[aprssig] RFM22B UHF Transceiver Module

John Wiseman john.wiseman at cantab.net
Thu Dec 13 01:07:27 EST 2012


The board wasn't designed with APRS in mind - APRS was just a very simple
way of proving it worked and getting some idea of the range that could be
achieved. The aim was to make it part of a network node - initially running
a high speed backbone within the current packet network (ie NETROM)
achitecture, but with possibilities for a better mesh based system in the
future. I haven't yet tested above 9600, but that is on the to-do list. The
RFM23BP also gives another 10 dB outpur with very little cost increase, and
is software compatible. I did look at the RFM12, but it is a differenct
architecture, and more difficult to program.

You don't even need a data feed to the shack - just have another module
there - and maybe it could even run off solar power, although that of course
would take you well over the $20.

Keep dreaming!


-----Original Message-----
From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On Behalf
Of Robert Bruninga
Sent: 12 December 2012 23:22
To: TAPR APRS Mailing List
Subject: Re: [aprssig] RFM22B UHF Transceiver Module

> A while ago (22 September) Bob posted a message about the RFM22 
> modules. I was working on a TNC for the Raspberry PI at the time, so 
> decided to try building a TNC round these modules.

Fantastic Work, John.  And of course, another tiny device for APRS is a
great project, but when I first saw this chip and its ability to do 100 kB
so cheaply, I actually was thinking more of a tiny $20 box that *EVERY* ham
on the planet might put up on his antenna tower or mast and become another
node in an all-ham digital backbone.

It would not be limited to just APRS type situational awareness, but would
be that general purpose digital network we have always needed in

The transciever in a cigareete sized package on the tower with nothing but
data and power coming into the shack would maximize RF range and minimize
installation effort.

Also it would make a great "club project".  If cost was low enough, and some
hams still did not want to btoher, then others in the club would buy one for
every hamd so tht the network was dense, and not just a few adopters... but
EVERY ham with a PC supports the network as well as every hams CAR too.

Just dreaming outloud of that ham cloud ON RF.


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