[TowerTalk] Stacking 20m and 15 meter mono banders on the same mast.

[kk9a@arrl.net]

I have a similar situation at my home in Aruba.  I have a homebrew 4 el 20m
(36' boom) and a 4 el 15m (24') 7' above it.  The 20m antenna is unaffected
by the 15m.  The 15m appears to still have good gain and a nice SWR curve,
but the curve is a little different than when tested alone.  I also did some
modeling and research before installing this and it appears that the biggest
effect on 15m is some loss of F/B.  Your proposed 10' spacing would
eliminate more of the F/B degradation and it should work fine.  I use an
aluminum mast for corrosion resistance and had to settle on less separation
and I am very pleased with the performance.   I mounted my 10m antenna on a
TIC Ring 30' below the 20m antenna.  My next challenge is to find a small
40m beam that I can put on the mast that won't screw up the 15m or 20m
antennas.  You can see a picture on http://www.qrz.com/p40a

73,
John  KK9A / P40A



To: towertalk at contesting.com
Subject: [TowerTalk] Stacking 20m and 15 meter mono banders on the same
mast.
From: KT2Q dxdx at optonline.net

All:

Was thinking about replacing my existing multi-band HF Yagi with 4 element
M2 monobanders for 20 and 15 meters. Specifically the 20M4DX and the 15M4DX.
The antennas would be mounted on the existing tower on a 20 foot mast.

The first thing that comes to mind is stacking the antennas with enough
space between them to avoid any detuning. The other question is where to
mount my existing six and 10 meter Yagi's to avoid the same.

The plan is to mount the 20m Yagi at the botom of the mast and the 15m Yagi
about 10 feet above. The 10 and 6 meter Yagi's will have to be close at the
top of the mast. Not sure if this is the best way to go.

Any comments on how M2 mono-banders compare to others manufacturers in terms
of performance, workmanship and quality components would be appreciated.
Another concern is consistent gain and F/B accross the band. My main
interest is CW and the M2 20m Yagi looks like it can be "peaked" for the
lower end of the band.

Thanks,

73 Tony KT2Q