News Flash! All NIFC VHF Frequencies to be Toned

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SCPD

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I just came across the following information on page 3 in the "2013 National Incident Radio
Support Cache User’s Guide" released in April of this year.

http://www.nifc.gov/NIICD/docs/NIRSC_UG.pdf

Incidents will be assigned a tone by the NIICD-CDO. Incidents will be advised to tone the following:
• All VHF Repeaters (RX & TX)
• All Tactical Channels/Frequencies (both RX & TX)

I knew that tone guarding on the repeater input had been implemented in the last few years, but I did not know it was mandatory and I didn't know the tone was to be carried over onto the output frequency. Toning both TX and RX on the tactical frequencies is a new development. NIFC will now be assigning one of the (presumably 8 or perhaps all 16) national tones for each incident using the national cache (NIFC or sometimes referred to a NIRSC). The tone will be common to all the VHF frequencies used on the incident. The wording seems to be saying that this would apply to air to ground and air to air FM tactical frequencies as well.

This will be helpful near the Mexican border where illegal frequency use booms across and causes a lot of problems on incidents occurring on the four southern California National Forests. I've experienced those problems and assume that the same is true for incidents in Arizona on the Coronado National Forest, the Gila District of the BLM as well as Saguaro National Park and Chiricahua National Monument.

It probably results from incidents interfering with each other in areas of the country far from the borders also, otherwise it would not be a requirement nationwide.

I've also found a list of the wildland fire interagency communications centers that utilize their own local flight following frequencies. I will post that soon.
 

Mike_G_D

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Hmm...ok, if I am understanding this correctly the tones will be assigned on a case-by-case (incident) basis so that would mean a lot of on-the-fly tone changing - is this practical for all of the assigned radios? I know that multiple tones are used to access different repeaters in many cases but that is a relatively small set and can either be channelized or separately selected in a reasonable fashion plus the repeater outputs usually have one common output tone but now doing this for RX and TX and on all channels including tac's and multiple input AND output (receive tone for the mobiles and portables) - is this practical per incident?

I guess if it now easy enough to change RX and TX tones on a radio in the field by a standard user then ok?!?

I would think that for the area fixed repeaters it would be better to have one common output tone and multiple different input tones as has been done for awhile now - or are they talking about portable deploy-able repeaters?

-Mike
 

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Many vendors produce radios that allow for user selectable multi PL, this makes tone selection quick and simple it also makes assigning tones on a incident by incident reasonably manageable.
 
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radioprescott

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... is this practical per incident?-Mike


I think if we are talking incidents that require a NIFC ComL then likely they would be programming all the radios for the incident on site, as the responders arrive.

They do that for freqs for visiting resources now, I believe.
 

SCPD

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I think if we are talking incidents that require a NIFC ComL then likely they would be programming all the radios for the incident on site, as the responders arrive.

They do that for freqs for visiting resources now, I believe.

There isn't anything to debate as to whether this is going to happen or not, the linked message is clear. All 16 tones are easily selected on Kings and probably on the other radios that may be in use that I'm not familiar with. The tone selection is independent from the channel selection - any channel selected can have a one of 16 tones. Most Kings have 16 groups with 2-3 programmed with NIFC and other mutual aid frequencies. Crews arriving on fires are advised what command and tactical channels and will be used and with this direction in place, will also be informed what the tone for the fire is. There will be one tone for all channels used on a fire.

The crews receive the shift incident action plan that contains the comm plan for the fire. There is very little cloning being done anymore as gradually all the units of the various agencies are using the NWCG 16 standard tones. These were originally developed in the FIRESCOPE program. The only radios cloned are those with only one group and fewer of these exist. Type II crews may have some as the radios carried by members of these crews are those from other functions such as timber, recreation and the like. Many Type II crews consist of regular agency personnel whose daily job is not in fire management, rather one of the other functions. I used to program my own radio when I arrived at a fire, then clone the rest of the radios my crew carried. The other functions are using the same radios fire management has and the one group 14 or 16 channel radios are being purchased less if at all. The cost savings for a one group radio is probably not much as the manufacturer has to produce radios of this type specially, so the price difference between the full 16 group radio and the one group radio might not be that much. The 16 group radios may be the only type that can be purchased now. The NIFC comm division site has this type of information, but I don't have time right now to look it up.
 
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SCPD

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I think if we are talking incidents that require a NIFC ComL then likely they would be programming all the radios for the incident on site, as the responders arrive.

