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[TowerTalk] Open Wire

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Subject: [TowerTalk] Open Wire
From: (Guy Olinger, K2AV)
Date: Tue, 16 Nov 1999 13:57:46 -0500
A 30% tuner loss is huge and would be dissipating 500W of a 1500 watt
input in a closed space. That wouldn't take long to set it on fire
internally, and would quickly make it too hot to touch.

On the other hand my ATR-30 runs stone cold at 1500 watts on
anything/freq that I use. A thermometer on top of it after several
hours use on 160 CW test at 1500 watts showed room temp, just as when
I started. If there was even 50 watts dissipation inside it would have
gotten quite hot. I'd have to say it had less than 1% loss. Even a 15
watt light bulb inside would have warmed it up some degrees

One CAN misapply circuits that wind up being extremely lossy. I *have*
turned an open-air #12 6 tpi 3" diameter preformed coil stock into a
smoking slinky dripping goo. Actually that was fun to watch... Sent me
back into the books to figure what I did wrong.

On Tue, 16 Nov 1999 08:12:29 +0000, you wrote:

>My simple question about why one would use open wire in these days
>generated quite a bit of "noise" for open wire fans.
>There are two chief benefits from them:
>1) Long runs like 1000' plus are not affordable with coax.
>(Like guys on 100'x100' lots care).  I can't imagine stringing 1000'
>of open wire line.  The supports must cost a fortune and the work
>involved seems overwhelming.
>2) You can load an 80 meter dipole on all bands with it.  The same
>people pointing this out as a benefit admit to RF in the shack
>It seems that one thing has been forgotten.  The line may be lossless.
>The tuner isn't.  Read QST and you will see that many of the
>units available today have power losses of 30% or more.  The best unit
>quoted was a Johnson Matchbox.
>So you've substituted line loss for tuner loss. 
>Again where's the benefit?
>73 de Brian/K3KO

--.  .-..
73, Guy

Guy Olinger, K2AV
Apex, NC, USA

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