Fox-1 Update – Slow Speed Telemetry

The Fox-1 series of satellites feature a slow speed telemetry, with 200 bps data being sent along with the transponder audio or voice ID activity.  This allows telemetry to be sent continuously during normal transponder operation while QSOs are taking place.

The slow speed data is contained in the audio spectrum below 300 Hz.  Using DSP techniques, high pass filtering is applied to the uplink signal and voice IDs, low pass filtering is applied to the telemetry audio which is generated by the IHU, and the combined audio is sent on the downlink as the voice and data.  Forward error correction added to the downlink stream provides data recovery for up to 1/4 second signal fades.

Fox-1A slow speed telemetry

Screen print of actual Fox-1A downlink slow speed telemetry received over the air on a FUNcube Dongle Pro+ with SDR# and a decoded/displayed with command line version of the AMSAT ground telemetry decoding software used in our testing

The slow speed data on Fox-1A contains four different payload types: Current telemetry readings, High telemetry readings, Low telemetry readings, and Vanderbilt University radiation experiment telemetry.  The payloads are transmitted in a scheduled rotation that delivers one payload or frame about every 5 seconds.  Current telemetry is thus received every 15 seconds, experiment telemetry is received about twice every 15 seconds, and high or low telemetry received once every minute (alternating minutes between high and low).

The telemetry contains many satellite health and operation values, including readings such as solar panel output, battery voltages, temperatures from various areas of the satellite, IHU performance, and the Penn State University MEMS gyro experiment data.

AMSAT will be providing free GUI software for decoding and displaying both slow and high speed telemetry from the Fox-1 series of satellites, as we get closer to launch.  The software will be similar to the user software that was provided for ARISSat-1.

Fox-1A Engineering Unit Testing Videos

A couple of short videos showing some of the Fox-1A Engineering Unit testing are now on YouTube.  Each video is a time-lapse condensation of a segment of testing, to give you a look at some of what is going on.  More videos will be added as Fox-1A moves forward.

A 2 1/2 minute video showing about 25 minutes of testing.

A 3 minute video showing about 30 minutes of testing.

Fox-1 Engineering Unit Back on Test Bench

After a couple of weeks of tweaks and upgrades, the Fox-1 Engineering Unit is back on the test bench in AMSAT VP Engineering NØJY’s shack on July 22, 2014.

A full suite of tests are being performed including on the air use of the transponder. Fox-1 Team members participate in the testing via GoToMeeting and a PTZ IP camera in the NØJY shack, from their homes throughout the U.S.A.

You can read more about the Fox-1 testing process in the July/August 2014 edition of the AMSAT Journal.

Fox-1 Engineering Unit

Fox-1 Engineering Unit

Fox-1 in the Sun

Fox-1 prepares to catch some rays. Just pull the RBF pin!

Fox-1 EU transponder on the air

Fox-1 EU transponder on the air connected to N0JY’s attic antennas. Local hams in Granbury and Hood County TX help with QSOs and signal reports.