Dennis, the Dunestar StackMatch will work just fine on seperate towers
without having equal lengths of coax. No worries about this, we have
lots of customers doing it.
Actually if you took the time and effort to make the coax equal the
effect would be lost as you change directions of the beams. Say as you
point them at EU and one tower is in "front" of the other you would get
a phase difference anyway. BUT Lets say you have the two towers in a
perpendicular line to EU. Then You would get GAIN toward EU if the
antennas were both in Phase. (Remember, that the dissimilar antennas may
be 180 degrees out of phase due to the balun being different, or the way
they feed the antenna, gamma, hairpin, dual-driven elements, etc)
But this scenerio lets you have a pencil like lobe on EU. Actually at
100 feet separation between towers it may be too narrow. Use your
antenna software to model it.
A good friend of mine tells me at N5AU they used a 15m array like this
to JA with great results.
GL.
Jay, WX0B
Jay, WX0B
Dennis Schaefer wrote:
>
> I'm probably going to end up with two 60 foot towers, spaced about 100 ft,
> one with a 204BA and one with a KT-34A. This should provide some casual
> multi-multi fun. Although beams are generally stacked vertically, it
> occurred to me that these antennas might be fed in phase to get more gain
> on 20 meters.
>
> Would you get real gain from this, or just some "diversity" effects on
> receive? Would the Dunestar device be appropriate, or does it need equal
> lengths of coax going to each antenna? I assume that even if I didn't
> measure the coax cables before putting up the antennas, I could find the
> best directions (I assume there would be two good directions, 180 degrees
> apart) by turning the antennas and comparing "both" to "either". Then I
> could add coax to one antenna's feedline in increments for other directions.
>
> Sounds like a cheap way to get a little punch on 20 meters when needed,
> even with short towers. Will it work?
>
> Dennis, W5RZ
>
> --
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--
+---------------------+-----------------------------------------------+
| | Jay Terleski |
| /\ | Director Sales, Central Region |
| /\/ \ | |
| /\ / \ \ | Summit Design, Inc. Phn:(972) 203 2008 |
| / \ \ \ | 350 Gloria Rd. FAX:(972) 203 8811 |
| SUMMIT DESIGN-TSSI | Sunnyvale, TX 75182 Email:jayt@sd.com |
+---------------------+-----------------------------------------------+
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: owner-towertalk@contesting.com
Sponsored by: Akorn Access, Inc. & N4VJ / K4AAA
|