[TowerTalk] Fwd: 15m monster finally up - EME and Video

Wed Feb 6 10:01:07 EST 2013

There was no noticable shift. I guess that is the case on HF.

73
tonno

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Hans Hammarquist
Sent: Wednesday, February 06, 2013 5:51 AM
To: towertalk at contesting.com
Subject: [TowerTalk] Fwd: 15m monster finally up - EME and Video

How much was the frequency shift due to the moon's movement?

Hans - N2JFS

-----Original Message-----
From: Tõnno Vähk <tonno.vahk at gmail.com>
To: towertalk <towertalk at contesting.com>
Sent: Tue, Feb 5, 2013 8:49 am
Subject: Re: [TowerTalk] 15m monster finally up - EME and Video

Hi,

After two fruitless attempts at moonrise I got EME QSO with myself done during moonset.

Here is the video of the best minute out of ca 10 minute period the signals were audible with strong QSB on January 13th, from 1615 to 1625z ca 2 hours after sunset:

 <http://youtu.be/QCP0kisTbME> http://youtu.be/QCP0kisTbME

Moon was setting at ca 243 degrees azimuth and the signals were audible while the moon was from 3.3 to 2.2 degrees of elevation peaking at 2.6 degrees. Antenna was pointing within 3 degrees of the correct direction.
Radio: FTDX5000 + ACOM2000A.

It is noteworhty that the band was not 100% closed as even some SA signals were heard. Also the amazing strength of the signals at expecially the 3rd time the signals come back is probably also attributable to some ground gain at this elevation.

I wish I had also tried SSB and maybe the 4 high tribander stack for comparison but was too excited to remember. Should also try if changing the radiation angle to say even 30 degrees would allow hearing moonbounce from that elevation. Next timeJ

Now all I have to do is to find someone interested in attempting real 15m EME QSO (anyone done that before?) who would have coinciding sunset/sunrise and high gain antenna on 15m.

Can anyone recommend a good program that would picture moon grayline (like DX Atlas for sun) that would enable to easily identify possible paths for EME at any given time/day?

Here is also the high resolution video of the tower erection put together by ES5PC. It also includes the very first QSO with the new stack with Paul,
K8PO:

http://youtu.be/Z9fDlbIFhMs

I have also made tests regarding the use of different elevation angles (by shifting the antenna pairs 180 degrees out of phase) and the first results are very interesting. Proving that for DX normally the lowest 4 degrees is best but even for DX sometimes 7 or 10 degrees is noticably better bringing an otherwise not audible signal out from the noise. The same is true about some EU signals that peaked at 15 degrees while almost not being audible on low angles. So I will do more testing but I am more convinced now that even in contest the switching of angles might be useful trying to get a weak signal out from the noise and high angles are sometimes very necessary.

73

Tonno

ES5TV

From: Tõnno Vähk [mailto:tonno.vahk at gafm.ee]
Sent: Tuesday, September 25, 2012 9:48 PM
To: towertalk at contesting.com; cq-contest at contesting.com
Cc: es5tv at erau.ee
Subject: 15m monster finally up

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/

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
<http://www.optibeam.info/index.php?article_id=76&clang=1> &clang=1

Tower is produced by 4O3A/YT3M: 

http://www.4o3a.com/index.php?option=com_content
<http://www.4o3a.com/index.php?option=com_content&view=category&layout=blog&
id=99&Itemid=499> &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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