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Message-ID: <uOZOPiAo9wX+EwdL@telemetry.demon.co.uk>
Date: Fri, 28 Feb 2003 07:27:36 +0000
To: rsgb_lf_group@blacksheep.org
From: "Tom Boucher" <tom@telemetry.demon.co.uk>
References: <001c01c2dec6$044de5a0$6507a8c0@Main>
In-reply-to: <001c01c2dec6$044de5a0$6507a8c0@Main>
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Subject: Re: LF: O/C chasing at LF
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I wondered who owned the S9+20 signal Alan!
73, Tom G3OLB

In message <001c01c2dec6$044de5a0$6507a8c0@Main>, Alan Melia
<Alan.Melia@btinternet.com> writes
>Hi all, I thought this little episode might prove interesting and it
>certainly finds a use for the "below 50MHz" part of a hand-held scanner. I
>have an AOR 2700 which purports to operate down to 100kHz, but like a lot of
>this kind of kit is very deaf down there. I did think it might be useful for
>DFing TV interfence, but it is too deaf even for that, without a pre-amp.
>
>I restrung my 60m-top Marconi last weekend and was disappointed to see that
>the tunning when paralleled with my 30m top inv-L was not at the original
>position. As it is a receive aerial is is strung with 1mm PVC coated wire. A
>quick measurement of the tuning inductor indicated only 80pF more capacity,
>which I guessed would mean a break inside the insulation about 16m from the
>feed point (5pF / m). After a little thought and a couple of coffees, I
>plugged the end of the unloaded 60m wire into the 600ohm output of the PS-12
>(W&G SIG GEN) turned up full and with the interenal resistor set to "0". I
>then walked down the wire (now dropped to the ground again), running the
>wire at right-angles over the closed telescopic aerial on the AOR2700. The
>"S-meter" gave fullscale on AM, and about 15m down the wire it dropped
>significantly ( to "S3"). A quick waggle of the wire confirmed two breaks at
>that point. I was quite pleasantly surprised that point indicated by the
>scanner s-meter was with an inch of the break. After a quick soldering job
>and a tape-up the aerial tuning inductor was back to where it was expected
>to be.
>
>I know its not rocket science but its nice when these little tricks really
>work. The feed voltage from the PS-12 was about 0.7V r.m.s. It also proved
>my contention that a wide coverage receiver is one of the most useful bits
>of test gear you can have (I might add "portable" to that as well now!!)
>
>Cheers de Alan G3NYK
>alan.melia@btinternet.com
>
>
>
>

-- 
Tom Boucher
'Hedgerows'
Sheldon
Honiton
Devon EX14 4QS