They do that for freqs for visiting resources now, I believe.

There isn't anything to debate as to whether this is going to happen or not, the linked message is clear. All 16 tones are easily selected on Kings and probably on the other radios that may be in use that I'm not familiar with. The tone selection is independent from the channel selection - any channel selected can have a one of 16 tones. Most Kings have 16 groups with 2-3 programmed with NIFC and other mutual aid frequencies. Crews arriving on fires are advised what command and tactical channels and will be used and with this direction in place, will also be informed what the tone for the fire is. There will be one tone for all channels used on a fire.

The crews receive the shift incident action plan that contains the comm plan for the fire. There is very little cloning being done anymore as gradually all the units of the various agencies are using the NWCG 16 standard tones. These were originally developed in the FIRESCOPE program. The only radios cloned are those with only one group and fewer of these exist. Type II crews may have some as the radios carried by members of these crews are those from other functions such as timber, recreation and the like. Many Type II crews consist of regular agency personnel whose daily job is not in fire management, rather one of the other functions. I used to program my own radio when I arrived at a fire, then clone the rest of the radios my crew carried. The other functions are using the same radios fire management has and the one group 14 or 16 channel radios are being purchased less.
 

RodStrong

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There is very little cloning being done anymore as gradually all the units of the various agencies are using the NWCG 16 standard tones.

Not sure if that's completely accurate based on some fires I was on last summer. Maybe something's changed since then though. I dunno.
 

RodStrong

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There is very little cloning being done anymore as gradually all the units of the various agencies are using the NWCG 16 standard tones.

Not sure if that's completely accurate based on some fires I was on last summer. Maybe something's changed since then though. I dunno.
 

zerg901

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Mike G_D - I believe you are correct. I am pretty sure that the NIRSC radios are the deployable repeaters that are brought in on the largest wildfires. They are typically shipped via ?air freight from the big warehouse in Boise. ("NIFC cache" is another common name for the NIRSC)

From the document -

Page 5 - Group 3 is the VHF FM air freqs

Page 16 - Log 1 to Log 7 are the UHF repeater pairs (for use at the fire camp and maybe for use linking the VHF repeaters)

Page 17 - Command 1 to Command 6 are the deployable VHF repeater channel names

Page 20 - only scan 3 channels so batteries are not exhausted

Many of the newer radios might have a blank zone/group/bank so that they can be flashed when arriving at a major wildfire.

If there are 6 Command channels available west of the Mississippi River, with 12 unique freqs, than there is no need to put a tone (PL) on anything unless there are more than 6 major fires in progress in 1 area. (this is just a general conceptual statement to help explain the situation)

Generally speaking - normal fires are handled on local channels. The largest fires require extensive "mutual aid" (out of area resources). The "out of area" units typically will not have the correct freqs programmed in their radios. These are the people that need to be flashed when they arrive at a fire. You can Google for "Incident Communications Plan" to see a typical flash load. It is typically 16 channels. Ch16 is typically 168.625. Ch 1 2 3 seem to be typically 168.05 168.10 168.20 IIRC. Then 1 or 2 command (deployable) repeaters are added. And a couple of local repeaters. And maybe 154.28. Before you know it, you have 16 channels to use in the flash load.
 

SCPD

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Not sure if that's completely accurate based on some fires I was on last summer. Maybe something's changed since then though. I dunno.

Oops! It's not completely accurate because it is not the case at all. I'm not sure what I was thinking when I said that cloning doesn't happen at incidents much anymore. The tactical and command channel combination in use on an incident may be available in groups in a radio but each might be in different groups. Radios need to be programmed according to the comm plan so resources can then start referring to the channels as listed in the plan. For example a fire may have a command frequency for the western portion and another for the east. A division sup may be called by another with "division alpha, division echo, switch to channel 2," where channels 1 and 2 are the two command frequencies in use on the incident.

The preprogrammed groups with NIFC frequencies are used when arriving resources are given a direct assignment to a location on the fire without stopping by the command post first. After being relieved they get their radios cloned at the comm unit on their off shift time. Resources that have to use frequencies from different groups in their radios on a hot assignment usually have a person that can program the two into their blank groups quickly and clone other radios as necessary. Division sups need to switch from tac to command frequently and in my experience almost every one of them had the equipment and knowledge to do it in a short period of time. Sometimes that initial assignment can last 36 hours making the availability of the NIFC channels in a radio critical.

