Upgrading Radio System for a School. Tech Questions

[contrak10]

I am currently in the research phases for designing a new radio system for a large high school about 1700 students. I will be assuming a position in June that would put me in charge of all the radios in the school. I want to get all the plans ready early so I can submit a price estimate to the board. The question that I have is about the Deskset series. What I'm looking to do is instead of buying three mobile radios and sticking in them in the locations need ( Main Office, Guidance, Administrators) I want to buy three MC2000 desksets OR something like that to communicate with the rest of the school portables. I want to hook them up via parallel connection to one mobile, most likely a MAXTRAC mobile. I want to make the entire system MDC1200 compatible, I have already choose CP200 and HT1250 radios to include in the new system which will be UHF. I want to make the system 4 freq. on 4 separate channels or 1 freq. with 4 different PL codes on 4 different channels, what ever you think is better. However going back to the MC2000 issue, would it be more cost effective to go with that system or to go with three base mobiles. Just to note we will have 24 portables talking on the system. I hoping to keep the dollar value under $3500.00.

[Will]

Four different PL or DPL codes on the same RF channel is going to cause different 'user groups' to step all over others on the the radio. Maybe use the Busy Channel Lockout on the portables and Control Station (maxtrac), poor man's trunking!!..
Adding an RF channel requires a seperate repeater, duplexer and antenna, going to three or more seperate repeaters you can use a Tx combiner/duplexer/RX distrubution pannel and one antenna.

Use a R1225 radio chassis only, don't need the dash board, and a ZR310 or Zetron TP38 to do multi- PL's. Mount it simmular to the photo on my website, The Duracom power supply and the duplexer is mounted on the back of the 19' rack pannel. You can also mount everything on a plywood back board, saving the cost of the GR cabinet, ect;. With the R1225's heatsink vertical it gets rid of heat much better and running 1/2 power or less you may not need any fan.

[KG6EAQ]

I'll warn ya now it's sorta long

I am currently in the research phases for designing a new radio system for a large high school about 1700 students.

I'll assume you don't work for the Los Angeles Unified if you consider 1700 to be large Most of our junior highs are larger than that!

I want to make the system 4 freq. on 4 separate channels or 1 freq. with 4 different PL codes on 4 different channels, what ever you think is better.

What do you have licenses for? Find out from your district radio shop what frequencies they are licensed for and what you can use. You may not have the option of four different frequencies. All the schools I've worked at and the one I am based out of now only have one frequency and one PL and everything works fine. I wouldn't want every office on a different PL as how will they hear if someone says there is a shooting going on?

However going back to the MC2000 issue, would it be more cost effective to go with that system or to go with three base mobiles. Just to note we will have 24 portables talking on the system. I hoping to keep the dollar value under $3500.00.

I'd just give each office a portable. They don't need the power or the antenna of a mobile, it will be a lot of work so the guy a mile away can listen to the office. If everyone has 4 watt portables you won't have any problems covering a high school campus without a repeater. Put one mobile in the main office so they can hear everything and everyone else a portable. How often is the guidance office really gonna need a radio? Maybe the guidance counselors if they have supervision duties during lunch times but the office itself would be fine with a portable. If the guidance office needs the main office they can pick up the phone and talk to them.

I know you probably want to have a nice cool system but you need to be realistic, this is a school not a police force. The price range you are talking about REALLY limits you to portables as even if you get the radios and all the needed accessories for $250, with 24 portables you are already at $6000. I don't see money there to buy the equipment to have all those mobiles installed properly and slapping a mag mount on top of a filing cabinet doesn't count! Dump the ideas with mobiles in every office to cut the costs. Also look in the the on going maintance issues that come with having several mobiles, or desksets. How long do you plan to be at this school? Unless you plan on being around for a few years to support it I wouldn't put them in that position to have to find a good shop later to fix problems. Schools are a big place to keep it VERY simple.

