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Short Range Communications: What’s on offer in “walkie talkies”? They’re not exactly something you have to buy every day – but when you do, what do you look for? What’s available these days? What licences are required? Are they any good? A couple of months ago I was the local toy stores (seriously!). We Uniden equivalent. asked to look at small two- ended up with a reasonable range to But there are others out there. . . way radios suitable for sports look at, albeit covering only three or Licence requirements use. My brief was simple: find the four brands. most suitable radio for the purpose, There are many other brands with Everyone knows that you need some keeping in mind that budgets were similar specifications and its not form of licence to operate a radio trans(very!) limited. unreasonable to assume these would mitter, right? Well, that certainly used With an interest in radio going back perform much the same way as those to be the case but this is a new century to school days I thought this was go- we looked at. and the situation is somewhat changed. ing to be quite an easy task – after all, For example, we’ve seen Icom handIn fact, for a large number of users how many different types no licence is required. are there? But my invesNot one of the “CB” and tigations revealed quite “LIPD” two-way radios a number of variables looked at in this article which made the choice require a licence. We’ll that much more difficult. explain why shortly. While hand-held radios It’s only when you are not something SILICON want to have a frequenCHIP readers have to buy cy or channel that’s every day, we’re often exclusively yours that asked questions about raa licence is required. dios like these. And there This also means you are have been recent developmoving from “consumments you might not be er” into “commercial” aware of. So we thought equ-ipment which in our investigations might turn means significantly be of interest – if only higher prices. to let you know what is Our application was specifically for surf carnival control but we Obtaining frequencies available these days. that are yours alone can imagine many other sports would have similar requirements . . . This is by no means an also be rather difficult exhaustive comparison. these days – after all, We simply approached two of our helds with very similar features to the spectrum space is limited, especially advertisers and asked them what they Uniden models. We didn’t chase these, in the capital cities. There are other had available in hand-held radios. And mainly because the cheapest Icom options available – trunked systems for good measure, we also looked in unit was exactly twice the price of its for example – but once again these are By Ross Tester MARCH 2001  7 rather expensive options, way outside what we can afford. Trunked radio systems, by the way, have a number – often a large number – of users sharing the same channel through digitally encoded transmissions. The Sydney Olympic Games, for example, had a large trunked radio system in operation. Commercial users and organisations with big budgets do have a variety of choices – and there are plenty of suppliers who can help you out. Of course, using equipment shared with other users does mean that you (or they) have no “right” to use a particular channel, nor can you expect any remedy if someone interferes with you (either accidentally or deliberately). In the past, some CB radio users assumed “squatters rights” to a channel, particularly if they were using it for a business for some time and even more so if they were out in the country. If anyone dared to use “their” channel(s) they were told – literally – where to go! Of course, they had no legal right to do so – but who’s gonna argue with a 125kg truckie with a 20t truck behind him? Using short-range equipment tends to nullify a lot of the problems; using equipment with many available channels means there is much more likelihood of an “empty” channel. OK, so let’s get back to the type of radios we can afford. CB radio You’ve almost certainly come across the term “CB” before. But just in case you spent the last twenty years or so in a Tibetan monastery, CB stands for Citizen’s Band. Initially, Australian CB was limited to just a few channels, crystal locked in hand-held transceivers on the 27MHz band. 27.240MHz was probably the most popular channel. Then people started importing vehicle-mounting transceivers designed for the US Citizens Band with 23 channels. Wow! 23 channels! Oh yes, one minor detail: CB radios were also illegal. Ahh, the good old days! Then after much agitation – especially from truckies and CB clubs, CB radio was legalised. But the government, in its wisdom, decided upon an “orphan” system of 18 channels which shared most (but not all) of the old 23- channel frequencies. After a lot of pressure from importers (and also the fact that they hadn’t killed off 23-channel – and later 40-channel US-type CBs), the government relented and allowed the full 40-channel US system. In even more wisdom, they later decided to introduce another 40-channel CB radio band, this time centred around 477MHz. This was the “UHF” CB band. It was intended as a shortrange communications system without the “skip” of 27MHz CB which often meant CBers could talk to overseas