Re: [EXTERNAL] [RaspberryPi-4-HamRadio] TNC-Pi Now Available


I used to be down on 9600 baud.  It was too expensive for the result, plus just going to dedicated links or getting rid of acknowledgments was a bigger deal.   

But then I found out about surplus radios and NinoTNC.  

On Oct 19, 2020, at 5:05 PM, David Ranch <rpi4hamradio-groupsio@...> wrote:

There is a reason why it hasn't been really adopted for APRS:  diminishing returns   Check out WB2OSZ's write up on this:

Basically, higher speed needs faster key-up and settling times which is just not available in HAM voice-grade FM radios.  Once upon a time, there were HAM data-grade radios from vendors like Tekk, SCS, which were more than an order of magnitude faster but all of those are essentially gone now.  Also remember that for an effective network, both sides of the link needs fast radios.


On 10/19/2020 12:43 PM, Zonker Harris via wrote:
  I’ve been using 9600 for APRS in the SF Bay Area, documented here…
Sadly, there is not much adoption, since I haven’t managed to find a way for 9600 users to hear local 144.39 stations, or vice-versa. We thought it could alleviate some of the local congestion, but never completed a gateway that filtered only for “nearby” stations to repeat to the “other” band.
         Best regards,
From: <> On Behalf Of Mark Griffith via
Sent: Monday, October 19, 2020 12:33 PM
Subject: [EXTERNAL] Re: [RaspberryPi-4-HamRadio] TNC-Pi Now Available
Yeah, it's not such a great deal.  I've been wondering if I should offer it as an option for pre-built PiGate systems.  Since nearly all of the packet users in the US are at 1200 baud, and all of the TNC-Pi9k6 boards that I send out are setup for 1200 baud, I wonder if the capability to go to 9600 baud is a pressing need.  Given that is also takes a radio that is designed to do that, it seems unlikely that 9600 baud will become a common mode in the US.
I have encouraged 9600 baud usage, but I have no idea if anyone is taking up the challenges to use the higher speed, given the requirements for a really good signal, which means much more attention needs to be made to antennas, betters radios, attention to RF in the shack, etc etc.  Since 9600 baud that is running without a lot of packet resends is faster than any of the other current modes, I'm surprised.
I guess it depends upon the usage.  9600 baud doesn't really achieve it's best usage until the size of the file to transfer gets fairly large (by RF standards), such as around 25k.  Smaller than that you only get a fairly few seconds faster file transfer than at 1200 baud, or no advantage at all.  So if sending fairly small email messages is the goal, 1200 baud may be as good as you'll get in nearly all cases.  Since the vast majority of packet RMS stations operate at 1200 baud, having a larger number of receiver stations is a definite advantage.
So perhaps I'll stop offering the 9k6 board unless it is a special request.  Still thinking in it.
On Monday, October 19, 2020, 2:10:28 PM CDT, N5XMT <dacooley@...> wrote:

Wow. 80 bucks and it's not even the 9K6...

On Oct 19, 2020, at 09:39, John Hansen <john@...> wrote:
For those who have been patiently waiting for MFJ to begin to offer the TNC-Pi, it is now available here:

John W2FS 

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