[contrak10]

The cost of the portables has already been approved so they have technically been paid for; they cost in total a little over $2,000. I didn’t buy 24 new ones just ones that needed to be replaced, about 14 old radios. We have four licensed frequencies with the FCC under two different contracts though. One of the reasons why we need a new system is because all the staff talk on the same channel, administrators cant get the word out there is a fight because the custodians are arguing about whose going to clean the spill on the third floor. It's really about creating an effective communication system that will last about 30 years without needing replacement. The reason why I thought the desksets would be good is because people can use the feature of selective calling and intercom between desksets. Suppose you were a guidance counselor and you wanted to see if an administrator or student was available to call down from class or from their office, you could just go on deskset and intercom and address the issue. We have already adopted a policy of no names over the air after students were seen walking around with scanners. MDC1200 is another feature I would like to utilize that the desksets have. So still would it be wiser to still go with the desksets or a look-a-like. Or should I settle for something else, however I would still like to utilize selective calling and MDC1200. Note the district has never appointed a radio shop to handle all of its needs. It’s always been up to the individual school to find a use a radio shop. That’s what I have been told by the administrator currently in charge of the radios who is leaving at the end of the year.

[RKG]

If I understand correctly, you have a 4-channel system using distributed portables and you have 4 positions you want to use essentially as control stations. (I am assuming the system is repeaterized on all four freqs.) You are asking whether it is better to have four independent "small control stations" (you need the line in your license for that) using four independent mobile radios, or to use a single mobile radio accessed by four tone-controlled remotes.

I would go with the independent control stations. For one thing, finding a remote that will handle channel change to a mobile radio is not that easy; you are likely to end up with something that has a fair dose of "jury rigging" in it that, when you change radio shops (or even change techs within a shop) is going to cause problems. Moreover, if the four remotes are connected to a single control station, that station can only be used by one remote at a time; since the purpose of having four channels is to permit simultaneous operation on different voice paths, funneling the remotes through single control station is likely to defeat this goal, not to mention the training hassles involved in getting the operators of the remotes to read and follow the indications of line in use, channel change, etc.

If the cost of four control stations is a problem, then I agree with the suggestion that you can get by with portable radios for at least 3 of the control points, particularly if you buy the battery-eliminators that are available for many (but not all) models of Motorola portable radios. However, a portable on a desk is not nearly as easy to use as a remote with the desk mike, and expensive portable radios have the sometimes annoying habit of growing legs in the middle of the night and walking away.

As noted, the control stations (even if portables are used on fixed power supplies) have to be licensed, but they can be licensed under the "small control stations" provision. Power should be reduced to the minimum necessary for full quieting into the repeater(s), which is probably far less than the factory default.

[contrak10]

We are on a simplex system with no repeaters. We do have base stations though, but they are crystal controlled and only operate on one channel. They look like a box with a speaker and microphone coming out of it. However the main things I am looking for is base mobile or desktop controllers I don’t care by whom, but I want to be able to both make selective calls and utilize MDC1200. I just want to know my options but I want to use those features. Like I said we are UHF with 4 channels with 4 different freq. on them.

[SlimBob]

We are on a simplex system with no repeaters. We do have base stations though, but they are crystal controlled and only operate on one channel. They look like a box with a speaker and microphone coming out of it. However the main things I am looking for is base mobile or desktop controllers I don’t care by whom, but I want to be able to both make selective calls and utilize MDC1200. I just want to know my options but I want to use those features. Like I said we are UHF with 4 channels with 4 different freq. on them.

shoot man, just get some mitreks and a few HT500s or something...

[contrak10]

Upgrading is key word here, going with HT500 doesn't do me any better then using p10 radios.

[KG6EAQ]

This is a school.... all you need is it to work. What will be decoding this MDC1200? If nothing is decoding then why bother sending it. Get them some HT600's or SP50's and keep using the 1 simplex channel. There is a reason that most K-12 schools do it this way. You want everyone to hear all traffic. Every employee's job at the school is student safety. If there was a fight on campus I think you'd want anyone nearby to help and break it up. If janitors are on a different frequency they wouldn't know, nor would the guidance office, or the administrators if it was announced on the main office channel. Follow KISS... keep it simple stupid. Don't make it more complex then it needs to be.

Sounds like proper radio etiquette would help this school out...

