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

Tue Feb 5 22:50:59 EST 2013

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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