It's entirely possible that instead of optimizing your lobe you were
moving a notch.
Dave AB7E
On 3/1/2012 8:27 PM, Bob K6UJ wrote:
> Jim,
>
> I'll look and see if I can find some examples. I plan to dive into HFTA but
> I was hoping to have
> a better idea on this for the SSB contest that begins tomorrow.
> One thing I know for sure is that lowering the beam down to 50 feet made a
> real improvement.
> I'm anxious to do the HFTA analysis, should have a few
> surprises................
>
> tnx,
>
> Bob
> K6UJ
>
>
>
>
> On Mar 1, 2012, at 5:54 PM, Jim Lux wrote:
>
>> On 3/1/12 4:45 PM, Bob K6UJ wrote:
>>> Has anyone used the HFTA program and can tell me the best height for a 15
>>> meter yagi for 6000 miles.
>>> Assuming there aren't any hills obscuring the take off angle.
>>>
>>> The carribean is about 6000 miles from my qth and from experimenting I have
>>> noticed that lowering the beam
>>> down from 90 feet down to 50 feet it is markedly better for 15 meters.
>>>
>>> I just bought the new antenna handbook and plan to dive in and learn how to
>>> do the HFTA myself but was
>>> hoping someone else had an idea of the best take off angle angle for 6000
>>> miles on 15.
>>> I believe 50 feet is about 3/4 wavelength high and gives me a 20 degree
>>> takeoff angle on 15.
>>> Hope this all makes sense, hihi.
>>>
>> There's some example charts in the Antenna Book that might work for you.
>> Pick another path that's of comparable length and see what it says.
>> Europe is about 6000 miles from 6-land, isn't it?
>>
>> What you need to look at is the arrival angle statistics, and there's
>> charts for that.
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