[Lowfer] VLF TONIGHT

[rick kirby]

Conditions are pretty nice on VLF right now .All 3 ALPHAS are audible and
JXN is just starting to creep in:

http://ka2pbo.com/grabber.htm

                   Rick
         
-----Original Message-----
From: Garry and Linda Hess [mailto:k3siw at sbcglobal.net] 
Sent: Sunday, February 12, 2012 16:22
To: rick kirby
Subject: Re: [Lowfer] TACAMO on 53.95 kHz?

On 2/12/2012 9:58 AM, rick kirby wrote:
> Thanks Garry !
>
> The ALPHAS are still in there but the noise is picking .I guess people are
> waking up and turning on all their electronic noise generators.
>   I cant figure out what the 2 signals are on 22.8 and 23.2 khz ? I cant
find
> them on any list .
>
>       Rick
>
>
Rick,

I don't see anything on 22.8 or 23.2 kHz here but I'm pretty sure I know 
why you do. NAA is VERY strong on 24 kHz. Also, NML4 on 25.2 kHz and NLK 
on 24.8 kHz are strong. The LSB IM (intermodulation/mixing) between NAA 
and NML4 falls on 24-(25.2-24)=22.8 kHz. The LSB IM between NAA and NLK 
falls on 24-(24.8-24)=23.2 kHz. NML4 and NLK will mix too but their LSB 
falls above 24 kHz so you don't see it. If you can sample faster and see 
up to say 48 kHz, then you'll see all those mixing products on your 
waterfall. The non-linearity isn't necessarily in your receiver. Any 
rusty metal in the neighborhood will act like a diode to strong signals 
and radiate mixing products. Nothing you can do about that other than to 
live in a world of plastic, hi.

73, Garry


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