M.R.Investigations

Radio equipment for the Private investigator

After reading various posts on different PI forums there seems to be a fair bit of confusion as to what is the best radio to get for the Private investigator. One of the most vital pieces of equipment you will need if you wish to perform a surveillance operation is good reliable radio communications.

Yes you can use mobile phones but you can't always get through and also, unless you are on a conference call can usually only speak to one person. Mobile phones are for use in lulls in radio comms. E.g. nothing has happened for some time and you need to relay a message that is not going to tie up the net, then use your phone. Note: Very slowly a system called PTT (Push to talk) is being rolled out in the UK with some commercial users using this system. Basically it’s a feature of a mobile phone that allows it to be used as a radio but without the range restrictions. However, I doubt very much that this will be free and will have the same restrictions of network coverage, another good reason for sticking with radio.

Out of radio range (usually means one of you has got held up) then use your mobile. Live commentary? Radio only!
Okay so what radio will you need and where should you purchase them from?

I have heard people say that they bought "a lovely little set from Argos for 20 quid" they will go on and say that they were great radios for the price etc. First of all you do not want to be buying cheap radios from Argos. These are the PMR 446 Licence free radios that every kid on the block had for Christmas, 8 channel jobs. This means that if you are using these radios on say, channel 1 any kid (or adult) that has a set of these tunes in to channel 1 quite innocently and is in your vicinity then he is going to be hearing your transmissions with great interest. Not only that but these radios being licence free are restricted to half a watt ERP (Effective radiated power) which is not good enough for our needs as the range is far too short. Most sets do not have a removable aerial either which means using any sort of vehicle mounted antenna is out of the question.

What you need is something designed for professional use. First of all you will need a radio licence. You will have to apply to ofcom and fill in a form stating the use of the radios. As they are radios not used at a fixed site you will require a UK general licence which covers the frequencies of.

Low VHF
Mid VHF
UHF

The licence costs around £60 and you can use any number of radios on that licence.
Radios are either VHF or UHF, you take your choice. Note this is in no way a statement condoning the practice of not bothering with a licence but its fact that if you don't then no one is policing the airwaves, checking that every transmission is being used by a licenced operator. If you fool around interfering with legitimate users then yes you will draw attention to yourself. But the law is the law so you should adhere to the rules and purchase a licence.

Personally I would not bother with the low VHF frequencies as the lower the frequency, the larger the antenna that is required, resulting in a large antenna at these low frequencies. The Mid VHF is more practical and it’s said that VHF glides through open spaces better than UHF.
UHF is supposed to be better at cutting through buildings in built up areas and requires a smaller antenna. I must say here that radio is an unpredictable science, sometimes you can be amazed at the ranges that can be achieved, other times you can be dismayed at the lack of range. Usually there can be an explanation such as a high vantage point for achieving long range and being in a dip for short range but sometimes there is no obvious explanation for the range extremes. Whilst we are on the subject I have heard statements like “We get ten miles range with our handhelds” Ok maybe if you are on top of a tower block on one side of the city you may achieve this, especially if the other chap is on a high vantage point too as radio works on line of sight. But in real life situations you are going to be getting a lot shorter range on a 5 watt hand held radio. So how do taxi drivers etc. get such extreme ranges being able to communicate all over the city with good clean signals? They use what is known as a repeater.

Basically a repeater can be an antenna system on top of a hill top or block of high rise flats that rebroadcasts the radio transmission it hears from a mobile unit. Example, A council worker driver wishes to tell his colleague who he knows is going to go on a certain route later and witnesses a car accident that is likely to congest the road for several hours and he wishes to tell him of the hold up. As he is seven miles away his transmissions will fall short and he won’t be heard by his friend or at best will receive a very scratchy signal. So a repeater is utilised, how this works is like this: Pete sees the accident and transmits on his radio on 459.950 (the frequency the radios are programmed to transmit on) the signal is easily heard by the high up repeater system and is re broadcast on 453.150 (the frequency that the council radios are programmed to receive on) as the repeater is high up and higher powered than the vehicle radios it is easily received on Bob’s radio and the message is clearly received. This system is called Duplex. Think of it like this, you and a friend are working on a house, your friend is in the front garden and you are in the back garden. You wish to relay a message to your friend in the front garden but the house is blocking your voice to your friend. Now if there was another chap on the roof he could hear you and relay your messages to your friend and vice versa.

So how does this all work for a Private investigator? We do not have such a luxury we will be using what is called Simplex, where the radios transmit and receive on the same frequency at a lower power, usually 4-5 watts handheld and 25 watts mobile. I will discuss later how to increase your range on such a system.

