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Reduce noise and increase radio sensitivity with Frosty SDR

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@BanBot wrote:

First of all, thanks to all at Outernet for their efforts to create a library in the sky- I have had a blast pushing the diy Outernet kit to its limits. In fact, this was my time using an E4000 based SDR and I wasn't disappointed. I do a lot of radio work and I found that this dongle performed much better at receiving NOAA APT and Meteor M2 transmissions than its R820T2 counterpart. But there is room for improvement.

This dongle like most in its class has much better sensitivity when it's cool. Once it warms up the SNR drops and signal quality degrades. When I first tried to receive Outernet's Inmarsat-4 satellite signal I was unable to get a positive SigDet for more than a couple of seconds. I knew I was aligned properly and that the hardware was functional so something else had to be responsible for the failure. On a hunch, I decided to tape an ice pack to the dongle and the OuternetInABox software almost instantly received a frame lock and began downloading packets with a SNR of around 4 indoors.

It worked so well that I decided to make a permanent contraption utilizing a thermoelectric cooler, heat sink, and a fan. If you decide to build one for yourself, make sure you properly insulate the entire dongle and the end of the usb cord. Otherwise, you will have condensation issues. This unit gets very cold.

I'm powering Frosty SDR at 7v using a variable power supply. If I was doing radio astronomy or very sensitive radio work I would increase the voltage to 12v or somewhere in between.

Sorry, I had more pictures but the system would only let me post one. If you have any questions, feel free to ask.

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