br0adband
Member
Dynamic memory allocation is the future of our hobby, and here's a short paper I put together recently explaining why.
In a nutshell (and forgive me for repeating if this has already been discussed - and I'm sure it has) it works like this:
In the old days scanners worked on channels, which was another way of saying frequencies. Before the digital displays in use today, we had crystal scanners - each channel required a crystal tuned to the specific frequency you're trying to monitor.
If you had a police department in your area that used a frequency of 460.100 MHz as Police Channel 1, then maybe 460.250 MHz for Police Channel 2, you would program the older scanners (or you'd purchase the proper crystals) with two of the available memory channels, one would be for Police Channel 1, the other for Police Channel 2.
Of course, on older scanners all you'd probably see on the display (if it had/has one) would be the channel number you assigned, the frequency you're listening to, a notification that you're in Scan or Manual mode, Priority on or off, etc.
Not only did you typically have channels, but when the handheld and base versions of scanners changed to using LCD displays and microprocessors to control the scanning activity, they also introduced the concept of banks - a specific amount of channels that were grouped together based on your needs. You could program one bank for one city in your area that contained all the known public safety frequencies or whatever you wanted, another bank would be the same for a different city, etc.
This type of channel and memory allocation becomes very problematic with trunked systems. Trunked communications uses a set amount of frequencies for an entire system and each group of people/users that needs to communicate are assigned a code, called a talkgroup, as an identifier. So people using a talkgroup (TG or TGID) for Police Channel 1 will only be able to communicate with other people using the same TG when they key up their radios and transmit.
Modern scanners typically only need to tune the control channels to access the communications on the system you're monitoring. You don't have to program in each individual frequency in use - the scanner monitors the control channels and locks in the frequency as required. With the 246T in particular, there is a specific system-wide option (meaning you can enable it or disable it for each system you create) that monitors only the control channels or not.
So with this type of system, say you have a citywide public safety comm setup. It uses 10 frequencies in the 800 MHz public safety band, 4 of those are assigned as control channel frequencies that alternate on either 12 hour or 24 hour shifts, changing as required
If you have a scanner that has 1000 channels in 10 banks of 100 channels each, and you only need to monitor those 4 control channel frequencies, you effectively just lost 96 possible memory locations in one of the banks you choose to program those 4 control channel frequencies in.
While there are ways around this massive loss of memory (locking out the control channels and using the remaining memory channels for other purposes, etc), it's tiresome and still pretty damned inefficient. Imagine that example and then having to unlock 96 possible memories when you want to listen to the other stuff you programmed into the same bank, and then relocking them when you did want to monitor the trunked system. Ouch.
That's the past.
Welcome to the future of hobbyist scanning.
Now we have dynamic memory allocation starting with the Uniden 246T and I believe all future Uniden scanners, hopefully Radio Shack/GRE also. I think the Pro-96 offers something similar but not quite the same as Uniden's implementation.
Dynamic memory allocation, aka "virtual folders" by some people/companies, has been a long long time coming but now that it's here it's going to revolutionize our hobby like not much else ever has.
I'd hesitate to say dynamic memory allocation is as important as trunk tracking was years ago when first introduced, but that's just me. It's that important.
It works like this:
Take the above example and translate it to dynamic memories. You need the 4 memories for programming in the 4 control channel frequencies. As mentioned above, on the 246T you can even tell the scanner to monitor only those frequencies specifically - a big plus that means you don't have to program in all the frequencies in use in a trunking system, just the ones assigned as control channels.
On the old system you'd maybe use one entire bank for one particular system, say your local Police dept. Another bank would contain the Fire dept, then maybe the City Services/Public Works. With trunking systems, they all use the same radios and frequencies but each particular use is designated with a talkgroup (TG or TGID).