What I meant to communicate is that the need for hundreds of cache radios given to each arriving resource is no longer critical. In the days of the crystal radios a cache radio had to be issued to each user when they arrived, even for USFS/BLM/NPS/USFWS units as their home radio didn't have more than local unit channels in them. Some of the first crystal radios that had the additional channels were from southern California as a result of the FIRESCOPE program.

A poster above thought that a given combination of frequency and tone required one channel. The first King I was assigned in the mid 80's was capable of independent tone selection for each channel so the need for separate channels has never been a limiting factor, at least so after crystals were no longer used. Some local units have their radios programmed with a channel for each repeater, so the same frequency combination is used over and over each with a different tone. That may create the impression that each combination of tone and frequency needs a separate channel. I'm not sure why some units choose to configure radios like this as it takes up less memory to use the frequency combination once and allow the user to select the necessary tone. I wonder if the techs think the field units can't figure out how to do that or what, but the radio is not a limiting factor. By the way, the use of different tones on the input and outputs of a repeater pair is easily programmed into a King, however such a situation, especially on an incident is highly unlikely.

zerg901 said:
Mike G_D - I believe you are correct. I am pretty sure that the NIRSC radios are the deployable repeaters that are brought in on the largest wildfires. They are typically shipped via ?air freight from the big warehouse in Boise. ("NIFC cache" is another common name for the NIRSC)

From the document -

Page 5 - Group 3 is the VHF FM air freqs

Page 16 - Log 1 to Log 7 are the UHF repeater pairs (for use at the fire camp and maybe for use linking the VHF repeaters)

Page 17 - Command 1 to Command 6 are the deployable VHF repeater channel names

Page 20 - only scan 3 channels so batteries are not exhausted

Many of the newer radios might have a blank zone/group/bank so that they can be flashed when arriving at a major wildfire.

If there are 6 Command channels available west of the Mississippi River, with 12 unique freqs, than there is no need to put a tone (PL) on anything unless there are more than 6 major fires in progress in 1 area. (this is just a general conceptual statement to help explain the situation)

Generally speaking - normal fires are handled on local channels. The largest fires require extensive "mutual aid" (out of area resources). The "out of area" units typically will not have the correct freqs programmed in their radios. These are the people that need to be flashed when they arrive at a fire. You can Google for "Incident Communications Plan" to see a typical flash load. It is typically 16 channels. Ch16 is typically 168.625. Ch 1 2 3 seem to be typically 168.05 168.10 168.20 IIRC. Then 1 or 2 command (deployable) repeaters are added. And a couple of local repeaters. And maybe 154.28. Before you know it, you have 16 channels to use in the flash load

There is more than one location where NIFC caches are kept. I don't remember those locations but they might be at one of the four or so major incident caches stationed in different areas of the west. I know that one of these locations is at the Prescott Fire Center in Arizona.

Remember that the group assignments shown in the document are for cache radios only and local radios are configured differently.

A set of UHF frequencies for repeater use and for simplex camp use are available and are mutually exclusive and are also so with the set of UHF frequencies used to link repeaters, which is further subdivided into those used to link repeaters and those used to link aviation frequencies. I listed all of these in the wiki, accessible from the database page for the NIFC system, listed under the "nationwide frequency" tab on the first page of the database.

There are 12 command frequency pairs in use. I've done a lot of searching and printing of manuals, maps and local channel plans to include in my own travel notebooks in the last two weeks. Somewhere is an official document listing those 12. Some of the 12 are from the VHF Incident Response frequencies in the national interoperability plan. These frequencies have been used on wildland fire incidents for nearly 10 years.

When I was assigned to large fires I didn't like scanning additional channels at all. I already had my hands full keeping track of 20 people, the fire, aircraft overhead and adjacent resources so I just kept mine on the tactical channel all the time. A fire in the mop up stage can get very monotonous so I would scan tactical, command and the local unit net just to keep me awake, but that is the only time I scanned. Battery life was not really a problem for me as I always had 9 alkali batteries in my line pack and scanning in slow times did not eat up much storage. It is not the scanning that eats up the power, it is the increased amount of reception time that results. Division supervisors have to keep track of traffic on both the division tac and the incident command at the same time. They need to scan both, plus keep track of the fire, the resources in their division and be available for the ops chief and other ops people all at the same time. The division sup is right at the point where the rubber meets the road in a way that no other position really does. The highest op position I was qualified for was "Strike Team Leader - Crew" trainee. It is hard for me to imagine how a division supervisor handles the multiple tasks of the position. My trainee assignments with division sups were all on fires where the rate of spread had been stopped or was very slow, so I never worked with a division sup on a hot situation. I was qualified as a Type IV and V IC but an entire incident of that type is not nearly as complex as one division on a Type I or II fire.

