Walkies for school emergency lock-down

Bit of a left-field question that I was wondering if anyone can help me with.

I am a network manager at a primary (elementary) school in London, UK. We are currently looking into ways of getting an emergency tone to play across the school site to warn everyone that a lock-down is in place. We have been getting quotes for a standalone tannoy system to be installed, with a speaker in every classroom and corridor. However these quotes have been very expensive as it is quite an old school and a very large wiring job.

I have been wondering whether we could use our two-way walkie talkies to sound an alarm. We currently use around 20 Kenwood TK-3301 walkies around the site, mostly so staff who are outside on the playground can contact those inside. These are all tuned to channel 1. I notice that this model has an alert tone feature, which I’ve tested and is quite nice and loud.

My initial thought was that we could purchase more of these walkies that could be left in situ in every classroom/corridor and be left permanently turned on at a loud volume. The first problem with this that I thought of is that we occasionally get interference on channel 1 from a local motorcycle training company who use radios. I haven’t tried changing the channel site-wide to see if this is eliminated, but obviously if there were interference noise on the radios in a classroom situation, this would be no good - especially if they were turned up to a loud volume. Does anyone know if there is a smart way to stop interference other than just trying all the channels?

Another thing I was wondering is does anyone know whether on this model you can play a constant alert tone? The only way I can see to do it at the moment is to hold down the button on the walkie. Also, does anyone know if an alert tone can play across different channels? If we were top get walkies for the classrooms, these would be on a different channel than the walkies that staff use outside - but ideally we would like walkies on both channels to receive the alert tone.

Finally, does anyone know whether there is such a thing as a radio speaker? I don’t know what the correct term is, but I’m envisaging a permanent powered speaker that could be in each classroom and be tuned to a particular channel that would receive the alert tone.

Sorry for waffling. Please let me know if you have any questions. Would really appreciate some advice! Many thanks.

Radios are great for secondary systems, but any emergency system is only as good as the weakest link - in this case, batteries and volume knobs.

Maybe you could get somebody to build some RF systems?

I’m thinking of a modified hand held, in a box, with a small aerial and a mains connection - small power supply. A dedicated channel, CTCSS tone, and a speaker fitted to the inside of the box. At the emergency end, a similar one, a small warble circuit, and a mic for announcements - Much depends on how critical the system needs to be.

Other non radio options could be mains borne RF systems, using mains wiring for the comms. Maybe you have somebody on staff who could build such a thing for you? If you have to have cabling, then maybe you could even configure a system with speaker stations in the classrooms, but have some that provide another access point for mics? Although designed for the theatre, investigate Canford Tecpro systems - these could be a useful system, as the head would be able to speak into the system from their office, but so would perhaps reception and they have a facility to have voices automatically override any volume control - as they could be used for background music too - if it annoys, turn down the volume, but an emergency call comes through loudly. Needs a microphone type cable system - ground and two conductors.

Thank very much, paulears. We have the school holidays coming up soon, so I think the first thing I’ll try are our existing Kenwood TK-3501 walkies, and set them up with a new channel using Kenwood’s programming features, so they’re less susceptible to interference from other PMR446 devices.

If that works in terms of range across our site (which it should), then I’ll try an extended test over a few weeks in a classroom setting to double check that we’re OK from local interference.

You’re right about the weakest link being the power and volume. I would set them up in classrooms where they can just be left plugged into the mains, and give a strong word of warning to all staff/pupils that they are not to be touched. Not a foolproof solution, but it’s a much more affordable one! Will let you know how I get on.

Be careful - remember the school head who installed a cellphone jammer and got in hot water with the LEA and OFCOM - if you reprogram PMR446 radios, then they become illegal. It’s fine to experiment with different CTCSS tones, but not frequencies, but I’m sure you meant the tones.

Those radios, in a public band would also seem to be a little problematic with safeguarding. It only takes one member of staff to mention somebodies name or personal information and you’ve broken one of the golden rules. Hence why many schools are moving to encryption and licensed systems. Others, kind of pretend that they never pass personal information, when they actually do it all the time. Maybe, with the safeguarding issue being high on the agenda, you could move to a digital system with proper alarm facilities, and find the budget from a central fund, rather than your departmental one. Always worked for me when I was in education - spend another departments budget!

Seriously though - they need to appreciate the purpose of any system, and find the budget. Lack of funds does not stand up in an emergency situation, and nowadays, they are always looking to pin blame.

