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Old June 23rd 08, 10:28 AM posted to rec.radio.amateur.antenna
Wimpie[_2_] Wimpie[_2_] is offline
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First recorded activity by RadioBanter: Mar 2008
Posts: 329
Default feeding an 80 meter loop question

On 23 jun, 08:28, VK3XL wrote:
Hello all, I am planning to erect an 80 meter full wave loop antenna in
the back yard. The articals I have read so far all seem to feed the
antenna at a corner with either 450 ohm open wire line or feed direct
with 50 ohm coax. Due to the layout of my yard it would be preferable
that I feed the antenna at the mid point of one side of the antenna
with 450 ohm open wire line to a tuner (4:1 balun included in the line
and coax to the tuner). Is there any disadvantage in feeding the loop
mid way along one leg rather than at a corner?

any assistance greatly appreciated
Mike
VK3XL

--
VK3XL


Hello Mike,

Nothing to worry about. Feeding at a corner or feeding in the middle
of the edge/leg has insignificant influence on radiation pattern (it
will be very good for NVIS operation).

The input impedance remains low (450 Ohm). Feeding with coax is
possible. Add a common mode choke to reduce influence of cable on
radiation pattern and local noise pick up. I assume that your loop is
almost square (so occupies large area).

Best regards,

Wim
PA3DJS
www.tetech.nl
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