Hello Rich:
Another data point from here. I have a rotatable M2 80 meter dipole with K7ZV
very hi Q coils in the centers of each half element mounted at 245 feet (a
little less than one wavelength above ground). The dipole is 108 feet long. A
good ground mounted 4 square here beats the dipole by 4 to 5 dB on most DX
signals. When I use the two 4 squares here in phase the difference is 8 dB in
favor of the phased 4 squares.
73
Tim K3LR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Richard
Thorne
Sent: Tuesday, July 7, 2020 3:39 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] 80 meter antenna choice
Bill,
I've been real happy with a JK801 rotatable dipole at 138'. I use a
Green Heron RT-21dc (the other option is an MFJ-1924 mobile antenna
controller) to control the Tornado Tuner. It gives me full band
coverage in 40khz increments.
According to Ken's modeling (unconfirmed by me as I have no clue how to
model) a JK801 at a 1/2 wave length in height is at least equal to a
good 4 square.
https://jkantennas.com/jk801.html
Rich - N5ZC
On 7/7/2020 9:50 AM, Bill via TowerTalk wrote:
> I've pretty well figured out what I will be doing on 40-6 meters. However,
> 80 is still undecided. Shunt feeding the tower is not going to work since I
> have all kinds of rotating antennas up the side of the tower. So, I'm left
> with three solutions.
> Since the last guy point is at 96 ft I could have two inverted Vees apexed at
> 96 feet down to around 60 ft on the ends, at right angles to each other.
> That would give me the ability to switch directions and gain/lose around 5-10
> db.
> Second choice is to have a full size wire vertical with 60 full sized radials
> over average ground.
> Third choice is more complex- a wire 4 square but...although the SE and SW
> facing verticals would be pretty close to having a good radial system The NE
> facing one is pretty limited due to lot lines and the location of the
> house/garage and the NW facing antenna is even more limited by the same
> constraints. This one has a driveway in the way. Most of the decent sized
> radials would be pointing away from the direction the NE and NW are facing
> and the others would be fairly short.
> Of course laying down the radials for the 4 square is quite a chore and I
> would hate to go through all that work to come up with crappy system.
> Easiest of course, would be the inverted Vees. I've used this system in the
> past and it performed quite well. I'm concerned the lack of similar radial
> systems would ruin the F/B and gain and the compromised radial system of two
> of the antennas would also be an issue.
> Your thoughts?
> Bill KH7XS/K4XS (soon to be V31XX)
>
> Location of the station is V31 and interest is contesting and DXing
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