April, 2013 | EB3FRN

In the middle of 2009 I bought a 26GHz transceiver to use in amateur-DSN. It was to try to receive the 25GHz downlink of the Lunar Reconnaissance Orbiter spaceprobe. After much time without succes and after the confirmation of Paul J Marsh, that he never has received the probe too I decided give a new life to the module and try to use in 24GHz amateud band.

Thales TGTR-26 trasnceiver

The module is a THALES TGTR-26 and googling a bit, looks the some Autralian amateurs are using the module without problems. The first was get a suitable local oscillator , this unit should accept a frequency range from the 10 to 14Ghz. The idea is ise a IF of 1.3Ghz then need a LO over 11.45Ghz. Using the cavity and electronics of a Magnum MC PLS22 that accepts 10MHz input reference and the SRD and output filter of a Magnum MC PLX31 that cover from 10.4 to 10.7GHz, I put all totgether and after retuning the SRD I get a nice brick of 11.36 GHz, pefect to use as LO.

Magnum brick oscillator

The TGTR-26 uses +5V (1A),-10V and +8V to enable the TX branch. One time solved the power issues, the unit was start to receive very well, giving a conversion gain of 29dB aprox. To test the RX branch I was use the Marconi / Aeroflex 6203 microwave test set as signal reference.

RX Test setup

Marconi 6203 tuned at 24.050GHz as RX reference

Marconi 6203 tuned at 24.050GHz -90dBm

IF at at 1.3Ghz, signal at -63dBm

After to verify the good results of the RX branch, is the time of the TX branch. To put the transceiver in TX only need aply +8V in the TX pin. The result was amazing, receiving peaks of 32dBm, it can be more than 1.5W! This test has ben used a 10dBm IF at 1.3GHz.

TX Setup

Signal generator as TX IF

TX Signal plot

TX Image signal plot

The unit is suitable for amateur use in 24GHz. Really amazing how this modules that can be purchased in ebay and can be recycled to give a new life.

One of my challenges is detect a pulsar using my small dish antenna. The pulsars are vey weak radiosources and not easy to get for the amateurs, maybe be the most difficult signal to detect. The only way to detect the strong pulsars with my antenna is using a massive bandwith. Looking the sdr radios market dont find any radio that give-me more than 20Mhz of BW inside of the PC to process it, the trouble is the bootleneck is the USB and Ethernet. But in the middle of 2012 appears a new sdr radio called PHI from a young canadian company called Pervices. Looks that can give me the bandiwth that I need to detect pulsars.

The PHI / Notcar is a 8x PCI-E with two 125Msps ADC and one 250Msps DAC handled by a Altera FPGA. The card gives up to 250Mhz of bandwitdh and a throughput of 5Gbps. The card have two RX branches one working in base band with real type signal ideal for IF, and a I/Q type signal in a direct conversion setup that covers up to 4GHz.

The PHI SDR card

The most important before to start the card, is get a very power PC. You will need a lot of horsepower to process the high samplerate that handle the card. In my case I’m using a Intel I7 3770k that is performing very well.

The first impression is very good, is a card with a lot of potentail, but is important to say that it not is a plg&play finished product, really is a open development platoform. To get good results, you will have to put a good rf frontend.

This are the screenshots of my firsts tests: