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From: "PC" <paulc@snet.net>
To: rsgb_lf_group@blacksheep.org
References: <3C691C9E.61A8BCA1@netscapeonline.co.uk>
Subject: LF: Re: LITZ WIRE
Date: Tue, 12 Feb 2002 09:13:51 -0500
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Mal, and group

To what do you attribute the changes in tuning using the higher Q litz wire?
I mean when the wind blows?. Is it movement in the antenna wire itself? Or
is it an effect of the air/moisture,temp. change passing over the coil?

Sorry if this was already answered but I missed Rik's post. I will need to
read it tonight when I get home from work.

My question all stem from the root question of  is it possible to build a
small multiturn loop, say 3 meters on a side,
that would radiate reasonable well if it were elevated from the ground, and
out in the open with no trees.

Also if great care was taken in the design to eliminate losses.  Thus the
litz wire questions etc.

I want to persue this type of antenna within the confines of the 1 watt
limit we have here in the state

Best DX so far was with 80 milliwatts into the antenna is 120 miles using
QRSS 60
Still a good 10 db down from the legal limit.


Thank you Mal and all


----- Original Message -----
From: "gii3kev" <gii3kev@netscapeonline.co.uk>
To: "rsgb rsgb" <rsgb_lf_group@blacksheep.org>
Sent: Tuesday, February 12, 2002 8:46 AM
Subject: LF: LITZ WIRE


> Rik gave a good description of Litz wire in a recent message and the hi
> Q qualities and theory is correct, however in practical terms it depends
> whether you really need a hi Q coil or not.
> My experience shows-
>
> 1. A loading coil used to resonate a 136 khz antenna using normal 2.5 mm
> insulated wire has a lower Q than Litz but more stable and less prone to
> seasonal changes like, rain, sunshine, leaves on or off trees, wind
> blowing the antenna wires about etc ie needs no retuning once set up for
> optimum matching for a long period of time.
>
> 2. A loading coil of the same inductance wound with 4mm litz wire
> behaves differently. Because of the much higher Q  the slightest breeze
> or some rain and it needs retuning to resonance, also sudden
> fluctuations are not good for the FET pa. It needs to be watched
> carefully.
> So it depends whether you want the last drop of RF and hi Q or a
> fraction less RF and less trouble.
> I cannot notice any real difference as regards radiating efficiency
> between the two coils.
> Anyone using 160 metres /M with the usual 8 ft loaded whip will have
> noticed this when passing close to other vehicles or close to trees etc
> and the higher the coil Q the worse it got.
> I am currently experimenting with a 0.4 mh litz wound coil to resonate
> my LF antenna and find it hard to keep spot on resonance with the recent
> windy conditions. I did not have any problems in similar wx conditions
> using 2.5mm insulated wire for the coil of the same inductance.
> My system is all matched to 50 ohms and the swr monitored continuously
> when transmitting so any fluctuations or changes are immediately
> noticed.
> I thing a  loop antenna wound with litz wire and exposed to the elements
> would be even harder
> to keep resonant because of the Q factor.
> It would be interesting to hear others observations about Litz v Normal
> insulated wire for outside resonating coils.
> 73 de Mal/G3KEV
>
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