I have finished a complete Rotor-Control-System for the unusual EGIS rotor, which has been lying around for several years over here and was mechanically rebuild last year by me and now it has a new life. Itís carrying a 2 Meter dish from the German Air force 7 Meters up in the air. (To small for big EME, but thatís all I can have over here in our community) Since two years I have been working on a new 10 GHz "small" EME system for my self and all by myself. More about DC9UP @ dc9up.de
I am able to get a position accuracy less then 0,05 degrees from the rotor (VE1ALQ encoders + F1EHN tracking interface ). The biggest problem on the rotor was the non-linear behaviour (mechanically fixed) in the ELV axis. This was cured by an translation EPROM between encoder and the 16 bit parallel ELV input after a long and hard fight to get the right correction-table calculated by EXCELL. So far I know I am the only one which learned this kind of rotor turning the right way..hi.

The other parts of the "small" EME Stn are:

  • LO 106,5 MHz steered by a Rubidium and a design by F5CAU, which makes 106,5 out of 10 MHz from the RB. The RB is long-time monitored by a GPS RX and a Brooks Shera controller. The QRG on 10 Gig is in the order of < 2 Hz.
  • A homemade noise-amp. with a bandwidth of 5 MHz is used for moon-noise and sun-noise measurements, also for peeking the rotor in case of small rotor errors. The noise-amp has a Voltage to Frequency converter built in for audible search.
  • A FERISOL mV Meter connected to the IF in the DSP-10 TRX can be used for fast direction-finding during terrestrial work.
  • But the heart of the whole system is my fantastic DSP-10 TRX developed by Bob Larkin W7PUA. With this TRX I can "see" into the noise by more then 27 dB.
  • Transmitting is done by a DB6NT converter and a PWR Amp with 18 Watts from DL2AM.
I know this is not a "big" EME Stn, but this is all I could do so far under all circumstances. Last week I finished the Shepard Crook for the dish and after fast adjustments, I made my first QSOs on rainscatter.
Then all at sudden I started thinking to give the moon a try. With only 10 Watts (not to overdrive the PA) I started the mode EME2 with my DSP-10. EME2 mode is transmitting automatically for 2 secs and then listening to the return from the moon, calculating the result and then transmit again. So on as long as I wish. The integration after some minutes showed up in the waterfall screen and I opened up a bottle of Champagner.....


DC9UP - Hermann