This was a direct answer to someone who asked for some details- forwarding
it on to the group too.
I have EZNEC models for:
Cushcraft 6 el 70 cm
HyGain 3 el 2M
HyGain 5 el 2M
Cushcraft 3 el 6M
Homebrew 10-15M interlaced yagi (K1NQ design)
4 el 10M OWA (ARRL ant handbook)
3 el 20M OWA (ARRL ant handbook)
Let me know if you would like any of them.
In my situation, the modeling showed that my 3 el 2M yagi should be spaced
48" from a 10-15 yagi, the 6M yagi should be as far as possible from a 20M
yagi (I have it about 9' above), and when putting up a 70cm yagi that it
should be away from the 10-15 yagi but it was OK to have it pretty close to
a 3 el 2M yagi. On 70cm I think I wound up with this yagi about a foot from
the 2M but 3' from the 10-15- it is between the two.
This seems consistent with the idea of not overlapping apertures. FWIW,
YMMV.
73
Chet, N8RA
-----Original Message-----
>From: "Chet, N8RA" <chetsubaccount@snet.net>
>Sent: May 12, 2009 10:00 PM
>To: 'John Kemker' <john@kemker.org>, vhfcontesting@contesting.com
>Subject: Re: [VHFcontesting] Stacking different Yagis
>
>John,
>
>I don't think there is an easy answer to that.
>
>What I do is model each antenna in EZNEC and then compare an antenna's
>pattern by itself to various placements amongst the others.
>
>This is laborious at first but now with most of the antennas modeled it
>is getting easier.
>
>GL, 73,
>Chet
>
>-----Original Message-----
>From: vhfcontesting-bounces@contesting.com
>[mailto:vhfcontesting-bounces@contesting.com] On Behalf Of John Kemker
>Sent: Tuesday, May 12, 2009 3:28 PM
>To: vhfcontesting@contesting.com
>Subject: [VHFcontesting] Stacking different Yagis
>
>I'm working on a tower project and it's nearing completion. One of the
>items I'm looking into is putting up four different yagis on four
>different bands on the tower:
>
>(From the top of the mast, down)
>M2 432-13WLA on 70cm
>Cushcraft 13B2 on 2m
>Cushcraft A50-5S on 6m
>Mosely CL-33 tribander on HF
>
>
>How much vertical separation do I need between each antenna on the
>stack in order to avoid unwanted interaction?
>
>--
>--JohnK
>73 de W5NNH
>10X 75371/M&M 117/SMIRK 6185/TRA 2499/Norcross 228 F&AM
>
>
>
>
>---
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>
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