With a 90 foot high apex and the ends supported by 35-foor masts, it will be
possible to maintain about a 90 degree enclosed angle, a good match, a
close-to omni-directional pattern, and increased gain at lower elevation
angles for better DX performance.
If total overall "length" were no consideration, with enough rope, the
anchor points could be at ground level and still have the ends of the
inverted V at 35-feet above ground. With 35-foot high supports at each end
the overall "length" of the antenna will be much shorter.
Yes, in 1960 when I started out I though my 40M dipole at 25 feet worked
pretty well. My "DX" antenna for 20M was #12 wire taped to a cane fishing
pole mounted on the roof with 4 sloping radials and was fed directly with 50
ohm coax. My Globe Chief 90A seemed to be happy with the antenna.
73,
Marsh, KA5M
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Jim
Hargrave
Sent: Friday, August 28, 2015 9:04 AM
To: 'Ham - Tower Talk'
Subject: Re: [TowerTalk] 80 meter inv V
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 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@gvtc.com
>> -----Original Message-----
>> From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf
>> Of Marsh Stewart
>> Sent: Thursday, August 27, 2015 10:16 PM
>> To: 'Marv Shelton' <marvs@att.net>; 'Ham - Tower Talk'
>> <towertalk@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@contesting.com] On Behalf
>> Of Marv Shelton
>> Sent: Thursday, August 27, 2015 9:21 PM
>> To: towertalk@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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