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Old June 10th 06, 06:25 AM posted to rec.radio.amateur.antenna
Owen Duffy
 
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Default Buyer Beware - Cobra Ultralight

On Fri, 09 Jun 2006 05:13:04 GMT, Owen Duffy wrote:


The Cobra Junior, a 72' long linear loaded dipole, looks interesting
in terms of a short antenna for low HF bands with reasonably low
losses. I have run some preliminary NEC models and analysed the feed
system loss with 25m of W551 ladder line, they look promising.


Well, the antenna system looks promising on some bands, but not
others. Draft article is at http://www.vk1od.net/cobra , constructive
comments appreciated.

The article includes a link to a graph of the modelled system losses
for the Cobra Senior, but it looks pretty uninteresting with ~9dB of
system loss at 160m... there is no shortage of poor performing
antennas on 160m.

Owen
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