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EME : Thanks to Rasto, OM6AA Thu, 8 Mar 2007
Posted by big-dish on 2007/3/8 10:36:13 (1881 reads)

Hello Mike,

congratulation to the excellent project and performance of your 8N1EME station to you and to all of your participants. Here, in Czech and Slovak republic your station has attracted a lot of attention among VHF and UHF ham-radio community. It was a challenge for us to work on such splendid project. We are also very glad, that our designed feed and loops have worked as predicted. We think, that your "marketing" (publicity, education etc.) was also excellent. Your web-site is very nice. We guess, that your transmition from KDDI has been not only ham radio event but also function.
Mike, as we have already informed you, we would like to write some article about design of used feed systems and their construction. We think, that using a dish antenna as prime feed for Cassegrain system is unique solution worth to describe in an article for European Conference on Antennas and Propagation in Scotland or for DUBUS magazine. Also, we appreciate any measured datas of KDDI system applied for ham radio bands, if you have any to share with us.

Rasto, OM6AA behalf of Mr. Hazdra- CTU & Milan, OM1ATT
Dear Rasto, OM6AA:

I would like to report you with great pleasure that the performance of IBA-4 EME antenna was surperb.

As we expected with the simulation, the SWR and beam pattern on each band are satisfactory.

The idea to use loop feed for low bands using the subreflector as a ground plane seems to be the best and ideal, and contributed a lot for multi-band operation of this big dish.
Marionette sytem also contributed for the best performance to maintain the best position of the feed and the impedance matching during the experiment.

Small dish feed to illuminate the subreflector worked satisfactory. I wonder if someone can expect the better performance with some other methods.

We worked about 300 QSOs in total on 144, 432, and 1296 MHz, including some small stations. Detailed QSO data will follow soon.

Unfortunately the restriction on the dish operation maintained by the KDDI staffs limited the data collecting, even though the degree of their dedication to the project is uncountable.
We measured the Sun noise, twice on each band, once by tracking the Moon, and another by watching the Moon with fixed antenna position, on 144, 432, and 1296 MHz.
The data will be reported later.

We are very pleased to see the cover page of the recent DUBUS magazine, 1/2007.
Most of the cover boys are involved in the BIG-DISH operation.
They dedicate a lot for the activities of the BIG-DISH project.
It is our pleasure also to find in the same issue, your theoretical article on septum feeds.

We performed slide lectures and open-house experiment on March 03, with some 100 attendants. Several school boys and a girl came to the IBA-4 EME class on 1296 MHZ, to listen to the echoes of the anouncement of their names by USA EMEers.

In spite it was after mid-night, Al K2UYH, Wayne K9SLQ and J. K5JL came in the EME class. Their efforts contributed a lot to our educational activities of the project.

An eleven-year boy with the first class amateur license (!) joined us to contact with K5JL on 1296 SSB. Perhapse this is the world record of the EME operation by the youngest amateur.

By now all of the antenna feeds are removed for the next experiment on 5760 MHz on March 24. Already we heard our own echo on this band, not strong but very clear. I think we need more receiver gain, or adjust the antenna position more
exactly. This could be the most difficult work in the operation.

We would kindly offer you the most heartful thanks to you and your engineering staffs of Czech Technical University.
The round septum feed of 1296 MHz, made by OM1ATT, showed the best performance for our BIG-DISH system.

Our activities are reported on occasion at:

Pelase listen to the booming echoes with 32-m cassegrain at KDDI Ibaraki Sattelite Communication Center, closing their operation by the end of March 2007.


Mike Watanabe, JH1KRC
8N1EME/Project BIG-DISH 2007

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