24 GHz transverter

My 24.048 GHz transverter is an easy and cheap solution with less Tx power. I use an old mixer design made by Michael DB6NT.
Only a few parts are needed. A 12 GHz module, harmonic-mixer module, IF transmitter/receiver and an antenna.





Click on image, download and extract my Excel sheet "Link budget v2.1" to calculate microwave links up to 1000 GHz. Calculation of atmospheric attenuation (ITU-R P.676-12) is included.

1. Offset dish and tripod with pan/tilt mount

Same design as for my 76 GHz transverter and pan/tilt head.

2. W2IMU dual mode feed horn

hdl_ant software by W1GHZ is a good choice to calculate a dual mode feed horn. It is a circular wave guide with a diameter of 10.1 mm and the aperture is 19.4 mm (depth of 30.6 mm).
Wave length = 12.5 mm
WR-42: 10.7 x 4.3 mm

3. Transverter

1st version: MK II transverter

I use this mixer design from the 90s of last century.
RX NF = 8 dB (DSB)
TX power max = 0.5 mW (SSB), 1.3 mW (DSB)
To get maximum TX output use short diode leads, mount both diodes "overhead" and flat on the PCB. I used flags between diodes and waveguide pin. I reached 0.85 mW (DSB).
Needed external reference power is approx. 25-60 mW (14-18 dBm) @ 12 GHz
11952 * 2 + 144 IF = 24048 MHz









NORT PLL with arduino, transceiver with dual mode horn:




2nd version: MK III transverter

Again a DB6NT transverter with coax output. Size is only 44 x 24 mm and a I made a small aluminium housing 50 x 30 x 18 mm. Same performance as MK II.
Power consumption: 20 mA @12V

4. PLL with 11952 MHz output

1st solution:

I use a modified NORT PLL to obtain 11952 MHz for the transverter input. I removed the internal 20 MHz quartz and mounted a SMA connector which is an external reference input now.
See more under electronics.
Output power : 13 dBm



ADF4153 parameters for reference frequency of 20 MHz. VCO output is 2988 MHz and this gives 2988 *4 = 11952 MHz for our mixer.



I prefer 23.715 MHz as reference frequency. The reason is that I use output B (locked to output A) of my GPSDO for my 76 GHz transverter and output A for my 24 GHz transverter.




2nd solution:

LO/2 power could be higher to get more power for the mixer and 24 GHz output. I built a 12 GHz LO module designed by DB6NT.
11.952 GHz ouput: 70 mW (18.5 dBm)
Current consumption @12V: 220 mA

5. New system with preamplifier, power amplifier and cavity filter

DB6NT preamplifier:

Noise figure: ~2 dB
Gain: 24 dB
Current consumption: 60 mA

Power amplifier module:

I got this modified Ceragon REMEC ED-0416 PA module from OE2JOM. Gain is extremely high and therefore a low cost/performance transverter with low output power is sufficient.
Gain: ~50 dB
Output power: ~1.5 W

OE9PMJ cavity filter:

I got this used cavity filter from OE5VRL.

Assembled system:

6. GPS disciplined reference oscillator to set PLL reference input

Here I use a nice unit by Leo Bodnar. It has 2 separate outputs (3.3V CMOS level) from 450 Hz to 800 MHz and it uses GPS reveiver for very stable output frequency.
Output power up to 13.7 dBm
Current consumption @ 12V DC: 190 mA

7. IF receiver/transmitter

Therefore I use the good, old FT-290R.

8. Accu Pack

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

9. Test results

8th of November 2019: First successful 24 GHz (SSB, FM) test QSO.