So these days it's not about frequencies and channels anymore, really. It's about memories and TGs. Nowadays the memories in scanners are designed to hold the TG identifier and the alpha tags you create for them. For all intents and purposes now, a talkgroup and a channel are interchangeable terms. That's a very important distinction, especially for old timers like myself that still think "channel" means frequency. The best thing to do is stop thinking about frequencies at all unless you're talking about conventional (meaning non-trunked) communications.
If everyone using a specific talkgroup can only communicate with each other, that's analogous with users on the same channel only being able to talk to people tuned to that channel.
So, talkgroups == channels in trunking systems. Remember: this only applies to trunked communications systems; this information about talkgroups has no bearing on conventional systems (the older frequency/channel based ones) which are still referred to as channels by most people.
When you program a scanner with dynamic memory allocation, you do something like this:
First, you create a system. Typically most people use either a city name or some other identifier to name a system. Then you have to create groups within that system.
Let's say you want only the Police dept TGs in a system to keep them seperate from the Fire/EMS or City/Public Works comms. Let's say you have 15 known TGs for the Police dept culled from sources such as Radio Reference, or perhaps a local Radio Shack or CB shop.
You program the scanner with those TGs, or you can usually just scan for them and acquire them when they come up on the scanner. Write them down and then just by listening you can figure out which TG is associated with which purpose. I myself did that during a major hurricane here in my area in 2003. I sat down with a Pro-94 for about a week (we had no electricity) and just listened and wrote a lot of TGs down. Within that week I had named off 74 TGs accurately in 4 cities in my area which I later confirmed with online data when the power returned.
Say you want to create three groups in that system: Police, Fire/EMS, and City/Public Works. Inside each of those groups will be the talkgroups that you program. In my area, I have 9 TGs for Police-specific comms:
55568 Police Primary (main dispatch)
55600 Police 2 (secondary, mainly for license/SSN checks)
55632 TAC 3 (tactical comms)
55664 TAC 4 (tactical comms)
55696 TAC 5/Detectives (tactical comms, especially Detective one-to-one)
55792 TAC 8/Supervisor (tactical comms, one-to-one for shift Supervisors)
55728 Police Mutual (mutual aid TG for city-to-city comms)
55760 Sheriff (city jail operations, civil services like subpoenas)
55824 Narcotics/SWAT (special ops, drug enforcement)
So, the system I created is Portsmouth and the first group is Police, which contains those TGs/alpha tags above.
The cool thing here is that the dynamic memory allocation is dead on efficient: I only use the memory I need to contain the data involved with the TGs and the alpha tags and the 4 control channel frequencies. I then created the Fire/EMS group and programmed in the TGs and alpha tags, then the City Services and it's associated TGs and alpha tags.
The beauty of this system is that now, once everything is programmed and assigned, I can choose to either scan through all the Portsmouth system itself, or I can choose only the Police group, or perhaps I want to hear the waste management/trash trucks - and I can do all this with a button or two at most. I can even lock out specific talkgroups or monitor only specific ones. Once again, sometimes it's interesting listening to the trash trucks in my area on trash collection day, other times I don't care to hear it or have the scanner stop when a transmission in that TG happens so I lock it out.
In some respects, people reading this might think, "That's not so clever, it works almost the same as the bank/channel scanners." And you're right, in some respects we're still just programming in things we want to listen to and then listening.
The clever part is that we're not wasting memory/channels/banks, we're only using exactly what we need to use. From the example way back near the beginning of this little FAQ of mine, we can see that on conventional/older scanners, programming in those 4 control channels could cost us a considerable amount of possible memory/channel slots that simply go to waste if you program your scanner(s) in a "this bank is for xxx, this bank is for yyy" sort of scheme. With dynamic memory allocation, the waste of memories and channels is ancient history at this point.
Is this harder to deal with? Well, for old timers like myself (30 years of scanning/monitoring under my belt), it can be. But I make a hobby of consumer electronics, computers, scanners, HAM radio, Walkmans, CDs, mp3 players, etc. I pick this stuff up fast.
