[Towertalk] Freq on Ground and On Tower

[n4kg@juno.com]

There was a note in QST some years ago pointing out that
standing antennas UP to check SWR before installing would
give better results if the reflector is ABOVE ground.  The 
Lower the F/B, the HIGHER it needs to be to prevent detuning
effects from the ground.  Unfortunately, I don't remember
the recommended heights for high and low F/B.  I believe they
were in the range of a few few feet to maybe 10 ft or so for 
high band antennas.

Tom  N4KG

On Wed, 06 Nov 2002 Tom Martin <tmartin@chartermi.net> writes:
> I should have mentioned that it is a two element wire beam using 
> bamboo to support the 12 gauge stranded wire.  I will tilt it and
measure 
> again.  I am feeding directly with RG 213 with a .20 spacing.
> 
> Tom W8JWN
> 
> Tom Martin wrote:
> 
> > I built a 15 meter beam with the DE cut for 21.250.  The MFJ 
> analyzer
> > reads 23.000 for a 1-1 match.  I added about 8 inches and the best 
> SWR
> > is at 22.500.  These tests were made at 10 feet.  Will the 
> frequency go
> > down when the beam is at 40 feet?  I can't believe that I have to 
> keep
> > adding to the DE.
> >
> > Tom W8JWN
> >
> > _______________________________________________
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> _______________________________________________
> AN Wireless Self Supporting Towers at discounted prices, 
> See http://www.mscomputer.com 
> 
> Wireless Weather Stations now $349.95. Call Toll Free, 
> 888-333-9041 for additional information.
> _______________________________________________
> Towertalk mailing list
> Towertalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
> 


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