[TowerTalk] Fwd: Fwd: 160m T vs. Inverted L

[Joe Subich, W4TV]

> Note: I presently have an inverted "L" which comes off the 115 ft
> tower and the horizontal component goes East to the 92 ft tower. It
> is a cloud warmer to EU, but fantastic to the west coast and the
> Pacific. It may be due to the close proximity of the vertical portion
> to the tower. It shouldn't be, but it is!
What is installed on the top of the 115' tower?  At 115' it's quite
close to resonant t0 2 MHz and any significant top loading (mast,
antenna booms even with insulted elements) may move the resonant point
down to 1.8 MHz or lower.  It will most certainly couple heavily to
the inverted L and will seriously impact performance.

Given that you can not get the vertical part of either a "T" or inverted
L more than 30 feet (0.06 wavelengths) from one of the towers, I would
expect coupling to be significant unless you can detune both of the
towers.

You my be better served to construct an N4KG "reverse fed vertical"
<June 1984 QST by Tom N4KG> on the taller tower and detune the short
tower.

 > Assuming an "L" antenna, that would mean the horizontal component
 > will be approximately 48 feet while each half of the horizontal
 > component of the "T" would be about 24 feet.

The "T" will be about 10% longer than the top wire on an inverted "L"
(assuming both are flat).

73,

    ... Joe, W4TV


On 8/21/2017 2:15 PM, Carol Richards wrote:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Hello...
> 
> I am now in the final stages of putting up a serious 160m ant. Either
> will have a K2AV FCP. and a common mode choke.
> 
> Question:
> 
> 
> Both antennas will be approximately 80-90 feet vertical between two
> towers which are 60 feet apart, plenty or room for either. Actually one
> tower is 115 feet tall and the other is 92 feet tall. The guy wires on
> the towers are broken up in numerous non-resonant lengths. To be
> resonant at 1.830mhz, I calculated the resonant length to be 127' 10.5
> ". Assuming an "L" antenna, that would mean the horizontal component
> will be approximately 48 feet while each half of the horizontal
> component of the "T" would be about 24 feet.
> 
> Suggestions are welcomed as to which way to go before I get up on the
> tower. I have a pair of marine pulleys which would eliminate the
> necessity for repeated climbs.
> 
> 
> Note: I presently have an inverted "L" which comes off the 115 ft tower
> and the horizontal component goes East to the 92 ft tower. It is a cloud
> warmer to EU, but fantastic to the west coast and the Pacific. It may be
> due to the close proximity of the vertical portion to the tower. It
> shouldn't be, but it is! I also use 4 tuned elevated radials.
> 
> 
> 
> Carol
> 
> 
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> 
> 
> 
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