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Yep
folks, these are commonly referred to as "Phasing Harnesses" just like we
use in the contest circles to stack multiple antennas and phase them so the feed
point impedance still "sees" 50 ohms at the design
frequency.
Ron Rogers
-WB8ERB-
I think you will find that the feed point is
50-Ohms when feeding one of these single unbalanced dipole
elements. The harness is for making the multiple elements on
the array look like one element to the transmission line. Look
at their (DB's) folded unipole antenna for low band. It's
a ground-plane antenna with a similar radiating element that's fed with
50-Ohm line. The difference is that it's got radials on it instead of a
mirrored counterpoise. There may be other subtle differences,
but...
Steve, aa5sg
----- Original Message -----
Sent: Thursday, April 15, 2004 1:19
PM
Subject: Re: [Repeater-Builder] Decibel
repeater antenna question-unbalanced radiating loops
There are not any baluns on these antennas. If I remember right,
they use 75 ohm coax on each bay (odd multiples of quarter wave length) and
35 ohm coax on the feed (again odd multiples) to match the impedance to 50
ohms. This info was on the group a while back, somebody must still
have it.
Paul, kb9wlc
Would a close up pic of a DB304 work for your needs, or I have the
DB420 there as well.
Mathew
bradley glen <[EMAIL PROTECTED]>
wrote:
Hi
I
have been studying the db stacked array and the
bayed array seems to
use unbalanced dipoles as the
radiators .I have tried to find a close
up view of a
single dipole so I can confirm my ideas.
If
anyone has some good tech info on these antennas I
would appreciate
the info.
It would make sense to " by-pass " the need of
baluns
for each dipole -cost and balun
loss?????
Regards
Brad
ZS5WT Repeater Owner
[EMAIL PROTECTED]
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