One other thought for your original problem. Is there an IP based solution - plenty of comms devices can use wireless IP networks now, so with computers running in every area nowadays, could a software solution work rather than radio comms?

Yeah I meant the tones. It’s in the Kenwood manual. Uses their QT/DQT feature and is totally kosher. Just doesn’t open the squelch unless both radios are programmed to the same settings. This would also help from a safeguarding perspective as it would be highly unlikely that someone would be using the same Kenwood DQT settings. You’re right about the purchasing of our own frequency. I may bring this up with the Head and see what he thinks. It’s pretty cheap I think.

We did also look at IP systems. However, these were also pretty expensive as would involve more network points being put in. Another negative is that it becomes defunct if our network does down in a power cut etc. At least with radios the batteries will keep them active.

I’ve just ordered some new Kenwood walkies that I’ll be putting on their own DQT frequencies for testing. Will let you know how it goes. Thanks very much for your help. Appreciated.

It doesn’t work that way - re tones. Your transmissions are totally in the clear to anyone with a scanner - no security whatsoever. Tones are simply to stop you being annoyed by other users on the frequency - it doesn’t cut it for safeguarding. Every single thing said on them can be listened to, and recorded if they want. PMR446 is a totally insecure short range system. Loads of schools assume because the tones appear to make the radios linked one to one, that they are secure - sadly, they’re not - and hundreds of people listen to PMR446 as a hobby!

Sorry for the super late reply on this! Many thanks for your advice - it’s really helpful and very much appreciated! In the end, uur Head went for a subsidiary pulse bell, which sends a pulsing bell over our fire bell system. So no need for radios.

Interestingly, for the first time in the 3 years I’ve been here we seem to have had someone outside the school talking over our frequency on our radios. I’m now doing some investamagating of how we can purchase our own frequency and how to re-program our Kenwood walkies. Do you know the best place to go in the first instance to inquire about purchasing a frequency? Thanks very much.

OFCOM - their site is a bit difficult to navigate - but you go to the bit about buy a licence and then away you go. They actual licence system is quite simple - you select the band. UHF business being what you want and the licence type is a technically assigned licence. This they allocate locally and in rural areas, there’s rarely a need to share a channel, but they give you the frequency and you tell them which CTCSS tone you want to use, (if your radios can be reprogrammed) or probably digital if you are buying new radios. A few days after you order it, you get the details and licence through and that is that!

visit https://hamfiles.co.uk/index.php?page=downloads&type=entry&id=radio-programming%2Fkenwood-programming%2Fkenwood-kpg-121d-rss and get the software BEFORE you order the frequency because I don’t know what band that one will cover - bearing in mind it is supposed to be only used on PMR446 with low power. You could be lucky and find it also lets you up the power output too! Once you know what the frequency coverage is, you can apply for the licence. They’re good radios and at least the average person with a licence exempt radio cannot annoy you!

Thanks Paulears. I’m on it. I’ll let you know how I get on. Going to check with DTS Solutions (from whom we purchased our walkies) whether our model can be re-programmed. Fingers crossed!

If you download that software - you can try it - just need the right cable that’s all, and if you run the software, in the drop down window that deals with the radio model, it will usually give the transmit and receive limits.

Thanks mate. I manually re-programmed one of each of our different models to the same Kenwood bespoke channel and tone settings, and it worked. So at least that’s slightly better than what we have now. I think I’ll order myself a cable to give the software a whirl, as the manual setting was a bit of a faff.

I’ve bought up the safeguarding concerns with the head. I’m hoping he will fund the purchase of our own band and new radios so we’re a bit more secure.

I am with my friend Paul on this one. From what I can see, the radios are pretty solid. But you are using consumer-band shared frequencies designed for family chit-chat, for your critical safety purposes.

Get your own frequency. It is the cost of doing business.

If the radios can be reprogrammed to your own business frequency, then keep them. If not, stop pissing around with frequencies that every kid in a 5 mile radius can listen to, and do PROPER business frequencies. What would happen if the one-in-a-billion should happen and your school goes into a REAL critical lockdown - and some kid in the drive-thru at Humptys down the street interferes with your communications.

The only alternative to PMR446 radios (which are similar to what we call FRS in North America) as far as licence-free are the Motorola DTR radios. They broadcast on the 2.4GHz band, but hop frequencies so fast that NO ONE can follow them (at least, on consumer-grade scanners.)

They are designed for exactly your type of purposes. The down side is that you need to sell off all your PMR446 radios and get all new ones.

The other downside is that Motorola does a poor job marketing this capable radios, and Lord knows where you will find the UK version for sale. They are NOT cheap.

