Message-ID: <01ae01ccbca5$b1a07350$1502a8c0@Clemens04>
From: "Clemens  Paul" <cpaul@gmx.net>
To: <rsgb_lf_group@blacksheep.org>
References: <CAA8k23Rn9WpQM3Ukf=cq5-bLmWy+o4SEsH2abf7cAX=BpLWExQ@mail.gmail.com> <003301ccbbec$db7fbf00$927f3d00$@com>
Date: Sat, 17 Dec 2011 11:21:42 +0100
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Subject: LF: Re: RE: Wellbrook Loop
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Terry,

> I am looking for a suitable circuit to use with the blown loops

this one might also be worth looking at.
http://www.activeloop.de/html/english.html

>Unfortunately I made the silly mistake of using a transmitting 
>antenna
> too close to them

It would be very interesting to hear some more details,e.g.:
QRG of transmitter,TX power,TX-antenna type,
how close was the TX-antenna to the loop?
Was the loop amp on or off when it was fried?

You may guess why I'm so interested in your experience.-:)
We have a ALA 1530 mounted on top of a mast with 2m (50W)
and 70cm (35W) yagi antennas.
The HF dipole (1kW) is about 6m below.
So far the loop amp is still alive...

73
Clemens
DL4RAJ


----- Original Message ----- 
From: "Terry GW0EZY" <gw0ezy@sky.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Friday, December 16, 2011 1:18 PM
Subject: LF: RE: Wellbrook Loop


> Hi Andy
>
> I use Wellbrook loops - 1530 for hf (150 kHz - 30 MHz) and 1010 (10 
> kHz - 10
> MHz) for lf. They work very well with my SDR-14 and SDR-IQ.
>
> The loop feed box is filled with a potting compound to provide 
> weather
> protection so you can't see the configuration and no info is 
> supplied with
> them. Unfortunately I made the silly mistake of using a transmitting 
> antenna
> too close to them - Wellbrook do not repair them but send a 
> replacement loop
> unit.
>
> On request Wellbrook replaced my 1010 loop with an lf-enhanced 
> version to
> improve response below 10kHz I think by using a coupling transformer 
> giving
> a better lf response but degraded hf response. It seems to work well 
> as I
> can see the Russian Tx at 11.905 kHz and also get good results at 
> 136 kHz.
> I'm building a Miniwhip, so will get the opportunity to compare 
> soon. I can
> confirm the benefits of noise reduction. Mine are mounted one above 
> the
> other at 20 feet on a fibreglass pole with rotator (I am building 
> your
> rotator controller for more accurate control as the null is quite 
> sharp).
>
> I am looking for a suitable circuit to use with the blown loops 
> (they are
> not completely dead but have a serious loss of sensitivity but 
> disassembly
> is certain to destroy the loop amplifier). I suspect it's not so 
> easy to
> form a 1 metre loop with aluminium tubing so the loops can be 
> re-used for
> experiments.
>
> I was thinking something along these lines:
>
> http://www.pm.keirle.com/3_radio/hf_loop_ant/hf_loop_ant.htm
>
> http://www.ik4hdq.net/doc/testi/smlloop.pdf
>
> http://www.vlf.it/looptheo7/looptheo7.htm
>
> http://www.vlf.it/lowfloop/lowfloop.htm
>
> However, I look forward to seeing one of your designs Andy!!
>
> If you need more info on the Wellbrooks please email direct.
>
> 73 Terry GW0EZY
>
>
>
>
>
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