[Elecraft] OT what the heck is this?

[Geoffrey Mackenzie-Kennedy]

Bill,

One possibility is that this rogue signal's frequency is not actually at 
28.002 MHz, but at some other frequency which coincides with one of the K3 
receiver's spurious responses when the K3 is tuned to 28.002 MHz. An example 
of one spurious response is the so-called image, which in the case of a K3 
receiver tuned to 28.002 MHz would be at 44.432 MHz. Typical Superhets have 
many other spurious responses above, below and sometimes in the band being 
tuned.

Because you also hear this signal at 28.002 MHz when using another battery 
powered rig, at first glance my thought that the signal is not at 28.002 MHz 
would seem to be nonsense because the frequency used in the IF of your 
battery powered rig and the K3 are probably not the same, therefore the 
spurious response pattern in terms of frequencies of the two receivers would 
not be the same. But there is the possibility that some responses might in 
part cover the same frequencies.

If I can be of any help, please contact me off-list.

73,

Geoff
GM4ESD




Bill Hammond wrote on Saturday, October 23, 2010 at 18:40 + 0100:

> It has been there for years, but isn't really a problem until someone 
> happens to be on that frequency and you want to talk to them. Like this 
> morning when FO8RZ was working up 1 from 28.002 and with the receiver set 
> on 28.003 I had the pleasure of listening to this repetitive tone until I 
> worked him :)
>
> So what the heck is it??  Obviously local, it is always there and never 
> misses a beat.  I have pulled the big switch and listening with a battery 
> powered rig, it is still there.  I assume some consumer product uses 10 
> meters for some unknown purpose...ever encounter this Elecrafters?