Some general suggestions as a starting point:
1. Sell the tribanders. With just three towers, they really can't help you
much and will certainly interact with everything else.
If you can build taller towers, put the cash into increased tower height. You
will do well to have:
-- 150' 20m stack at 50, 100 and 150 ft.
-- more height for the tower that contains a 40m stack.
2. Try to keep the antennas for the same band on the same tower. Otherwise,
you will have complex pattern interaction issues to
worry about. A common arrangement for 3 towers is:
-- 10 and 40m on one tower.
-- 15m on another tower.
-- 20m on the third tower.
You did not say where you were located. The choice of which bands to
double-up on the same tower depend a bit on what you need
to do with your antennas during the contest. For example, if you are in the
northeast and put a 10m and 40m antenna on the same
rotator, one approach is for the two antennas to point in opposite directions
to held during those hours when both bands are open.
3. Sacrifice the 80m rotatable dipole if it forces compromises in the other
bands. You could consider:
-- putting it on the 15m tower.
-- eliminating the rotatable dipole. Use the space between two towers for a
wire dipole or 2-element reversible beam with a
cardiod pattern. Put the cash into taller towers and good rotators.
4. Assemble your yagis into a system that can be driven as a stack. You can
always twist the top antenna(s) off to different
directions to chase multipliers. My article in the next issue of the National
Contest Journal (Sep/Oct) discusses this in detail.
5. Bandpass filters and well-designed coax stub systems should be adequate to
address inter-station interference issues.
Good luck. This is a big project but you will have a great station.
73,
-- Eric K3NA
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com]On Behalf Of Don Havlicek
Sent: 2003 July 18 Friday 21:58
To: Dennis Brickey
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] Need Advice on SO2R Antenna Arrangement
Dennis,
Doing a quick [file card] sort ... I find .. you need another tower !
Can't see how you're going to get all those antennas on three ...
without the interaction you want to avoid .. especially those tribanders.
YMMV
Don
N8DE
Dennis Brickey wrote:
> Good Evening guys,
>
> I have been licensed since January of 1989, and have since scrounged,
> bought, and
> traded until I have amassed what I think are the makings of an SO2R antenna
> farm, and it
> is time to put some of this stuff in the air. Here is the list of tower and
> antennas available to
> assemble this antenna farm.
>
> 120' 45g
> 100' 55g
> 100' 25g
> 4 Hygain 105BAS 5 element 10 meter beams
> 3 Hygain 155BAS 5 element 15 meter beams
> 3 Hygain 205BAS 5 element 20 meter beams
> 1 KLM 40M4 4 element 40 meter beam
> 1 HYgain 402BAS 2 element 40 meter beam
> 1 80M1 80 meter rotatable dipole
> 1 KLM KT34XA 6 element tribander
> 1 Hygain TH5xx 5 element tribander
> 1 Hygain TH3 3 element tribander
>
> I am limited on space. I have 300 feet of lot depth on which to place 3
> towers, and there is barely adequate room to guy the towers. They will be
> placed in a straight line from west to east with the tallest tower being in
> the middle. I say the tallest (45g) in the middle to accommodate rotation
> of the 80 meter rotatable dipole which is 92 feet in length; that is if it
> is reasonable to use the antenna.
>
> All that said, I need advice as to which antennas to put on which tower.
> The
> consideration that comes to mind is that the bands should probably be split
> up such that there
> would be a low probability of operating on two bands on the same tower at
> the same time. I have
> bandpass filters, but I have no idea whether or not bandpass filters are
> sufficient to keep down
> interference between the radios at high power if utilizing the same tower.
> Finally, antenna
> interaction is a concern. I know that 40 meters and 15 meters don't work
> well together, so I will
> avoid that combination.
>
> Is there someone among this list of outstanding tower experts and contesting
> gurus that can point me
> in the right direction? All replies are appreciated.
>
> Thanks in advance for your time, and Happy Contesting!!
>
> 73,
>
> Dennis N4DD
>
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> Weather Stations", and lot's more. Call Toll Free,
1-800-333-9041 with any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free,
1-800-333-9041 with any questions and ask for Sherman, W2FLA.
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