CalFire Narrow Banding

[lbfd09]

My mistake, that's pretty clever!

FWIW, some Northern CA fire departments are also Tx 192.8 but Rx CSQ on the CDF Tacs.

I think that was what I tried to say but ajohansson got all over me as if it was a sin to program the radio like that. Most all of the mobile radios I know will switch to CSQ when you pick up the mic to talk to someone as you do not want to double is someone else is using the frequency. HTs are not as critical but can help to make a smoother transitions and tranmissions.

Ah but what do I know, I am new to this and have only been using radios for some 44 or so years.

 

[ajohansson]

I think that was what I tried to say but ajohansson got all over me as if it was a sin to program the radio like that. Most all of the mobile radios I know will switch to CSQ when you pick up the mic to talk to someone as you do not want to double is someone else is using the frequency. HTs are not as critical but can help to make a smoother transitions and tranmissions.

Ah but what do I know, I am new to this and have only been using radios for some 44 or so years.

Please dont take things personaly on here, this cal fire change is causing some hiccups. The same time I was reading your post about folks not programing in the new decode i recieved an email about an air attack who couldnt talk to ground units on the division tactical. You then went on to say my radio doesnt decode when off the hook.

Like i said before the decode is imperitive for the duplex channels for the talk around feature to work.

I appologize if you think I was going off on here but firefighter safety hangs in the balance of all of these changes. If you know anybody not putting in the decodes please tell them to put them in and beaware of how to go into monitor mode if needed this fire season during the transition.

 

[lbfd09]

Please dont take things personaly on here, this cal fire change is causing some hiccups. The same time I was reading your post about folks not programing in the new decode i recieved an email about an air attack who couldnt talk to ground units on the division tactical. You then went on to say my radio doesnt decode when off the hook.

Like i said before the decode is imperitive for the duplex channels for the talk around feature to work.

I appologize if you think I was going off on here but firefighter safety hangs in the balance of all of these changes. If you know anybody not putting in the decodes please tell them to put them in and beaware of how to go into monitor mode if needed this fire season during the transition.

I got you. YES having decode on Local, Command, or Support channels is required to car to car ops to work. But on the tacs it's almost better to just encode and then use carrier squelch until all have the encode ability. One tends to miss too many radios calls otherwise.

I think the other confusion might also be in the use of "duplex" mode. This in radio talk is when you can talk to each other at the same time, much like a phone call. This was the case in the old San Francisco Fire VHF Hi/Low system. CHP can also do this with their low band pairs, however in both of those cases ONLY dispatch is able to hear while dispatching (when the dispatcher position is properly configured). But this is not getting way above the normal level of conversations here....

Have a safe 4th there....

 

[ajohansson]

Yes i am using the term "duplex" incorrectly but it seems to be adopted as such in the lay fire operators vocabulary as any channel with a separate tx and rx. I have heard full duplex used to describe the definition you gave.

There are some operational areas that are recommending their units to be in monitor/SQ while in initial attack for this season. I dont disagree with that recommendation at all. Hopefully by next month this shouldn't be an issue.

I think we are going to get busy this 4th holiday. Looks like lightning by early next week. Take care.

AJ

 

[gmclam]

Full duplex vs repeated

Yes i am using the term "duplex" incorrectly but it seems to be adopted as such in the lay fire operators vocabulary as any channel with a separate tx and rx.

Educate your firefighter friends. Any channel that is repeated will use separate tx & rx frequencies. You talk on the repeater input and listen on the repeater output.

Full duplex usually does not involve a repeater and is used when mobiles are not supposed to hear each other. A good example is a taxi company. All cars only hear the dispatcher.

 

[lbfd09]

I forgot about the taxi cab example, as it is so perfect to use and easy to understand. I guess that's what happen when one is studying ICS 300 and 400... brain goes to mush.

 

[ajohansson]

I think the fire service took simplex direct and made repeated duplex. Its all good...

 

[ramal121]

Like i said before the decode is imperitive for the duplex channels for the talk around feature to work.

This is true. However, the state load uses only encode in its OST list to make it usable throughout the state. If OST is enabled, the receive will be CSQ. Without testing, I suspect using talkaround will also change the encode to NONE.

This would not be a problem if all units are using the OST list. However, some departments do not use the OST list and put all possible combinations of say a command channel, into different channels on the radio each with encode and decode for ease of use. now you have the problem of going car to car and missing a call.

Maybe though when using TA, the radio dumps the OST list and goes back to use whatever is written into the channel assignment using the decode as encode also. A little experimenting may be needed.

 

[ramal121]

Full duplex usually does not involve a repeater and is used when mobiles are not supposed to hear each other. A good example is a taxi company. All cars only hear the dispatcher.

Using split frequencies is considered duplex. If the frequencies are the same, this is simplex.

A repeater runs FULL duplex, this is the nature of the beast. Taxis and CHP cars use split frequencies but are unable to transmit and receive at the same time. This is referred to as HALF duplex. You need to apply the right term to the system you are using.

 

[ajohansson]

This is true. However, the state load uses only encode in its OST list to make it usable throughout the state. If OST is enabled, the receive will be CSQ. Without testing, I suspect using talkaround will also change the encode to NONE.

This would not be a problem if all units are using the OST list. However, some departments do not use the OST list and put all possible combinations of say a command channel, into different channels on the radio each with encode and decode for ease of use. now you have the problem of going car to car and missing a call.

