Joachim's Ham-Radio and Radio-Frequency Blog (A Solderful of Secrets) - from Longwave to Microwaves
Saturday, April 10, 2010
WARC bands - WSPR/QRSS Crystals
OK, 30m is trivial, so let's forget about that for a moment.
What about 17m and 12m?
For 17m I found a very suitable combination:
13.104MHz + 5MHz = 18.104MHz
Some upwards pull by 600Hz, and we are there. Personally, I would build the filter(s) from 5MHz crystals, the pulled XO would therefore be at 13.104MHz. Both crystals are available from Pollin (www.pollin.de).
12m will be somewhat more tricky:
16.9344MHz + 8.000MHz = 24.9344MHz
Here, a downwards pull by 9.8kHz is required to reach the WSPR band, that is a lot. However, it should be doable with the 16.9344MHz crystal, which would therefore serve as XO while the 8MHz crystals will form filters. Those crystals are also available at Pollin.
Just as a quick reminder, there is nothing wrong with operating QRSS next to WSPR.