'd say we baked the raspberry pi's predecessor at around 1600F for most if an evening.

Eager to try it out, Glen. You are a masterful tinkerer, my friend, and the flying APRS community is indebted to you. After 2020, we may not need any of this, but until then, its nice to be able to keep tabs on the Russian, and others.

-Bill
 
Just a quick update (and probably the end of this thread) ...


I'm officially a bit surprised. The SDR iGate is performing a tiny bit better than the Baofeng radio version and just a tiny bit worse than my Kenwood radio version.

Using standard parts this iGate is about $90 and using knock-off parts, this iGate can be assembled for less $40.
 
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