Saturday, December 5, 2009

Grabber news: WSPR2 works

The new version of WSPR allows to set a RX BFO other than 1.5kHz. The usable range stops at 3kHz, just enough to use the subharmonic direct conversion receiver for spotting WSPR signals.

Assume the following: The mid-qrg of the WSPR band on 30m is 10140.2kHz. With a "BFO" setting of 1.5kHz, that gives the famous 10138.7kHz. The subharmonic receiver's LO runs on about 5068.8kHz (depending on the individual canned oscillator). Double that, it will give 10137.6kHz, resulting in a "BFO" frequency of 2.6kHz to reach the WSPR-band.

My resulting LO frequency is a about 69Hz further off, here comes a correction in, one has to measure first. For me, it results in a "Dial Frequency" of 10.137531MHz and a "Rx BFO" of 2669Hz.

Good news for WSPR-users, I will be now monitoring whenever the grabber is set to 30m.

1 comment:

  1. That is really good news, I look forward to do that, too

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