On 8/10/2016 9:46 AM, Tom_N2SR via TowerTalk wrote:
I know some guys have tribanders at 30/60/90 feet, but I chose not
todo that.
30/60/90 looks good in HFTA based on "no nulls" in key directions
for most areas over flat ground - particularly on 10 and 15 meters.
However, it is not really good on 20 meters. Similarly 50/100/150
feet looks good on 20 meters and to some extent 15 meters as long
as one is not in New England for Europe or South America for Florida.
40/80/120 feet seems like a better overall compromise if one has the
ability to use the bottom antenna alone or bottom two out of phase
for some paths on 10 and occasionally 15 meters.
It is certainly easier to "optimize the nulls" for a single band
(using monoband antennas and multiple towers or even multiple
fixed stacks) than it is to cover all bands with a single set of
multi-band antennas.
73,
... Joe, W4TV
On 8/10/2016 9:46 AM, Tom_N2SR via TowerTalk wrote:
I used to operate at N3RS, who has 5/5/5 on 20, 5/5/5 on 15, and 5/5/5 on 10.
I forget the specific stacking heights/distances, but IIRC, they are 20:
37/77/117 feet, 15: 47/77/127 feet. 10: 25/50/87 feet.
I am using 2 C31XR tribanders at 40 and 80 feet, with separate feedlines. On
10, I have added a 5 element 10 at 25 feet, so while the distances are a
compromise, I will have 3/3 @ 40/80 on 20, 4/4 @ 40/80 on 15, and 5/5/5 @
25/40/80 feet. Which seems very similar to Tim's and well as Sig's stacking
distances and heights.
I used HFTA not for the gain numbers, but as someone else pointed out, to
eliminate or move the nulls for the arrival angles from Europe (mainly) and
other directions.
As John also pointed out, I only have 1 tower, and the C31XR's are just above
the guy wires. So that's what I have, and I have no plans to take the tower
down to reconfigure the guy wires. I know some guys have tribanders at
30/60/90 feet, but I chose not to do that.
Tom, N2SR
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