There is a need for toning, don't second guess the direction the NIFC comm division has given. In southern California and Arizona the problem of illegal frequency use in Mexico has been an issue since the NIFC frequencies have been in use, a time period I can't pin down, but I first heard it in the late 70's or early 80's. The expression in southern California used during such interference was "repeat, the Julios stepped on you." This expression may not be favored or tolerated now, but that is what I used to hear. Away from those border areas the electronic environment has become increasingly noisy and tones are needed to deal with it. Even with high standard commercial mobile radios in place I used to pick up interference when I passed certain businesses and at almost every gas pump. The computers used in camp mess with handhelds also. The interference of one incident with another is one thing, but this other noise is the bigger issue. Part 15 regulations are not effective.

Channel 16 is not used for Air Guard in every local radio in the country. That practice seems more prevalent outside California to me. Those in California are usually filled with primary nets of adjacent federal units or Cal Fire nets and tacs. Automatic interagency response is the rule and not the exception on portions of half or more of the 18 National Forests in California. Mutual aid frequencies are not used for these initial attacks as much as the local nets and tacs of the agencies involved. You are correct that there are a lot of combinations of frequencies in use on incidents.

Standard NIFC cache frequencies might not be used on an incident. Unique, one time uses of frequencies allocated for other agencies that are currently not in use in a given area may be employed if that is what the NIFC comm unit duty officer deems necessary. This is another reason radios have to be cloned at incidents as these frequencies will not be in any radios of the wildland fire management agencies.

I've been on more than a few very large and/or complex incidents where the entire 16 channels not filled. I've been on fires where 2-3 command repeaters were used, each on a different frequency, but tied together on one net using UHF link frequencies. This was due to topography and/or size of the incident. Then the fire may have multiple branches with a tactical assigned to each division that can only be reused if distance or topography allows. If the fire has a large structure protection group then the now named V Fire 21-26 tacticals will be mixed in. More than one air to ground might be used. Even in those situations the use of more than 14 channels is not all that frequent, at least it is outside my experience.
 
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Mike_G_D

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Fred, as usual, good info - thanks! You've made the comment before, I believe, that fire personnel are usually more radio competent than law enforcement field personnel. Given all of the frequent mutual aid necessary and all of the national shared resources during large incidents it's understandable. So, given the flexibility of the radios in use and the competency of the field personnel in the usage of said radios, I guess the added "complexity" of tone selection is really a non-issue. And they have been used to using multiple transmit tones on repeater systems for a very long time now.

I just am curious how the handheld receive tone selection will work with the fixed area repeaters - will each repeater be setup to automatically regenerate whatever tone is received on its input so that whatever tone is assigned the repeater will simply regenerate that on its output during transmission? This is easy and simple technically (my "comfort zone") but I am just wondering if that's how it will work in this instance. This would be for the fixed area repeaters. For the portable/transportable repeaters, those could be programmed per incident as with the handhelds in use.

As to the need for the tones - I absolutely see it as I live in southern California and experience much interference from Mexico as well as the extra interference from other electrical devices as ExSmokey mentioned. Just a couple of notes regarding this - not all of the Mexican traffic is necessarily "illegal" as the Mexican VHF bandplan is setup differently from the US bandplan. Much of the portion we set aside for federal operations may be allocated for business use in Mexico - I don't have official documents that state this but am just going by past experience - so the interference may simply be a consequence of that unfortunate situation. Given all of the current headache we have had getting Mexico to come to agreements over the 800MHz re-banding effort along the border areas (it's only very recently that it got resolved) I can imagine that complaints from even official sources in the US regarding interference tends to get either ignored or given very little attention by the Mexican authorities. I won't speculate as to the reasons but I expect that that is just how it is.