In the past 20 years, the biggest things to happen to hobbyist scanning in my opinion are:
800 MHz coverage in scanners in the late 1980's (major contribution)
Trunk tracking in the mid-1990's (the biggest contribution of all)
Alpha tagging on the heels of trunk tracking (the biggest help when scanning)
High capacity memories (allowing a lot of stuff to be programmed in)
Computer programming (an ease of use tool, definite timesaver)
Computer control (the next step)
And finally, dynamic memory allocation gets added to that list.
Was the 246T I got last week difficult to program? Yes, for about 2 hours I was stumped by the dynamic memory allocation system. But I have a friend that already owns a 246T and with his brief assistance and with the manual (you know, that funny looking paperback thing they include with most scanners when you buy them, has all sorts of text and stuff in it, supposed to be helpful?
Yeah, that thing) I got "over the hump" with the 246T in about 3 hours.
The next day I could do anything with the scanner that it can do save one or two operations that I figured out (again, I read the manual) later on that evening.
I'm currently a big fan of the Butel Software ARC246 software for not only programming the 246T but also controlling it. Uniden gets a big plus for at least offering some basic rudimentary software for download for the 246T, although you have to purchase it to unlock the full functionality (ARC246 is the same way: they offer a trial/limited version and when you pay for the software you get a bit more featurewise). Radio Shack/GRE need to get on the ball in that respect - but that's only my opinion, mind you.
If you own a PC and you get a 246T or any modern scanner that's either programmable by software on the PC or even better controllable by the software, don't hesitate for a second about doing it that way. Trust me, for the 4 cities I have in my area, it would have taken the better part of a day programming in all those systems/groups/TGs/alpha tags by hand. I would start wearing out the scroll knob on the 246T. I chose to check out ARC246 and had all the stuff programmed into the scanner in about 2-2.5 hours roughly.
It's a major MAJOR timesaver and it makes it really easy to share the data with other users in your area. Most modern scanners have the ability to "clone" the data when connected to another scanner of the same model. The 246T offers this option, but it's not always possible to get face to face with another owner and even so, one of you might forget to bring the cloning/data cable. Possibly both of you. So having the ability to save the data in a file and just email it to a friend so he can then upload it into his scanner is awesome stuff indeed.
Look, it's not that hard to learn something new. Yes it's different, yes it's a totally new way of doing things. But look at it this way: it's the future of our hobby, so why not jump in while the gettin's good and in no time at all you'll be teaching every new forum member "Oh yeah, it was tough at first... for about 3 hours... here, lemme show you how it works..."
That is the spirit of this type of community. To have a question, to ask it, get an answer and then share that information with others so everyone helps everyone else.
I hope this little FAQ-of-sorts helps someone get an idea about how much better the dynamic memory allocation system is and will continue to be. If anyone has any questions, don't hesitate to ask in this thread or you can email me at: br0adband2004@gmail.com anytime.
I'd like to thank UPMan here at Radio Reference for his assistance with customer issues and suggestions, as well as giving us information about future products. I haven't been a forum member for long, but I can see his presence is definitely a positive to the community.
I'd also like to thank Uniden for finally putting out a scanner that really does create a new paradigm for the hobbyist scanning market. Great piece of hardware guys, and we can't wait to get our hands on the 396T when it's finally available.
In all, I have only two cons (negatives) about my 246T: I wish it covered the Milair band (225-400 MHz) because I live in the largest naval operations area in the world with several Air Force bases to boot so I do have some use for that band; and the keypad isn't backlit as I had hoped. Aside from those two nitpicks, it's as close to perfect as I might want. For it being a non-digital (APCO 25) scanner, nothing can really touch it for a price/feature ratio.
The 396T will probably turn out to be the creme de la creme of handheld scanners, assuring Uniden the top spot in the hobby. I will definitely be getting one even though the cost of the 396T is going to be very high for its features. It's the price we pay for our hobby, as with any other.
I think it's worth every cent.
