OT? Police/fire/etc. scanner usage

Hi,

Apologies as this isn't strictly on-topic. But, figured

*some* folks here could provide hints or pointers to other forum...

I rescued a handheld scanner with some battery issues. Now that it's working, it seems an interesting "toy" to add to my bug out bag. (I don't have much interest in listening to that sort of sporadic chatter on a daily basis!)

But, I'm clueless as to the most *practical* way of "programming" it. To be clear, I understand how to get the parameters *into* it; rather, I'm curious as to the best way to map those frequencies onto the scanning order, etc.

The device has 10 groups of 10 channel assignments. The first of each can be treated as a "priority" channel (there is a mode that gives preference to monitoring these above the others). Entire groups can be (easily) enabled/disabled. And, individual channels can be disabled (though a bit more work to do this for many channels).

After a bit of thought *imagining* how it might be most useful in an emergency, I think the best approach is to group similar services (from different municipalities, etc.) into each group. E.g., fire in group 1, police in group 2, etc. So, in a given geographical region, you would tend (??) to just be able to pick up one set of services -- and, they would be distributed across multiple groups. This would allow you to easily disable that particular service without affecting other services from that municipality (e.g., wanting to listen to the police chatter without being distracted by activity on the fire channel(s)).

Since there often are several frequencies for each service, you could assign N groups for police traffic, M others for fire, etc. This would afford you the same sort of easy "gating" for those individual channels -- instead of having them compete with each other in the same *group*.

Having neighboring municipalities also present in these same groups (but "out of broadcast range?") would allow you to migrate with the device picking up the *local* services as you move between jurisdictions (without having to manually reprogram or enable/disable new groups for each locality).

[Remember, this sits in my BoB, not on my desk!]

Any hams or "casual listeners" who can comment on the utility of various approaches to this?

Thanks!

Reply to
Don Y
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There are websites that list your local frequencies. Just search for 'scanner frequencies' FYI, some departments are/have switched to trunking equipment, so you cant listen to them with a non-trunking scanner.

My old Bearcat has the group buttons. I used to scan and add the frequencies of interest manually.

Cheers

Reply to
Martin Riddle

Yes, I already have those. My question concerns how best to *map* those onto the channel assignments in the scanner.

E.g., if I put every service for my local community into Group 1, the next municipality into Group 2, etc. then I can easily disable "there" vs. "here". But, *being* "here" (instead of "there") already does that for me -- the signals just don't propagate that far!

So, it seems more *useful* to spread the services across different groups so that they can be (easily) enabled/disabled and let geographical location take care of enabling/disabling different municipalities services sharing a single group.

(e.g., if you're in D.C., channel 1x receives the fire dept for D.C. while channel 2x receives D.C. police; move to NYC and channel 1y receives NYC FD while 2y receives NYC PD; etc. Being

*in* NYC means the ?x channels (from D.C.) are out of range. So, no need to explicitly be able to disable them, individually. OTOH, being able to disable group 1? allows you to keep fire chatter from interfering with police chatter) [this example is intentionally naive as I realize certain frequencies can be "reused" in different localities, etc.]

Yes. Again, consider the application: emergencies. Presumably, there would be an interest in disseminating information instead of

*hiding* it (though obviously there would also be interest in hiding certain *types* of information).

E.g., I also have a portable CB radio in the BoB as it would allow contact with other folks when other means of communication are down.

But, *where*? To which particular channel assignment? Or, just "ad hoc"?

(In an emergency, you wouldn't want to be wasting time trying to find or think of particular frequencies to monitor -- hence my idea to just cover the surrounding localities)

Reply to
Don Y

The Bearcat with the group buttons is meant for race team monitoring, so

1 team per group. 1 fire dist per group, 1 police department per group, 1 airport per group, etc.

Get it?

Each group can be added or left out of the scan on the Bearcat (Sportcat).

I'm sure yours is similar.

Cheers

Reply to
Martin Riddle

I don't know if this is the best way for you, but I used the group for geographical location. Mainly because my county home is about 80 miles from my city home and, believe it or not, the Sheriff's repeaters will frequently break the squelch from that far away, especially if I'm using an external antenna. If the signal breaks the squelch, it will tie up the scanning until that signal goes away.

