Topband: 2 wire beverage - transformers

[Tom Rauch]

The antenna in figure A will be a poor performer no matter what you 
do with transformers because grounding one wire and leaving the 
other open does not behave anything like a reflection transformer. 
It's good you dismissed that scheme.

> The 2 wire beverage is 10' high with a spacing of 1' vertical with #14
> wire and 580' long.

I have a 1500 foot long open wire feedline 12 feet high with 2.75 
inch spacing. The ratio of height to spacing is pretty large, but 
unless I transpose the wires every 1/4 wl or less it is impossible to 
keep the line balanced!  

If that were my antenna, I'd transpose the wires every 1/4 wl or 
more often. In 580 foot of length, especially when wire spacing is 
about 10% of height, the wire will unbalance itself a considerable 
amount and the (balanced mode) connection to the far end will 
become contaminated unless you electrically "twist" the wires. If 
you look at any article on installing balanced lines, and even at old 
telephone lines, the line is always transposed to insure balance. 
The wider the spacing, the more often you need to transpose the 
wires. John suggests that when he talks about using feedlines
to make Beverages.

It would be much better to mount the wires at the same height, so 
they have identical exposure to earth along the length of the line. 
Even then, they still should be transposed at fractional wavelength 
intervals.

73, Tom W8JI
w8ji@contesting.com



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