Have fun, always...
Paul
EDITED to correct some typos...
In a nutshell (and forgive me for repeating if this has already been discussed - and I'm sure it has) it works like this:
In the old days scanners worked on channels, which was another way of saying frequencies. Before the digital displays in use today, we had crystal scanners - each channel required a crystal tuned to the specific frequency you're trying to monitor.
If you had a police department in your area that used a frequency of 460.100 MHz as Police Channel 1, then maybe 460.250 MHz for Police Channel 2, you would program the older scanners (or you'd purchase the proper crystals) with two of the available memory channels, one would be for Police Channel 1, the other for Police Channel 2.
Of course, on older scanners all you'd probably see on the display (if it had/has one) would be the channel number you assigned, the frequency you're listening to, a notification that you're in Scan or Manual mode, Priority on or off, etc.
Not only did you typically have channels, but when the handheld and base versions of scanners changed to using LCD displays and microprocessors to control the scanning activity, they also introduced the concept of banks - a specific amount of channels that were grouped together based on your needs. You could program one bank for one city in your area that contained all the known public safety frequencies or whatever you wanted, another bank would be the same for a different city, etc.
This type of channel and memory allocation becomes very problematic with trunked systems. Trunked communications uses a set amount of frequencies for an entire system and each group of people/users that needs to communicate are assigned a code, called a talkgroup, as an identifier. So people using a talkgroup (TG or TGID) for Police Channel 1 will only be able to communicate with other people using the same TG when they key up their radios and transmit.
Modern scanners typically only need to tune the control channels to access the communications on the system you're monitoring. You don't have to program in each individual frequency in use - the scanner monitors the control channels and locks in the frequency as required. With the 246T in particular, there is a specific system-wide option (meaning you can enable it or disable it for each system you create) that monitors only the control channels or not.
So with this type of system, say you have a citywide public safety comm setup. It uses 10 frequencies in the 800 MHz public safety band, 4 of those are assigned as control channel frequencies that alternate on either 12 hour or 24 hour shifts, changing as required
If you have a scanner that has 1000 channels in 10 banks of 100 channels each, and you only need to monitor those 4 control channel frequencies, you effectively just lost 96 possible memory locations in one of the banks you choose to program those 4 control channel frequencies in.
While there are ways around this massive loss of memory (locking out the control channels and using the remaining memory channels for other purposes, etc), it's tiresome and still pretty damned inefficient. Imagine that example and then having to unlock 96 possible memories when you want to listen to the other stuff you programmed into the same bank, and then relocking them when you did want to monitor the trunked system. Ouch.
That's the past.
Welcome to the future of hobbyist scanning.
Now we have dynamic memory allocation starting with the Uniden 246T and I believe all future Uniden scanners, hopefully Radio Shack/GRE also. I think the Pro-96 offers something similar but not quite the same as Uniden's implementation.
Dynamic memory allocation, aka "virtual folders" by some people/companies, has been a long long time coming but now that it's here it's going to revolutionize our hobby like not much else ever has.
I'd hesitate to say dynamic memory allocation is as important as trunk tracking was years ago when first introduced, but that's just me. It's that important.
It works like this:
Take the above example and translate it to dynamic memories. You need the 4 memories for programming in the 4 control channel frequencies. As mentioned above, on the 246T you can even tell the scanner to monitor only those frequencies specifically - a big plus that means you don't have to program in all the frequencies in use in a trunking system, just the ones assigned as control channels.
On the old system you'd maybe use one entire bank for one particular system, say your local Police dept. Another bank would contain the Fire dept, then maybe the City Services/Public Works. With trunking systems, they all use the same radios and frequencies but each particular use is designated with a talkgroup (TG or TGID).
So these days it's not about frequencies and channels anymore, really. It's about memories and TGs. Nowadays the memories in scanners are designed to hold the TG identifier and the alpha tags you create for them. For all intents and purposes now, a talkgroup and a channel are interchangeable terms. That's a very important distinction, especially for old timers like myself that still think "channel" means frequency. The best thing to do is stop thinking about frequencies at all unless you're talking about conventional (meaning non-trunked) communications.