Maybe though when using TA, the radio dumps the OST list and goes back to use whatever is written into the channel assignment using the decode as encode also. A little experimenting may be needed.

Ramal, both the Kenwood 790/5710 and BK radios the state uses allows for an encode picklist and maintains the per channel decode when in OST (790) OST UP/DOWN (5710) mode on the Kenwood and using a tone on the BK. On a 5710 you have to use OST UP/DOWN not OST. If you use OST it will use the decode on the OST list no the channel. When in TA all the radios use the per channel decode as the encode. This has been tested alot because when the Kenwood 5710 first came out is was supposed to do this out of the box like the 790 did but it did not and required a firmware fix for it. We also had to get a firmware fix for our 2180s because of CAL-FIRE tone protection change for this year. We are in the process of getting it fixed for the 5210 as well for some cooperators in Riverside County. This highlights the importance of running the 16 standard Firescope encode picklist and putting in the correct decode per channel.

 

[ajohansson]

Using split frequencies is considered duplex. If the frequencies are the same, this is simplex.

A repeater runs FULL duplex, this is the nature of the beast. Taxis and CHP cars use split frequencies but are unable to transmit and receive at the same time. This is referred to as HALF duplex. You need to apply the right term to the system you are using.

Ok I was right duplex for the repeater like I said originally. Truthfully all they need to know is it uses two separate frequencies and we call it repeated. Thanks for the reply.

AJ

 

[ajohansson]

My mistake, that's pretty clever!

FWIW, some Northern CA fire departments are also Tx 192.8 but Rx CSQ on the CDF Tacs.

Are they putting in the decode on the CAL-FIRE command and local nets? They need to.

 

[gmclam]

Using split frequencies is considered duplex. If the frequencies are the same, this is simplex.

Duplex means you can transmit and receive at the same time, not listening and talking on different frequencies. If you are talking on repeater input and everyone is listening to you on the repeater output, it is NOT duplex.

With the CHP or Taxis, the dispatcher and a car can both talk and hear each other simultaneously. Yes, the car might not hear the dispatcher because their radio is in transmit mode, but regardless; that is DUPLEX.

 

[zerg901]

Simplex communication - Wikipedia, the free encyclopedia

Simple enough for you? Not really - huh?

Now I have to go back to operating in duplex mode on my duplex channel - "dupi dupi" as I like to call it.

Bottom line - whenever "duplex" or "simplex" is mentioned, you might want to double check exactly what is meant.

 

[ajohansson]

My brain hurts...

 

[lbfd09]

Are they putting in the decode on the CAL-FIRE command and local nets? They need to.

I think we are only talking about the newly adopted Pls on the channels like the CDF Tac channels. One should (almost) never mess with the repeater channel's tones, unless one is selecting form the 16 standard selectable tones tones as required by the incident radio plan.

My brain is too mushy to hurt.

 

[ajohansson]

I think we are only talking about the newly adopted Pls on the channels like the CDF Tac channels. One should (almost) never mess with the repeater channel's tones, unless one is selecting form the 16 standard selectable tones tones as required by the incident radio plan.

My brain is too mushy to hurt.

CDF has adopted PL tone on all of their channels but 3 or 4 that I can think of off hand.

All CDF Commands but 1 and 2 decode 103.5 (Firescope tone 8)

All CDF Local nets decode per the second number of their 4 number unit ID. i.e. BDU is 3500 and decodes tone 5, RRU is 3100 decodes tone 1. RRU 3 no decode.

All CDF TACS decode/encode tone 16 (192.8)

No PL tones on aircraft frequencies.

AJ

 

[ramal121]

Duplex means you can transmit and receive at the same time, not listening and talking on different frequencies. If you are talking on repeater input and everyone is listening to you on the repeater output, it is NOT duplex.

With the CHP or Taxis, the dispatcher and a car can both talk and hear each other simultaneously. Yes, the car might not hear the dispatcher because their radio is in transmit mode, but regardless; that is DUPLEX.

You're right, repeated communications user to user are not full duplex. I am referring to just the repeater. Since it transmits and receives at the same time, it is a full duplex device.

I'm not sure of your second statement. In the case of CHP, yes the dispatcher can listen to a unit AND transmit out at the same time, but not back to the unit that is still transmitting. To reply to that unit dispatch will have to wait until the button is released to answer back. This is half duplex. Full and half have two different meanings. I guess you could consider simplex and half duplex one in the same, but I consider simplex on a single communications path while half duplex uses separate TX and RX paths.

To ajohansson, thanks for the clarification on the OST and OST up/down functions. I didn't know that.

Boy this thread sure needs a shave.

 

[f40ph]

CDF has adopted PL tone on all of their channels but 3 or 4 that I can think of off hand.

All CDF Commands but 1 and 2 decode 103.5 (Firescope tone 8)

All CDF Local nets decode per the second number of their 4 number unit ID. i.e. BDU is 3500 and decodes tone 5, RRU is 3100 decodes tone 1. RRU 3 no decode.

All CDF TACS decode/encode tone 16 (192.8)

No PL tones on aircraft frequencies.

AJ

Oh nuts - no decode on RRU-3??? All the state info we got for my dept said RRU 1, 2, 3 had decode 110.9. Do I need to reprogram?

 

[SCPD]

In the fire service, at least wildland, and on natural resource agency systems the term "direct" and "repeat" or "repeater" is used. The terms "car to car" and some others were used early on in my career in Arizona and New Mexico. Direct and repeater are much more understandable.