It is interesting to note that an antenna with 13 dB of loss would also
"appear quieter on receive", due of course to that loss.
----- Original Message -----
From: "Steve Hunt" <steve@karinya.net>
To: "Discussion of Ten-Tec Equipment" <tentec@contesting.com>
Sent: Monday, June 02, 2008 4:16 AM
Subject: Re: [TenTec] Bazooka antenna
> Folks,
>
> At the risk of stirring up a hornets' nest ......
>
> .... I continue to see claims that the Double Bazooka exhibits a wider
> VSWR bandwidth than the equivalent thickness half-wave dipole. But I
> thought that W2DU had showed conclusively that the "reactance
> cancellation" mechanism claimed for the DB was a fallacy, and that AI1H
> (ex-W1DTY) had showed that the real explanation for any bandwidth
> increase was losses in the coaxial elements. In other words, the same
> effect as putting a resistor across the feedpoint!
>
> Am I missing something? Is there subsequent work that has proved W2DU
> and AI1H wrong? Or do folks just like using unnecessarily-complex, lossy
> antennas :)
>
> I have an interest in the topic because I just did some related
> experimental and modelling work on using coaxial elements to "shrink"
> the size of a HexBeam. Yes, you get the expected "velocity factor" size
> reduction, but you also get unacceptable losses introduce by the coaxial
> stubs. A HexBeam driver constructed of RG58 would exhibit coax losses of
> about 13dB. If you're interested you can read about it at:
>
> http://www.karinya.net/g3txq/coax_antennas/
>
> I know my test configuration was different from the DB, and that DB
> losses will not be of the same order, but the message is the same:
> "quarter-wave inductive coaxial stubs are lossy, low-Q, elements."
>
> Now I think I'll turn off the computer for a few days until the hostile
> reaction dies down :)
>
> 73,
> Steve G3TXQ
>
>
>
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>
>
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