users. (It’s still illegal to use a 27MHz CB to talk overseas). The other big change they made with this new CB band was that business and commercial use was allowed. While fairly limited in range, UHF CB found ready acceptance in country areas. Farmers, loggers, contractors – they flocked to it. It was relatively cheap, very reliable (within limits) and required no technical expertise to use. In fact, licences forbade any modifications to sets. Licences? We nearly forgot those. One of the components of a legal CB system was that every set required a paid licence issued by the Department of Communications (and Transport). They were very easy to get: you simply applied for them and paid your money and you received your licence (and callsign). But guess what? The number of licences issued was a small fraction of the number of sets sold. Woops! Something must be wrong with the accounting system. . . And as far as callsigns were concerned, the use of official (government issued) callsigns was, well, more in the breach than the observance. It didn’t take a rocket scientist to work out what was “wrong”. For years, thousands upon thousands of (illegal) CBers had operated without licences and with their own self-issued callsigns. So why change just because the Government said so? Several methods were tried to get users licenced, including making the licence a conditon of sale. But it was all in vain. Eventually, the powers that be in Australia relented and the US model was followed – as long as the set used was approved, no licence was required. UHF CB repeaters were also allowed, which significantly increased the range of sets. And because UHF CB uses FM, reception was much clearer than on the old AM/SSB (27MHz) system. Apart from the fact that AM is prone to interference anyway, the main reason CBers started using 27MHz was that very few other users wanted it. It’s regarded as the “garbage” band, with lots of naturally occuring (and some man-made) noise. A lot of industrial, scientific and medical equipment is in the 27MHz band. 2000 rule changes We included this shot of one of the Dick Smith Electronics “digitor” sets mainly to show the right way to talk into a walkie talkie: across it, rather than into it. Most people talk directly into a radio which results in distortion. Use ’em like a mobile. 8  Silicon Chip Quite recently, the Australian Government announced some new rules associated with UHF CB which to some extent legitimises what has been happening for some time. They allowed the use of CTCSS – so-called “Tone Squelch” – which had been available on many transceivers but which was not allowed to be used. Perhaps more importantly, they allowed two channels – 22 and 23 – to be used for data transmission; more specifically for telemetry and telec-ontrol. At the same time, they prohibited speech on these channels. This is quite a change from the Government’s previous position on CB, which was purely as a short-range voice medium. But as we said, it only recognises what has been fairly common practice in the past anyway. That’s not dissimilar to pretty well all of the “advances” in CB radio since its inception! And that’s where today’s personal radio history lesson concludes. But wait a minute – there’s another type: the LIPD mentioned before. These 69-channel microprocessor-controlled 433MHz LIPD handhelds from Jaycar Electronics (shown here about life size) certainly attracted our attention – and that of a number of people who saw them during our tests: “Ooooh! Aren’t they cute...” But it was their performance and features which really made them stand out. We were sorely tempted to go for these little pocket powerhouses! LIPD LIPD stands for low interference potential device and is a term given to a whole raft of radio equipment – not limited to (but definitely including) two-way radios. We’ll limit our discussion to twoway radios. There are many frequency bands available to LIPDs but the equipment we’re interested in uses the 433/434MHz UHF band. As the LIPD name suggests, these radios are low-power devices (much less than CB radios) and, theoretically at least, don’t have enough power to interfere with other services using the same bands. Unfortunately, this has not quite proved to be the case and some LIPD radios have caused great angst amongst the amateur radio fraternity. The problem is that many of the LIPD radios are fitted with channels which happen to be the same frequency as the input to amateur repeaters (which also share the 430MHz band). Amateurs also maintain that these attractively priced radios are being used – quite legitimately – by users whose safety could be compromised by the fact that (also quite legitimate) much higher power amateur transmissions could easily break through. They cite cases such as crane drivers and dogmen communicating with each other and ask who would be responsible if an amateur conversing with another amateur said something like “drop down now” and the crane driver mistook that as the dogman’s command… As you can see, there is room for concern. Despite this, however, we will look at the use of LIPD transceivers in our quest for the perfect unit. Our requirements We said before that the transceivers were to be used in sport. To be more specific, we wanted them for use at Surf Life Saving Carnivals for communication between the carnival