Tuesday, January 17, 2012

600m SDR RX (TX)

As we know, presently there are a couple of frequencies of the 600m band open to amateur radio operators.
Most of authorities allow transmission somewhere above 500kHz. In The Netherlands the permitted range is 501-505kHz. In the future, depending on the decision of the WRC12, this will possibly change to 472 to 480kHz. The U.S.of A. proposed the following ranges 461-469 and 471-478 kHz.

Lets look at the (inexpensive) option the box73 SDR. The 80m version of this receiver uses a 14.000MHz oscillator. Operation on the 600m band can be achieved by changing the front-end filter and the SDR-LO.
Considering 48kbps sampling, the LO-frequencies would be the following
  • QRG: 470kHz - LO: 1.843MHz
  • QRG: 500kHz - LO: 2.000MHz
This will result is RX-ranges of:
  • 460.8 -/+ 24 = 436.8 .. 484.8
  • 500.0 -/+ 24 = 476.0 .. 524.0
Concluding, a decent 600m receiver can be built with LOs using regular canned oscillators.

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