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TNC-Pi Now Available


 



On Mon, Oct 19, 2020, 2:05 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:

   https://github.com/wb2osz/direwolf/blob/dev/doc/Why-is-9600-only-twice-as-fast-as-1200.pdf


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.

Those were the days.   9k6 packet through a regenerating digital Repeater (not lame bandwidth destroying digipeater) was a thing of beauty to watch in operation.

It was not unusual to transfer (FTP) large files.  My favorite exercise was the 300K SETI work unit.  Another op used it for multiple megabyte ampr.org domain files.  Since the Repeater equalized access to the system the other users were not noticeably affected.

Twenty five years later the Repeaters are gone and only the Kenwood radios standout as COTS equipment that wasn't available way back then.


August Johnson KG7BZ
 

Bill,

I still have a TAPR 9600 baud modem. It doesn't have the regenerator option installed, but I have the PALs and the files to program them to install the option. You aren't kidding about how great a 9600 baud regenerating repeater was! It wouldn't be hard to build regenerators now, you remember the two-chip one I did with a PIC 16C71 for 1200 baud.

August KG7BZ


On Mon, Oct 19, 2020 at 3:13 PM Bill Vodall <wa7nwp@...> wrote:


On Mon, Oct 19, 2020, 2:05 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:

   https://github.com/wb2osz/direwolf/blob/dev/doc/Why-is-9600-only-twice-as-fast-as-1200.pdf


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.

Those were the days.   9k6 packet through a regenerating digital Repeater (not lame bandwidth destroying digipeater) was a thing of beauty to watch in operation.

It was not unusual to transfer (FTP) large files.  My favorite exercise was the 300K SETI work unit.  Another op used it for multiple megabyte ampr.org domain files.  Since the Repeater equalized access to the system the other users were not noticeably affected.

Twenty five years later the Repeaters are gone and only the Kenwood radios standout as COTS equipment that wasn't available way back then.


Siegfried Jackstien
 

and now in germany such a fast user radio is developed around a pluto ...

base station fullduplex with filters ... user end with superfast rx tx "relais" (diode switching special ic)

as far as i know 400kb data rate so a tiny bit faster as 1k2 or 9k6

greetz sigi dg9bfc

Am 19.10.2020 um 22:13 schrieb Bill Vodall:



On Mon, Oct 19, 2020, 2:05 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:

   https://github.com/wb2osz/direwolf/blob/dev/doc/Why-is-9600-only-twice-as-fast-as-1200.pdf


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.

Those were the days.   9k6 packet through a regenerating digital Repeater (not lame bandwidth destroying digipeater) was a thing of beauty to watch in operation.

It was not unusual to transfer (FTP) large files.  My favorite exercise was the 300K SETI work unit.  Another op used it for multiple megabyte ampr.org domain files.  Since the Repeater equalized access to the system the other users were not noticeably affected.

Twenty five years later the Repeaters are gone and only the Kenwood radios standout as COTS equipment that wasn't available way back then.