[TowerTalk] Short Booms

[Howard Klein]

----Original Message Follows----
From: Jim Lux <jimlux at earthlink.net>
To: Jerry Keller <k3bz at arrl.net>, Ward Silver <hwardsil at centurytel.net>, 
Towertalk Reflector <towertalk at contesting.com>
Subject: Re: [TowerTalk] Short Booms
Front to Back (or Front to Rear) ratio is something that the SteppIR type
beam will excel at. Also, the SteppIR concept allows you to free one of the
parameters that otherwise you'd have to optimize: bandwidth.  You can set
the SteppIR up for performance at a single frequency.

As an interesting exercise try something I inadvertently found out about the
other day.  Take almost any 3 element 20m beam that has been optimized for
gain or F/B at a particular frequency.  Run a series of patterns at 100 kHz
steps covering from, say, 13.9 to 14.5 MHz.  Ignore the change in Z, and
look at the gain (which doesn't change with the reactive part of feedpoint
Z) The gain won't change all that much, but the back lobes change
dramatically.

I suspect that for the vast majority of situations, the beam works better
than the dipole or omni because it suppresses the stuff off the back and
sides, not because it ekes out an additional 3 dB of gain.

Jim,
I have a pair of 4 el SteppIR's and my real world impressions are exactly as 
you describe. The patterns are much sharper than any of the monoband beams 
or tribanders I have used over a span of 40 years. I optimize my beams for 
gain at a given frequency most of the time. I am still refining the combo in 
a stack since I have had them up for only a couple of weeks.
73,
Howard..K2HK

_________________________________________________________________
Get 10MB of e-mail storage! Sign up for Hotmail Extra Storage.  
http://join.msn.com/?PAGE=features/es