Trunking reverting to simplex on signal loss

[Deziel0495]

First of all, apologies if this is in the wrong section. Not really sure where to place a topic like this.

Second, I do not know much about the technical inner workings of a trunked system but I do understand the basics of how it all works.

The system I'll be referring to is the Maritime Public Safety Radio Network

Story:
After years of being plagued with interference issues from an unknown source(s) and poor communications in general, our FD is in the process of moving from our analog VHF simplex system to the provincial TRS to increase reliability, range, and reception among other things. We have done extensive coverage testing in our district over the past 5 months with excellent results. From time to time we may respond as mutual aid for another department where system coverage may not be as reliable as our own district. I understand that if trunking fails, the system will revert to site trunking. However, if radio(s) lose contact with the system altogether will they revert to simplex operation until the connection can be established again? From what I'm gathering this may be system/radio specific or perhaps I'm dreaming this up and it is not actually a real fail-safe option.

Our neighboring province Nova Scotia has simplex frequencies licensed systemwide for every user for this exact reason, due to coverage issues. A few months back I asked this question to our EMO contact who oversees the system in our province when we first acquired about switching and his reply was "that is not necessary".

Not only is this upgrade a huge financial undertaking for a volunteer department, but we also want to be absolutely sure we have all the bases covered and we will not have any gaps in communications. Also, is it not an NFPA requirement to have access to a simplex frequency should the need arise? Perhaps I can throw that at him as well.

PS... We will be keeping the licensing for our analog VHF frequency as it is shared with a neighboring department and used for paging for both departments. However, the new radios we are purchasing (Kenwood VP5430) for the TRS are not multiband.

Any input/feedback is very much appreciated.

 

[KevinC]

As far as I know no such feature exists. And if it did how would the radio know to switch back to the trunked system?

If your subscribers support it I guess you could do geo-fencng, assuming the dead spots are known and repeatable. But I'm not sure that's a good option for this situation.

 

[wa8pyr]

The radio will not automatically revert to simplex if signal is lost completely. As long as the radio is programmed correctly you'll get an "Out of Range" alert; your SOP should then specify what to do in that case (revert to your old VHF, 700 or 800 MHz simplex, whatever).

We have all five 800 MHz interop repeaters at our backup site; local SOP is to switch to them if the trunked system dies completely.

 

[Deziel0495]

Thank you both for the clarification. That is how I assumed it worked but was not 100% sure.

I will continue to push EMO on the need to include a 700/800 MHz simplex frequency into the radios before the programming is complete and the units are in service.

Unfortunately, we have all the funds approved and in place to cover what we were quoted for by Bell Mobility. Wanting to change now to a multiband radio so we could incorporate our own simplex frequency would likely exceed our funding.

 

[a1emt]

From a fellow firefighter, you are ABSOLUTELY going to want a simplex frequency in an easy-to-access location in your trunked radios. Even if you can't get "your own" frequency, put a regional or national interop frequency in. My department operates on a large regional P25 network and nearly every department has placed the same 800 MHz analog simplex frequency in the "channel 16" (last knob position) in their portable radios. It is licensed by the state as an interoperability frequency. This allows for a quick switch to simplex, by simply turning the channel knob clockwise until it stops. The system has worked very well and most "hazard zone" operations are conducted on this simplex channel. The P25 trunked systems work great, but we need to have the ability to use alternate communications systems in some very dangerous and difficult to cover areas.

 

[a1emt]

These national interop frequencies should be part of your programming template. Use one of those in simplex mode. Program it where it is easy to access. Get your neighboring departments on board to do the same.

Interop (Canada) Scanner Frequencies and Radio Frequency Reference

Scanner Frequencies and Radio Frequency Reference for Interop (Canada)

www.radioreference.com

 

[mmckenna]

These national interop frequencies should be part of your programming template. Use one of those in simplex mode. Program it where it is easy to access. Get your neighboring departments on board to do the same.

