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Re: [TowerTalk] Multi-band dipoles

Subject: Re: [TowerTalk] Multi-band dipoles
From: Jim Lux <>
Date: Fri, 22 Apr 2011 09:39:26 -0700
List-post: <">>
On 4/22/11 9:18 AM, Bill Aycock wrote:
> Joe--
> You mention "actually tested" and "actually measured" in your post. Who
> did this, how was it done, and where is it published? I have never heard
> that these antennas were very good, and would like to hear any thing
> different.
> Bill--W4BSG

"good" can mean different things to different people.

If you aren't concerned about efficiency (i.e. Tx Power vs Radiated 
power) then these are a convenient solution to wideband operation, 
installation in a variety of places, etc.

I suppose the advantage of these things over just putting a 4 dB pad in 
the line is that if the antenna does happen to be just the right length, 
you dissipate less power in the load.

a 4dB pad at the antenna plus a dB of loss in the feedline would mean 
your amp would never see worse than 2:1 VSWR.

The question might be whether in a "transmitter power" limited but not 
power efficiency concerned environment (e.g. ham radio, vs, say a 
spacecraft), whether you could claim your transmitter is "at the antenna 
feed point", so you could have your 1500 W PEP *after the 4 dB pad*

 From the "intent" of the rules: don't radiate too much power, I would 
think that would fly.  Back in the "DC power to the final stage" days, 
there was more importance to PAE (Power Added Efficiency)

(for that matter, you could put the 4 dB pad inside the transmitter, but 
then you get more feedline loss)

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