referee, the various area referees, the first aid people, the announcers, the carnival organisers and, very importantly, the inshore rescue boats (“rubber ducks”) on water safety duty. The range we needed was not particularly great – about 1km or so would be the most needed for all but the very largest carnivals. We imagine that most other sporting applications would find this range more than adequate. However, we needed reliability – it is imperative that the radios operate when needed, particularly where safety is concerned. Other considerations were: battery life and cost; the availability of accessories such as headsets or earpieces and microphones; durability and service backup. Some radios scored well in some of these areas, some not at all. To get a good sample from which to select, we chose models right across the price range. The cheapest radios were, basically, toys (in fact they came from the toy department at Coles!) and sold for $20 pair. The dearest was a fully waterproof UHF CB handheld which sold for $356 each. Here’s how each stacked up: MARCH 2001  9 (A) HF (27MHz) Single Channel AM “Walkie Talkies” Coles Supermarket, $20 pair. The performance of these sets certainly reflected the price. You pay peanuts, etc. They operate on 27.145MHz ( HF CB channel 14) and as such, could well experience interference from other CBs even some distance away on this popular frequency. There is no volume control and no squelch (so you constantly receive a rather annoying and intrusive – and loud – background noise). The only “control ” as such is the push-to-talk button. There isn’t even an on/off control: the transceiver is turned on by releasing the pop-up antenna and turned off by retracting it. There is a telephone-type keypad on the front of the sets but it is purely decorative (despite the beeps each key makes!). A major disadvantage (at least as far as we were concerned) is the power source: a 9V battery. If you’re only buying these occasionally that mightn’t be such a problem but with 9V alkaline cells now retailing for five dollars (plus), buying batteries for, say, 20 transceivers is a significant bite out of the budget. Rechargeable 9V batteries could be an option but the initial expense is high. Transmission range was claimed to be “up to 100m line of sight”: we were flat out getting them to work well over this distance. Hey, you can yell that far! Our Verdict: Yeh, well, er... (C) VHF (55MHz) Single Channel FM “digitor” brand, $69.95 each, Dick Smith Electronics This type of transceiver is quite an attractive package with some advantages for our application, albeit with a couple of disadvantages. First “plus” is the frequency – 55MHz: this is well above the “CB” bands and is not therefore subject to significant interference. Only if transceivers operating on the same frequency are used in close proximity could you expect interference. Another is the fact that optional headset/microphones are available for hands-free operation. There are several channels available for 55MHz transceivers but many hand-helds have only one fitted. If you look around you can find 2-channel sets and some we have seen have up to six channels fitted, selected by a knob. We have had a fair amount of experience with 55MHz sets – in fact, we have used “Realistic” brand sets (from Tandy Electronics) for some years. The major cause for concern we have had with them was range: up to about 200m or so they have been fine but they suffer sudden dropout in the 200-300m range. And as we needed up to 1000m or so, this was a problem! The “digitor” brand sets we looked at for this review were quite different to what we had used – for a start, these had flexible rubber antennas instead of the mini-telescopic type we were used to. That’s a big plus (see above). While there is no squelch control, they had automatic squelch (no annoying noise!). There is a mic sensitivity control which is used in conjunction with an optional mic/earpiece for VOX (ie, hands- free) operation. Incidentally, we have also used Realistic headset transceivers (on the same frequency as the hand-helds) for many years but our experience with these has not been good. The head bands themselves are not robust enough and are easily snapped, while the wire antennas do not allow a broad-brimmed hat to be worn – a definite no-no on the beach! We asked Tandy about replacement head bands only to find the cost is much the same as replacing the whole unit! One point of warning for any organisation planning on using any set with VOX capabilities. Most (non-technical) people do not have a clue what “VOX” means (voice operated transmission, by the way!) and you will experience a lot of unintended conversations until every set is switched back to PTT (push-to-talk) operation. This, even when you hand out the sets already turned on and switched to PTT: people can’t resist fiddling with switches! Claimed range is up to 300m – as already stated, we’ve found this to be a little on the optimistic side. Our Verdict: could be a contender in many applications. But not ours! 10  Silicon Chip (B) HF (27MHz) Single Channel FM “digitor brand”, $69.58 each, Dick Smith Electronics The frequency of operation is the same as the above but these use the FM (frequency modulation) mode of transmission which is supposed to result in clearer transmission. Whether they achieve