This week marks the 45th anniversary of the first operational packet radio repeater! The repeater went live on the 10th of December 1980 and it operated on a frequency of 146.580 MHz
The new packet radio repeater was installed by Hank Magnuski, KA6M (now SK) at his home at Menlo Park near San Francisco.
In a report on the new repeater, KA6M wrote... "Since its initial turn-on in December of 1980, the repeater has been transformed from an experiment to a major Bay Area repeater serving a user group now approaching 30 stations. The repeater has been extremely important in testing new hardware and software, and in provoking interest in the area’s amateur community.
From its initial turn-on in December, 1980, and through most of the Spring of 1981 the packet repeater was operating out of my residence in western Menlo Park, California, a location which is in the foothills which border the western shore of the San Francisco Bay. It was an experimental machine then, but could be heard well through most of the northern end of Silicon Valley, even though the power level was modest. The only station equipped to use it then was located in the same house, so there was never any real problem with signal path.
Since then we have installed a couple of upgrades to the control software, we have used a better CPU card, increased the power level, moved the repeater up to a/00 ft. elevation, and integrated its operation to be 100% compatible with the protocol used by the Vancouver Digital Communications Group’s terminal node controller. The repeater has changed from being a laboratory curiosity to a major Bay Area repeater heard from Marin/Berkeley to south San Jose, and the user community has grown from a couple of stations to a network approaching 30 users. (See the April, 1981, QST for the initial announcement on the machine.)
The KA6M/R repeater is currently operating on a simplex channel assigned (in the San Francisco Bay area) for non-voice use, 146.580 MHz., and transmits data at a speed of 1200 Baud. The machine consists of a Z-80 microprocessor, a Bell 202 compatible modem, and a solid-state transceiver with power amplifier.
The repeater hardware is based on STD bus cards. The STD bus uses 56-pin 4 1/2" x 6 1/2" cards and is very popular. for industrial process control applications. There are now many manufacturers supplying cards for this bus, and the repeater uses the Z-80/CPU-2 card from Mostek, which costs about $195. The STD card is very compact, and does not have unneeded extra circuitry which is typically found on more versatile personal system CPU cards. A WD1933 chip was breadboarded onto a Vector STD board, and one additional card to control the transmitter is all that was required.
A Bell 202 modem uses a mark tone of 1200 Hz., and a space tone of 2200 Hz. The modulation is AFSK-FM using unmodified voice-frequency radio equipment."
From those humble beginnings packet radio would go on to become hugely popular with radio amateurs in the 80's and 90's. It was of course when most people didn't have access to the Internet yet at home and packet gave rise to bulletin boards and dx-clusters all over the radio.
In the late 90's, packet radio waned as more and more people got on the Internet with much higher speeds and a huge variety of content. Packet radio on 2m today is used primarily for APRS - Automatic Position Reporting System.
Links...
1) Internet Archive - ON THE CARE AND FEEDING OF YOUR PACKET REPEATER by Hank Magnuski, KA6M