You now have your licence and ready to purchase some radios so where do you go? Well you could go to a PMR (Private mobile radio) dealer (Think it’s now changed its name to PBR-Private business radio) and pay top end prices or you could look on eBay. There are countless radios for sale on there from cheap Chinese radios to top end Motorola’s. So what about these cheap Chinese radios? Yes they are cheap but surprisingly good. I have purchased Puxing 777 radios for a very cheap price and they are very good value for the money giving excellent range and features.
Another word of caution here. By law all radios have to be type approved which means they are suitable for transmitting without causing interference on adjacent frequencies etc. these Chinese radio are not type approved. This does not mean they are not up to the job in fact they are more than capable. When a radio goes out of production it is also no longer type approved but does that mean it's no longer up to the job? Of course it doesn't. Again no one is policing this, and there are still people using gp300 radios which are still at this time considered one of the best pmr radios ever built but as it's no longer produced, technically it has no MOT! But again the law is the law!

There are numerous models of radios out there from Icom, Yaesu, Vertex, Motorola just to name a few, most of which should be up to the job. If using handhelds you want at least 4 watts which is the norm for UHF or 5 watts for VHF.
Mobile (car mounted) 25 watts. (Although this will infringe your UK general licence rules which is restricted to 5 watts) Again no one will probably know or care but again the law is...You know the rest.

CTCSS/DCS
Most Commercial radio users use a sub audible tone programmed into the radios that will open the squelch only on radios with the same sub-audible tone. Their own
radio system will all have the same CTCSS (Continuous tone coded squelch
System) or DCS (Digital coded Squelch) tone. This ensures that if any one
else on the same frequency but with a different tone transmits within range
then their radios will not hear any interference from those radios. This tone is
transmitted along with your voice but as stated earlier is sub audible so is not
heard.

A good example of this is a community repeater, not used as much today as they were a few years ago could have several users on a single frequency. So lets say there was a community repeater on say 453.050 MHz you could have say Bobs taxi’s, Sids skip co. and a veterinary surgeon all using the one frequency but as long as they all use different CTCSS tones, Taxi co. on one tone, skip co. on another tone and the vets on another tone, then they would be able to use their radios without interfering with each other.

So now you see the importance of having this set up on your radios? It would be no good you being on a job watching a worker from Morrison’s and finding you are on the same frequency/ctcss tone as Morrison’s who also use UK general frequencies. However, even if you are on the same frequency but using a different tone you should not interfere with each other. Don’t be fooled into thinking these CTCSS/DCS tones make your transmissions secure because they don’t. Motorola calls this feature PL or Private line which can cause some people to feel that their transmissions must now be private i.e. secure.

To make your transmissions more secure it helps to keep radio traffic down when it’s not needed. Surveillance voice traffic stands out like a sore thumb and anyone using a receiver such as a radio scanner will soon lock on to you with interest as your voice traffic will add a bit of excitement to their day. Even another radio user can tune in that is on the same frequency but using another tone. What normally happens on a radio that is using the same frequency is although their radios remain silent due to being on a different sub tone, on some radios the tx/rx (transmit/receive) light on top of the radio will flash red and a lot of radios have a squelch defeat button that when depressed lets in the audio from the other users radio!

To further secure your transmissions try to avoid using specific road names as you may find some unwanted guests turning up for a nose and most probably compromising your position.
Also remember if using 25 watt radios, although this is great for longer range comms, it also makes you fair game from eavesdroppers from further a field.

If you want to get serious about avoiding your comms being compromised you should consider some form of encryption. The Puxing radios mentioned earlier in the Puxing 777+ guise offer basic voice scrambling which should lock out all but the most determined of eavesdroppers. It has been said that if someone stumbles across a scrambled transmission it will make the listener very inquisitive and determined to hear what is going on. I say so what? If you were in the clear he would be tuned in anyway, if you are using scrambling then the chances are unless he is very determined and downloads the relevant software he won’t be able to listen to what is being said.

There are more advanced encryption solutions out there should you really want to get serious (Personally I wont use any insecure radios on any of my jobs) such as rolling code inversion scrambling and digital scrambling.

