Marsh,
That sounds very worthwhile then to raise the ends ! I have several TV type
push up masts
that are lying there waiting to be used. I think they are 30 feet fully
extended. I think I will
slide in a 5 foot section of conduit in the ends and go for the 35 feet. That
comes to
2.17 dBi improvement then, thats great.
Thanks Marsh for running the EXNEC calculation. Much appreciated !
73,
Bob
K6UJ
> On Aug 27, 2015, at 1:12 PM, Marsh Stewart <marsh@ka5m.net> wrote:
>
> For an 80M inverted V with the apex at 90 feet, ends 10 feet above ground,
> and an inside angle of about 90 degrees, EZNEC+ 6.0.6 calculates -3.47 dBi
> gain at a 15 degree takeoff angle. Moving the ends up to 30 feet above
> ground improves the gain to -1.67 dBi at a 15 degree takeoff angle - a
> little less than 2 dB improvement. Moving the ends up to 35 feet above
> ground increases the gain to -1.31 dBi. That's more than a 2dB gain
> improvement at a 15 degree takeoff angle over the ends at 10 feet above
> ground. Tom N6BT wrote in his book that "the amount of difference in an
> antenna system that makes a significant performance difference....is 2 dB".
>
> 73,
> Marsh, KA5M
>
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
> Robert Harmon
> Sent: Thursday, August 27, 2015 1:44 PM
> To: Ham - Tower Talk
> Subject: [TowerTalk] 80 meter inverted V
>
> I have an inverted V strung from my tower for 80 meters. The apex is at 90
> feet and the ends are supported by 10 foot poles at the corners
> of my property. The inside angle of the V is about 90 degrees. I am
> considering extending the poles to 30 feet high which would make the
> angle about 120 degrees. For DX do you think this would be worth the effort
> ? The radiation pattern has to be improved but but maybe not
> that much ?
>
> Bob
> K6UJ
>
>
>
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