P25 System Presentation at Local Hamfest Forum

[Skypilot007]

15-20 minutes at the most is all you should need. Any longer and the crowd will be bailing out and heading for the food trucks!

Ares/Races group in my area just want cool radios that make that chirp sound when you key up, they don't care how the system works. Heck they don't even have a clue how DMR works.

 

[kv6o]

I am also the system admin for a P25, multi county system. And also a ham. I have given presentations to ham clubs on how our simulcast system works, but that's it so far. One area I think hams could use some education around is the what/why behind a digital, trunked system. I seem to run into a common whine, "Our county/city/state/whatever switched to this multi-million dollar "system" with all this fancy stuff - why? Our 30 year old analog repeater works better and is cheaper! Why did they go with this new-fangled digital crap?"

 

[wa4zko]

As others have eluded to, I would be careful about how detailed you get with such a presentation due to an audience that will be of varying tech savvy when it comes to LMR system aspects. That's not saying the audience is stupid, just that you may have some present that are just starting to learn the basics of what a conventional FM repeater is.

Also, I would regard such a system as critical infrastructure and be highly restrained with certain details that don't need to be in public domain in a world where threats/attacks against critical infrastructure are on the rise.

Suggest maybe 30 to 60 minutes max on presentation length. Provide a high level overview of the system, what problems the new system addressed, impacts of current vendor/supply chain challenges, and the various challenges of maintaining large complex radio communication systems. Cover the basic pros and cons of trunking systems, details on coverage challenges, the different needs of users/agencies on the system, voice/data needs, antenna systems, grounding, surge suppression, why P25, the P25 standards, etc etc. Keep it to a basic high level overview, then let a Q&A portion give you a feel for how well the audience took it in.

 

[kc8jwt]

I've always liked to read info about these types of systems and how they work. I don't necessarily want a radio for the system or anything like that, but it's always been neat to look at those systems and get a feel how they work.

In Ohio, the statewide MARCS system has been impressive for years to me on how it works. When I was in RACES, we had a radio room in the EOC that we all worked out of. The room had an HF radio, 2M radios for voice and packet, there were radios for the public safety bands in the room as well and one of the first MARCS radios that the county had. We were impressed when we were doing a drill and one of the tasks that they wanted us to do was contact the state EOC via the MARCS radio. We were over 100 air miles from the EOC and to use the MARCS radio to me to talk to someone in Columbus was magical. It made me want to learn more about those systems and how they worked.

Over the years I've read more on what I can about these types of systems and in general the technology behind it is fascinating.

 

[xmo]

Start with technical basics like modulation, VOCODER, simulcast principles, talkgroups, etc. Then highlight some operational benefits of the system like: "there is a dedicated talkgroup in every hospital ER. Every squad in the multi-county region can simply turn a knob to talk to any ER."

Things that are part of the justification for the significant expenditure.

I also agree that pictures of sites, site construction, and equipment installation will add interest.

 

[xmo]

mmckenna wrote: "One thing I'd cover would be to explain how the system isn't as fragile as some would want them to think. Some hams love to rip on public safety radio systems."

This is a great idea. There are a lot of hams who have been inculcated with the "when all else fails" mentality, sitting around waiting to step in when the local public safety system 'goes down' when reality is that there is virtually no chance of that happening.

After educating folks on the extremely robust nature of a modern regional system, rather than disparaging their well intentioned desire to volunteer, provide them with contact information so they can learn how to become a reliable resource available to assist EM during times of need.

 

[mmckenna]

This is a great idea. There are a lot of hams who have been inculcated with the "when all else fails" mentality, sitting around waiting to step in when the local public safety system 'goes down' when reality is that there is virtually no chance of that happening.

After educating folks on the extremely robust nature of a modern regional system, rather than disparaging their well intentioned desire to volunteer, provide them with contact information so they can learn how to become a reliable resource available to assist EM during times of need.

That's probably what I'd focus on.
I try not to sound disparaging against hams, but some do have a lack of understanding about public safety radio systems. It's a good place to start with the education.
Discussion of the robustness of the system would be good. Failsoft, site trunking, alternate interop repeaters, back up systems, redundancy, other radio systems, simplex channels, etc. would all shed some light on the capabilities that many hams are not aware of.

Maybe a brief mention of this, just in case any of them want to know if they can access the systems:

 

[n5ims]

mmckenna wrote: "One thing I'd cover would be to explain how the system isn't as fragile as some would want them to think. Some hams love to rip on public safety radio systems."

This is a great idea. There are a lot of hams who have been inculcated with the "when all else fails" mentality, sitting around waiting to step in when the local public safety system 'goes down' when reality is that there is virtually no chance of that happening.

After educating folks on the extremely robust nature of a modern regional system, rather than disparaging their well intentioned desire to volunteer, provide them with contact information so they can learn how to become a reliable resource available to assist EM during times of need.

And one other thing that hams don't appear to realize is that the public safety system is designed to work 24/7/365 with no downtime 100% of the time. They have backup systems and often backups to those backups. When all of that fails, they have agreements with neighboring agencies to allow them to use for the really critical agencies. Many times these are with the same agencies where they provide mutual aid services so even this fallback is tested regularly. Then there's them going simplex on their own channels and cell phones so the likelihood of a ham being needed to communicate for the PD and/or FD is so close to zero it's not worth doing much planning and testing for.

More likely they'll be needed for communication between shelters or their sponsoring agency or to send health and welfare traffic to the families of who is staying at the shelters in the off chance that their cell phones won't work at the shelter (another low probability issue). There is important work for hams to do to help out, just not the exciting ones that they think of with their "When all else fails, Ham Radio" motto.

 

[n2nov]

There is important work for hams to do to help out, just not the exciting ones that they think of with their "When all else fails, Ham Radio" motto.

Maybe this should be constantly brought up with the little boys in Newington. They keep trotting out their fantasy and are actually doing harm and creating confusion. Nowhere in the FCC rules does it talk about providing radio services to government agencies and NGOs. However, it does talk about providing service to the public, AKA the general public like your neighbors. Maybe a localized service to your neighbors like teaching them about FRS and that you are listening on a particular channel in case their phones and internet go out when they have an emergency that needs help.

 

[maus92]

40-50 minutes, tops. I'm not a ham, but I am a network guy (radio systems are essentially networks.) I would love to get into the weeds.

 

[AK_SAR]

I think a lot of hams would be interested in your topic. I certainly would be interested. Our volunteer SAR teams have limited access the State's ALMR (Alaska Land Mobile Radio) P-25 system for missions and training. I've attended a few trainings, but it would be fascinating to learn more about what goes on under the hood. Obviously you can't cover certain details, but I would think you could give a nice overview based on what's already in the public domain.