How to do it... satellite work with one IC-706MKIIG rig

Do you want to work via the modern radio amateur satellite AO - 40 and you only have one ICOM - 706MKIIG transceiver? It's easier than you think.

The prerequisite is the use of a suitable antenna system. For downlink, for example, a satellite dish with a converter (modified to 145 IF) from a digital TV antenna in focus and a suitable antenna for uplink. To connect the TX antenna and the RX converter, it is necessary to use a suitable one on the transceiver side duplexer for example MFJ-916 with sticker 144/440.

It is advisable to modify the connectors on the MFJ duplexer - replace them so that they fit the 706 and rx tx ports, it is also advisable to supplement the duplexer connection with powering the converter with a crossover via the power coaxial cable. You may have some other suitable device with the correct connectors or use adapters according to your needs if you don't want to modify the MFJ.

The secret lies in delaying your own signal back from the satellite. The distance to the satellite and back is roughly 2x 65000 km, which causes a signal delay of about 0.1-0.25 seconds. This time is more than enough to hear your own echo.

Nastavenie transceivera je veľmi jednoduché – prvé VFO nastavte na 145.000 USB pre príjem a nastavte úroveň výkonu na 0 (LOW) ! Druhé VFO nastavte na 435.650 LSB s normálnou úrovňou výkonu. Na prvom VFO vstúpte do menu M1 a stlačte tlačidlo SPL, čím dostanete 145.000 USB a split sa zobrazí na displeji. Stlačte PTT and you will see 435.650 LSB when transmitting TX, release the PTT and you will return to 145.000 USB. Save the specified setting to memory.

Another trick is to find yourself on the passband. First of all, find the satellite beacon signal on 145 MHz and set your receiver about 10 kHz higher. The beacon frequency on the uplink is 435.655 MHz (do not transmit here, you would interfere with the beacon signal), set the transmission frequency about 5kHz lower and transmit briefly (say "hello" for example). Then quickly release the PTT, retune the receiver 1-2kHz down until you pick up your own signal with the reverse delay from the satellite. After capturing the signal, tune the receiver for good readability and that's it.

The author has done many stations from all over the world with this setup and many hams 🙂 were surprised how easy it is to work via satellite. Try this method.

A way to use one coaxial to feed the uplink antenna and the downlink converter with one device, such as IC-706MKIIG. The diagram shows the modified wiring of the MFJ duplexer.