If you want to do this easier just get the MFJ active
noise reduction unit. I have one because I live near
some big power lines and a substation about a mile
from my house. Its only noisey on humid days or with
rain. The MFJ unit eliminated that and many other man
made noises and is worth every penny. On summer days
you will really like the results on 160 and 80 meters.
Try one if you don't like it they take them back no
questions asked.
--- JimN0OCT@aol.com wrote:
>
> Hi Tom,
>
> The technique you describe below has been around
> awhile, and you could build
> it yourself for a lot less than $190. It is covered
> in my 1941 Radio
> Handbook, and I'm sure it is covered in others. It
> consists [if i remember
> correctly] of a "voltage probe" type of antenna
> [small whip] that is tuned
> out of phase with the main antenna, and the signals
> are combined. The
> drawback with this technique is that it needs to be
> readjusted for every band
> change, and should only be in line during receive.
>
> If you want more details than the scant few I can
> provide here, I will check
> my old handbook tonite at home.
>
> 73, Jim NØOCT
>
> In a message dated 27-Apr-99 23:59:30 Central
> Daylight Time, tscott@eni.net
> writes:
>
> > I've also heard from two sources that another
> treatment may be effective.
> > That is a technique for receiving the QRN with a
> device that is essentially
> > an out of band receiver which nonetheless
> receives essentially the same
> > power line QRN which is then inverted and with
> careful phase adjustment,
> > used to cancel the QRN as a common mode
> rejection. I have found what
> appears
> > to be one such device from JPS Communications,
> their ANC-4 for around $190.
> > (MFJ has something that looks very similar
> (MFJ1025 or MFJ1026), but I
> think
> > it actually uses a different technique, that of
> nulling signals from a
> given
> > direction. That wouldn't be very useful in my
> case since the power lines
> are
> > along a broad line to the east of me where much
> of my listening would be
> > directed.) I understand from an old Motorola
> commercial communications
> > systems engineer that they once used that
> technique, but one flaw in the
> > theory it had was that in a crowded metropolitan
> area you could have
> trouble
> > locating the necessary alternate frequency band
> that was devoid of traffic.
> > Any signal other than the QRN in the alternate
> receiver would not cancel
> > properly with the QRN signal in the primary band
> and would therefore become
> > an inverted spurious QRM in the primary band.
>
>
> --
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>
===
Carl S.HYDE
W2CSH
Politics: From the Greek word Poli, meaning many and
the word tics, meaning blood sucking parasites.
"No man is safe while the congress is in session" (Will Rogers)
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