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Cellular Phone Forum / Country Specific / Australian Group / September 2004CDMA high power phone/car kits
Hello, As I understand it, one way CDMA can get better reception in country areas is by boosting it's signal significantly. (GSM is more restricted in it's signal strength.) Could anyone recommend any CDMA car phones (or handsets with a car kit booster) that are higher power and thus (hopefully) keep better connection? Thanks, > Hello, > As I understand it, one way CDMA can get better reception in country [quoted text clipped - 4 lines] > booster) that are higher power and thus (hopefully) keep better > connection? Signal boosting is illegal for CDMA because that system depends on each phone limiting its tranmission power so that it doesn't block out others sharing the same frequency. They might might been legal for analogue phones, which don't share frequencies as much as CDMA, but we don't have analogue in Aust anymore. (They still have it in the USA). Probably what you're thinking of is a high-gain roof-mounted antenna, which is more sensitive and can pickup a better signal from the base station. > As I understand it, one way CDMA can get better reception in country > areas is by boosting it's signal significantly. In Queensland a lot of the boys have cars with CDMA aerials at least over 1m. They all tell me helps considerably with reception. Looks like repo agents or something similar.  SignatureAcid absorbs 10 times its weight in excess reality. > As I understand it, one way CDMA can get better reception in country > areas is by boosting it's signal significantly. CDMA boosters are illegal in Australia, unless they comply with the A-Tick standard, which none do to the best of my knowledge. A few legal GSM boosters do exist and are approved accordingly. (GSM is more > restricted in it's signal strength.) Actually, you will find received signal strength in -dBm is better for GSM than CDMA off the same site - it's just that CDMA can efficiently operate at lower signal levels, and doesn't suffer the 35KM limit like GSM. > Could anyone recommend any CDMA car phones (or handsets with a car kit > booster) that are higher power and thus (hopefully) keep better > connection? The problem with the illegal boosters is that they don't reduce power output when near a BTS. This has no effect on you, but "blinds" the BTS sector to signals further afield which are not boosted. Including emergency calls - not very nice at all, some would call this selfish. I have a legal GSM booster as part of my car kit that actually reduces signal strength the closer it gets to a BTS - but when I'm 40KM north of Marlborough it's pumping out 5W to keep the RF link connected. As others have suggested, a large high-gain antenna would do well if the terrain you traverse is mainly flat. If your travel is predominantly in hilly/mountainous areas, an antenna with a lower gain will be better as the beam pattern is better suited. Mounting of the antenna isn't really that important, but purists will insist right in the middle of your roof is the best. For signal yes, but having a 4' colinear omni in the middle of your 4WD's roof has its own problems :-) Try to stay away from glass mounted antennas as well - in my testing there is about a 5dBm drop in signal through the capacitive coupling of the windscreen. Magnetic or bolted-on antennas are better. Hope this helps. Albinus. > > As I understand it, one way CDMA can get better reception in country > > areas is by boosting it's signal significantly. > > CDMA boosters are illegal in Australia, unless they comply with the A-Tick > standard, which none do to the best of my knowledge. A few legal GSM > boosters do exist and are approved accordingly. If you had read the WHOLE post you would see he was not referring to CDMA boosters > > Could anyone recommend any CDMA car phones (or handsets with a car kit > > booster) that are higher power and thus (hopefully) keep better [quoted text clipped - 4 lines] > signals further afield which are not boosted. Including emergency calls - > not very nice at all, some would call this selfish. I have a legal GSM Hardly selfish, more like highly illegal and you will be thrown through the courts for this by the ACA when caught > If you had read the WHOLE post you would see he was not referring to CDMA > boosters Sure did read the post: "Could anyone recommend any CDMA car phones (or handsets with a car kit booster)" No CDMA mobile to the best of my knowledge boosts the signal, car kit or otherwise. > Hardly selfish, more like highly illegal and you will be thrown through the > courts for this by the ACA when caught Take this point: I make a call on a CDMA handset equipped with a booster, stand right next to the tower and prevent people further away making a call. I call that selfish behaviour. Albinus. > > If you had read the WHOLE post you would see he was not referring to CDMA > > boosters [quoted text clipped - 13 lines] > stand right next to the tower and prevent people further away making a call. > I call that selfish behaviour. Yeah, badly written, wasnt implying it wasnt selfish, more like trying to highlight that the selfishness is diminshed by the fact that its highly illegal and possibly life threatening Telstra do some good work with the ACA to track down w.nkers like this > Albinus. > "Greg Alexander" <galexand@ozemail.com.au> wrote:> > > As I understand it, one way CDMA can get better reception in country > > areas is by boosting it's signal significantly. > > CDMA boosters are illegal in Australia, unless they comply with the A-Tick > standard, which none do to the best of my knowledge. Hi Albinus, thanks for your response (and thanks others too). As I understand it, a CDMA phone 'boosts' it's signal when the tower tells it to. Eventually some phones can't boost any higher, and they drop out. I thought that a car-phone would be able to boost it's power higher than a handheld... is that right? Otherwise I figured a standard handset with some booster - but looks like I'm out of luck there if they're not legal here in Australia! > A few legal GSM boosters do