domingo, 10 de febrero de 2013

ES5TV 21 Mhz EME

Es real...? lo que si el nuevo sistema de 8x5 elementos para 15 mts
de ES5TV esta dando de hablar..

After two fruitless attempts at moonrise I got 21 Mhz EME QSO with myself done during moonset with the new 8x5 element H frame antenna.

This 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:

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 time:)

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 

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:


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:

Tower is produced by 4O3A/YT3M:

Antenna has ca 16 dbd free space gain and over 24 dbi gain at 4 degrees over real ground. Beamwidth is less than 30 degrees. Testing confirms 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.

The stack has 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

Photo gallery from the tower erection is here:

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