Newbie homebrew qrp ....update
 

Regarding the 3-watt transmitter I'm building (and having trouble
with), here's an update.

I removed the lowpass filter and loosened the wiring, and for a while
it seemed to help. The transistor didn't get as hot. But the output
stayed the same (less than 1 watt). But then I noticed, as I've
noticed before, that the voltage measured at the dummy load doesn't
always drop when the key is released. And the transistor stays hot
even after the key activity has stopped.

I did as one poster suggested. I removed the antenna from my
receiver, tuned around while transmitting, and discovered the
following:
(Crystal is 7110 kHz)
at 3554 kHz, signal is S8
at 7110 kHz, signal is S6
at 14218 kHz, signal is S6
at 21326 kHz, signal is S7
at 28433 kHz, signal is S5

Even I can see that this isn't good. And the emitter of Q2 connects
to the same trace as everything else that's grounded in the circuit,
and it's not a very big trace.

I'm probably going to rebuild this rig, without the circuit board.
Many thanks to all who gave me advice on this. Any further comments
are also much appreciated.

I put the schematic on my website. The design calls for 28 VDC for a
5-watt output, but I am using 12, which is also ok according to the
article.

http://www.kcnet.com/~oyster/transmi...ansmitter.html

-John Sandin KC0QWE

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