Happy 39th Birthday AO-7 !

OSCAR 7 in Space

OSCAR 7 in Space

On the AMSAT bulletin Board (AMSAT-BB) Paul Stoetzer, N8HM reminds us that November 15 is the 39th birthday of the AMSAT-OSCAR-7 (AO-7) satellite which incredibly is still operational after so many years in space. A tribute to the engineering abilities of radio amateurs.

OSCAR 7 amateur radio satelliteHappy Birthday to AO-7! Launched on 11/15/1974 from Vandenberg Air Force Base.

Continued congratulations to all those involved in the design, building, launch, and operations of this satellite. It’s an amazing achievement that, other than the batteries, most of the circuitry continues to function normally 39 years after launch. Here’s to
hopefully many more years of service to the amateur community!

For more information about the lead-up to and the launch of AO-7, as well as the first years of operation, see the 1974-1981 AMSAT
Newsletters on KA9Q’s website:



N4HY has a wonderful gallery of photos from the construction and launch of AO-7 on his Smugmug page:


Paul Stoetzer, N8HM
Washington, DC (FM18)

Pat Gowen G3IOR in radio shack circa 1975

Pat Gowen G3IOR in radio shack circa 1975

The amateur radio satellite AMSAT-OSCAR 7 was launched by a Delta rocket from Vandenberg Air Force Base on November 15, 1974 and provided many years of service until it went silent from battery failure in mid 1981.

For 21 years nothing more was heard until June 21, 2002 when Pat Gowen G3IOR came across a beacon sending slow 8 -10 wpm CW on 145.973.8 MHz. It sounded like old OSCAR satellite telemetry, it had the familiar HI HI followed by a string of numbers in groups of three. After monitoring by many radio amateurs it turned out to be OSCAR-7, and it seemed to have come back from the dead.

Pat’s email to the AMSAT Bulletin Board announcing his discovery can be seen at

It is believed that in 1981 the batteries failed short-circuit, however, in 2002 they became open-circuit enabling the satellite to run again from the solar panels. Since that day OSCAR 7 has been operational when in sunlight and provided radio amateurs with many long distance (DX) SSB/CW contacts.

Remember when working OSCAR 7 use the least uplink power possible to minimize your downlink power usage, and maximize the number of simultaneous contacts supported in the passband.

A BBC News report Radio ham finds lost satellite about the reception of OSCAR 7 by Dave Rowan G4CUO can be seen at http://news.bbc.co.uk/1/hi/england/2149381.stm

Video of 2E0HTS Working the OSCAR-7 Satellite https://amsat-uk.org/2012/01/26/2e0hts-working-the-oscar-7-satellite/

OSCAR-7 http://ww2.amsat.org/?page_id=1031

AMSAT Bulletin Board (AMSAT-BB) http://www.amsat.org/amsat-new/tools/maillist/