[TowerTalk] 15m monster finally up

[n8de at thepoint.net]

Considering that 40m is 3 times 15m in wavelength +/- a smidge, looks  
like 210m tower to me.
Gotta win the lottery two or three times to do that one!

73
Don
N8DE


Quoting K8RI <K8RI-on-TowerTalk at tm.net>:

> On 9/25/2012 2:47 PM, Tõnno Vähk wrote:
>> I am happy to inform all friends that a project of last 4-5 years was
>> completed during the last weekend at ES5TV KO38CS central ES QTH and a
>> double H frame on 15m was finally erected what is probably one of the
>> biggest 15m setups in the world today.
>>
>>
>>
>> See the full 2-day gallery at:
>>
>> http://pontu.eenet.ee/es5tv/
>
> Impressive!
>
> I wonder how well that'd scale to 40 meters and what tower height would
> be required.
>
> 73
>
> Roger (K8RI)
>
>
>>
>>
>>
>> Go to the last 16th page if you wish to see the final product right awayJ
>>
>>
>>
>> 70 meters high tower carries 8 5-element 15m yagis as pairs separated
>> horizontally by 12 meter distance and vertical stacking is 14 meters. The
>> heights of the antenna pairs are 64, 50, 36 and 22 meters.
>>
>>
>>
>> Antennas are Optibeam OB5-15:
>>
>> http://www.optibeam.info/index.php?article_id=76&clang=1
>>
>>
>>
>> Tower is produced by 4O3A/YT3M:
>>
>> http://www.4o3a.com/index.php?option=com_content&view=category&layout=blog&id=99&Itemid=499
>>
>>
>>
>> Model shows ca 16 dbd free space gain and almost 24 dbi gain at 4 degrees
>> over real ground. Beamwidth is less than 30 degrees. Testing has been so
>> far limited but the results confirm exactly the modelling results. Pattern
>> measured with signal generator and SDR was almost identical to what the
>> computer suggests and signal levels drop ca 12 db when antenna is 20
>> degrees off and already 20 db when 25 degrees off the correct direction.
>> There is huge -50db+ null at 90 degrees confirmed with real measurements
>> (!) and ca -20-30 db signal drop on the other directions.
>>
>>
>>
>> First comparisons with my best antenna so far (4 high tribander stack) show
>> ca 10 db advantage to US when pointed right. That is huge of course.  At
>> the same time east coast and west coast can´t be covered with one directionJ
>>
>>
>>
>> The stack will have phase switching capability which allows any pair of the
>> 4 to be switched out of phase to change the radiation angle. Pre-configured
>> steps are 4, 7, 10, 15, 30 degrees while maintaining most of the gain as
>> all antennas are always connected. The phase switching is not yet connected
>> but will be very interesting to see the results and to get some real
>> insights into how the different angles play.
>>
>>
>>
>> We briefly tried to hear the moonbounce when the moon was on horizon but
>> did not succeed yet. But 15m was wide open and signals probably did not
>> penetrate the ionosphere. I still hope to be able to complete some EME QSOs
>> with the stackJ
>>
>>
>>
>> CQWW RTTY on the coming weekend will be the first contest for the monster.
>> Let me know how ES9C will sound on 15 meters. As the rotating is still
>> manual will keep it either to US or JA.
>>
>>
>>
>> 73
>>
>> Tonno
>>
>> ES5TV
>> _______________________________________________
>>
>>
>>
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>
>
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