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[TenTec] " A Low vswr will kill you !"

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Subject: [TenTec] " A Low vswr will kill you !"
From: RMcGraw@InfoAve.Net (Bob & Linda McGraw K4TAX)
Date: Tue, 23 Jan 2001 07:54:52 -0800
That's the reason I use an external balun (external to the Tentec 238
tuner) to feed my balanced feed antenna system.  The 4:1 balun is rated
at 5KW.  The donuts (4) are about 4" OD and 2" ID.  The windings are #10
with teflon insulation.

73
Bob K4TAX

Steve Ellington wrote:
> 
> Yes indeed and that's exactly why the swr is so low on a G5RV when you
> use the suggested 70ft of RG8m.  In addition to a Johnson Matchbox, I have
> an Ameritron ATR-15 tuner which has a large 1:1 current balun. The balun
> doesn't get hot on any band so I assume it's pretty efficient but
> Ameriton gives directions for rewiring it as a 4:1 voltage balun. I've
> tried this and the balun gets quite warm on some frequencies. Now consider
> the fact that most tuners, including the TenTec 238, have these 4:1
> voltage baluns. Try feeding an 80m dipole with 130ft of open line on 40m
> and the poor balun sees several thousand ohms. What's going to happen?
> Then try feeding this same antenna on 160m and it sees some real low
> impedance and divides this by 4! Where's the logic in this?
> 
> Steve N4LQ
> 
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