In terms of Part 15 - actually, having had to work on gear for type acceptance (for Part 15 as well as other applicable "Parts") I can say that I think it's a double edged sword if they were to be tightened up significantly. In terms of interference, tightening up Part 15 would be a good thing, of course, but in terms of consumer costs derived from the extra design, development, manufacturing, and certification costs it wouldn't be too welcome. I can see both sides and have experience with both - it's really a challenge to meet FCC rules in many cases for unintentional radiators and keep the cost down. The consumer market is so very cost conscious, understandably, that margins are already razor thin and any added complexity derived from heavier government regulations will severely impact the situation. Like I said, I can see both sides - it would be nice to have heavier shielded devices with real metal shielding and tightly constrained components and pcb layout, etc. but the cost for the metal is more than the plastic or metalized plastic or foil covers, etc., and the public probably wouldn't tolerate the larger heavier nature of their beloved teeny-tiny and light weight tech toys. Even the larger stuff like appliances, car electronics, desktop PC's, etc., would be bumped up in cost quite a bit if the rules were heavily tightened. Now, I think there is still room for improvement. I think the corresponding rules in Europe are tighter already and most of the devices made for the US market have to meet those rules as well. I think the biggest improvement could come from the industrial and commercial computing devices being tightened up as the Part 15 regulations are, as I recall, allowed to be loosened for non-residential usage (like your gas pump experience). I think that segment could tolerate the added cost and weight issues a bit better than the consumer device market. But even so, these days nobody wants to bring up added government regulation let alone one that could even slightly negatively influence an economy already in not the greatest shape.

Waayyy off topic, sorry! Just wanted to add in some experience of my own when it comes to electromagnetic interference and the need for protecting radios and their users from said interference. Really, of course we all know that CTCSS and DCS tones don't protect the radio so much as the user from said interference as the interference is still there and still could block a desired signal if strong enough but the tones do keep the users from having to hear the garbage throughout the monitoring and usage time and in critical use cases anything that can take away some of the human stress and irritation causing factors is welcome. Repeaters, of course, are an obvious case of needing tone protection as they hear and transmit over a very large area - I've heard many a large coverage repeater without tone protection in the past getting hung up on some nasty gunk (yes, even on a remote mountain it can and does happen especially when it's shared with many other repeaters) and broadcasting their electronic irritation across their full coverage area for all to hear!

I guess, for us scanner hobbyists, the easiest solution will be to leave the frequencies in question on CSQ though we will hear whatever gunk is on the channel (usually worse for consumer scanner equipment). The only other option would be to use multiple channels to accommodate all of the possible tones - what I will probably be forced to do as I get A LOT of garbage due to both the Mexican interference and to local hash. Problem is, I already have pretty much used up all of my memory slots in my gear. Oh well...

-Mike
 

rfburns

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They are typically shipped via ?air freight from the big warehouse in Boise. ("NIFC cache" is another common name for the NIRSC)
Peter that's mostly not true. There are "local" caches at various locations. A limited number of radios are staged, usually a Starter kit and maybe a couple of boxes of handhelds. When they go out the door they are replaced by radio equipment from NIRSC. The radios that went out, go back to the NIRSC when the incident is over. When you have multiple large incidents starting at the same time, obviously there's not enough radios at the GACC's logistics site to fill all of the orders and a lot of orders have to be filled directly from the NIRSC. I always found it quicker to take a full starter kit from a "local" location and use only what I needed from the kit than to order piecemeal from the NIRSC.
 

SCPD

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Mike

The tone situation is very simple. When the radio is programmed a receive and transmit tone is entered into each of the channels on a Bendix-King. The 16 standard FIRESCOPE tones, common in California for many years have been adopted by the National Wildfire Coordinating Group. The Forest Service is very close to having adopted these tones nationwide. I've seen a few channel plans of late that throw in a non-standard tone, but these are few and far between. Unfortunately there are many forests that do not use the same numbers for the same tones. Example, some forests label 100.0 as tone 1, 107.2 as tone 2, etc. in a tone frequency order rather than the order in the NWCG standard. Tone 1 per the NWCG is 110.9 and tone 2 is 123.0.

The BLM, especially in Nevada have the anti-California attitude that they don't want anyone in California to tell them what tones to use. This isn't an assumption on my part, rather from a conversation I had with one of their radio techs some years back. They don't even have a statewide plan! Some tones are different, not just in order, but in frequency between all six districts in the state. If someone comes in from out of the area, they may have the frequency pairs of all six districts, but have to reprogram the radio to get the right tones in it.

The National Park Service, as far as the channel plans I've seen of late, have adopted the sixteen tones as labeled in the NWCG standard. FIRESCOPE has NAC standard equivalent for each tone, but I'm not sure if that is being followed yet or if the NWCG standard.

