What is the SO-50 uplink frequency?

SO-50 listens on 145.850 MHz (FM).

What is the SO-50 downlink frequency?

SO-50 transmits on 436.795 MHz (FM).

When does SO-50 pass over my location?

Open SO-50 on the live map and enter your Maidenhead locator or use GPS: the tracker lists the passes of the next 24 hours with AOS, maximum elevation and LOS, and shifts the frequencies for Doppler.

SO-50 (SAUDISAT 1C): Frequencies, Status & Passes

Next passes over your station

Pass times depend on where you are. Track SO-50 on the live map to see its next passes over your station.

SO-50 frequencies

Uplink	Downlink	Beacon	Mode
145.850 MHz	436.795 MHz	—	FM

Nominal frequencies, without Doppler. The live map shifts them for your station during a pass. Frequencies: SatNOGS DB (modified: working amateur transmitters only, in MHz), CC BY-SA 4.0.

About SO-50

SO-50, also known as SaudiSat-1C, is one of the most popular FM repeaters in orbit and the satellite many operators make their first contact through. It was built by the Space Research Institute of King Abdulaziz City for Science and Technology in Riyadh and launched on 20 December 2002 on a Dnepr rocket from Baikonur.

The repeater listens on 145.850 MHz FM and needs a 67.0 Hz CTCSS tone. It has a 10-minute timer that must be armed before use: at the start of the pass, send about two seconds of carrier with a 74.4 Hz tone, then switch back to 67.0 Hz. The repeater then stays on for 10 minutes. The downlink on 436.795 MHz is weak, around a quarter of a watt, so a handheld Yagi such as an Arrow or Elk antenna works much better than a rubber duck.

On 70 cm the Doppler shift reaches about ±10 kHz. Start the pass about 10 kHz above the downlink frequency and step down in 5 kHz steps as the satellite passes over. SO-50 is busy on weekends and during Field Day: call once with your callsign and grid locator, listen, and keep each exchange short so others can get through.

Status

Active: amateurs reported hearing SO-50 on AMSAT 3 h ago.

From reports filed on AMSAT, last 30 days.

Orbit

Type	Low Earth orbit
Altitude	571–667 km
Inclination	64.6°
Period	97.1 min
TLE epoch	2026-10-28 10:59 UTC

Orbital elements: CelesTrak, checked every 3 hours.

Questions about SO-50

What is the SO-50 uplink frequency?: SO-50 listens on 145.850 MHz (FM).
What is the SO-50 downlink frequency?: SO-50 transmits on 436.795 MHz (FM).
Is SO-50 active?: Active: amateurs reported hearing SO-50 on AMSAT 3 h ago.
When does SO-50 pass over my location?: Open SO-50 on the live map and enter your Maidenhead locator or use GPS: the tracker lists the passes of the next 24 hours with AOS, maximum elevation and LOS, and shifts the frequencies for Doppler.

SO-50