[Elecraft] 40 M interference

[Fred Jensen]

Ralph Tyrrell wrote:
> 7040 KHz is one place for me to find new states or rag
> chews. Have noticed racket there sometimes. Tuned
> across the band and found this racket about every
> 10.66 KHz across all I can tune of 40 M (6998 - 7084)
> with my K1. 7040.6 KHz is the center of one signal.
> Seems to be about 1 KHz wide. Not there all the time.
> I do not hear it on 30 M.
> Does anyone know where this comes from and what it
> might be for and how often it is on? 
> I always turn of my computer when using the radio to
> keep local noise down.

Hi Ty,

Not sure but you may be hearing the [or one of the] OTH radars, 
variously attributed to the Chinese, Australians, N. Korea [and us, of 
course -- maybe also the correct choice :-) ]

"Racket" is the best description, and it/they do have some of the 
characteristics you describe.  If you're old enough to remember LORAN A 
on what is now 160 and you lived near either of the coastlines then, 
you'll remember it.  Various peaks as you tuned across and around it.

I've heard it recently on 40m, a couple of days ago while trying to work 
N8S on 7005 up 5, but it moved up the band after a little while.  There 
are frequent comments on the DX Spotting net about it too.

Inasmuch as OTH tend to be national security-related, no one ever fesses 
up to them.

Regards,

Fred K6DGW
- Northern California Contest Club
- CU in the 2007 CQP Oct 6-7
- www.cqp.org