exist and are approved accordingly. Do you know which GSM phones have the boosters legally available? I remember a Nokia car-phone that had up to 8W (I think 8W anyway), and Vodafone allowed a phone to use up to 6W (Telstra and Optus both restricted the phones to 2W, which was a standard handset). Do the boosters work better with any network? > > (GSM is more restricted in it's signal strength.) > > Actually, you will find received signal strength in -dBm is better for GSM > than CDMA off the same site - it's just that CDMA can efficiently operate at > lower signal levels, and doesn't suffer the 35KM limit like GSM. I thought GSM had higher signal strength but only used it 1/8th of the time, so overall it was around the same. Still, only my lay-man's understanding. > > Could anyone recommend any CDMA car phones (or handsets with a car kit > > booster) that are higher power and thus (hopefully) keep better [quoted text clipped - 7 lines] > closer it gets to a BTS - but when I'm 40KM north of Marlborough it's > pumping out 5W to keep the RF link connected. Yeah, I certainly want to 'play nice' and will stick with the legal stuff. > As others have suggested, a large high-gain antenna would do well if the > terrain you traverse is mainly flat. If your travel is predominantly in [quoted text clipped - 7 lines] > is about a 5dBm drop in signal through the capacitive coupling of the > windscreen. Magnetic or bolted-on antennas are better. This is for a boat, so I'm not sure where I stand on that one. Will certainly go for a low gain antenna though after what you've said. I haven't tried out a CDMA handset on the Hawkesbury (north of Sydney), it's a low reception area for all the GSM networks. The Orange website shows coverage for the Hawkesbury, and also roams onto Telstra, so it may actually have a really good coverage (I'm assuming Orange CDMA automatically roams to Telstra CDMA, even in the Sydney area?). Thanks again everyone. > As I understand it, a CDMA phone 'boosts' it's signal when the tower > tells it to. Eventually some phones can't boost any higher, and they More the other way round. They must *reduce* their power as they get closer. By a factor of 1,000, 10,000 or less. The signal received at the base station must be at the *lowest* usable level to match that received from the most distant phones. > drop out. I thought that a car-phone would be able to boost it's power > higher than a handheld... is that right? Otherwise I figured a Quite true of AMPS (analogue) and GSM too. >>>(GSM is more restricted in it's signal strength.) No, it's CDMA that has very, very strict limitations on phone's transmission power. The 35 km restriction in GSM is due to way it shares each frequency between up to 8 users, in which each phone take turns at transmitting/receiving in a short time slot. Each slot only allows enough time for the signal to travel 35 km between the phone and the base station. CDMA doesn't use time slots, but transmits continuously so it doesn't have any time limit. But it still allows several phones to use the same frequency at the same time, and depends on each phone to limit its transmission power to avoid drowning out the others. > I thought GSM had higher signal strength but only used it 1/8th of the > time Correct, but the GSM limit is due to timing, not power. > > > Could anyone recommend any CDMA car phones (or handsets with a car kit > > > booster) that are higher power and thus (hopefully) keep better > > > connection? The limit with CDMA is not power either, but the sensitivity of your phone. The base station has no trouble picking up the signal from your phone - a couple of watts is more than enough. They use huge antennas to pick up your signal. The problem is the the tiny antenna on your phone - you need a bigger one. > > As I understand it, a CDMA phone 'boosts' it's signal when the tower > > tells it to. Eventually some phones can't boost any higher, and they [quoted text clipped - 3 lines] > at the base station must be at the *lowest* usable level to match that > received from the most distant phones. I understand that a CDMA tower/antenna requires that the signals from all the phones on it's frequency are all received at the same strength, so that it can separate out the various messages into their separate telephone calls. Hence the closer phones broadcast very low power signals, while the distant phones are more powerful. I'm also aware that when the signals start overlapping too much and the tower can't differentiate the signals, it instructs every phone to boost it's signal. Some phones may already be transmitting as high as they can, so they can't boost their signal and will now not be powerful enough to be heard (the caller will lose their connection). But let me get this straight - you're saying that all CDMA phones have the same power output. If you know you'll be operating from a particularly distant point, there's no option to buy a higher powered phone. It sounds weird to me, but I haven't heard or seen anything to dispute that - I'd appreciate if you could confirm I'm understanding right (or if anyone disagrees?) > The limit with CDMA is not power either, but the sensitivity of your > phone. The base station has no trouble picking up the signal from your > phone - a couple of watts is more than enough. They use huge antennas > to pick up your signal. The problem is the the tiny antenna on your > phone - you need a bigger one. Well regardless of power, it seems I could use a big, low gain antenna for the hills then! > > > As I understand it, a CDMA phone 'boosts' it's signal when the tower > > > tells it to. Eventually some phones can't boost any higher, and they [quoted text clipped - 22 lines] > dispute that - I'd appreciate if you could confirm I'm understanding > right (or if anyone disagrees?) CDMA phones vary their power output many times per second, depending on received signal strength and also instructions from the base station. This mechanism for this is tightly controlled and all phones must conform to the standards before they are allowed on the network. The general idea behind the algorithm is that each phone tries to