[contrak10]

Ok lets move back to the main topic which was about Tone controllers. I have no idea why we are talking about portables. The system we have doesn't work, people are stepping on each other and things are all over the place. I need to organize that system so its together and working efficiently. I said in my first post that I have already invested in HT1250 and CP200 radios which are MDC1200 compatible. The portable issue has been resolved, now I need help designing a base system by EITHER using a mobile base or tone controllers. I need them in three different offices thats why I have an issue. So my question is more of a what should I do? I need something that can both encode and decode MDC1200 and be able to make selective calls. I don't want hear anything about procedure or staff issues, thats not important at this point. Your asking me to keep it simple, I'm asking you to get to the point already. (GTTPA)

[KG6EAQ]

Ok, I'll just put away all my experience as a technician for the 2nd largest school district away and shut up. You just don't seem to get that you are going for overkill. Splitting up the users in a single school site will only add to the problem. What happens when one of the guidance counselors changes channels to talk to a janitor and forgets to change back, now he can't hear what he needs to. Not one of our schools generates enough traffic to split it up on four different channels and we have high schools that break 4600 students. Those schools have two channels, facilities on one channel and everyone else on the other, but those schools are the sizes of most hospitals and all have over 20 custodial staff during the day. The other channel has never had any problem with over crowding. Set the radio to TX inhibit on busy channel and leave it at that. There is a reason we've setup over 750 schools on a single channel, it works great.

[RKG]

Let me add one point: don't assume that "Selective Calling" on a non-trunked system really ensures any privacy, i.e., that other users won't be able to listen in on the traffic. All SelCall does on a non-trunked system is page the called radio via MDC and direct it to open squelch; the MDC is sent without PL, so that other radios hear neither the MDC nor -- if the called party responds via SelCall and not by simply pressing the PTT -- the reply. But if any other user keys up, they will talk over you (remember, they can't hear the voice traffic), and if they press monitor, they will hear the whole thing.

SelCall on a trunked system really works as advertised. On a non-trunked system, it is useful only for short, one-way announcements that you don't want to bother the entire user group with, not for something you want to keep private.

[SlimBob]

My high school of 2,500 students and three "chief" administrators only had four 2W handie talkies -- and those covered the 5 acre school pretty well. They didn't run tone squelch or anything -- just the cheapest JobCom handies you could find... and they did the job. Granted, facilities wasn't linked into it at all, but they did thier own thing and could be found when needed with ease.

Unless you're looking to pad the ol' resume, it's really not worth it.

[Quarterwave]

You asked for opinions, and I think these fine fellows are trying to give you that. It is hard to "see" the entire situation without being there, but unless you have some detailed concerns that you are trying to accomadate and are not able to spell out completely here, I think the advice is sound. Especially from a guy that does radio for a large school now as his job.

I can't see why you would want to complicate a radio system for users that are not radio savvy. Changing channels is a problem! Most of us know and love radio, we like the gadgetry of it all. These folks just need a box to talk to each other on. If you don't make it simple, somone will slip in there and sell them Nextels and then you are out of a cool job function!

MDC1200 Why? To id the user? Who is policing that? If you do not have a display console or a mobile to decode it and use if for security reasons, then it is just a noisemaker.

Select Call could be useful to summon one user to the radio with an alert if in a situtation where they can't hear initial voice that well.

If you really need a base station, put one in an equipment room on or near the roof, 10 watts will do you, and wireline some desktop remotes to them.

But you really need to keep it simple or the people you are trying to help will be at you all the time beacuse of operational difficulties.

I would go with Kenwood TK3160's (hate to say that, I'm a M guy) if you want to use encryption to keep the scanners around the neighnorhood from hearing stuff. Oh, sorry, you already picked the portables!

[Cam]

My high school of 2,500 students and three "chief" administrators only had four 2W handie talkies -- and those covered the 5 acre school pretty well. They didn't run tone squelch or anything -- just the cheapest JobCom handies you could find... and they did the job. Granted, facilities wasn't linked into it at all, but they did thier own thing and could be found when needed with ease.

Unless you're looking to pad the ol' resume, it's really not worth it.

I guess every school had different needs.

Back when I was in high school, the school district was putting in a Motorola SmartNet system that cover the whole school district. The high school I when to had about 1400-1500 students. They had about (hard to remember ) 3 talkgroups just for the school and the rest in the MTX8000 were for city wide use. The only radio they used were MTX8000, no bases or desksets. In the offices they use had an portable.

[contrak10]

A lot of the reasoning behind the upgrading has to do with an incident where administrators could not hear an emergency call due to custodians chatter. This happens on a daily basis. I do not want to put a portable in the main office due to the fact people are always in and out.

