SDR – 3950.net

by Kevin Strom, WB4AIO

WE ARE delighted to report that Fred Stark, KA2YLZ, has now come home from the hospital and has resumed his normal life after successful surgery to correct his heart condition. Welcome back Fred!

Listen: Liberty Net 12/26″]

Here’s my short summary of — and remarks on — a few of the topics brought up during this week’s net session:

• The development of adaptive predistortion in Software Defined Radios (SDRs), as typified by Apache Lab’s PureSignal, is very significant: It can make an amateur’s transmitted signal dramatically cleaner. (7 minutes)

• It was wonderful to give and receive Yuletide greetings this season, not only on the regular Liberty Net sessions, but also on the special holiday edition of the Liberty Net that took place on Christmas Eve. (31 minutes)

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by Kevin Strom, WB4AIO

TO PROVE THAT STANDARD AM (a mode that is very close to my heart) isn’t the only HF mode offering good fidelity these days, here’s a 10 MB mp3 audio file I recorded (with one of the Flex SDR-1000s I’ve been experimenting with lately) Labor Day evening of some ESSB operators on 3630 kHz. The band hadn’t completely formed yet, as these Central Daylight Time fellows were propagating to the East Coast at about 7:30 pm their time — full daylight. And static from the remains of Hurricane Isaac was very much present. Yet these only moderate strength signals — some just equal with the static crashes — are still quite intelligible. I think the good intelligibility is because of the wide broadcast-style frequency response, not in spite of it.

It’s amazing what excellent sound some of these experimenters are getting out of single sideband. For years — decades really — only (highly modified to broadcast standards) AM gear was getting this kind of audio quality on amateur radio. But improved techniques have really made SSB sound better than ever!

For best results, listen on a high fidelity set of speakers or headphones:

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