[aprssig] APRS protocol replacement ideas: protobuf

Steve Dimse steve at dimse.com
Sat Feb 12 14:04:57 EST 2022

> On Feb 12, 2022, at 1:44 PM, Dana Myers <k6jq at comcast.net> wrote:
> On 2/12/2022 10:18 AM, Andrew Pavlin via aprssig wrote:
>> That was one of the reasons for Mic-E: to have the packet take as few bits as absolutely possible while still complying with AX.25 and still sending something useful.
> Is that really a reason for Mic-E? I thought it was to fit an APRS encoder into a microphone,
> but admittedly I wasn't paying attention at the time.

I think Andrew was talking about the reason for the Mic-E _protocol_, it was indeed to be as short as possible. The idea behind the Mic-E _hardware_ was it would go between the mic and the radio (either built into the mic as Bob's original version or as a separate box as in the TAPR version), and send a position/status packet when the mic button was unkeyed. The desire to keep that data burst (which was audible to repeater users) as short as possible was the reason Bob kludged the protocol so much.

Bob dealt alone and in secret with Kenwood when they did the D7, and he got them to adopt the MicE format. Before that there were very few MicE packets on the air. I created the base91 protocol as an alternative that was about the same length and much cleaner, but because Bob dealt with Kenwood it never got traction there.

Steve K4HG

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