(Robin Cassidy VK3AYZ) wrote in message . com...
Are you using a switch mode power supply to run your radio's?

You can get modulation products produced by switching noise on the supply rail.

Regards

Robin Cassidy

I think there are no tests that can be conducted to determine the
source of the spurs. RF radiated from antenna could cause interference
and non-linearity at spectrum itself. Unless I could 100% shield the
spectrum from RF, all tests would be invalid. Even if I stood faraway
from spectrum, the spurs could also be observed. However, by
transmitting into spectrum using 50 Ohm coaxial cable, no spurs were
seen. Possibly because RF was transmitted into spectrum without any
leakage which could have large effect in causing interference.

And can get EVEN WORSE! Tho realize that these type supplies seldom
used,nowdays, back in dark ages, had SQUARE WAVES-- generate infinate order
of (if memory serves me) odd harmonics!! when filters went bad, baseband
looked like a picket fence on spectrum anaylizer! ant, at 600 channels,
that loaded to about 2.5 MHz!! But you could hear these heck of a lot
higher with low band rcvr!! Jim NN7K


"Dummy" wrote in message
om...
(Robin Cassidy VK3AYZ) wrote in
message . com...
Are you using a switch mode power supply to run your radio's?

You can get modulation products produced by switching noise on the
supply rail.

Regards

Robin Cassidy

I think there are no tests that can be conducted to determine the
source of the spurs. RF radiated from antenna could cause interference
and non-linearity at spectrum itself. Unless I could 100% shield the
spectrum from RF, all tests would be invalid. Even if I stood faraway
from spectrum, the spurs could also be observed. However, by
transmitting into spectrum using 50 Ohm coaxial cable, no spurs were
seen. Possibly because RF was transmitted into spectrum without any
leakage which could have large effect in causing interference.