Most repeaters of all the above federal agencies, in addition the U.S. Fish and Wildlife Service as well, use the input tone on the output side. There are some exceptions, for example on the Sierra National Forest, located over the crest of the Sierra Nevada from me, uses output tones that are not part of the sixteen, on the output of their repeaters. I'm not sure why, perhaps just to alert the dispatchers console of what repeater is being received. Other forests, BLM districts, NPS units and Refuges use the common input/output tone to do the same.

Each channel in a King can be programmed with different TX and RX tones. This is sometimes necessary for local systems that are typically contained in one of the sixteen groups of the King. Most local departments know that this makes mutual aid communications problematic, minimizing the number of these situations.

The NIFC portable repeaters have the same input/output tones.

One thing I didn't mention is how the tone squelch is enabled on a King. With the squelch adjusted past threshold the tone functions for transmit only. When the dial is turned to the far side there is a detent or switch marked "CG" at which point the tone squelch is enabled.

This is all very simple and fire management personnel with more than a few years of experience usually pick up how a King is programmed and how to do it themselves. With the new alphanumeric displays it is more time consuming to program one, but if time is short the frequency can be entered as the alphanumeric. Because of the time needed to program the newer radios, due to the alphanumeric display, cloning saves time.

Several years ago I read a directive from NIFC that indicated the new portable repeaters in the cache would be tone capable, of course with the TX and RX tone being the same. That directive indicated tones 1-4 of the NWCG standard would be used. That is, 1 - 110.9, 2 - 123.0, 3 - 131.8 and 4 - 136.5. I'm not sure if more than four are to be used now. Locally, Type I and Type II incident management teams are not used often, although one Type II last year had a repeater set up where is boomed into town and 136.5 was being used.

I have a mysterious interference problem in the area of my home that interferes with the Inyo National Forest's north net, along with a few more frequencies. To deal with it I've programmed each of the six repeaters I can hear from my place with their respective tones. I'm glad I have a PSR-600 with lots of capacity because using attenuation eliminates the reception, but I can only hear two of the six repeaters.

I hope this answers your questions.
 

Mike_G_D

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I think the problem is that I am really asking a question that contains one part operational and one part technical aspects. You've attempted to answer the operational part but the technical part is of considerable interest to me and it does affect the finer points of the operational part.

Let me see if I can rephrase my question or better yet give an example -

Firstly, for this hypothetical situation example let's make the following assumptions:

1) All fixed and portable repeaters use an output tone that is equivalent to its input tone.

2) All handhelds and mobiles are easily programmed on-site for tone usage and all users are familiar with the procedure for doing this.

3) The 16 tone standard is being used throughout.

4) The new procedure is in effect wherein the tones are assigned on a incident by incident basis.

For most people reading this the above should be clear and decisive and there should be no question about how the tones work and my question should be answered - except, it really isn't.

My primary concern regards the repeaters. I see two ways to "assign" tones to a fixed repeater:

1) Program them remotely using hardwired or microwave links (or possibly UHF links) such that when an incident occurs a given fixed repeater intended for use for said incident is remotely commanded to use whichever tone is so desired for that incident. Possibly old style DTMF codes sent over the input side could also be used to dos this but would be less reliable, especially with the new narrower deviation, I would think, though technically possible.

2) Setup the repeater to operate autonomously such that it includes a CTCSS logic system that automatically regenerates whatever tones are used on the input side on the output side. This would provide flexibility and ease of use on the fly compared to method #1 above but with potential problems as outlined below. (Just in case anyone is wondering - yes, you can make a repeater operate such that it simply "passes through" the tone used on the input as well as the audio but that is usually less reliable due to the pass-through audio path being subject to noise and other reliability issues so that it is almost always a better solution to re-encode a tone on the output that simply matches the input tone [or not, of course, if you want to use a different tone or no tone]; from a listener's perspective, it is transparent and a non-issue with the exception of perceived reliability of the CTCSS operation.)

Method #1 is reliable and effective but does require that extra step of having to actually send a command to the repeater remotely to engage whatever tone is being used per incident and may contain a slight risk of mis-operation if that step is either forgotten or done incorrectly.

