[TowerTalk] 80 meter inv V

Robert Harmon k6uj at pacbell.net
Fri Aug 28 13:33:15 EDT 2015


Jim,

I see your point.  I have easy to install (and extend up in the air) telescoping supports for the ends of the V.
I've  found I can go from 10 feet to 38 feet with them.  I am going to test the antenna at 10 foot high
ends and then 38 foot high ends.   I have a ZL friend in New Zealand that will give me the signal 
differences.  It will be a fun test to see what happens.  I have a big Johnson matchbox in line to 
match any increase in SWR.  

Thanks to you and Marsh for the info.  I will let you know the results.

73
Bob
K6UJ



> On Aug 28, 2015, at 7:04 AM, Jim Hargrave <w5ifp at gvtc.com> wrote:
> 
> Another consideration: As you increase the apex angle, the feed
> impedance will increase and the radiation pattern will no longer be
> Omni-directional. A Mismatch can result in offsetting any expected
> gain and the radiation pattern might not be in the desired
> direction.
> An Apex of 90 degrees provides a good 50 ohm match and near
> Omni-directional pattern.
> 
> I have used successfully used Inverted Vs and Slopers for 61 years
> and subscribe to the college of hard knocks: Try it, If it works to
> your satisfaction, be happy. That gives you bragging rights.  In
> 1954 we never heard of EZNEC, but the antennas didn't know the
> difference.
> 
> 73, Jim - w5ifp at gvtc.com
> 
>>> -----Original Message-----
>>> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On
>>> Behalf Of Marsh Stewart
>>> Sent: Thursday, August 27, 2015 10:16 PM
>>> To: 'Marv Shelton' <marvs at att.net>; 'Ham - Tower Talk'
>>> <towertalk at contesting.com>
>>> Subject: Re: [TowerTalk] 80 meter inv V
>>> 
>>> Suppose the ends of the 80M inverted V were each raised to 90
>>> feet - the height of the apex of the original inverted V. The
> apex
>>> angle would increase to 180 degrees and the antenna would be a
>>> flat-top dipole. The elevation angle of maximum gain would
>>> decrease. At elevation angles lower than the maximum gain angle
>>> the gain would also increase. The original post as I understood
> it
>>> was about increasing gain at lower elevation angles for better DX
>>> performance.
>>> 
>>> 73,
>>> Marsh, KA5M
>>> 
>>> 
>>> -----Original Message-----
>>> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On
>>> Behalf Of Marv Shelton
>>> Sent: Thursday, August 27, 2015 9:21 PM
>>> To: towertalk at contesting.com
>>> Subject: Re: [TowerTalk] 80 meter inv V
>>> 
>>> Doesn't the take-off angle increase as the apex angle increases?
>>> 
>>> Sent from my iPad
>>> And YES it's cool!
>>> 
>>> 
>>> _______________________________________________
>>> 
>>> 
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