Just a thought.

John

Reply to
John S

Yikes! I had assumed signal would fall off much quicker than that. OTOH, I hadn't been planning on anything other than the rubber ducky for an antenna.

Exactly. That was my rationale behind moving the various "services" to different groups -- so they could *easily* be disabled (turn the group off) to keep their traffic from interfering with something that you actively want to monitor.

The few times I have used this were to monitor "situations" that were happening and the "other (UNRELATED) traffic" kept interfering with the monitoring of those *conversations*.

So, I figured moving tactical frequencies to a place where they could be isolated from "dispatch" might have some merit, etc.

I will have to look at the frequency allocations with a more critical eye towards how to factor geography into the partition more effectively...

Reply to
Don Y
[much elided]

OK. But, I would imagine that all of the traffic on that group at any different time is related to that "race". E.g., you don't have the team's *accountant* chatting with the tax attorney on a frequency in that group at the same time. If so, you would want to be able to easily filter that out.

E.g., police dispatch and tactical frequencies both could be lumped together as "police" and assigned to a single group. But, if you were then interested in following what is transpiring on "TAC1", you end up also listening to other dispatches at the same time -- as well as TAC2, etc.

I figured assign N groups for police (since there might be several different UNRELATED "conversations" going on at any given time and this would allow you to *easily* drop those channels that aren't pertinent to your interests -- *or*, leave them in play!) and M groups for fire (same reasoning).

It just seems easier to enable or disable groups than individual channel assignments (push button, group is disabled, push again, group is *enabled* -- and, you can see the status at any time by looking at the display! Not so for the individual channels in a group)

Reply to
Don Y

Hold that thought.

A recent news item I saw said that the police in Pasadena, California are encrypting their radio traffic. With the Federal Gov't copiously handing out bucks to turn local police departments into paramilitary outfits, expect to see a lot more of that nationwide.

Reply to
JeffM

"JeffM"

** All radio traffic for police, fire and ambulance in NSW Australia is encrypted and has been so for many years - same goes for the rest of the country AFAIK.

Why you Yanks so far behind ?

No mobile phones and very few cordless phone exist with simple FM modulation in Australia.

My AR1000 scanner is now used purely for checking FM radio mics on VHF and UHF.

... Phil

Reply to
Phil Allison

Phil Allis>Why you Yanks so far behind ?

Installed base. People who don't want to pay taxes. Huge amounts of the taxes that -are- collected going to militarism / military misadventures.

Reply to
JeffM

Old news (well, maybe not for Pasadena, but this has been going on for a LONG time)

Unfortunately (?), it seems that many of those grants are going towards "toys" that will have little practical impact in a true emergency. I know some folks who deal with this sort of thing on the State level and they shake their heads when they describe some of the crap ^H^H^H wonderful stuff that goes through on these grants.

But, then again, look at the sorts of folks who are making those "low level" decisions. Can you spell "Peter Principle"?

It is painfully obvious that you had best look to your *own* preparations (if that wasn't intuitively obvious before!).

OTOH, you can get just as silly throwing (*your*!) money at a problem that may never (touch wood!) materialize.

[programming a freebie scanner seems to be low hanging fruit, IMHO. YMMV]
Reply to
Don Y

On a sunny day (Sat, 18 Feb 2012 20:11:16 -0800 (PST)) it happened JeffM wrote in :

Yep, Europe, and especially Germany is bringing up a totally encrypted system. Plenty of problems with it too.

Reply to
Jan Panteltje

It's simple: They don't want you to know what they are doing.

--
You can't have a sense of humor, if you have no sense.
Reply to
Michael A. Terrell

It is called SDR. (Software Defined Radio).

The only reason the military is involved is because the enabling hardware already exists in that channel. Funny that it is called SDR, but so much Hdw is Rqd to get it UAR. :-)

It will likely require a complete switch-out of all current transceiver gear sets.

Reply to
WoolyBully

Emergency responders do not design their systems to disseminate information. They aren't hiding information. They are making maximum use of the frequency spectrum available.

A trunked system does not have frequencies assigned to a particular function, like "traffic". There is a control channel. Otherwise, frequencies are assigned to "traffic" when someone needs to send "traffic" information. The channel assigned can be any of the channels that are available. Listening to a trunked system without a scanner made for trunking is very problematic.

