Topband: PHASING SHUNT FED TOWERS

[Jon Zaimes AA1K]

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