Portable EME on 10.368 GHz (3 cm)


As I have some experiance with my 10 GHz rain radar and microwave I want to try EME on 10 GHz. I can use nearly 70% of my 10 GHz rain radar system and Rx should be ready in short time. Again I want to build up a portable, small system. With a 85 cm offset dish, high quality preamplifier, at least 8 Watt Tx power and WSJT-X software it should be possible to get -25 dB signal-to-noise ratio (2500 Hz bandwidth reference) with high quality stations on the other end.







EARTH-SPACE ATTENUATION:

Click HERE, download and extract my Excel sheet "Earth-Space-Attenuation" to calculate microwave earth-space attenuation up to 1000 GHz. Calculation of atmospheric attenuation (ITU-R P.676-12) is included.



1. Offset dish with azimuth/elevation drive

Therefore I use my 85 cm RADAR offset dish with azimuth rotation system.

  


DC motor with encoder for azimuth (0 to 360° degrees)

12V (5A, 5Nm, 40 rpm) worm gear motor (windshield wiper motor) with additional worm gear (20:1) to get 2 rpm.
Torque is approx. 100 Nm.
HH-12 Encoder has a resolution of 12 bit and an accuracy of approx. 0.2° (made by DF1SR).

   



DC linear motor with encoder for elevation (0 to 90° degrees)

Linear motor DSZY1-12-40-A-200-IP65.
Power supply: 12 V/DC
Speed: 8 mm/sec
Stroke length: 200 mm




HH12-inclinometer made by DF1SR.




2. Dish rotor OE5JFL controller

OE2JOM made this controller board based on the OE5JFL original design and ON4BCB updated design.




Controller housing with 20x4 LCD and push button boards:









Test of antenna controller with elevation sensor and linear motor.




3. (W2IMU dual mode or corrugated) feed horn

W2IMU dual feed horn:

Corrugated feed horn:

I use a special corrugated horn designed by Gibertini for my Gibertini dish. As waveguide adapter I use a circular C120 to WR75 adapter.





4. Waveguide switch

In front of the feed horn I mounted a WR75 waveguide switch to minimize signal loss and to have a sufficient decoupling between Tx and Rx. So there is no need to use the SMA switch in my existing 10 GHz transverter.




I use a WR75-WR90 quarter-wave adapter plate to minimize return loss.
Thickness: 10.1 mm
Waveguide dimension: 21.1 x 9.8 mm





5. Transverter

1st solution:
W1GHZ mixer concept, enough for line-of-sight path.

10224 + 144 IF = 10368 MHz

Noise figure : 8-9 dB
Output power : 5-10 mW
Input LO power : 10 mW at 10224 MHz



I use a OE2JOM IF-interface with RX amplifier and TX attenuator. This IF interface is connected to the 2m receiver/transmitter and to W1GHZ mixer.




The LO is a cheap Chinese ADF5355 board controlled by an Adruino Pro-Mini 3.3V/8MHz.

I have done some improvements:
- removed C21, C37 and placed these 2 capacitors between pin2 and 4 of both voltage regulators
- placed 3300µF/6.3V between J1 and ground to reduce phase noise
- placed a SNA-176 MMIC amplifier in front of port B (5V goes to 27 Ohm, after that a 1 nF against ground, after resitor a 10 nH to amplifier output, 2.4 pF blocking capacitor in front of port B) to get approx. 8 dBm output level.




2nd solution:
A used "Simple 10 GHz transverter" designed by DB6NT. It is a design from 1990 but it fulfills my requirements.

Noise figure : 2-3 dB
Output power : 12-13 mW
Input LO power : 10 mW at 2.556 GHz
Power supply: 12 V
Current: 85 mA @Rx, 125 mA @Tx

Transverter with 2.5 GHz oscillator and 106.5 MHz TCXO.






I use a 106.50 MHz OCXO (DF9LN design) with a 2.5 GHz oscillator (DF9LN/DC8SE design) to get 2556 MHz.

106.50 MHz OCXO:
Output power: 0 dBm
Power supply: 8-24 V
Current: 40 mW (700 mA after switch on)



2.556 GHz oscillator:
Output power: 10 mW
Power supply: 9-15 V
Current: 80 mW





6. Preamplifier for 10 GHz

It is an EME-preamplifier made by DB6NT and it has a WR90 connection.

NF : 0.7 dB
Gain: 22 dB





But first Rx tests are possible with a modified LNB (corrugated horn with integrated low noise amplifier and downconverter) in combination with a SDR receiver. I use the model QO-100 Bullseye TCXO LNB (ultra stable LNB for QO-100 and Ku band satellites).





7. Power amplifier for 10 GHz

Not decided at the moment. But I need at least 8-10 W that I can be heard by larger stations.



8. IF receiver/transmitter

Therefore I use the FT-817.



As connection between the DATA, ACC (DIN socket) and the computer I use the Digimode-4-Yaesu cable (with built-in USB sound, USB CAT control).





9. Accu Pack

I use a 12V LiFePO4 accu with 10Ah because of its light weight, only 1.4 kg.



10. Moon noise meter

Either I use a SDR (Airspy, Funcube dongle pro+) with Spectravue software or SDR# software. Other solution could be moon noise meter by DB6NT.



11. Computer and software

WSJT-X


PstRotator

PstRotator works great in combination with my OE5JFL rotor controller. Now I can't track only sun and moon I can track satellites too.



12. Test results

??th of February 2021: It was only a RX test. I tried to hear the DL0SHF moon beacon. Therefore I used a LNB in combination with the Funcube Dongle Pro+ and SDR#
Moon noise was ?? dB.