[600MRG] Hunting the noise source - loop mods.

[Kenneth G. Gordon]

On 15 Mar 2014 at 17:37, Lee Mushel wrote:

> Ken,
> 
> I missed the start of this thread and am very curious.   Are you saying that
> your noise source is only on wavelengths longer than broadcast band?

No. Not at all.

>  And this
> is why you want to DF there?

Again, no.

At the moment, the only equipment I have available is a 3' diameter Stoddart 
shielded loop which is part of the AN/URM-6(*) system, and an FT-890 which 
can be battery powered and tunes from 150 KHz through 32 MHz. 

The AN/URM-6 system tunes from 14 Khz through 250 KHz. The loop I am 
using is resonant at about 500 KHz, (500 uH shunted by 200 pfd).

Therefore, since the loop is resonant there, and is actually too big to provide 
sharp nulls at frequencies much above about 2 MHz, I am going to start 
where the loop is resonant, and work up from there.

>   My own problems with "noise" always involved "all
> frequencies."

Same here, but I am starting where I presently have equipment. What forced 
me to get into this exercise is a constant 20db over S-9 noise level on 80, 
with periodic bursts to over 30 over 9.

>  I"ve always found that techniques that allowed me to "view" 50 or
> 100 kHz wide slices of spectra  to be really helpful.

Yes.

Here is what I am planning:

I have an AN/PRM-1 or NM-20B RI/FI "meter" system which tunes from 150 
Khz through 25 MHz. Parts to complete the refurbishment of that only arrived 
this afternoon.

I also have an NM-30, which tunes from 20 MHz through 400 MHz.

I also have an NM-50 which tunes from 375 MHz through 1000 MHz.

I am also going to own a Collins 37FB-4 folded dipole very soon. This tunes 
from about 330 MHz through about 400 MHz.

Lastly, I have a laptop with both Argo and Spectran software loaded.

I am BEGINNING this process with the FT-890 and URM-6 loop.

Then will step up to the other equipment as I get it working.

Ken W7EKB