[Boatanchors] Coax Switches and Wire Antennas

[Bill Stewart]

Tnx Dennis for the response.
I use the classic windom for some of the homebrew rigs and it works quite well. In the coax switch situation, I will probably be using a simple 80 mtr half wave wire, which has the max voltage at the feed line end..so, maximum arcing possibilities. I may expand it to a full wave just to see how it works..more length dependent on tree density. I'm using low power xmtrs such as the AT-1, Lysco, Globe Chief 90A, etc, so no big power. I will be using it on harmonically related bands. I do use some knife switches, but it takes several with the number of xmtrs I will be using. 

73, Bill K4JYS 
----- Original Message -----
From: "mac" <w7qho at aol.com>
To: "Bill Stewart" <cwopr at embarqmail.com>
Cc: "boatanchors" <boatanchors at mailman.qth.net>
Sent: Wednesday, March 30, 2011 4:40:24 PM
Subject: Re: [Boatanchors] Coax Switches and Wire Antennas

Bill,

  If you plan to use the classic Windom (half wave top section, single  
wire feeder) the impedance looking into the feedwire "should" be  
something around 600 ohms. Cut and try required to find the correct  
tap point on the flat-top and the length of the feed wire and the  
ground system used also have an effect.  Probably OK through your coax  
switch at the 75 watt level but only for the frequency/band for which  
the flat top was cut.  On harmonic related frequencies (ex. 40M  
operation on a flat top cut for 75M) the impedance looking into the  
feedline could be just about anything.

For the end-fed case, how long is the wire and what frequency/ 
frequencies are you using?  OK for your switch if the feed point is  
anywhere near a current loop.

Dennis D. W7QHO
Glendale, CA

*****

On Mar 30, 2011, at 7:07 AM, Bill Stewart wrote:

>
>
> Good morning all,
>
> Can a normal coax switch be used to switch single wire fed antennas  
> such as a long wire or OCF Hertz (windom-a hi imped. antenna), in my  
> case. No coax feed used, just a wire from the wire antenna thru the  
> center conductor of the switch and then to the xmtr or tuner. I have  
> 'heard' that a coax connector presents a 50 ohm 'lump' in the line.
>
>
>
> I know this can be done electrically, but just wondering about the  
> '50 ohm' situation. Tnx for helping with a stooopid question.
>
>
>
> 73, Bill K4JYS
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