Quite interesting topic.
I have a wire 4-sq for 80M around my tower. Elevated feeds. Three of the
feed points are over grass with the feedpoints about 12' up. Then the wires
go vertical for about 20' then are pulled into the tower at 80' (Tnx 'LPL).
I have the feedpoints elevated because the NW feedpoint is over a stone wall
with a rocky slope that deer use as a path. Ground mounted radials in that
quadrant do not last long.. The NW feedpoint is 6' up to keep all 4
feedpoints level. I do not know if that makes a difference I could possibly
use gull wing radials at that point if I lowered the feedpoint.
I use RG6 with 100 #31 beads on the coax at the feedpoint. Feedlines are
elevated and attach to the tower at 7' and connect to a Comtek box.
The spacing of the feedpoints, length of the coax and the verticals are set
at 3650. Each feedpoint has 5 elevated radials that are 42'. I use a coil
from the shield side of the feedpoint to the 5 radials to resonate the
antenna at 3.770 (lowest indicated power in the shack in a dummy load). I
switch in a coil to bring the resonance down to 3.550.
My questions based on this thread:
- If I go with 3/4 length coax and use a large core I can bury the coax
which would make things look better. But do I give up anything over the
present 1/4 lines?
- Besides having beads at the feedpoints do I gain anything by putting beads
a the Comtek box? Noticeable improvement?
- Any other suggestions?
What I have works "okay". But always trying to improve within my limited
space.
Tnx for nay feedback
N2TK, Tony
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
jimlux
Sent: Sunday, September 25, 2016 12:48 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] 4 square for 80
One could of course make the transmission lines 3/4 wavelength long, and
have plenty of length to wrap dozens of turns on however many cores spaced
however frequently along the length of the cable.
On 9/25/16 9:25 AM, Jim Brown wrote:
> I see.
>
> 73, Jim
>
> On Sun,9/25/2016 5:41 AM, Joe Subich, W4TV wrote:
>> Jim,
>>
>> The problem is that, in that application, the cables must be 1/4 wave
>> long electrically. That already makes them shorter than desired and
>> "wound" chokes on each end would shorten them by another 5-7 feet
>> making the spacing of the 4 square much too small.
>
> On Sun,9/25/2016 6:49 AM, Steve London wrote:
>
>> What problem(s) are we attempting to solve with chokes on the
>> 4-square feedlines ?
>>
> Noise.
>
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