[Lowfer] 29.499 again tonight-OP2H

[jrusgrove at comcast.net]

Dex

77 material is fine at 29.5 kHz .... you may just need more turns. A three stack of FT240-77 needs 
12 turns minimum on the 50 ohm side. I wouldn't get too excited about 25 degrees temperature rise 
... but I would put on some extra turns.

Jay


----- Original Message ----- 
From: "Dexter McIntyre W4DEX" <dexter.mc at gmail.com>
To: "Discussion of the Lowfer (US, European, &amp;UK) and MedFer bands" <lowfer at mailman.qth.net>
Sent: Friday, March 14, 2014 8:45 PM
Subject: [Lowfer] 29.499 again tonight-OP2H


> I'm in receive mode tonight running OP2H and uploading Argo grabs of Bob's big signal at 10 min 
> intervals:
>
> www.w4dex.com/grabber
>
> I found an antique RF ampmeter which tells me the antenna current was .4 amp with 150 watts 
> leaving the shack.  Then with an IR thermometer I discovered the stack of three FT-240-77 toroids 
> that work well for antenna matching on 73, 137 and 500 kc was heating up about 25 deg above 
> ambient temp.  I've located some J type toroids.  Would I be wasting my time trying those for 
> impedance matching?
>
> Dex
>
>
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