View Single Post
  #3   Report Post  
Old April 29th 04, 03:42 PM
John Smith
 
Posts: n/a
Default

Your spurs sound very strange, too close in 32 kHz, 62KHz, normally they are
further out several MHz if generated by the RF chain. That is like an audio
part/circuit getting into the transmit RF. Try rearranging or twisting up
the power cables to the radio.
If spurs are low, not much power is there, so little damage to radio
rts. -65dBc sounds good for a CB. The farther you look down the more spurs
there. The antenna could be reradiating RF power back onto circuit
components, which could be a cause too.


"Dummy" wrote in message
om...
I'm having a two-way radio. One wide-band antenna was hooked up on a
spectrum analyzer. Video BW and RES BW was adjusted to 3khz and 1kHz
respectively at spectrum analyzer. Span was 300KHz.

When radio was being keyed up, spurs could be seen at around plus
minus 32Khz and 62khz. However, the amplitude were quite low, about
-65 to 70dBc. I was wondering what caused the spurs to appear. If
radio was connected directly to spectrum analyzer, this problem could
not be seen.

When radio was transmitting to different load with different VSWR (up
to 8:1), no spurs were seen. Spurs could only be observed while using
antenna. Could the VSWR of antenna be worse than 8:1? Just could not
figure out the source of the spurs. Please help.