Interop (Canada) Scanner Frequencies and Radio Frequency Reference

Scanner Frequencies and Radio Frequency Reference for Interop (Canada)

www.radioreference.com

That should be mandatory, and if Bell won't do it for you, they need a good talking to. The whole reason behind those frequencies was to make sure public safety agencies have some common channels for interoperability. Any good radio shop should have those in a template and adding them to one of the zones in your new radios should be simple. If they want to charge you extra for it, that would be a red flag.

 

[Deziel0495]

Thank you guys, this is all great info.

Like I said, Nova Scotia operates on the same system and all their users have access to interop simplex frequencies licensed by the province. Not sure why EMO thinks they are not necessary here.

I can say without a doubt the 8 radios we have now for the system and every other FD radio using the same codeplug do not have simplex programmed and never have from day 1. We will be the 5th department in the province to use the system as our primary communications and I will continue to push to have a simplex frequency available to us. If I have to go around EMO and deal directly with Bell Mobility to get it done, so be it.

 

[Deziel0495]

So after requesting a second time for a 800 MHz simplex frequency to be added with the programming this was his response:

We can have simplex added if you like for the new ones, as this feature should be standard. As for the older ones I would need to check because if they currently do not have that feature, then they would not be able to be upgraded.

Our existing radios are 5 Motorola XTS 1500's and 3 XTL 1500's. The 23 new radios will be the Kenwood VP5430's.

Hopefully it can be done.

 

[mmckenna]

So after requesting a second time for a 800 MHz simplex frequency to be added with the programming this was his response:



Our existing radios are 5 Motorola XTS 1500's and 3 XTL 1500's. The 23 new radios will be the Kenwood VP5430's.

Hopefully it can be done.

Probably depends on the flash code of the XTS/XTL and if there are channel slots available.

While I know it's a volunteer department, XTS/XTL's are getting to be the age that they probably need to be replaced. 7 radios will be expensive, but it should be on the radar of the department. Running radios more than 10 years comes with risks and replacing them is a really good idea.

 

[buddrousa]

Could it be possible that a person not knowing any better is getting confused on what FAILSOFT is?

 

[Project25_MASTR]

There are three operational modes of a P25 site.

First is your normal mode of operation where the site can communicate with zone/system core controller.

Second is Site Trunking which means the site cannot communicate with the Zone/System core. In Site Trunking, any SU programmed with the system info can register and affiliate to the site (can't communicate with the core...so can't check to see if they are valid ID's or talkgroups for the site). Of course, no multi-site trunking in this configuration but also SU's will avoid a site in site trunking unless there are no other options or they have "Always Preferred" selected in their site preferences (which overrides the desire to search for a site not advertising site trunking).

Third is Failsoft (sometimes called Fallback). This is...all trunking function is broken every repeater at the site key up and announce failsoft (there's usually some accompanying warning beeps on the SU) and the SU's will revert to conventional operation (which has to be specifically programmed into them) using the groups of repeaters as somewhat of a community repeater (Groups A, B and C share Repeater 1, Groups D, E, F share Repeater 2, Gropus G, H, I share Repeater 3, etc). Also a SU will avoid failsoft if possible.

Now, depending on how the SU's are programmed, you could see one of four different prompts on the display. Nothing (meaning normal operation or the good details aren't enabled), No Comms (meaning the SU can hear the control channel but can communicate with it), Out of Range (meaning no control channels can be heard or communicated with) or Failsoft. Highly recommend making sure these are programmed on display radios as having a little info about why the radio isn't working is better than...it just isn't working.

 

[GTR8000]

Two points piggybacking on @Project25_MASTR's post...

1) When in Site Trunking mode, subscribers can continue to operate fairly normally with regard to communicating with each other, however any system consoles will be severed from the site. In simple terms, units in the field can talk to each other, but you'll lose comms with dispatch unless they're also subscribers on the system (i.e. consolettes transmitting on the inputs).

2) Motorola ASTRO 25 and APX subscribers will display SITE TRUNKING in addition to NO COMMS, OUT OF RANGE, and FAILSOFT status messages.

