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Old January 16th 04, 05:30 PM
Tom Bruhns
 
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Since "bazooka" conjures up at least three pretty different images for
me (and that's just with respect to antennas), could you explain a bit
more just how you're thinking of building it? Is it like
http://www.qsl.net/we6w/projects/baz_std.txt? If so, I believe you
want to make the coax sections close to 1/4 wave long, accounting for
the velocity factor of the coax you use. Expect the coax part, as
transmission lines, to reflect a reactance back to the feedpoint...the
reactance they reflect as a function of frequency does depend on the
impedance of the line you use. You could model it with EZNec, or use
any of the many available transmission line calculators to find it.
What's across the feedpoint is just the two sections in series. The
radiating part of the antenna is just the outside surface of the coax
(or whatever conductors you have).

Cheers,
Tom

Phillip Jockell wrote in message . ..
How does one construct a bazooka using 75 ohm coax for the radiating
portion and 50 ohm coax for the feed (as usual)? The obvious reason
is that I have a pot full of random length, unused 75 cable I would
like to find a good use for. Most of it is RG-6 TV coax variant or
such.

I have not seen design equations for the bazooka, just articles
saying "cut it to these dimensions" (don't worry your pretty
little head implied, but not stated...)


Thanks for any help,

Phil - N4GWV

 
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