[TowerTalk] 15m monster finally up

[K8RI]

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
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>