If everyone using a specific talkgroup can only communicate with each other, that's analogous with users on the same channel only being able to talk to people tuned to that channel.
So, talkgroups == channels in trunking systems. Remember: this only applies to trunked communications systems; this information about talkgroups has no bearing on conventional systems (the older frequency/channel based ones) which are still referred to as channels by most people.
When you program a scanner with dynamic memory allocation, you do something like this:
First, you create a system. Typically most people use either a city name or some other identifier to name a system. Then you have to create groups within that system.
Let's say you want only the Police dept TGs in a system to keep them seperate from the Fire/EMS or City/Public Works comms. Let's say you have 15 known TGs for the Police dept culled from sources such as Radio Reference, or perhaps a local Radio Shack or CB shop.
You program the scanner with those TGs, or you can usually just scan for them and acquire them when they come up on the scanner. Write them down and then just by listening you can figure out which TG is associated with which purpose. I myself did that during a major hurricane here in my area in 2003. I sat down with a Pro-94 for about a week (we had no electricity) and just listened and wrote a lot of TGs down. Within that week I had named off 74 TGs accurately in 4 cities in my area which I later confirmed with online data when the power returned.
Say you want to create three groups in that system: Police, Fire/EMS, and City/Public Works. Inside each of those groups will be the talkgroups that you program. In my area, I have 9 TGs for Police-specific comms:
55568 Police Primary (main dispatch)
55600 Police 2 (secondary, mainly for license/SSN checks)
55632 TAC 3 (tactical comms)
55664 TAC 4 (tactical comms)
55696 TAC 5/Detectives (tactical comms, especially Detective one-to-one)
55792 TAC 8/Supervisor (tactical comms, one-to-one for shift Supervisors)
55728 Police Mutual (mutual aid TG for city-to-city comms)
55760 Sheriff (city jail operations, civil services like subpoenas)
55824 Narcotics/SWAT (special ops, drug enforcement)
So, the system I created is Portsmouth and the first group is Police, which contains those TGs/alpha tags above.
The cool thing here is that the dynamic memory allocation is dead on efficient: I only use the memory I need to contain the data involved with the TGs and the alpha tags and the 4 control channel frequencies. I then created the Fire/EMS group and programmed in the TGs and alpha tags, then the City Services and it's associated TGs and alpha tags.
The beauty of this system is that now, once everything is programmed and assigned, I can choose to either scan through all the Portsmouth system itself, or I can choose only the Police group, or perhaps I want to hear the waste management/trash trucks - and I can do all this with a button or two at most. I can even lock out specific talkgroups or monitor only specific ones. Once again, sometimes it's interesting listening to the trash trucks in my area on trash collection day, other times I don't care to hear it or have the scanner stop when a transmission in that TG happens so I lock it out.
In some respects, people reading this might think, "That's not so clever, it works almost the same as the bank/channel scanners." And you're right, in some respects we're still just programming in things we want to listen to and then listening.
The clever part is that we're not wasting memory/channels/banks, we're only using exactly what we need to use. From the example way back near the beginning of this little FAQ of mine, we can see that on conventional/older scanners, programming in those 4 control channels could cost us a considerable amount of possible memory/channel slots that simply go to waste if you program your scanner(s) in a "this bank is for xxx, this bank is for yyy" sort of scheme. With dynamic memory allocation, the waste of memories and channels is ancient history at this point.
Is this harder to deal with? Well, for old timers like myself (30 years of scanning/monitoring under my belt), it can be. But I make a hobby of consumer electronics, computers, scanners, HAM radio, Walkmans, CDs, mp3 players, etc. I pick this stuff up fast.
