Also I'd suggest that you use HFTA with your terrain to see what is best for
you. You might find that what is nominally high for others is far too high
for you! I've stuck with the M2 recommendations - and have in modeling
confirmed they work well. That is 60' on 20 and 45' on 15. The former at
134' top height and the latter at 90'. I will have BOP available as HFTA
does show the three best configurations are: BIP, bottom, BOP. The top is
for all practical purposes never better than BIP ... on 20 the BOP probably
isn't going to be used much - possibly in SS when the propagation is
short... but on 15 and definitely 10 it should make a difference
occasionally.
Gary
K9RX
-----Original Message-----
From: Grant Saviers
Sent: Monday, August 8, 2016 10:04 PM
To: john nistico ; towertalk
Subject: Re: [TowerTalk] Stacking question
If the top antenna is at 2 or 3 wavelengths, there isn't much more to be
gained with height, IMO. My 2 high modeling put the lower beam a little
less than 1 wavelength below top and I interlaced the 2 by stacks 20, 15
and 10m downward, in my case 5 over 5. Two high was enough for me
with all on one tower. Big guns might use 3 highs and several towers
like K9CT and K3LR, look at their websites. There seems general
agreement that BOP is not useful.
The tradeoff of elements per antenna vs stacking depends on the desired
results. For known DX, more is better. For contesting the far
footprint gets pretty small for more than 5 elements, but I heard a
6+6+6 in a QSO on 20m yesterday, top at 170', and tighter than 1
wavelength spacing to keep the lowest antenna at 80'.
As one contester told me, if you have to move your antennas, you will
lose, hence several fixed antennas pointed at high mult areas are the
way to go in contesting.
With all that tower steel, why not go to 200' for 40m real 4 over 4 on
long booms such as the JKantennas 404 Grande and even more height to get
1 wavelength up for a 80m 3L if you can stand the hassles? With the 40m
at 200 and 100' they will be real pile up killers.
Given the likely prop the next few years, 10m is probably not worth the
effort. Optimizing now for 80/40/20 makes the most sense to me. A long
boom 17m might catch some DX though. And something for 30m will stand
out from the crowd. So, my current design project is for 6L 17m
interlaced with 2L or 3L 30m on a 48' boom. Getting close to a design
that models well.
Grant KZ1W
On 8/8/2016 18:02 PM, john nistico wrote:
I ordered 4 150 foot towers and am going to place the antenna order in a
few weeks. My question is I have read so much about stacking space 5/8 .64
3/4 1/2 wave. Where do I get the most bang for my buck with mono banders?
I am not that advanced to model these on eznec.
NY6DX
John J. Nistico
911 Electric Inc.
516.325-8993
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