[TowerTalk] 80 meter antenna choice

[Tim Duffy]

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 at contesting.com] On Behalf Of Richard Thorne
Sent: Tuesday, July 7, 2020 3:39 PM
To: towertalk at 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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