[nos-bbs] JNOS rig control of frequency

Thu Jun 9 13:55:31 EDT 2022

That’s all interesting, and let me answer the Airmax thing after a one-paragraph diversion.

The challenge I face is how to bridge networks that are on different frequencies, using a single radio and a single computer. Not related to physical distance between networks. The path of least resistance for me seems to be the suggestion to use VHF for one and UHF for the other, which IS practical in my case. Requires no additional JNOS software engineering. Happy with that. Actual distance for me on VHF and on UHF is about 2 miles in each case. I use 20+W ERP which gives a strong signal over that distance. I can write Python scripts on my RasPi to route messages between the two destinations. Looks like problem can be solved. (Requires some $ for TNC and radio.)

Returning to your reply about Airmax, on our BAM/SFWEM ( https://SFWEM.net/ <https://sfwem.net/> ) there are about 50 people involved in building out this net and some experimentation leading to possible use of Airmax right out of the box for “backbone” connections. We get multi-megabit cross-Bay connections now, which compared to commercial service is just a trickle, but compared to packet is a landslide. There are many issues, and not enough time and people to explore all of them, but my personal quest has always been to finds ways to cross-connect communications systems, so I’m more focused on connection than on speed at the moment.

That was a diversion — now back to packet radio...

Packet radio using JNOS and other tools still seems like a solid backup service, though I clearly recognize the channel capacity is limited. I compiled JNOS two years ago, did a lot of work on the edges (the Python scripts), and it just keeps running without any tinkering at all. I love that I was able to automate the heck out of it and didn’t need to mess with its internal code (except one file — small change).

We did a 2m packet test a year ago where we crammed hundreds of “ICS-213” style messages down one frequency and found we could transfer around 180kB of messages thru a JNOS-to-JNOS connection in an hour. Kind of what you would expect if you do the math on a 1200 baud channel’s capacity and “noisy” messaging rather than straight file transfer … meaning lots of overhead but a clear frequency so few collisions. Also keep in mind that JNOS can use LZW compression, which I would think improves that figure significantly. 

—Sky

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
"Sky" (Jim Schuyler)
—Amateur Radio AA6AX
Online at aa6ax.us <https://aa6ax.us/> 

> On Jun 9, 2022, at 7:12 AM, maiko at pcsinternet.ca wrote:
> 
> Don't know what kind of funds you guys have, or the distance between
> networks that you need to bridge, but there are some interesting devices
> on the market. A friend of mine who is in the WISP business, just put up
> these nice 60 Ghz dishes recently, tired of all the interference on the
> 2.4 and 5 ghz bands, and they are smoking hot (rain fall can be issue),
> lookup the unit below, tons of this stuff around :
> 
>   Ubiquiti Airmax Gigabeam Long-range Wireless 60 Ghz Radio Bridge
> 
> The documentation is terrible of course, and it's quite new, firmware
> is constantly being updated. It's still radio of course, just an idea,
> doesn't have to be this one in particular, depends on your distance of
> course.
> 
> You could 'bridge the networks' using internet as well, but one could
> be construed a land line lid, that's what Charles N5PVL would always
> chime in on (changing the subject a bit), it's been years since I've
> heard or seen any post from him on this topic.
> 
> I miss the guy in many ways, don't even know if he's still alive, he
> had health issues back in 2017 from what I've read. He was big into
> the flexnet stuff, which I also was back in the day.
> 
> Maiko / VE4KLM
> 
> 
> On 2022-06-08 15:41, Sky via nos-bbs wrote:
>> Also acknowledging Maiko's response saying essentially "no."
>> My initial question(s) came from a desire to bridge two 2m packet
>> networks. One is a localized packet frequency also designated for
>> emergency use, and the other is a high-level BBS frequency that lets
>> me reach from San Francisco way down past San Jose in the south Bay
>> Area.
>> But I stupidly ignored that the high-level BBS has a UHF frequency as
>> well as a VHF frequency.
>> So tha coaching has been useful, even though the problem as posed is
>> insoluble.
>> -Sky
>>> On Jun 4, 2022, at 12:56 PM, Andrew Pepper <anpepper at gmail.com>
>>> wrote:
>>> You'd be better off using one port on vhf and the other port on uhf.
>>> All you'll need is a dual band antenna and a diplexer... Or just use
>>> two antennas. Then you'll avoid the need for expensive VHF duplex
>>> filters and worrying about both transmitters TXing at the same time.
>>> Andrew
>>> On Sat, Jun 4, 2022, 15:19 <maiko at pcsinternet.ca> wrote:
>>>>> Please confirm the following:
>>>>> •     The second interface would allow JNOS to simultaneously
>>>> listen to
>>>>> both frequencies, logging all traffic and serving its BBS on
>>>> both
>>>>> frequencies. (This one I am sure of.)
>>>> Of course.
>>>>> •     JNOS will not trigger a second radio to transmit at the
>>>> same time as
>>>>> the first. (This was one of my earlier questions, and I honestly
>>>> do
>>>>> not know the answer.)
>>>> There is no way for JNOS to know, especially in KISS mode, it
>>>> sends the
>>>> data when it wants to send the data, so it has no idea when PTT is
>>>> going
>>>> to be active or not. Unless it controls PTT direct for some of the
>>>> more
>>>> recent code I wrote, but even then there is no 'check if another
>>>> radio
>>>> is active' type of code. I could put in code, but that could
>>>> possibly
>>>> introduce longer delays, since you still don't really know when
>>>> the TNC
>>>> is going to PTT the radio ? I have no experience with this, but
>>>> this is
>>>> what my sense would be.
>>>> But it gets worse, even if one radio is not transmitting, suppose
>>>> you
>>>> are receiving a packet on the one, and you key up the other ?
>>>> Signal
>>>> will most likely get WASHED out anyways by your own TX on the
>>>> other
>>>> frequency ? Hopefully I am not making a fool of myself, it's been
>>>> years since we played with stuff like DIODE MATRIX interconnected
>>>> systems and the sort, that was a LONG time ago, oh my gosh ....
>>>> Either huge duplexor cans or TNCs that can be GPS sync'd (never
>>>> heard
>>>> of that, but it would be cool, similar to motorola canopy
>>>> systems).
>>>> Yeah, if anyone wants to better educate us, please do :)
>>>>> This would allow continued use of JNOS without additional work
>>>> from
>>>>> anybody.
>>>> There would need to be some type of additional work in my opinion,
>>>> unless
>>>> you could somehow manage to separate the antennas really really
>>>> good ...
>>>> Maiko / VE4KLM
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