Scott Anderson wrote:
I am going to betray my entry-level lack of understanding about the
inner workings of radio electronics here, but my question (out of
curiosity, more than anything else) is this: Ramsey Electronics offers
kits for QRP transmitters for the 20, 30 and 40-meter bands
(http://www.ramseyelectronics.com/cgi...key=QRP-SERIES)...
they are dual crystal control (they provide one, and leave space for
one more)-- is it the frequency of the crystal *only* determining the
operating band in *these particular radios* (and they are being
marketed as being for the different bands based on the frequency of the
one crystal provided), or is it something relating to the other
circuitry itself that (again, with these particular transmitters) that
is determining the operating band? I read the .pdf manual on the Ramsey
site, but I am still not certain.

Thanks for any insight-
Scott Anderson

In general when you build a transmitter you need filters designed for
the frequency band -- if no where else, then there should be a final
filter that prevents harmonics getting out.

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Tim Wescott
Wescott Design Services
http://www.wescottdesign.com