Open-Hardware Licensed Handheld Software-Defined Radio In the Works

An anonymous reader writes "Chris Testa recently presented at TAPR Digital Communications Conference and annouced his development work on a hand-held software defined radio. Running uClinux on an ARM Corex-M3 coupled to a Flash-based FPGA, it will be capable of receiving and transmitting from 100MHz to 1GHz. Designed to be low power, Chris has designed the radio primarily with the Amateur 2m and 70cm bands in mind. Currently in early prototyping stage, Chris intends to release the design under the TAPR Open Hardware License."

Re:Why just 2m and 70cm?

[dtmos]

But I don't know enough about designing this kind of thing to know if that is feasible.

The SDR is feasible, in fact, easier, but the problem is the "handheld" part -- "emphasis on the word, 'handheld.'" The physical size of the antenna starts becoming uncomfortably large as the frequency goes down -- or, said another way, the efficiency of the antenna goes down with frequency if the physical size is held constant. A full-size 50 MHz quarter-wave whip antenna is 1.5 meters (or metres, if you prefer; about 59 inches) long; that's pretty unwieldy for a handheld radio.

Re:Why just 2m and 70cm?

[maird]

Then if the future of 2m, 70cm is narrower channel bandwidth than is currently used (how could it not be given the public service channel bandwidth now used) the nice thing here is that you only have to install the ROM image with the new modulation, keeping the old bandwidth as a feature anyway. Leading to more space for local groups in the long term from free software. I'd bet the lack of 6m comes from one of the chips at the RF end being limited to 100MHz. It's quite easy to fill-in the 0-100MHz block for receive with a cheap mixer (see the article in this month's QST, pg 30 I think).

Re:I hate to be _that_ guy...

[Anonymous Coward]

Found text link in the comments to the video:

http://blog.testa.co/