But, trust me, get a dozen DTR radios - if they can afford it - and you will never go back to analog again. You will never be interfered with; no one will ever monitor your calls, and every call will come across at 100% readability (or not at all.)

Sorry for being blunt but in my humble opinion, you are using consumer-grade radio frequencies for critical business-grade needs.

Thanks Chickenhawk. I don’t really know anything about radios - so you guys on here are a real help. I shall forward your message to the headteacher - he’s the sort of straight-talking chap who would appreciate it!

I agree - I think it’s foolhardy and wrong to use public bands for a very private purpose. Thanks for getting my knowledge to a level where I feel I can convey my findings with (some!) authority.

Most UK schools have a safeguarding policy on their website, plus they often have communications policies designed for email and other electronic comms systems - yet they transmit private data over public bands (usually in ignorance, and I can’t blame them). I’ve been speaking to a head recently and frankly, he didn’t get it - so I spent three lunch times listening, and typed it all up - including the name of a child with a protection order that prevents her photos be taken - let alone her name and other details being spoken about. I know a few kids who have parents away from home, being looked after by relatives, and I know the name of troublesome kids. When I go to see him next week, he’ll be shocked.

I don’t usually sell radios to consumers - my radio business is hire and using them ourselves on projects, but I’m an ex-teacher, with the DBS checks still current, so I like to help where I can.

Recently our school administration has asked me to look into updating our emergency protocols. Specifically, what would be the best form of communication during a crisis. Right now our plan is to use the phones in the room along with our cell phones, but I’m concerned that would have definite problems in the case of a power outage or bad reception, which we have. I’ve been looking at two way radios and it seems like the right way to go. I used to run a daycare and we used radios all the time, but I’ve been reading now that we might need a license from the FCC if we use it in a school? (I’m located in the U.S.) What types of 2 way radios should I be looking for? I’ve been looking through some of the models on and was looking at the more affordable models. They also spent quite a bit of time with me on the phone. Does anyone have a suggestion on specific models to look into before I pull the trigger?

You are correct in looking for two-way radios. In an emergency, telephones and cell phones cannot be relied upon. In fact, without elaborating on the particular nature of the emergencies, in some situations authorities will shut down cell towers in an immediate area, even if full power is available.

The above advice on two-way radios in this thread is a bit dated and applies to the UK, but the advice remains the same. Don’t cheap out when it comes to the safety of our kids. If you cheap out and buy “affordable” radios that use publicly-shared radio frequencies on bands designed for families at Disney World, you are putting people at risk. Every kid in a 2-mile radius can monitor and potentially interfere with your radio calls. There is zero privacy, and all it takes is the mention of a kid’s name, location, medical information, etc. and your school becomes seriously liable. Please do NOT use consumer radios designed for shared FRS channels for professional purposes.

You can buy affordable business-class radios with your own dedicated frequencies, and this provides less possibility of interference but you need to budget for the acquisition and maintenance of an FCC business licence. Plus, all radio calls can still be overheard by anyone with a consumer-level scanner.

The best solution for you is to buy good quality radios that cannot be easily monitored by anyone else unless they have the same radio plus the correct ID codes. The Motorola DLR radios are ideal. They are compact, durable, military-grade digital radios with excellent range and sound quality. They come with two channels (DLR1020) or six channels (DLR1060) and operate on a frequency-hopping spectrum of frequencies in the 900 MHz band. With 18 possible channels (that aren’t really channels, but more like pre-programmed “hopsets”) and 10,000 possible unit ID numbers, there are almost 200,000 possible combinations. They cannot be monitored by any consumer scanners, and even if another user has a Motorola DLR or DTR, they would still have to know the correct combination of channel and ID number.

They are licence-free and can be programmed directly from the radio. If you want to get fancy and get the radios to speak the name of a channel instead of just the number, you can program them with free Motorola software and an inexpensive programming cable.

But you don’t need an FCC licence or even a programming cable to get them working. Charge the battery, turn them on and start talking. Take five seconds to change the preprogrammed unit ID numbers that come as the factory defaults, into your choice of any four-digit number from 0000 to 9999 on all your radios and no one will be able to monitor your transmissions.

They are not cheap, but will last for years.

Our forum hosts at buytwowayradios probably know more about the Motorola DTR and DLR radios than nearly everyone else. Give them a call.

‘Discount’ in a trading name shows where their core business really is. Pro dealers have the ability and time to make systems that really work properly at all levels of security.