On 23 Mar 2014 at 19:14, Scott Yost wrote:
> Yes, sir, the article on the noise phasing unit you mentioned in your post. I
> could not find a link to tell me which articles were in issues prior to the
> current month. Thanks for checking
OK. That is in ER Magazine (www.ermag.com) for February 2014 beginning
on page 2. I am almost certain that none of the 2014 issues of ER magazine
are in that searchable database. Maybe not even 2013 issues.
> ER is a great magazine. I should subscribe.
Yes, you certainly should!!!! :-)
> How are you making out on tracking your RFI issue?
Making slow progress. I am looking at the map (even as I type) that my son
Brendan KB7QEU and I compiled from the 8 DF bearings we took yesterday.
Three of those bearing make a very perfect, almost CLASSIC, crossing at a
Cenex station about 2 blocks from me. I think the problem resides in a large
transformer that is on a pole there. Trouble is, I am not at all sure that that
particular "noise" is the one that has been giving me the most trouble.
I have made up some printable Excel charts and he and I will do some more
DFing next week some time.
> If your NM-20 is unable to serve at the HF range,
Ha! It covers from 150 KHz through 25 MHz. :-)
I also have other Stoddart receivers which cover from 30 Hz through at least
3 GHz...and maybe higher yet. The only other one I may dig out and fire up
covers from 20 MHz through 400 MHz.... but we'll see. I hope I won't need to
use it. It is kinda big.
> I can recommend the National
> Radio HFDF RDF unit.
During WWII those were called Huff Duff. HFDF.
> I bought one a couple years ago
>From where?
> to track an HF source and
> it is outstanding. I velcro'ed it to a bicycle and slung a Panasonic RF-2200
> on
> the side of the bike (it has an attenuator which I found necessary) and it was
> really pretty low profile. Moreso than working on foot with the setup.
Well, the NM-20B is fairly large, although it uses "battery" tubes, so it is
"instant on", and draws very little power. 25 watts of 110VAC. I run it on a 75
watt inverter which meets FCC Class 15B regs for noise output. It is very
quiet.
Although I have not yet completely refurbished the NM-20B, it is working
quite well despite that. The frequency readout accuracy is not very good at
this point, though. It is off, high, by several KHz.
My next project is to output the audio to a laptop and Spectran to help in the
DFing.
As soon as I have found and destroyed this noise, I'll complete the
refurbishing of at least one of the three NM-20s I have here for future work.
Another ham, an OT, near me is having similar problems, and maybe I can
help him out.
Thanks, Scott.
Ken W7EKB
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