Another minor problem is, as far as I know, they are all digital. And some are encrypted (I don't think many of the systems, like police, encrypt much.)

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has information on trunking

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probably has the best information on what systems and frequencies are used for a particular user (like NYC police).

How active is CB these days? I don't know.

--
bud--
Reply to
bud--

I can usually find traffic on the CB a lot more often than something dribbling in over the scanner.

CB has lots of appeal (remember, "emergencies").

First, I *can* transmit. I can't do so on police/fire/etc. bands. (I've also got a 2m rig but I can't *legally* key that. It would have to be a really *personal* emergency to go that route) A pair of handhelds (I have three units in my BoB) allows any group I may be a part of to split while remaining in contact. And, anyone in that group could contact "outsiders" to request aid, information, etc.

Second, it has a reasonably large established base. And, many of the folks using it *tend* to be active on it. I.e., it's not sitting in a basement "ham shack" that gets visited "occasionally".

Third, that same community of users tend to be the sorts who would be involved in actively encountering and then disseminating information about an unfolding emergency (i.e., "they've closed down highway XXX", "A national guard caravan just passed me headed east on...", etc.).

Of course, the *quality* of that information could be dubious (would you prefer, instead, to be constrained to ONLY receiving information spoon fed to you over a

*controlled* medium? Recall, I have access to that just like any other "citizen").

I've also got a pair of pocket-sized GMRS handhelds for yet another "potential link".

The goal, of course, is to never NEED any of this! :>

Reply to
Don Y

=20

=20

Having used a trunked radio system for some years not too long ago i can make the following definite statements about that particular system:

Analog FM (with some GMSK control tones), some 48 frequency channels = (with some 200 logical channels) on the system.

Definite (logical and frequency) channels assigned to specific functions and by location as well:

=46unctions: Traffic management Maintenance Construction Traffic response team

Locales: LA basin San Gabriel Valley Coastal Ventura County

Orange county and San Bernadino + Riverside counties had their own subsystems. Statewide agency managed allocation.

Most individuals in had personal call signs.

Reply to
josephkk

About a year ago I tried to figure out trunking to figure out what I would need if I bought a scanner. I looked at my notes. It is not simple. There are multiple basic systems that have different and multiple features.

Looks like most communications in use now are analog. Some systems can use digital, and some can do encrypted. My impression was that state and local did not use encrypted much.

A function, like "traffic" (that is "Podunk traffic"), can be permanently assigned to a particular physical channel. But a basic feature of most trunking is assigning a physical channel to a "logical" use on the fly so a set of "logical" uses can use a much smaller number of physical channels.

I think that is consistent with what you wrote.

Particularly if someone is interested in listening to emergency responder and public service communications it would be a real good idea to find out what systems are in use. The old simple scanners work for some, but not for others. For some others you may be able to listen, but the conversation you listen to will constantly change. Last I read there was one trunked system that available scanners could not follow. The information should be available at radioreference. Also I think there are local forums at radioreference.

Reply to
bud--

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We are coming from somewhat different experience perspectives. I do not see any important inconsistencies. The trunked system i used was rather old (over 40 yo) and large. It was easy to follow with simple scanners = as a result. More modern and more software defined trunked radios can be = all but impossible to follow (or even receive) with anything but system matched equipment. =20

Various players are really starting to understand the tradeoff between interoperability and privacy/security of their radio systems. Large players with seriously old systems do not want to suddenly replace and entire fleet worth of equipment and their systems are the easiest to interoperate for now. Organizations with the newest systems have the = most capability but do not interoperate worth squat yet. Creates a big = problem for FEMA and the like.

Reply to
josephkk

I am surprised there were trunked systems 40 years ago, but it is certainly not something I keep track of.

My impression is that a major push for trunked systems (actually systems that can easily be built to interoperate) came out of 9/11 when some of the responders to WTC couldn't talk to other responders.

After the collapse of the I35W bridge in Minneapolis a couple years ago there were responders from mulitple police, fire and state agencies. The report was they could talk to each other very well. I believe the trunked system used dates to after 9/11. Some trunked systems that can be built as very interoperable can have encryption when needed.

Reply to
bud--

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