looks like my distance I was using is way off, I'll
digest this info and see what I come up with.
Very interesting, I knew there would be suprises, hihi
thanks Jim
Bob
K6UJ
On Mar 1, 2012, at 6:24 PM, Jim Lux wrote:
> On 3/1/12 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?
>>
>
>
>
> Here's the antenna book data for LosAngeles to EU (LA to Paris is about
> 6000 mi). It looks like you want an angle around 3-5 degrees, and maybe
> a bump around 8-10 degrees. These numbers come from VOACAP, I believe,
> so you could get a copy of that load it up, and run it for your link.
>
> HFTA would then tell you how high to make the antenna to make that first
> big lobe at 3 degrees.
>
> Los Angeles, Ca to Europe
> Elev 80m 40m 30m 20m 17m 15m 12m 10m
> 1 2.5 6.6 4.1 6.8 4.8 1.8 0.0 0.0
> 2 4.1 9.1 10.8 6.7 9.6 4.9 4.6 5.6
> 3 4.2 7.0 15.3 13.7 17.5 20.2 6.2 0.0
> 4 10.2 11.2 10.8 7.8 13.6 13.5 9.2 0.0
> 5 6.2 10.2 14.2 5.1 5.6 12.3 15.4 22.2
> 6 1.7 6.6 12.0 8.3 7.1 6.7 9.2 16.7
> 7 3.5 3.3 8.1 8.6 6.8 7.4 9.2 16.7
> 8 3.5 4.6 5.3 11.4 9.3 9.8 13.8 11.1
> 9 9.3 5.6 2.7 10.0 7.6 9.2 13.8 22.2
> 10 5.4 11.2 1.6 5.0 6.5 4.9 9.2 0.0
> 11 5.2 6.5 4.4 5.0 3.4 3.7 3.1 5.6
> 12 3.5 2.5 4.1 5.0 1.7 1.8 1.5 0.0
> 13 7.5 1.0 2.8 2.1 2.8 1.2 0.0 0.0
> 14 6.0 1.6 0.7 2.3 1.4 0.0 0.0 0.0
> 15 4.6 4.5 0.4 0.6 1.4 1.8 3.1 0.0
> 16 2.9 3.3 0.1 0.4 0.6 0.0 1.5 0.0
> 17 4.3 2.4 1.2 0.5 0.3 0.6 0.0 0.0
> 18 4.6 0.2 0.4 0.5 0.0 0.0 0.0 0.0
> 19 3.4 0.7 1.1 0.4 0.0 0.0 0.0 0.0
> 20 1.6 0.6 0.0 0.0 0.0 0.0 0.0 0.0
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|