[TowerTalk] BCB Intermodulation

[Jim Brown]

On Fri, 09 Jan 2009 09:33:35 -0500, Robert Morris wrote:

>Don't rule out the noise could be outside your system.

>Find a mobile and check the neighborhood.

Yes. Very good idea. Simply make sure that the radio you use isn't 
getting blown away. Put a BCB filter in front of it. 

Note that virtually ANY 12V radio works in a car -- all you need 
is an antenna for it. Invest in a hamstick tuned to whatever band 
and mount it. Or, borrow a neighbor ham's mobile rig that can work 
that frequency. 

When I lived in Chicago, I had 2-3 beats that came and went at 
random times. I never found the source. 

And has been noted, it wouldn't hurt to contact the engineer 
responsible for the radio stations involved in the mix. As has 
been noted, it's entirely possible for the mix to be generated in 
either of their transmitters if something is wrong. Only a year or 
so ago, a loud mix on 160 audible here on the west coast near SF 
was traced to a specific station, the station contacted, and it 
got fixed. 

One thing you'll find nowadays is that many (most?) stations, 
especially smaller ones, are maintained by contract engineers who 
don't work for the station directly, and maintain several 
stations. Some are likely to be sharper than others on issues like 
this. Don't be surprised if it's hard to find someone to talk to, 
or that they don't know how to respond when when you do. You may 
need to do some teaching, or hook them up with someone who can do 
some teaching. 

73,

Jim Brown K9YC