By Stephen McBain (M????) Disclaimer: Not Claiming to be an expert Amateur Satellites By Stephen McBain (M????) Disclaimer: Not Claiming to be an expert Amsat wiki: https://en.wikipedia.org/wiki/AMSAT

What’s the biggest satellite orbiting Earth?

What are Man Made / Artificial Satellites? Equipment launched into space either into earth orbit or to other planets or objects of interest. Used for: Communication (TV, Sat Phones, Military, Navigation Amateur, Telemetry relay) Earth observation (Weather, Surface Imaging) Scientific Research (ISS, Atmosphere monitoring)

Satellite Orbits HEO – high elliptical orbit, typically a few hundred kilometers altitude at its closest to Earth, and 40,000km or more at its furthest point. The orbit describes an ellipse. LEO – low earth orbit, typically 1000km in altitude in a near-circular orbit that usually passes near or over the poles. GEO – geostationary or geosynchronous, typically 35,800km in altitude and its orbit in synchronized with the Earth’s rotation. Many of our amateur radio satellites are LEOs and typically take about 100 minutes to complete each orbit. The International Space Station is a special case being a Super LEO at only 300km altitude and an orbital period of 91 minutes. Without a regular boost from the supply vehicles, the ISS would fall back to Earth. Geostationary: Above equator, always in the same position in the sky whatever time you look. Geosynchronous: orbital period matches earths rotation but the orbit can be inclined at any angle. Meaning it will be in the same place at a specific time of day.

Amateur Radio Satellites An amateur radio satellite is an artificial satellite built and used by amateur radio operators but are usually included as a secondary payload on other satellites or as a Cube Sat. Many amateur-satellites receive an OSCAR designation, which is an acronym for Orbiting Satellite Carrying Amateur Radio. The designation is assigned by AMSAT. Most satellites are referred to just by their Oscar number. Variations of the Oscar code are used, EG. AMSAT-OSCAR 92 (AO-92) & Saudi-OSCAR 50 (SO-50).

Types of Amateur Satellite SSB / CW Satellites: Listens on a range of frequencies on one band, translates those signals to a different band, and retransmits them in real time. By convention, the lower one third of the band is used for CW and data modes, leaving the remainder for voice and other analogue modes. Transponder Passbands: Linear: TX goes up, RX goes up Non-Linear: TX goes up, RX goes down Inverting: USB on TX, LSB on RX http://www.pe0sat.vgnet.nl/satellite/sat-information/passband/ Repeater (FM): Just like ground based repeaters, repeater satellites listen and transmit on a specific pair of channels. Satellite repeaters are cross band, meaning that their input and output frequencies are on different bands. Transponder / Multi Mode Example Non-Linear Inverting TX (USB) 145.930 145.920 145.910 145.900 RX (LSB) 435.220 435.230 435.240 435.250 Data / Digital: You can access both types of digital satellites by using regular packet radio protocols and equipment. The International Space Station (ISS) has an onboard APRS digipeater. Telemetry: Many of these satellites also transmit telemetry along with the audio. This can be decoded by software on your computer. Link: http://www.pe0sat.vgnet.nl/satellite/sat-information/passband/ Telemetry: Either on a separate frequency or the same as the voice downlink in the case of most FM satellites.

Antennas Working Satellites can be done with just a hand held with a stock antenna. A small collinear can also be used. Beams can be used on a simple azimuth rotator or with an azimuth elevation rotator. Hand held Crossed Yagi popular. http://www.arrowantennas.com/ A small collinear can also be used. (larger the collinear the more focused at the horizon) Beams can be used on a simple azimuth rotator. (Recommend installing Yagi's with slight elevation, 10o if used specific for satellite work)

Working the ISS Digipeter

Doppler Shift Due to the high orbital speed of the amateur-satellites, the uplink and downlink frequencies will vary during the course of a satellite pass. This phenomenon is known as the Doppler effect or Doppler Shift. This is the same thing that happens when the siren on an emergency vehicle appears to change note as it drives past you at speed. The faster the change in distance between you and the satellite the larger the affect. Don’t get this confused with change in the satellites orbit speed. It is the closing speed between you and the satellite.

Doppler Shift While the satellite is moving towards you, the downlink frequency will appear to be higher than normal. Meaning you will have to tune higher than nominal. Meanwhile… The satellite will be receiving your uplink signal at a higher frequency than normal so your transmit frequency must be set lower in order to be received by the satellite. When half way through the pass the uplink and downlink frequencies will reach their nominal values. After the satellite passes overhead and begins to move away, this process reverses. The downlink frequency will appear lower and the uplink frequency will need to be adjusted higher.

http://galileoandeinstein. physics. virginia http://galileoandeinstein.physics.virginia.edu/more_stuff/flashlets/doppler.htm Link: http://galileoandeinstein.physics.virginia.edu/more_stuff/flashlets/doppler.htm

Large Doppler shift Larger change in frequency. Frequency changes quickly as it passes over.

Small Doppler shift Small Change in Frequency. Frequency change is slower as it passes over.

Doppler Shift 70cm affected more the 2m. 23cm more than 70cm. 70cm can be +/- 10khz 2m usually +/- 3khz If using a radio a radio with minimum 5khz steps, 90% of the time you will not need to adjust the 2m frequency due to it being on average only +/- 3khz.

DON’T FORGET TO PROGRAM THE CORRECT CTCSS TONE WHERE REQUIRED Use Channel Memories M1 M2 M3 M4 M5 DON’T FORGET TO PROGRAM THE CORRECT CTCSS TONE WHERE REQUIRED Fox Sats are 67.0hz SO-50 is 67.0hz but requires the timer arming using 2sec carrier with 74.4hz tone.

SSB/CW Tuning Best to use CAT control. Manual control. This way your receive and transmit frequencies (At the Satellite) will remain fixed. You can also now specify the receive frequency (At the satellite) for an arranged QSO or an empty space you have found and the software will apply the Doppler shift’s that are required. Manual control. If CAT control isn’t an option the recommended method is to tune the highest frequency, whether that be you TX or RX, during your QSO then correct the lowest between QSO’s. This isn’t perfect but is better then nothing. Not correcting at all with cause your transmission to drift across the passband of the satellite over the top of everyone else's QSO’s.

RX Practice To practice all you need is a simple FM radio in the 2m or 70cm band. This can be as simple as a handheld with a rubber duck. AO-91 & 92 have a down link on 2m. SO-50 has a downlink on 70cm (bit trickier to receive as uses a lower TX power). If you have a radio that will tune down to 137MHz then weather satellites can also be heard. (As explained in Adrian’s Talk on Data Modes)

Satellite list (https://amsat-uk.org/) Link: https://amsat-uk.org/

Tracking and Frequencies N2yo.com AMSAT website. Frequencies usually listed on the specific page for each Satellite.

Tracking and Frequencies Android/Apple: ISS Detector, Amateur satellites Add-on required for ones other than the ISS. PC: Orbitron (possible to connect to radio for auto frequency control)

Upcoming / New Satellites Es’hail 2 FIRST AMATURE SATELITE IN Geostationary orbit. DATV 2.4Ghz up, 10.2Ghz down. Launched: 15th November. Will be in commissioning phase possibly till new year. Fox-1C (Cliff) FM Launch: DELAYED TBC 1st December Launch. Will be in commissioning phase. Other upcoming Launches (Same rocket as Fox-1C): ExseedSat-1 JY1-Sat KNACKSAT ESEO (FunCube4) Other upcoming satellites: Diwata 2 (Downlink 145.900MHz, Uplink 437.500MHz) Launched and available for use soon.

Thanks for Listening Any Questions?