[ih] Comments re the packet radio discussion (Ham Radio branch)

[Ulrich Speidel]

I was wondering when someone would bring the ham radio / AX.25 side up. 
It's what got me into digital comms in the late 1980's. Amateur packet 
radio at the time had started out with terminal node controllers (TNCs) 
making their way predominantly from the US to other parts of the world, 
but these had their own processor and thus were a bit on the expensive 
side for a lot of poor hams (like us students).

Well, I struck it extremely lucky as a student at the University of 
Erlangen-Nuremberg: One of the members of the uni radio club was 
Johannes Kneip DG3RBU, the hardware guy behind the BayCom team ("Bay" 
having nothing to do with San Fran, by the way, it's short for "Bayern", 
i.e., Bavaria for short, where all the team members hailed from).

The BayCom modem cut the cost pretty much to about a third as it was a 
pure modulator / demodulator connected to the RS-232 interface of a PC, 
which ran all the logic. To do so, the BayCom software repurposed the 
handshake lines of the RS-232 into the packet data lines and ran all 
packet assembly / disassembly and AX.25 protocol shenanigans in 
software. Cost aside, another advantage of this approach was that 
software upgrades didn't require the ability to flash an EPROM.

The main modem model was a 1200 Bd one for VHF and UHF, although a 300 
Bd version for HF existed also. Later they also came up with 9600 Bd 
versions for 70 cm and 23 cm transceivers with slightly widened bandpass 
filters.

On the eve of my departure from Germany to NZ, Johannes took me aside 
and gave me a floppy disk with the latest software and a circuit 
diagram, and said "I understand that there are a few people down in NZ 
who are interested in this, feel free to spread and share".

Little did I know what a wild ride I was in for. I got my reciprocal ham 
radio license a couple of days after arrival and the next day found 
myself in the office of the callsign trustee of the (at that time 
dormant) Auckland University Amateur Radio Club, the inimitable Gary 
Bold ZL1AN (aka NZ's "Morseman").

We got chatting, I walked out of the office as the acting club 
president, but most importantly Gary hooked me into the local ham 
community. Within a few weeks I was fielding responses from hams at the 
other end of the country who would send me self-addressed stamped 
envelopes with old floppy disks asking for the latest copy of software 
and circuit diagram.

I ended up supporting from the German manual, but it became apparent 
quickly that this wasn't scalable - so I ended up producing an English 
translation which found its way around the world. One of the local radio 
clubs produced a NZ circuit board and kitset with case and became the 
official BayCom distributor in NZ. Before we knew it the BayCom user 
community in NZ had grown from a few hardy souls to a few hundred, and 
it kept going strong for quite a few years beyond the 1990s.

Ulrich ZL1DDL / DL1NDB

On 23/04/2026 12:13 am, Lawrence Stewart via Internet-history wrote:
> Jack Haverty’s story is great.
>
> I hadn’t made the connection between NTS and the Internet until I read it, even though my experience was like his. I was in NTS through high school and even, for a while, TCC station K on Wednesdays until we moved to noisy radio conditions in Florida.
>
> The additional note I have is about collision detection!  If you were lucky enough to have QSK, or full break-in, you could listen between the dots and dashes, and the receiving station could break in, requesting an immediate retransmission of the last word.
>
> IIRC I built a vacuum tube transmit-receive switch that let me listen using my dad's war surplus HF receiver while transmitting with my own Heathkit.
>
> So it functioned much like collision detection on early Ethernet, letting you detect another transmission at the same time you were transmitting.
>
> -Larry/K4EO
>
>
-- 
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Dr. Ulrich Speidel

School of Computer Science

Room 303S.594 (City Campus)

The University of Auckland
u.speidel at auckland.ac.nz
http://www.cs.auckland.ac.nz/~ulrich/
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