The system we have is old, and was originally designed for the 5 relms we have ( They are huge, looking more like astros then anything else). As the system got bigger more and more people got radios we started to lose control. We have about 30 radios in service. I want to lower that to about 20. I'm tired of hearing "Main Office, we need more printer paper in room 212". Yes, it happens all day long.

I do have two MDC1200 displays that the police gave us when they upgraded there system about two years ago.

I under stand what you are saying about the people not understanding how to use the system. However forcing people to learn isn't that hard, two years ago when the school intercom system upgraded to Dukane people refused to learn how to use the paging telephone and learn the access codes. I went to the supervisor and threatened to deduct pay for each call missed. Since then I have been able to force them to learn new technology, the VoIP project for some reason for staff required an act of god to learn.

The main thing though is do I have a choice to go with either mobiles or tone controllers, from who, I don't care. I just want to weigh my options.

[kurt meltzer]

For your 4-channel system, connecting several (multi-freq capable) tone remote desk sets to a single radio near the roof would work. But remember, your one 4-freq radio can only tx/rx on a single freq at a time. Each time one tone remote sends a channel change command to the radio, all the parallel desk sets will also move to the newly selected freq. If Desk Set A needs to operate on frequency 1 at the same time Desk Set B is operating on frequency 2, then you would need a separate dedicated radio up near the roof for each frequency, and multi-LINE capable tone remotes at your dispatch points. This adds complexity, not to mention multi-line desk sets and the associated wiring might well cost more than just furnishing dedicated radios at each dispatch point.

If it were me, I'd probably lean toward individual maxtrac-type radios with power supplies at each dispatch point, provided they will provide the RF coverage you need (if it's a repeated system this would be easy with just a simple indoor antenna on each radio - for a simplex system it may require cabling each radio to an outdoor antenna to achieve the desired coverage. Something to think about.

[Cam]

I would say that other then a portable about each desk, a moble would be your best bet. The problem with the desk sets are that for your setup you will still need four radios. Placing the mobles right at the desk will cut out the desk sets and give you all the same things. The Maxtrac is no longer made and I would bet that you will be buying new radios so my may want to look at the CM200. Gives you four channels and can be programed by the same software as your CP200s.

CM200

[Robert HT220]

Our school uses the butt-ugly blue-green CP200's. They talk on them like they're cops. "What's your 10-20?" "10-4, i'm en route". The even funnier thing is, they don't have a FCC license, and they never put out a callsign. Once I find the freq I'm gonna turn 'em in to the FCC and see what happens. Before they got those they were using FRS radios. That was a stupid idea. Almost every one of us at school had one so we screwed with them all the time.

Robert

[contrak10]

HAHA, the funny thing is that we also talk like police on the radios. We have one custodian who talks like a trucker on the radio, its a bunch of laughs. Although the radios are for educational purposes and easy communication we have a lot a fun on them as well. This summer should be interesting when we get all the new stuff in. When I first got the job that put me in charge of the radios and bad students I was handed a box of radios and was told to manage these. I had to learn all this crap on my own, so with a little research it brought me here and so here I stand. I learn a new thing on the boards every day, now im attempting to learn about digital, VoIP and trunking radios, interesting stuff.

[nmfire10]

You should hear our engineering department. I want to add that channel on our console up to the recording system so I can make a "Greatest Hits" cd out of it.

[Zap]

This post has been off for a while and I'm am curious what happened.

What about this for a solution...

Channel 1, All radios scan as priority channel.
Used as a ALL CALL (emergency), or general call channel in case someone is on the wrong channel, and can't be raised on their channel..
NOT FOR CHATTING once contact is made, as everyone is FORCED to listen and would disrupt ongoing conversations on all other channels.
Otherwise it's hardly used.

Channel 2, ADMIN use, Office, Principal, Vice, Security.

Channel 3, STAFF paging, chatting, arguing, "CB channel 14" kiddie channel.

Channel 4, Maintenance.

"Party-line" ediquette applies.
If "you" continually violate the rules, you get the stinky radio, or none at all.

None of it will work if the Principal doesn't buy into it.
He's the boss, if you want to argue with the boss, you can do it at home on your own time, which you will now have lots of...

