Date: Tue, 23 Jul 2013 18:23:45 +0200
From: "Peter Voelpel" <dj7ww@t-online.de>
To: <towertalk@contesting.com>
Subject: Re: [TowerTalk] Which Balun with the TH7DXX
Jim, did you ever try that as a balun on the feed point of a yagi with the
power level RG393 is good for?
73
Peter
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Jim
Thomson
## 17 inches of type 77 1.025 inch OD beads slid over 393 coax = 68 uh.
Jim VE7RF
## No. That is my old F-12 Model B2 balun....which they rate at 25 kw !
It comes with a type N connector. I hate Type N connectors so would
not trust it. I used an inter series adaptor to get from Type N male to
UHF female,
and stuffed that into the balun.... just so I could use it as a low power
balun.
## all my uh readings were done on my B+K 875B digital LCR meter... which
takes the readings at 1 khz.... not RF freqs.
## Others have stuffed 10 kw pep into a B2..and never blew it up, but I would
not
trust a Type N myself for QRO+.
## Moot point these days..as Fair rite no longer makes type 77. It has been
replaced by
type 31. They still make type 75 though....but that stuff peaks at 1 mhz for
max Z...
and type 77 was very similar..peaking around 1 mhz. Then it drops off above
that.
## The Z of type 31 beads peaks at 250 mhz....and type 43 beads peaks at 400
mhz.
Type 75 + 77 peaks at 1 mhz. It sure would be nice is fair rite could come
up with a mix
that has a Z peak at 30-50 mhz. Then WAY less ferrite would be required.
Jim VE7RF
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