Set up a spectrum analyzer to look at the output of a transceiver through
a suitable attenuator. Set the transceiver to full output, full QSK and
key it at 30 wpm, all dots. The analyzer should sweep plus/minus 100 kHz
from the center frequency. The analyzer should be run with a narrow (500
Hz or less) and a wide (3 kHz) filter. Sweep rate divided by filter BW
should be less than one-tenth the keying rate in order to get an accurate
measurement of any spurous products caused by the keying edges. Also run
the tests in XIT and VFO A/B split mode at various separations.
To check a receiver - use a crystal oscillator keyed at a similar rate
into the receiver through a suitable attenuator. First run the oscillator
through the analyzer tests above to establish a baseline. Then tune the
receiver plus/minus 100 kHz from the oscillator frequency while listening
for clicks, watching the audio on a 'scope, and measuring both audio and
AGC with a good RMS voltmeter.
There are variations on the theme, but these are the basic tests.
73, Ward N0AX
> I'm afraid that receiver-based tests are never going to persuade
> manufacturers to clean up their act. Why can't we contesters persuade the
> ARRL to add an appropriately designed test or tests to their transceiver
> reviews? It would be even better (but maybe utopian?) if they could be
> persuaded to run a comparison of the top half-dozen contest radios for
> transient off-channel garbage on both CW and SSB. W8JI's already explained
> how this could be done from a technical standpoint, and the ARRL has proved
> open to changing its test procedures in the past when presented with a good
> How about it, HQ? Anyone reading the mail?
> 73, Pete N4ZR
> Contesting is!
> The World Contest Station Database
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