2 meter Netrom Node 9600 radio ?

Bob Donnell kd7nm at pugetsound.net
Wed Oct 7 12:20:08 PDT 2009


Well, there's no reason that the bit regen capability couldn't be built into
a TNC-X too.  The biggest differences that I think I know of is that the
TNC-X is a closed-source project, and the Tracker2 is an open-source
project.  Unfortunately, the tools for building code for the Tracker2 are
quite expensive.  So perhaps neither of these is a perfect solution.


Bit regeneration normally requires real-time access to the incoming data
stream, because what's being transmitted would normally be only a few
bit-times after it's received.  That's probably not what John Hansen has
implemented - I'd bet that what gets delivered to the accessory board(s) is
a fully decoded and framed packet, at high speed.   

The length of the delay is dependent on whether the transmitter is keyed at
the time the bit stream starts, and whether the bit regen code is written to
buffer bits while keying the transmitter, for a per-repeater configured
time.  If I recall correctly, the TAPR 9600 bps modem, as a fully
hardware-based design delayed 8 bit times, as soon as the DCD circuit
acquired lock.  The FIFO chip was 16 bits long, which allowed for received
data rates slightly slower or faster than the local clock rate on the modem.

Other extra features of a bit-regen box, for use in a repeater, could be ID
timing and generation, and squeezing the ID's in between received packets.
Additionally or alternatively, the firmware could also support KISS I/O, as
a parallel function, assuming enough RAM and CPU horsepower is available.

73, Bob, KD7NM

-----Original Message-----
From: seatcp-bounces at wetnet.net [mailto:seatcp-bounces at wetnet.net] On Behalf
Of Steve Stroh
Sent: Wednesday, October 07, 2009 11:35 AM
To: All things digital and fun
Subject: Re: 2 meter Netrom Node 9600 radio ?

Argent Data Systems sells this (or a variant) for VHF -

For UHF -

Both $149.

I'd be more tempted to order them from Argent than directly from Friend as
Argent obviously understands US Packet Radio requirements, is a US company,
and may be in a position to deal with service and/or returns better than
going direct with the Chinese manufacturer.

I'm pretty impressed with these for packet radio use!

I wish the TNC-X had a bit regen capability... and 9600... and while we're
at it, Ethernet :-)




On Tue, Oct 6, 2009 at 19:27, Don Fanning <don at 00100100.net> wrote:
> Maybe something chinese like this for the radio?
> http://www.friendcom.com/EN/301D.htm
> Then just pump it into a embedded/surplus PC with soundmodem?  I've 
> gotten soundmodem to run on Gumstix embedded computers easily (for
> power) but if power and space isn't an issue, P3's can be gotten in 
> bulk for very cheap.

steve at stevestroh.net
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