[RFI] receiver spurious response
Wed, 13 Mar 2002 10:56:20 -0800
By all means do check for a spur. Is your TX synthesized? How clean is the
PLL? For that matter, how clean is HIS handheld's synthesizer?
But it could be an IM problem. Has a new user moved in on your tower, at
453.4? Is there one in HIS area at 446.4? What do the 3rd order numbers
look like for sources local to his area?
A less innocent possibility is, someone retransmitting your link. This
happened up here, a malicious operator retransmitting one of the local
repeaters on another county's law enforcement frequency.
> From: Tony Dinkel <email@example.com>
> ...site or in our traffic reporter's aircraft over the air. So, I put
> up a transmitter on 450.725 mHz that puts our audio signal out in
> "pre-delay" 24 x 7. We are licensed for 55 watts tpo and around 800
> watts erp on Mt. Wilson.
> Here is the problem...I got a call from a ham 80 miles away that
> claims he is hearing my 450.725 transmitter on 448.060 mHz. Its not
> a mix, its just there all the time. He is using a Premier PR-460
> hand held and we are coming in strong. That is a frequency
> difference of 2.665 mHz. I did some research and determined that the
> radio uses a 21.4 - 455 IF. To me, this does not make any sense.