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Fireground analogue FM

Posted: 12 Oct 2018, 12:12
by Mikel
The storm has caused some flooding locally obviously, as the Fireground main channel around here 457.0375 Mhz is active this morning.

I know there are some that will tell you that the range of a UHF handie will only be a few hundred yards or so but I have consistently proved this to be wrong with experiments on PMR 446 and 70cm. Consequently 457.0375 is active most days around here and not all the incidents are within a hundred yards of my loft mounted dual band mobile antenna obviously!

The main point though is that all the Fireground signals heard here in the lower end of the Rhymney Valley are all analogue FM. I have yet to here the tell tale 'noise' of a DMR signal on the frequency at all yet.

I was wondering what the situation is in different parts of the country? Anyone else still hearing analogue comms from the Fire handies in their area or are the south Wales valleys the last ones?

Re: Fireground analogue FM

Posted: 12 Oct 2018, 15:41
by thelad
North Yorks seem to be still using in Analogue mode.

Re: Fireground analogue FM

Posted: 12 Oct 2018, 19:17
by Mikel
thelad wrote:
12 Oct 2018, 15:41
North Yorks seem to be still using in Analogue mode.
Thanks for the reply, it's interesting to know it's not just around here.

Re: Fireground analogue FM

Posted: 13 Oct 2018, 04:01
by pete_uk
Gloucestershire are still analogue. I think most places are.

Re: Fireground analogue FM

Posted: 13 Oct 2018, 18:04
by Metradio
Most Fire Services are buying DMR Tier II radios, this gives them the option of Analogue FM and DMR, also gives them compatibility with other Fire Services..

Re: Fireground analogue FM

Posted: 14 Oct 2018, 12:14
by Mikel
Metradio wrote:
13 Oct 2018, 18:04
Most Fire Services are buying DMR Tier II radios, this gives them the option of Analogue FM and DMR, also gives them compatibility with other Fire Services..
Yeah, had a chat with a mate of mine on 2 metres last night who said a similar thing. He said that in Cardiff the fire service use DMR for their handies and I have no reason to disbelieve him, but Cardiff and the Rhymney Valley are since 1996 all part of South Wales Fire and Rescue Service and if there was a major incident then appliances from the Rhymney Valley may have to visit Cardiff or vice versa.

I assume the dual mode radios are not user mode changeable so may be a bit confusing at an incident - Or maybe they are? Just a transition period I suppose and eventually all will be on DMR, before the next 'improvement' comes along.

Re: Fireground analogue FM

Posted: 14 Oct 2018, 14:48
by Metradio
Mikel wrote:
14 Oct 2018, 12:14
.... I assume the dual mode radios are not user mode changeable so may be a bit confusing at an incident - Or maybe they are? Just a transition period I suppose and eventually all will be on DMR, before the next 'improvement' comes along.
This has been planned for nationaly, I do not have the file to hand but it goes along the lines of DMR radios being 16 channel as a minimum, the first 8 will be the analogue Fire Ground frequencies and 9 to 16 will be on the DMR bandplan..

Mike

Re: Fireground analogue FM

Posted: 14 Oct 2018, 14:56
by thedeerhunter270
The Fire Service knocked on my door a few days ago to fit some smoke alarms. They had hand held radio's with then, and the audio sounded like DMR to me.

Re: Fireground analogue FM

Posted: 14 Oct 2018, 16:30
by radiosification
Mikel wrote:
14 Oct 2018, 12:14
I assume the dual mode radios are not user mode changeable so may be a bit confusing at an incident - Or maybe they are? Just a transition period I suppose and eventually all will be on DMR, before the next 'improvement' comes along.
You can't change the mode as a user, but when programming the radio you can simply program the same frequency in both FM and DMR modes, then all the user has to do is change the channel. You could even put the same channels (except with the modes different) into two zones. This way they would even be on the same channel as before after changing zone, just that it would be in the other mode to what they were on before.

Re: Fireground analogue FM

Posted: 14 Oct 2018, 17:37
by Metradio
I think the Fire Services and Ofcom have modified the thinking on the Fire Ground UHF frequencies, originaly the frequencies were allocated with 25KHz channel seperation to match the then current hand held FM radio specifications.
Now with 12.5KHz spec analogue and digital DMR equipment coming into use, the bandplan can be modified to cater for tighter specs and modes. For instance the legacy analogue kit can stay on it's original channels and new DMR kit programmed to use the same channels in DMR mode, but eventualy with the agreement of all the Fire Services, the DMR channels be interleaved between the existing channels, which would give the Fire Services 8 analogue and 8 individual DMR channels, eventualy after a complete change over they would have 16 DMR channels..

Mike

Re: Fireground analogue FM

Posted: 14 Oct 2018, 17:44
by Metradio
On a historical note, when the Police and Fire services used their old low band VHF frequencies, some areas used AM and some FM, to provide interoperability some radio manufacturers made dual mode mobile sets, the PYE Whitehall was quite popular at the time..

Mike

Re: Fireground analogue FM

Posted: 14 Oct 2018, 18:28
by radtech
As said there is a DMR standard bandplan based on 16 channels, however it seems not everyone has their code plugs up to date.

My local brigade have DMR radios but only use FM, whilst a neighbouring brigade is using DMR. Cue chaos when they both TX on 457.0375 at the same time!

They should have agreed this band plan earlier and set aside one of the seldom used frequencies as Digital CH1.

I suppose it's good that they have agreed a standard and programming can be changed eventually.

Re: Fireground analogue FM

Posted: 16 Oct 2018, 16:05
by Mikel
Metradio wrote:
14 Oct 2018, 14:48
Mikel wrote:
14 Oct 2018, 12:14
.... I assume the dual mode radios are not user mode changeable so may be a bit confusing at an incident - Or maybe they are? Just a transition period I suppose and eventually all will be on DMR, before the next 'improvement' comes along.
This has been planned for nationaly, I do not have the file to hand but it goes along the lines of DMR radios being 16 channel as a minimum, the first 8 will be the analogue Fire Ground frequencies and 9 to 16 will be on the DMR bandplan..

Mike
OK Mike that makes perfect sense - thanks for the information, I hadn't thought of that for some reason.

Re: Fireground analogue FM

Posted: 16 Oct 2018, 17:08
by thelad
1-8 will be DMR, 9-16 will be Analogue, all the same Simplex and Duplex frequencies as in the past. CCs same as the Ch number and same Tg on all 8. I wont post the Tg as they is no need to have it to RX and may result in a numpty Txing up but it can be easy worked out.

Re: Fireground analogue FM

Posted: 16 Oct 2018, 18:04
by Metradio