transmit as quietly as possible. Devices such as CDMA amplifiers are banned for this reason - if the signal in amplified outside of the standard algorithm it will cause massive problems to other users. The base station has no trouble picking up the signal from your > phone - a couple of watts is more than enough. They use huge antennas > to pick up your signal. The problem is the the tiny antenna on your > phone - you need a bigger one. Also, a rural CDMA site is emitting around 200W - if your handset was emitting that, many people would have cooked brains ;-) And it's a matter of economics. A big antenna is not necessarily better if it's poorly engineered (antenna construction can be fun finding out what works and what doesn't). Base station antennas need to be much more sensitive as the incoming signals from handsets are far weaker than the signal received at the handset from the base station. There's no reason why a handset can have a very well engineered antenna, but the laws of economics once again mean that most phones have yum-cha quality antennas. Albinus. > The base station has no trouble picking up the signal from your > [quoted text clipped - 3 lines] > > Also, a rural CDMA site is emitting around 200W - ... which partly compensates for tiny phone antennas. > And it's a matter of economics. A big antenna is not necessarily better if Not just economics, but convenience, comfort and style. Lots of phones are designed for people who never leave the city, but want something that fits comfortably in a pocket or purse. Which doesn't apply to car kits, of course. > Hi Albinus, thanks for your response (and thanks others too). No problems. > As I understand it, a CDMA phone 'boosts' it's signal when the tower > tells it to. Eventually some phones can't boost any higher, and they > drop out. I thought that a car-phone would be able to boost it's power > higher than a handheld... is that right? Otherwise I figured a > standard handset with some booster - but looks like I'm out of luck > there if they're not legal here in Australia! CDMA has extremely sensitive timings, much more so than GSM, which makes any 3rd party add-on a gamble. > Do you know which GSM phones have the boosters legally available? I > remember a Nokia car-phone that had up to 8W (I think 8W anyway), and I have an Ericsson A1018s in its corresponding car kit (forgot the model number) and 5W output is quite common when travelling country roads. > Vodafone allowed a phone to use up to 6W (Telstra and Optus both > restricted the phones to 2W, which was a standard handset). Do the > boosters work better with any network? Have you been reading Tim Merrell's site? Some good stuff on there, but I know for a fact that Optus do not limit phones to 2W, as my car kit is capable (and actually reaches) 5W output. I haven't come across a GSM handset that emits more than 2W when in handheld mode, as the radiation when next to your head would give you a very warm head at 5W! > I thought GSM had higher signal strength but only used it 1/8th of the > time, so overall it was around the same. Still, only my lay-man's > understanding. GSM utilises "pulsing" when communicating, that's why you often hear the timing bursts over cheap speakers. CDMA is true "Spread Spectrum" and uses a much more constant level of power over a wider range of frequencies, hence the reason why you never hear CDMA signals being picked up in speakers. > Yeah, I certainly want to 'play nice' and will stick with the legal > stuff. Good idea - many people who used CDMA boosters (mainly farmers) thought nobody would know they are being used - but Telstra certainly did. Areas around Hay in NSW were especially prone, the call dropout rate on CDMA (normally less than 1%) was soaring well into the double digits on occasions. Telstra knew it wasn't their network at fault, so worked with the ACA to track those responsible down. > This is for a boat, so I'm not sure where I stand on that one. Will > certainly go for a low gain antenna though after what you've said. A boat (as long as you aren't cruising around fjords) will normally work better with a high-gain antenna, as there is no terrain blocking the signal. Especially true on Moreton Bay, most signals are very weak unless a high-gain antenna is used. > I haven't tried out a CDMA handset on the Hawkesbury (north of > Sydney), it's a low reception area for all the GSM networks. The > Orange website shows coverage for the Hawkesbury, and also roams onto > Telstra, so it may actually have a really good coverage (I'm assuming > Orange CDMA automatically roams to Telstra CDMA, even in the Sydney > area?). I'm not familiar with the topography of that area, so someone else with local experience will need to fill you in on what may work best. Good luck. Albinus. > > This is for a boat, so I'm not sure where I stand on that one. Will > > certainly go for a low gain antenna though after what you've said. [quoted text clipped - 3 lines] > Especially true on Moreton Bay, most signals are very weak unless a > high-gain antenna is used. In the hawkesbury (Cowan Creek) we're actually quite close to towers, it's just quite hilly in the national park (and we're at the lowest points of course, on the water). We just have to find a bay which is a little more open to get a signal - or stand on the flybridge, write an SMS, hold the phone up as high as possible ;-), and keep resending until it works! I've got my sister coming on the boat tomorrow with her Orange phone, so I might have a few more ideas then! > In the hawkesbury (Cowan Creek) we're actually quite close to towers, > it's just quite hilly in the national park (and we're at the lowest > points of course, on the water). Then a low-gain antenna in the order of 1.5dBi to 3.0dBi would work best from my experience. Many people fall into the unfortunate trap of believing that a 12dBi antenna will always work better than a 1.5dBi one, that is true on flat, sweeping plains but useless in hilly terrain. If on a boat then an antenna that can be bolted onto it would ensure minimal signal loss in the coupling. Albinus. |
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