[kb9suy]

One of are local highschools with probably 4000 or more students with to seperate complexs on the same property utilizes 3 repeater systems set at like 15 watts output enough to penitrate the concrete buildings and cover the other building across the property. One repeater is used for the security and administration for calling for students cordinating fights and all the good stuff, then the maintance have their own repeater system and and the special ed department had their own repeater system. It worked flawlessly. No problem at all with communication to everyone. Everyone uses portables except the mobiles in the special ed vehicles. Thats the best way to go. especially when your operating in concrete metal structures with multiple storys or very spread out. That was our case their was no way you could talk simplex from the main campus to the north campus on simplex if you were in the basement. The repeaters are the best way to go.

[jim]

"Get them some HT600's or SP50's "

Why is it that somebody always has to "recommend" using a 20-year old eBay POS when building a system? Come on...this isn't ham radio. Any company or department is going to purchase NEW radios and not old crap from when Reagan was president. If you were in the market for a new, more reliable car to go to work, would you take someones advice to buy a Ford Pinto or Chevy Citation? Nope.

Instead of mobiles at the desks, why not just use a portable in a charger with a speakermic? You don't really need 25 watts and a rooftop antenna at each desk. Besides, if that person needs to leave their desk, just pick up your portable and go. Otherwise that one person will need both a portable AND a base.

As for MDC, it's understandable that they want the radios coded. Besides, they'll have HT1250s that can decode it. I'd rather use a very fast (50/25ms) 4-character DTMF burst instead, since it would be more pleasant to the ear.

For a repeater, it sounds as if you simply are in need of 4 low power (10W) repeaters to do the job. As stated, using a tone panel on one freq pair will just cause the lunch ladies to key up on the administration and such- even with busy channel enabled.
You could use a very basic GR type unit with a small antenna to cover any school ground. You're not gonna need alot of height here- a simple 10' mast over the roof will work great. As most schools have, go for the auditorium roof since it's the highest. Instead of placing all 4 in one location with rows of cans, you really could place them in 4 corners of the audiotorium roof for distance seperation and isolation. The repeaters could also be placed in the balcony area for ease of access and to be close to the antennae. This will make setup and maintenance easier too in the future since you don't have 4 repeaters into one antenna. No it won't be cheap, but the 4 seperate repeaters will allow all 4 talkgroups to communicate without interfering with one another. All portables can also be programmed with all 4 pairs plus simplex.

Also, for administation, consider adding a keypad to the radios and a DTMF decoder/patch to the administrator's repeater and tie the panel into the school's main PA system. This way, they can enter a 6 digit code from their radio and get into the PA system during an emergency.

[harrisjt2000]

Any updates on this post? i say keep it simple. i do all the coms for the school disrict here and its very simple. every school in the district has a repeater (gr300) with its antenna on the tower we use for the microwave links. at the high schools they have a phone interconnect. each school has their repeater channel and a talk around. there are repeaters on the county towers for the school busses and the school board admin and the county wide channel. the radios are HX482's set up with the schools repeater channel as the home mode and then they have all the other schools channels in them in case an admin had to work at another school. the standard hx 482's work great for this set up as it holds alot of channels.

[M1225]

The school district here use only one chanel as well when it comes to in building and building to building communications.It is a repeater chanel though. We have a large high school as well, They have 5 ofices, One main ofice and 4 smaller ones. All the ofices have HTs and they can all access the PA threw the phone. Their system works great as well and the main reason is radio etiquette!!! They dont chatter away on the radio for long periods of time and most of the time they get ahold of whom ever and then call them on the phone, Same goes for the high school they use the phone more than the radio most of the time. All the difrent pricipals and custodians at all the schools on one chanel and it works fine and its all becouse good radio etiquette!

[NickH]

How about the new DTR's? Great in-building coverage, no licensing and not scannable. Rugged and relatively cheap. You can set up call groups and lists all day long.

[440roadrunner]

For your 4-channel system, connecting several (multi-freq capable) tone remote desk sets to a single radio near the roof would work. But remember, your one 4-freq radio can only tx/rx on a single freq at a time. Each time one tone remote sends a channel change command to the radio, all the parallel desk sets will also move to the newly selected freq

Code: Select all

A freqin' men


That statement says it all

[derekjmu]

>Their system works great as well and the main reason is radio etiquette!!!

this is the biggest factor. My high school used 4w UHF HT-600s on 467.925 MHz simplex with DPL and had no problems. probably b/c they didn't talk on them like CB radios and chatter away just to hear themselves talk.