-----Original Message-----
From: Don Prater [mailto:praterdg@ornl.gov]
Sent: Tuesday, December 22, 1998 6:54 AM
To: N2TK
Subject: Re: [TowerTalk] FW: Help - 80m 4 square
Tony,
I am using the same antenna here. I have had confidence that this one seems
to be working. I say "seems" because the only thing I have to compare it
too is a 1/4 wave sloper and comparisons with locals running verticals,
dipoles etc. The best I remember the article indicates the antenna should
present about 2.3 db gain over a dipole. If you don't think it is
performing right first check the wasted power. It will normally not be more
than 5-10 watts max. If it is over that the performance goes fast. I have
seen on average 10-15 db front to back. I have seen 20-30 db front to side.
That is just watching the s meter, not a scientific measurement.
Performance wise it seems to beat the slopers, dipoles and other cloud
warmers. It will not compete with the beams, but there are not that many
beams on 80 meters anyway. Oh!...I forgot to mention the sloping part.
ON4UN states that if you come more that 19-20 degrees off vertical you
loose the vertical component. The way I got around that was to build a boom
structure and put it at about 75-80 feet. Each arm extends out 21 feet.
from the tower. That keeps the wires within the design requirements. My
radials are about 8 feet off the ground. Just high enough to not hang
someone. I use only one radial. There is not that much advantage to adding
more radials. If you add one more make sure it is in the opposite direction
to the one you already have. If you add more than that, add them in pairs
in opposite directions. I use 300 ohm twin lead to extend the tuning to
3.500 Mhz. Don't know if this is of any help but my experience.
73...DX...Don...W4TO
At 07:33 PM 12/21/98 -0500, you wrote:
>
>
>Presently I have a 4 square based on the article in section 6.3 of ON4UN's
>Low Band Dxing, 2nd edition.
>I have 4 posts with a vertical wire from each pulled up to the top of the
>80' tower. I am using 1/4 wave 70 ohm feedlines to the Comtek box. I have
>one radial on each leg pointing away from the tower. There is a current
>balun at each feed point.
>The differences being -
>- the vertical wires are tied into the tower at 80'. This adds more slope
to
>the vertical wires.
>- the radials and the feedpoint are 12' off the ground
>- the vertical wires and 1/4 wave coax are cut for 3.65MHz
>- the one radial on each leg is cut to for minimum dumped power at 3.79.
>- I switch in a coil in the radial at each leg to have minimum dumped power
>at 3.520.
>
>Performance - about 10-18 db f/b and very slight gain over a Cushcraft AV80
>36' vertical with 4 elevated 1/4 wave radials.
>
>My questions on trying to improve performance
>- Thought performance would improve by making the verticals more vertical.
I
>can do that by making them
>"T's". The vertical portion would be about 45-48' before I added the T.
>- Or I could put up aluminum verticals at each post. Thought was to use 8'
>pieces of 2" tapering down to 3/4".
>- With the radials, do you think I would get a measureable improvement by
>either adding one or two more per leg? What about the articles on 1/8 wave
>radials? Would that work with a coil?
>- Is performance suffering by cutting the verticals and 1/4 wave matching
>lines for 3.65 and then switching in a coil in the radials for phone and
cw?
>Tnx for any ideas and input. As to not clutter up towertalk, you can send
>direct to me any responses and suggestions and I will summarize on
towertalk
>Tony N2TK
>
>
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