this or not is quite subjective – like the cheaper variety above there is no squelch control so they constantly receive background noise. On the positive side, FM is subject to less interference from atmospherics so perhaps the noise won’t be quite so intrusive. One major disadvantage of this particular transceiver is the long (1m) telescopic whip antenna. While having a long antenna will theoretically achieve better range than a helical ( rubber) antenna, experience has taught us that these whips will very quickly be damaged – broken or bent. Like the first transceiver, this one is powered by a 9V battery and the same comments apply about cost of operation. Range is claimed to be “up to 200m” which was inadequate for our purposes. We were, though, able to verify that they worked up to this distance. Our Verdict: they'd be good for kids if it wasn’t for that whip. (D) UHF LIPD (433MHz; 69 channels). “Tek City” brand, $99 each, Jaycar Electronics Now here is one of the most amazing little radios we have ever come across. When we say little, we mean it: just 30mm thick, 65mm wide and 110mm high (or 150mm if you include the flexible antenna). That really is shirt pocket size. With 69 channels to choose from you’re sure to find a channel or fifty that is not in use. But there’s a lot more to it than that. These microprocessor-controlled transceivers have an amazing array of features. While offering “normal” two-way communication between other sets on the same channel, it has a variety of calling and listening modes which can call or listen to specific sets or groups of sets – including conference calls. You can select from any of 10 sub-tones which allow access to other sets having the same sub-tone and channel set (other sets with different or no subtones, even if on the same channel, are ignored). There’s even a built-in clock, stopwatch, alarm clock and settable auto power-off timer. Ten memories allow the saving of popular channel/subtone/etc settings for instant recall. And there is even a selection of transmittable melodies so that other users will know that you is you! All controls on the Tek City two-way radio are push buttons – and apart from the usual push-to-talk button it’s not particularly intuitive so until you get to learn the controls, the manual is a must. The case is said to be splashproof but we’d rather not put that to the test. With just 25mW output you might expect range to be very low but we found this not to be the case. Over 1km line-of-sight was no problem at all. 25mW output though has a big benefit when it comes to power consumption. 40 hours of continuous operation is claimed from the 4 x “AAA” batteries though no duty cycle (transmit/receive) is given. One point: AAA batteries are usually significantly dearer than AA cells. Bearing in mind our earlier comments regarding amateur repeater inputs, we would suggest steering clear of channels which coincide with amateur repeaters in your area (ask your local WIA office or radio club and they’ll advise you). But with 69 channels available, there still should be plenty which you can use. Incidentally, Dick Smith Electronics also plan to sell a 433MHz LIPD set (it was shown in last year’s catalog). So far, though, they haven’t reached the market because DSE are having special models manufactured which will not interfere with amateur operators or vice versa. Our Verdict: one of the most innovative hand-helds we’ve seen. Definitely on the short list. MARCH 2001  11 (E) Pocket-size UHF CB (476/7MHz); 40 channels Uniden UH-040XR, $99.00 each from Dick Smith Electronics These low power UHF CB sets were extensively advertised prior to last Christmas. We must admit that if we were impressed with the LIPD sets, we were also very taken with these. They’re also obviously microprocessor controlled and while they don’t offer as many features as the 433MHz sets they’re actually slightly smaller. They’re a tad higher (115mm) thanks to the volume control/on-off switch on top of the set and the integral, non-flexible antenna is higher (180mm). But they’re slightly thinner (27mm) and the taper-shaped case is 60mm at its maximum (makes it easier to fit in the pocket). All 40 UHF CB channels can be scanned or you can preset as many of those 40 channels to scan as you wish. It also has priority channel scanning where it monitors one preset channel every 1.5 seconds. Power output is limited to just 50mW. This equates to 150mA current drain from the 3 x “AA” batteries. One nice feature of this radio is its ability to switch to a “sleep mode” when the batteries are low. You cannot scan or transmit but receive is still available. The radio is cable of repeater operation (duplex mode) but for our purposes, this was not required. Squelch threshold is preset at 19mV but can be over-ridden in case of very weak signals. Uniden claim a range of up to 3km over flat open terrain. We were able to confirm this distance along the beach – in fact, we achieved 4km across water. Our Verdict: A great little performer at a very attractive price. (F) Splashproof UHF CB 476/7MHz, 40 channels. Uniden UH-052XR, $399.00 from Dick Smith Electronics This could be regarded as the “big brother” to the above UHF CB. It is bigger – significantly bigger – at 60 x 50 x 165mm (275mm including flexible antenna). At $399, it’s also a lot more expensive. For the extra