[GreenKeys] Coax type for simple vertical

[hwhall at compuserve.com]

I think I understand that you will be feeding it at one end.  

Do you have something that will be a groundplane, other half of a dipole or a counterpoise?  A 1/4 wave won't act like a 1/4wave vertical all by itself.  It will appear to be a too-short end-fed antenna. The impedence will almost surely be far from 50 or 75 ohms (don't have antenna modeling software here). 

 

 Do you have to collapse the fiberglass to stow it?  If not, consider winding it as a "continuously loaded" antenna to make it electrically 1/2 wave & feed the end with an L-match tuner, which for one band could be a simple fixed parts design.  A 1/2 wave won't need ground or counterpoise. But a physically shortened antenna will have a somewhat narrower bandwidth compared to a full size antenna.

Alternatively, maybe you could run the single wire along the fiberglass pole but insert a loading coil mounted somehow along the length to make an electrical 1/2 wave?

Another alternative: a pair of the 28 footers could be mounted in a V configuration for a true center-fed dipole. 

Just some thoughts.

Wayne
WB4OGM


 

-----Original Message-----
From: tony.podrasky <tony.podrasky at gmail.com>
To: Green Keys <greenkeys at mailman.qth.net>
Sent: Fri, Oct 13, 2017 6:45 pm
Subject: [GreenKeys] Coax type for simple vertical

GA OMs;

I'm going to try using a 28' telescoping fiberglass pole
with a wire taped to the top, running down the length
of the pole, to an SO-293. The pole will be attached
to my upstairs balcony - so I can take it down when I'm
done (CC&R stuff).

Should I be using 52 or 75 Ohm coax to feed it?

UE,
K2EAA - TONY
NNNN
ZCZC

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