The tricks are:
1) Make the two antennas quite identical.
2) Choose the heights at which they are
mounted carefully so that the match is
identical on each. Also, choose the heights
so that the lower is very close to half the
height of the upper. For example, when
two ten meter yagis are stacked, 35 and 70
feet would meet both these criteria. W6EEN
uses 3 10 meter yagis at 105, 70, and 35
feet, and can select almost any combination
of the 3. A good simulation program like
NEC-2 is helpful in determining the best heights.
3) Use equal lengths of identical coaxial
cable between the antennas and the match
box. Connect the two in parallel and match
for 26 ohms (2:1), or feed one at a time with
----- Original Message -----
From: "Victor Dively" <firstname.lastname@example.org>
Sent: Tuesday, September 10, 2002 10:14 PM
Subject: [CQ-Contest] Feeding Antenna Arrays
> I have a question about arrays - I read about phasing details, but I
> haven't seen anything about current distribution. Since an array
> on equal current getting to all the antennas, how (if at all) do you
> ensure that all antennas are receiving equal amounts of current?
> all, if one antenna is 1.5:1 on a frequency, and the other antennas
> at 1.2:1 on the same frequency, it would appear that the current
> flow the most towards the antennas with the best match, and upset
> expected radiation patterns for the array.
> I thought contesters may have the most experience with HF arrays...
> information or pointers to sources of information on the topic of
> correctly feeding arrays would be appreciated.... I'm hoping to have
> something better set up for CQWW this fall....
> Vic KG4HTT
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