Digital radios
It’s a fact that we are entering a digital age, our music is now digital and soon all our commercial radios that we listen to, Radio 1 etc on are now becoming digital with DAB radios coming to the fore. Also Television which is sent via radio waves is due for a digital switchover very shortly. All the blue light forces now use secure digital radios using a system called tetra http://www.tetramou.com/tetramou.aspx?id=44 and on a network called “Airwave” which is only open to government bodies. Slowly the same can be said for pmr radios. To the forefront of this project is Motorola with their Mototrbo digital radio system. http://www.zenitel.com/Global/Denmark/Dokumenter/Motorola/MOTOTRBO_System_Brochure.pdf The advantages being digital clear audio with no hissing or crackling as the range increases. One to one calling facility, with my radios I can call any of the team at any time and all other radios remain silent, should a group call come in from the rest of the team it will cut us out of the one to one call and put us back into the group call. Although I do not use this facility as it will be an unnecessary drain on battery power and can be done via the mobile phone. Text messaging is also available on the models with a display such as the DP3600. Kenwood have their “Nexedge” system Icom has IDAS and before we know it digital will be the norm.

Mototrbo does not use ctcss or dcs it uses another format called colour codes so if the colour code does not match your colour code then the radios will remain silent. Actually there’s a lot more programming that goes into a digital radio before it will talk to another radio such as a group ID number and an individual radio ID that has to be on the group setup.
Digital also means that any eavesdropper will be listening to digital white noise and just for good measure should they manage to decode it (Apparently it has now been achieved by using Linux and a discriminator tap on a receiver, however this is only possible on the systems that employ a repeater not simplex as we would use them) the software for programming these radios has a privacy (Encryption) feature that will stop them in their tracks! The range of these radios is supposed to be greater than their analogue counterparts, I have not however conducted any tests to prove or disprove this theory.

One thing to be aware of though, when you get out of range on these radios the signal will just drop completely as digital is all or nothing. Think how your mobile phone calls sometimes just drop when you are on a call, whereas analogue goes scratchy and intermittent at least you know you are moving out of range, but the advertising hype says that digital will stay audible where analogue struggles and will drop out beyond the range of analogue. Like I say I have not conducted any real tests.
Again these radios can be picked up on eBay
http://shop.ebay.co.uk/?_from=R40&_trksid=p3907.m570.l1313&_nkw=mototrbo&_sacat=See-All-Categories

Magnetic mounted (Mag mounts) antennas.
When a radio is in the confines of a vehicle with the supplied helical antenna. Commonly known as a “Rubber duck” the radio is restricted as it is shrouded by the metal of the vehicle. This cuts down on the range and to combat this you will need a mag mount antenna that sits on the outside of the vehicle. The vehicle metal acting as a ground plane to assist in the range of the radio transmissions giving you much better range. Obviously you will want to place it somewhere not too obvious such as hidden behind your existing broadcast antenna. I do know some people use the mag mount inside the vehicle for maximum discretion, however that for me defeats the object as I have run tests inside and out and there is a marked decrease in radio range when using inside the vehicle.

Remember that the antenna will have to be cut for size depending on the frequency used. In the case of UHF a small 6” quarter wave antenna can be used which does not stick out like a sore thumb. If lower frequencies are used then a longer antenna will be needed. Try to avoid using eBay mag mounts as they are mainly receive only scanner antennas that are not built with good quality components. I get mine from a pmr radio dealer. Just tell them the frequency you will be using and they will cut it to the appropriate length and will use good quality cable, as using cheap cable results in loss on the signal.

Speaker mics
You should also invest in some fist mics so that you don’t have to keep holding the radio to your mouth, these give far more flexibility and much easier to use than just using the radio. Try not to scrimp too much here as although you can buy cheap non OEM types they can be quite “tinny” in sound quality. Using speaker mics you can put the radio in a suitable spot in the car and not having to keep reaching for it and fumbling about if you have it in say the passenger seat. My car has an arm rest which lifts up and exposes a compartment for storing items. I find my radio sits lovely here and is away from prying eyes if anyone was to walk past and look into your vehicle.

Batteries
All radios unless they are mobile vehicle units in which case they will be powered from the vehicle. Will require batteries. Remember the more you use your radios for idle chit chat etc. the shorter the battery life. If possible take a spare fully charged set with you in case you are on plot for longer than was envisaged. Also remember if you charge up your batteries after a days surveillance and don’t use them again until a couple of months your batteries may well have self discharged so always charge the day before.

Ear pieces
I don’t like most ear pieces especially the supposedly “Covert” curly wired ear pieces that shout out “FBI” to all and sundry. If you can get them (probably have to have them made up) go for the walkman type earphones that everyone is used to seeing and people if they even take a blind bit of notice of you will assume you are listening to your ipod or if they hear you talking will assume you are on your phone. Wireless earpieces are another good option.

© M.Rattenbury www.investigateit.co.uk 2010