Recently I have been investigating the use of Orbiting Satellites for the purpose of ham radio communications. It is a fun ham activity to make contacts via satellites. Not only is there the romantic notion of sending messages into outer space, but you have to trace the orbit of the satellite with your antenna while tuning the radio, to compensate for the frequency change as it moves toward and then past you.
Working the satellites does not require any expensive investments in equipment, and can be done using a regular 2m/440 HT and a small hand held antenna. It can also be enjoyed by Technician class licenses. I already have the basic resources in my dual band Yaesu FT 60 handheld and a small whip antenna attached. Best antenna for receive and transmit is a dual band Yagi design (beam directional). These can be purchased for a reasonable amount or one could actually make their own quite inexpensively.
An amateur radio satellite is a little like a repeater in space, a station that relays signal over a broad territory because of the height of the transmitter. Normal transmission is line of sight and can be extended via a repeater. I can talk right now to most of coastal GA and a bit of south east SC through our local repeaters. Via a Satellite, I can talk all over the country!
Today, I researched the path of the SO-50 Satellite and at 7:11 this morning it was passing overhead. I was not programmed yet to transmit, but I was able to see some stations! I was excited just to do that! 🙂
The following is taken from the The Radio Amateur Satellite Corporation (as AMSAT is officially known) website.
SO-50 carries several experiments, including a mode J FM amateur repeater experiment operating on 145.850 MHz uplink and 436.795 MHz downlink. The repeater is available to amateurs worldwide as power permits, using a 67.0 Hertz PL tone on the uplink, for on-demand activation. SO-50 also has a 10 minute timer that must be armed before use. Transmit a 2 second carrier with a PL tone of 74.4 to arm the timer.
The repeater consists of a miniature VHF receiver with sensitivity of -124dBm, having an IF bandwidth of 15 KHz. The receive antenna is a 1/4 wave vertical mounted in the top corner of the spacecraft. The receive audio is filtered and conditioned then gated in the control electronics prior to feeding it to the 250mW UHF transmitter. The downlink antenna is a 1/4 wave mounted in the bottom corner of the spacecraft and canted at 45 degrees inward.
The International Space Station (ISS) also has a repeater onboard that hams can use, but occasionally, if you’re lucky, the astronauts turn on their radios to make contact directly with hams on the ground. I will be tracking it also, will attempt to monitor and if conditions are good, you can actually see the Space Station as it passes during it’s orbit.
I have some Ham software on my laptop that allows me to do some tracking and there are plenty of sources available on the internet for that purpose. Hopefully I can getting a little more practice tracking and then I will try a transmission.