The bottom line is that no trunking subscriber should ever be deployed without some sort of backup resources in the programming. The most desirable would be a conventional repeater that can be used to reach a dispatcher of some sort, but in lieu of that, at the very least there ought to be some simplex channels available so that not all comms are lost if the trunked site goes belly up. I realize you're in Canada so you probably don't have as wide a selection of nationwide interop channel available, but it does look like there are some in the 700 and 800 bands.

Of course having an SOP and training is most critical, as it doesn't really matter how many backup channels the radios have if no one ones how to use them or when to automatically switch to them!

 

[Deziel0495]

So just an update.

Bell Mobility is coming Monday morning to reprogram our XTS/XTL 1500's with our own operational talkgroups, something we've requested back in January. Turns out Bell is over 3 months behind on their work. I never did get confirmation if the radios are able to be programmed with a simplex frequency, so I guess I'll find out Monday morning when the tech arrives. We also requested the channel announcement feature too but not sure if that is possible either. I was told the tech cannot do programming changes "on the fly" and changes had to be requested days prior to their arrival.

I was told however that with the new VP5430's these options will not be a problem and will be completed during programming and activation. A codeplug is being developed and will be sent to me for review once it's completed.

 

[mmckenna]

Sounds about right. Making major changes to a trunking codeplug off the cuff like that can be a problem, especially if the tech isn't super experienced. Likely they take an existing codeplug and modify it. That gives them some time to really double/triple check it before rolling it out. I used to do that. Worst thing in the world was having the customer leaning over your shoulder asking questions while trying to modify codeplugs on site. I'm sure you wouldn't do that

 

[wa8pyr]

So just an update.

Bell Mobility is coming Monday morning to reprogram our XTS/XTL 1500's with our own operational talkgroups, something we've requested back in January. Turns out Bell is over 3 months behind on their work. I never did get confirmation if the radios are able to be programmed with a simplex frequency, so I guess I'll find out Monday morning when the tech arrives.

XTS/XTL1500 radios can do simplex. Only question is whether you have enough space in your template to add it; if there isn't enough space I'd make space so you have something to fall back to.

 

[Deziel0495]

XTS/XTL1500 radios can do simplex. Only question is whether you have enough space in your template to add it; if there isn't enough space I'd make space so you have something to fall back to.

Should be plenty of space. They have numerous channels repeated in all 3 zones just to fill them. Fire depts. currently only have access to 19 talkgroups in the standard layout, which 90% of them use.

 

[wa8pyr]

Should be plenty of space. They have numerous channels repeated in all 3 zones just to fill them. Fire depts. currently only have access to 19 talkgroups in the standard layout, which 90% of them use.

Then I'd start with the 8CALLxxD/8TACxxD channels, and add 7FIRExxD/7MEDxxD channels if you have space.

 

[kayn1n32008]

These national interop frequencies should be part of your programming template. Use one of those in simplex mode. Program it where it is easy to access. Get your neighboring departments on board to do the same.

Interop (Canada) Scanner Frequencies and Radio Frequency Reference

Scanner Frequencies and Radio Frequency Reference for Interop (Canada)

www.radioreference.com

No idea where the 220MHz channels come from. Nobody I'm aware of uses 220MHz for public safety in Canada.

The 700/800MHz interop list looks like the US 700/800MHz interop channels.

To the OP, you need to talk to Bell and program the same simplex channels as New Brunswick and Nova Scotia are using, and get licensing sorted with ISED.

Unless someone can point to a legitimate CANADIAN source for that interop list, I would be very hesitant on using it as a source of information.

 

[kayn1n32008]

Then I'd start with the 8CALLxxD/8TACxxD channels, and add 7FIRExxD/7MEDxxD channels if you have space.

The OP needs to sit down with a competent radio person at Bell, and the provincial agency responsible for the fire service and get simplex channels sorted out. I would be pushing for what ever simplex channels are being used by Nova Scotia and New Brunswick. If there isn't a standard set, the three provinces, Bell and ISED need to be figuring out a common set of simplex channels.

8Call/8Tac 7Fire/7Med are American terms for American interop channels.