Thanks All for the comments.
K5GO (Stan), Oops, yes, the longest element on the 6m beam is 10 Ft, not 5
Ft. Yes, I am aware of the differences of stacking same band antennas
versus just stacking different band antennas on a single mast. Please see
my general comments below.
KK9A (John), Yes, I would like more mast nested inside the tower as well.
When I got the 1026 DOM mast I said to myself, &*%$#, that?s heavy, and
LONG. That?s why I keep putting the 6m beam at the top, with its paltry 2.2
Sq Ft of wind area, albeit at 12 Ft atop the mast.
W1DYJ (Larry), thanks for re-directing me back to that very good article. I
did read it some time ago along with several others and many many comments
on various other formulas and/or rules of thumb, most of which aren?t much
better than a guess....which is why I come to the pool of experts here !!
All aside, it seemed to me that if I centered everything around the highest
frequency band (2M in this case) and try to keep everything out of its
aperture then all should be good with the world. With the 6m beam at approx
5 Ft above and the HF tribander at 5 Ft below, both are just inches inside
the aperture of the 2M beam, but it isn?t seeing much of that metal as there
are few elements and they are very wide spaced. The HF tribander is
completely outside the aperture of the 6m beam, yes the 2m beam is way
inside the aperture of the 6m beam but with its large aperture coupled with
the "small" elements of the 2m beam I didn?t think that it would result in
any major loss in gain. I can't guess on the effects it may have on SWR.
Several of you mentioned modeling the stack to get a better idea, what
software are you all using??
Brad, N8GLS
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Larry
Banks
Sent: Saturday, December 28, 2013 10:54 AM
To: n8gls@arrl.net; TowerTalk@contesting.com
Subject: Re: [TowerTalk] HF-VHF-VHF Stacked Yagi's on Single Mast
Hi Brad,
I would suggest you read HOW TO PLAN THE INSTALLATION OF MULTIPLE VHF
ANTENNAS ON ONE MAST on the Directive Systems webpage:
http://www.directivesystems.com/STACKING.htm.
73 -- Larry -- W1DYJ
----- Original Message -----
From: "N8GLS" <n8gls@arrl.net>
To: <TowerTalk@contesting.com>
Sent: Saturday, December 28, 2013 12:32 AM
Subject: [TowerTalk] HF-VHF-VHF Stacked Yagi's on Single Mast
Group,
I have a Hygain HG-54HD Crank-Up Tower which had a Hygain TH5MK2 HF tri-band
Beam and a Cushcraft 17B2 2m Boomer all on 8 Ft of mast (10 Ft total with 2
Ft inside the tower). I'm adding an M² 6m Yagi, changing the TH5MK2 beam for
a Cushcraft X7 (w/40m add-on kit) and keeping the Cushcraft 17B2 2m Boomer.
All to be on 12 Ft of new 1026 DOM Mast (14 Ft total with 2Ft inside the
tower). The stack will be as follows, from bottom to top;
At 2 Ft from top of tower---Cushcraft X7 (HF 40m-20m-15m-10m), 18 Ft boom, 6
elements, longest element 40 Ft, 9.9 Sq Ft wind area.
At 5 Ft above the X7---Cushcraft 17B2 (2m) Boomer, 31 Ft boom, 17 elements,
longest element 3.5 Ft, 3.9 Sq Ft wind area.
At 5 Ft above the 17B2---M² 6M5X (6m), 18 Ft boom, 5 elements, longest
element 5 Ft, 2.2 Sq Ft wind area.
At the end of the day, I have 12 Ft of mast to stack the above mix of beams.
The spacing above is in order of wind surface area, which is my main
concern. I have looked at capture area(s), recommended stacking distances,
and I end up needing a mast length that is not feasible for the tower. So,
does anyone have a better stacking arrangement than the above ???
This project started out as just taking down the old tower and painting
it...then after seeing it's not going to be easy to drop that thing without
some kind of raising fixture I bought a new US Tower raising fixture and
re-vamped it to fit the HyGain base, bought the new 6m yagi, then the
Cushcraft X7, all new coax and rotor cable, new mast, and now I decided to
have the tower re-hot dip galvanized instead of painting it (cant paint in
winter)....and of course it's December, the end of December actually, in
northeast Ohio, need I say more ?? Oh ya, and I'd like to get this done
before the VHF contest in a few weeks..Ha..
Thanks for any comments on the stacking...my XYL is already giving plenty of
commentary on all the other..
73 de Brad, N8GLS
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