OK, thanks Gary and Tom. I haven't been back to my modeling
computer for a day or so. I think I get the idea now that I
should try 3 configs each with the 7mhz and 160m
antennas (6 configs total) and see what the patterns are.
The 160m RX elements are the W8JI type @ 20ft
tall and the 40m transmit array elements are the full size
~33 footers.
I'll use ~10-11 miles of radials for the 40m ant
and feed the array with OWL on 40m TX and switch to RG-6
type coax on 40m RX or possibly use the OWL for RX as well....
depends on how much unwanted pickup I get with the OWL.
73,
Charlie
On Tue, 6 Sep 2016 07:32:58 -0400 "StellarCAT" <rxdesign@ssvecnet.com>
writes:
> John, Charlie,
>
> My apologies! I had done quite a bit of modeling for my own
> situation and
> found that what seemed like ANY piece of metal of most any length
> coupled
> current in (and it does) and screwed with the pattern (doesn't
> necessarily)
> ... I still find that for example if I want to use a 4 square (or 8
> element
> which is what I'm planning on) anywhere near - (within 800') of a
> tower say
> on 80 meters I need to break the tower up twice to get the pattern
> back ...
> if used on 40, the rx array, I'd have to do even more gymnastics ...
> however
> I shouldn't have volunteered those results as being correct for
> Charlie's
> situation - I just modeled a 4 sq with 80' side spacing with 4 33'
> verticals
> in their 'center' ... there's no impact on 160 ... again my
> apologies. This
> result is using single ungrounded elements for reference.
>
> Gary
> K9RX
>
>
>
> -----Original Message-----
> From: john@kk9a.com
> Sent: Monday, September 5, 2016 9:22 PM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Antenna modeling question
>
> Why would such short verticals effect the 160m RX array.
>
> John KK9A
>
>
> To: <n0tt1@juno.com>, <TowerTalk@contesting.com>
> Subject: Re: [TowerTalk] Antenna modeling question
> From: "StellarCAT" <rxdesign@ssvecnet.com>
> Date: Mon, 5 Sep 2016 07:51:34 -0400
> List-post:
> <towertalk@contesting.com">mailto:towertalk@contesting.com>
> the issue is more than likely not going to be 'what is the
> interaction of
> the 160 on the 40 ... rather it is going to be what is the
> interaction of
> the 40 on the 160 ... and my guess (after having played with a Hi-Z
> model of
> their 4 element) it will be significant! The pattern will be quite
> distorted. That I believe is easier to model as well - just leave
> the 4
> internal verticals un-terminated. I'd love to hear the results.
>
>
> K9RX
>
>
>
> -----Original Message----- From: n0tt1@juno.com
> Sent: Sunday, September 4, 2016 11:50 PM
> To: TowerTalk@contesting.com
> Subject: [TowerTalk] Antenna modeling question
>
> Gents,
>
> I'd like to build a 40m phased array "inside" my 160m
> receiving-only 9-circle and I want to check for any
> interaction between the two antennas.
>
> I have the layout in EZNEC 6, but I'm not sure how
> to "feed" the 160m array. Do I let it "float", ground the
> elements or what?
>
> Also, vice-versa...float the 7mhz array or....?
>
> Suggestions?
>
> Thanks,
> Charlie, N0TT
>
>
> _______________________________________________
>
>
>
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