John didn't say what bands he was referring to , just VHF. For some reason
I never think of 6 m as VHF. My comments were reference to my 2 m antennas.
6 m is indeed different.
David
----- Original Message -----
From: "Bill W5WVO" <w5wvo@cybermesa.net>
To: "David" <ke4yyd@gtcom.net>; "John Geiger" <johngeig@yahoo.com>;
<vhfcontesting@contesting.com>
Sent: Wednesday, November 29, 2006 6:49 PM
Subject: Re: [VHF] Re: [VHFcontesting] Optium antenna height
> For all VHF bands except 6M, higher is generally better. However, 6M is
> different because it supports short-hop sporadic-E and even occasionally
> F2
> ionospheric propagation. In these modes, take-off angle can come strongly
> into play, with higher angles doing a better job under many circumstances.
>
> Sticking to sporadic-E for the moment, single-hop paths range from around
> 350 miles to around 1400 miles in length, with take-off angles ranging
> from
> 20 degrees down to 0 degrees respectively. A very high 6M yagi will have
> deep nulls in its elevation pattern at various take-off angles, especially
> the higher ones -- and if the station you are trying to work falls within
> one of these null elevations, your antenna will not work well. A lower
> antenna (say, 20 to 30 ft above ground) will often outperform a yagi at
> 150
> ft over (for example) a 450-mile sporadic-E path, while the higher yagi
> will
> outperform over a long-skip sporadic-E path of 1300-1400 miles. This is
> why
> many 6M ops use at least two 6M yagis at different heights, with or
> without
> stacking/phasing arrangements. You can use ARRL's HFTA (or the older YT)
> software to model the elevation pattern (take-off angles) for antennas at
> various heights, with or without taking your own real-world ambient
> terrain
> into account. (To do the latter, HFTA is much more sophisticated and
> useful
> than YT.)
>
> Bill W5WVO
>
>
> David wrote:
>> I don't know John but I started with 30 ft, then 40 ft, 50 ft and now
>> 70 ft and each time it got better.
>>
>> David
>> KE4YYD
>> ----- Original Message -----
>> From: "John Geiger" <johngeig@yahoo.com>
>> To: <vhfcontesting@contesting.com>; <vhf@w6yx.stanford.edu>
>> Sent: Wednesday, November 29, 2006 1:43 PM
>> Subject: [VHFcontesting] Optium antenna height
>>
>>
>>> Another local VHFer and myself were having a
>>> discussion as I was driving to work today about
>>> antenna height for VHF. One thing we wondered about
>>> is if there is an "optium" antenna height for VHF, or
>>> is "higher always better." Is there a point where the
>>> extra height isn't worth the cost of tower, coax, etc,
>>> and the extra loss in the coax-in terms of the
>>> increased distance you will work? Or does extra
>>> height always outweight these other factors?
>>>
>>> 73s John W5TD
>>>
>>>
>>>
>>>
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