Method #2 is easy and reliable BUT contains one big potential issue IF the same repeater pair is being used by nearby (from a radio coverage point of view) fixed and/or portable repeaters that may be assigned to operate on an adjacent incident. Because the repeater will simply key up and operate with whatever tones are used on its input (even if it is setup only to respond to the 16 standard tones) it runs the risk of passing adjacent area traffic from a different incident through its output along with the desired traffic. In such a case, although the portables and mobiles on the desired incident will not hear the undesired traffic (assuming they are using receive tone squelch) destructive interference may occur if the undesired signals are strong enough to capture the repeater's input and block the desired units which may occur, for example, if the outside incident unit is an aircraft or a high powered mobile on high ground and the desired unit is a low powered hand held at ground level. Granted, this may be highly unlikely as I would assume strict coordination for repeaters and frequencies in an area BUT we are talking about the use of multiple per-incident assigned receive and transmit tones for everything including repeaters which presumes the need to re-use a relatively low number of area radio frequencies through the use of multiple tones as in simplex usage (where, given the relatively low level signal strengths encountered, it can usually be accommodated effectively).

Part of my problem is that I do not have an effective understanding of how the resources are setup in realistic situations despite the excellent information given by ExSmokey and others on here (not your fault, just my ignorance). For one thing, as far as I understand it, this new procedure refers only to NIFC/NIRSC frequencies and not to other USFS, BLM, etc. If so, then it may be that fixed dedicated area repeaters for NIFC/NIRSC use are either rare or non-existant OR that they are spread out very thinly. In other words, most of the usage will be through simplex and portable repeaters and not through dedicated NIFC/NIRSC fixed area repeaters (yes, I know, I need to review the database info for the NIFC, etc. - which may help answer part of my question).

As to the portable repeaters, I would expect that they, too, could be set up to automatically regenerate the input tones used as in method #2 above and would likely not suffer from as much of the issue I just outlined due to their lower level of operation but, then again, due to their possible proliferation in a heavy multi-incident situation the problem could be encountered. I would think it more likely that the portable repeaters would simply be programmed on-the-fly for a given assigned tone on-site (or just prior to being deployed) as would be done for the portables and mobiles. In that case, assuming good coordination, there should be no problem.

I am likely over thinking this but it's the little technical details that I tend to get caught up in - my background, I guess. From a typical scanner user's perspective I guess it's a non-issue (assuming you either experience no local interference and/or you have multiple memory slots available) - you either program the repeater output channels on the scanner as CSQ or in multiple channels to incorporate all 16 tone combinations and be done with it.

-Mike
 

com501

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The Sierra Front repeaters have different PLs on the output because they were interfering with dispatch centers more than 300 miles away due to their altitude. The repeaters at Mt Rose, (Relay Peak) are on top of the building at 10,400 feet. I can work Mt. Toro in Monterey County on a handheld from there. That's a good distance away. Then you add ducting.....

And you can't always reduce the power to be practical, either. With a 4w ERP at that elevation, the repeater was still clearly audible in a Type 4 on I5 near Sacto.
 

SCPD

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I think the problem is that I am really asking a question that contains one part operational and one part technical aspects. You've attempted to answer the operational part but the technical part is of considerable interest to me and it does affect the finer points of the operational part.

Let me see if I can rephrase my question or better yet give an example -

Firstly, for this hypothetical situation example let's make the following assumptions:

1) All fixed and portable repeaters use an output tone that is equivalent to its input tone.

2) All handhelds and mobiles are easily programmed on-site for tone usage and all users are familiar with the procedure for doing this.

3) The 16 tone standard is being used throughout.

4) The new procedure is in effect wherein the tones are assigned on a incident by incident basis.

For most people reading this the above should be clear and decisive and there should be no question about how the tones work and my question should be answered - except, it really isn't.

My primary concern regards the repeaters. I see two ways to "assign" tones to a fixed repeater:

1) Program them remotely using hardwired or microwave links (or possibly UHF links) such that when an incident occurs a given fixed repeater intended for use for said incident is remotely commanded to use whichever tone is so desired for that incident. Possibly old style DTMF codes sent over the input side could also be used to dos this but would be less reliable, especially with the new narrower deviation, I would think, though technically possible.

2) Setup the repeater to operate autonomously such that it includes a CTCSS logic system that automatically regenerates whatever tones are used on the input side on the output side. This would provide flexibility and ease of use on the fly compared to method #1 above but with potential problems as outlined below. (Just in case anyone is wondering - yes, you can make a repeater operate such that it simply "passes through" the tone used on the input as well as the audio but that is usually less reliable due to the pass-through audio path being subject to noise and other reliability issues so that it is almost always a better solution to re-encode a tone on the output that simply matches the input tone [or not, of course, if you want to use a different tone or no tone]; from a listener's perspective, it is transparent and a non-issue with the exception of perceived reliability of the CTCSS operation.)

