[SCCC] Phased verticals

[w6ph at aol.com]

Or an odd multiple of 1/4 wavelength 75 ohm cable, i.e. 3/4 or 5/4.  The best theoretical gain is spacing the two verticals 5/8 wave for broadside firing.  The 1/4 wave cable length is too short because of velocity factor.  So you would need two 3/4 wave 75 ohm cables to transform the 50 ohm to 100 ohms at the feed point.
Kurt W6PH
In a message dated 8/12/2019 7:52:13 PM Pacific Standard Time, n6vi at socal.rr.com writes:

Hi, Bob.

The most common way I have seen to match your transmitter to paralleled
50-Ohm antennas is to feed each antenna with electrical 1/4 wavelengths of
75-Ohm coax to the Tee.  That will transform each feed point impedance to
100 Ohms, and paralleling two of those gets you back to 50 Ohms.

73,

Marty N6VI


-----Original Message-----
From: SCCC [mailto:sccc-bounces at contesting.com] On Behalf Of Bob Grubic
Sent: Monday, August 12, 2019 6:25 PM
To: Southern California Contest Club
Subject: [SCCC] Phased verticals

I am considering using two 20-meter phased verticals for some portable
operations. (Later, two 40-meter verticals.)

Keeping it simple at first, I'd run coax from my rig to a T-connector and
then through identical, same length pieces of coax to each vertical
(driving them in phase). I've seen this scenario several times online, but
the fact that two 50-ohm antennas would be in parallel at the T-connector
to give you a 25-ohm load (in effect), somehow bothers me.

I've seen an article online suggesting using an UNUN to match the rig's
coax to the two legs feeding the antennas--essentially replacing the
T-connector (with a UN-22-25 from CWS). http://www.cwsbytemark.com/  I
can't find any other discussion of this particular subject online.

Has anyone had any experience with this or thoughts on the subject? I'd
appreciate hearing about it.

Thanks very much.

73,
Bob NC6Q
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