In the past 20 years, the biggest things to happen to hobbyist scanning in my opinion are:
800 MHz coverage in scanners in the late 1980's (major contribution)
Trunk tracking in the mid-1990's (the biggest contribution of all)
Alpha tagging on the heels of trunk tracking (the biggest help when scanning)
High capacity memories (allowing a lot of stuff to be programmed in)
Computer programming (an ease of use tool, definite timesaver)
Computer control (the next step)
And finally, dynamic memory allocation gets added to that list.
Was the 246T I got last week difficult to program? Yes, for about 2 hours I was stumped by the dynamic memory allocation system. But I have a friend that already owns a 246T and with his brief assistance and with the manual (you know, that funny looking paperback thing they include with most scanners when you buy them, has all sorts of text and stuff in it, supposed to be helpful?
Yeah, that thing) I got "over the hump" with the 246T in about 3 hours.The next day I could do anything with the scanner that it can do save one or two operations that I figured out (again, I read the manual) later on that evening.
I'm currently a big fan of the Butel Software ARC246 software for not only programming the 246T but also controlling it. Uniden gets a big plus for at least offering some basic rudimentary software for download for the 246T, although you have to purchase it to unlock the full functionality (ARC246 is the same way: they offer a trial/limited version and when you pay for the software you get a bit more featurewise). Radio Shack/GRE need to get on the ball in that respect - but that's only my opinion, mind you.
If you own a PC and you get a 246T or any modern scanner that's either programmable by software on the PC or even better controllable by the software, don't hesitate for a second about doing it that way. Trust me, for the 4 cities I have in my area, it would have taken the better part of a day programming in all those systems/groups/TGs/alpha tags by hand. I would start wearing out the scroll knob on the 246T. I chose to check out ARC246 and had all the stuff programmed into the scanner in about 2-2.5 hours roughly.
It's a major MAJOR timesaver and it makes it really easy to share the data with other users in your area. Most modern scanners have the ability to "clone" the data when connected to another scanner of the same model. The 246T offers this option, but it's not always possible to get face to face with another owner and even so, one of you might forget to bring the cloning/data cable. Possibly both of you.
So having the ability to save the data in a file and just email it to a friend so he can then upload it into his scanner is awesome stuff indeed.Look, it's not that hard to learn something new. Yes it's different, yes it's a totally new way of doing things. But look at it this way: it's the future of our hobby, so why not jump in while the gettin's good and in no time at all you'll be teaching every new forum member "Oh yeah, it was tough at first... for about 3 hours... here, lemme show you how it works..."
That is the spirit of this type of community. To have a question, to ask it, get an answer and then share that information with others so everyone helps everyone else.
I hope this little FAQ-of-sorts helps someone get an idea about how much better the dynamic memory allocation system is and will continue to be. If anyone has any questions, don't hesitate to ask in this thread or you can email me at: br0adband2004@gmail.com anytime.
I'd like to thank UPMan here at Radio Reference for his assistance with customer issues and suggestions, as well as giving us information about future products. I haven't been a forum member for long, but I can see his presence is definitely a positive to the community.
I'd also like to thank Uniden for finally putting out a scanner that really does create a new paradigm for the hobbyist scanning market. Great piece of hardware guys, and we can't wait to get our hands on the 396T when it's finally available.
In all, I have only two cons (negatives) about my 246T: I wish it covered the Milair band (225-400 MHz) because I live in the largest naval operations area in the world with several Air Force bases to boot so I do have some use for that band; and the keypad isn't backlit as I had hoped. Aside from those two nitpicks, it's as close to perfect as I might want. For it being a non-digital (APCO 25) scanner, nothing can really touch it for a price/feature ratio.
The 396T will probably turn out to be the creme de la creme of handheld scanners, assuring Uniden the top spot in the hobby. I will definitely be getting one even though the cost of the 396T is going to be very high for its features. It's the price we pay for our hobby, as with any other.
I think it's worth every cent.
Have fun, always...
Paul
EDITED to correct some typos...