Method #1 is reliable and effective but does require that extra step of having to actually send a command to the repeater remotely to engage whatever tone is being used per incident and may contain a slight risk of mis-operation if that step is either forgotten or done incorrectly.

Method #2 is easy and reliable BUT contains one big potential issue IF the same repeater pair is being used by nearby (from a radio coverage point of view) fixed and/or portable repeaters that may be assigned to operate on an adjacent incident. Because the repeater will simply key up and operate with whatever tones are used on its input (even if it is setup only to respond to the 16 standard tones) it runs the risk of passing adjacent area traffic from a different incident through its output along with the desired traffic. In such a case, although the portables and mobiles on the desired incident will not hear the undesired traffic (assuming they are using receive tone squelch) destructive interference may occur if the undesired signals are strong enough to capture the repeater's input and block the desired units which may occur, for example, if the outside incident unit is an aircraft or a high powered mobile on high ground and the desired unit is a low powered hand held at ground level. Granted, this may be highly unlikely as I would assume strict coordination for repeaters and frequencies in an area BUT we are talking about the use of multiple per-incident assigned receive and transmit tones for everything including repeaters which presumes the need to re-use a relatively low number of area radio frequencies through the use of multiple tones as in simplex usage (where, given the relatively low level signal strengths encountered, it can usually be accommodated effectively).

Part of my problem is that I do not have an effective understanding of how the resources are setup in realistic situations despite the excellent information given by ExSmokey and others on here (not your fault, just my ignorance). For one thing, as far as I understand it, this new procedure refers only to NIFC/NIRSC frequencies and not to other USFS, BLM, etc. If so, then it may be that fixed dedicated area repeaters for NIFC/NIRSC use are either rare or non-existant OR that they are spread out very thinly. In other words, most of the usage will be through simplex and portable repeaters and not through dedicated NIFC/NIRSC fixed area repeaters (yes, I know, I need to review the database info for the NIFC, etc. - which may help answer part of my question).

As to the portable repeaters, I would expect that they, too, could be set up to automatically regenerate the input tones used as in method #2 above and would likely not suffer from as much of the issue I just outlined due to their lower level of operation but, then again, due to their possible proliferation in a heavy multi-incident situation the problem could be encountered. I would think it more likely that the portable repeaters would simply be programmed on-the-fly for a given assigned tone on-site (or just prior to being deployed) as would be done for the portables and mobiles. In that case, assuming good coordination, there should be no problem.

I am likely over thinking this but it's the little technical details that I tend to get caught up in - my background, I guess. From a typical scanner user's perspective I guess it's a non-issue (assuming you either experience no local interference and/or you have multiple memory slots available) - you either program the repeater output channels on the scanner as CSQ or in multiple channels to incorporate all 16 tone combinations and be done with it.

-Mike
-
The NIFC command repeaters are never fixed always portable. The portable repeaters don't have fixed repeaters to interfere with so the tone assignments are made so that other incidents will not interfere. There are 12 command frequency pairs, so the possibility for interference is not great. If 12 are not enough then temporary assignments drawing from the pool of unused federal frequencies in the area are made. The repeaters are set up to be programmed at the incident using whatever frequencies are assigned to the incident. This programming occurs before the repeater is either driven and flown to a mountain top. If a change needs to occur then someone has to drive up to change the frequency, or fly as the case may be.

The NIFC portable and 80-90% of the fixed repeaters on local nets pass through the input tone to the output. The frequencies of the fixed repeaters carrying the local nets aren't changed very often and only when the entire system's frequencies are changed. There is no need to be able to remotely change the frequency or tone of the fixed or portable repeaters. This works and people smarter at this than you and I set up these comm systems, so yes, you are overthinking this. . It all seems rather simple to me.
 
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Mike_G_D

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Ok, I get it - sorry if I caused any frustration; I should have just asked if there were any fixed/permanent repeaters used by the NIFC in the first place the answer to which would have pretty much answered my question. I just reviewed the wiki and it is stated there that all repeaters were portable - stupid move on my part not to have checked that first anyway!

And I understand the local net repeaters are not affected; they're not part of the NIFC.

Still, for me, in my scanner I will have to continue to use CSQ as there is no way I could fit 12x16 channels into what little remains of my free memory space so the tones won't help me with my local interference issues - at least until an incident using those channels actually occurs near me and I can see what tone they are using at that time (which, of course, will only be good for the duration of that particular incident).

Thanks again for the info - sorry I was so dense or at least for not doing my due diligence or asking the right question in the first place!

-Mike
 
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