money, you get a much more powerful transmitter (5W – maximum legal power, switchable down to 1W). It also has a rechargeable battery (7.2V 900mAh NiCd) so at least you won’t be forever forking out coin of the realm to keep talking. (And at 5W output, you’d need lots of coins because the drain is 1500mA!). The radio is described as splashproof – exactly what this means is not too clear to us (it complies to US Military standard 810E Method 506.3, Rain II – so now you know too!). Uniden claim it will withstand splashes of water but not immersion. Unlike the UHF CB above, the flexible rubber antenna is removable to allow connection of an external (eg mobile) antenna if you wish. The UH-025XR has a wide range of user features including CTCSS (continuous tone coded squelch system), complete or programmable scanning, priority channel, power saving, busy lock-out channel and more. Unlike the other set, the squelch control on this unit is settable but it also has a monitor push-button for instant squelch override. Optional accessories include a VOX headset, speaker microphone, cigarette lighter charger and battery eliminator. As would be expected from a 5W system, the range of this handheld is very much greater than the 0.5W model. We gave up after a couple of kilometres of beach walking – we cheated and sent the other unit off in a car. It gave up the ghost after the car went around a large hill 4km away (it’s hard to find flat areas to check line of sight on Sydney’s northern beaches!). Bearing in mind our earlier comments about interference from other UHF CB users, this long range could actually be a hindrance in our application. Our Verdict: If we wanted maximum range, this would be the one we’d go for. 12  Silicon Chip (G) Waterproof UHF CB (476/7MHz, 40 channels) Uniden UH054A Aquamax. $356.00 from Dick Smith Electronics Here’s one that really attracted our interest with our beachside application: a waterproof radio! Despite everyone’s best intentions, accidents do happen and we have had a number of handhelds take an unwanted swim over the years. Well, a small swim wouldn’t worry this radio one bit. It’s rated to 30cm for half an hour – admittedly, not a great depth but the usual “oopses” we experience (eg, someone running along the water’s edge and the radio bouncing out of a pocket!) would be consistent with this depth. (Let’s face it – if you drop it overboard from a boat it’s going to go straight down anyway so your chances of recovery aren’t high). Otherwise this radio is not dissimilar from the other sets we looked at. Size is about half way between the other two at 32 x 62x 160mm or 245mm if you include the antenna. Controls are all push-button type (they have to be to achieve “waterproof-ness)” and are similar in operation to the other sets. One nice touch, and one which we would find useful, is its dual-channel watch capacity – you can listen to one channel while monitoring another. Power output is 0.5W and this set also has a NiCd battery supplied, sealed in by a gasket. Unlike the above model, it is supplied with a “drop in” charging cradle which doubles as a desk stand. The range of this set was more than adequate for our needs. With a smaller antenna and a lower output power we expected a smaller operating range and this proved correct in out tests. We needed a kilometre; these easily achieved the claimed three kilometres. The biggest disadvantage (as far as we were concerned) was the price of these radios: $356 each would be really stretching the friendship! Our Verdict: If only we could afford such luxury as a waterproof radio... So which one did we choose? It was a real toss-up in the end. We were very impressed with the Tek City unit from Jaycar and the tiny Uniden UH-040XR. Both were the same price, both had more than adequate range, both would do the job perfectly. Our final decision was made not by performance – there wasn’t much between them – but on the grounds of ongoing battery costs. For reliability and safety, we tend to replace batteries after each surf carnival so we figured eighty “AAA” cells each time (we use 20 radios for a carnival) would cost a lot more than sixty “AA” cells, especially with the bulk prices now available on alkaline AA cells. You might be wondering about fitting these sets with rechargeable cells. We wondered the same thing but this would have added a big chunk to the cost. More importantly, our experience with NiCd (or NiMH) cells in a marine environment has not been good. They seem to corrode very quickly and while this isn’t a problem if the battery is a throw-away alkaline, it is a problem with a (relatively expensive) rechargeable. Scratch that idea. If money was no object (huh!!!) we would have gone with the Uniden UH054. The obvious reason for this would be the ruggedness and waterproof characteristics of this set; the supplied sealed rechargeable battery a bonus in ongoing cost savings. But at more than three times the price we simply couldn’t stretch the budget that far. We’ll probably buy a couple of them for use in our water safety “rubber ducks” but that will be about it. Our thanks to Jaycar Electronics and Dick Smith Electronics for assisting with this survey. References: Australian Communications Authority – www.aca.gov.au Jaycar Electronics – www.jaycar.com.au Dick Smith Electronics – www.dse.com.au MARCH 2001  13