----- Original Message -----
From: "Jon Zaimes AA1K" <jz73@verizon.net>
To: "160" <topband@contesting.com>
Sent: Friday, May 31, 2013 4:31 AM
Subject: Re: Topband: PHASING SHUNT FED TOWERS
On 5/31/2013 12:43 AM, Tree wrote:
K6SE was the first guy I saw doing this - with much shorter towers than
mine.
Somewhere in my files I have a copy of a four-page letter Earl sent to
K2UU describing in detail the K6SE phased towers -- one of the few
multielement transmit arrays in use on the band in those days (1970s-80s).
If I recall correctly, they were HDBX style 64-foot self-supporting towers
spaced about 80 feet. One had a large tribander on it, and the other a
2-element shortened 40-meter yagi. Earl described how he raised and
lowered the 40-m. beam on its mast till that tower resonated at the same
spot as the other one. He used identical shunts and a coax delay line to
achieve the correct phasing. His letter included a formula for calculating
this delay line based on the distance between the towers.
This played quite well. We chatted many a night and Earl would flip the
switch and I'd see 25 db f/b or so.
73/Jon AA1K
Delaware
I sure miss Earl. One fine gentleman that wasnt afraid to share details of
any of his designs and answer questions with even more details.
Carl
KM1H
All good topband ops know how to put up a beverage at night.
_________________
Topband Reflector
|