what to look for in a walkie talkie (CB type with 5 Km range) - Page 1
Forum section: electronics / general

author: Simon
author_rank: Unknown
timestamp: November 13, 2011, 02:50:49 pm
content: Right, I've decided that it would be a good idea to have a pair of walkie talkies, the CB type ie with 5 Km range. I'd use these when travelling in "convoy" with friends so that the two cars can keep in touch and the leader can give directions to the follower.Any pitfalls to look for in buying stuff like this ? I'll be looking on ebay etc, maybe Argos

author: oliver602
author_rank: Regular Contributor
timestamp: November 13, 2011, 03:37:17 pm
content: PMR446radios might be good for this too. More compact but with less range. Just a suggestion if you haven't considered them.

author: Simon
author_rank: Unknown
timestamp: November 13, 2011, 03:44:38 pm
content: well I think much of what is sold on ebay is actually PMR446 like these:http://www.ebay.co.uk/itm/COBRA-MT975-WALKIE-TALKIE-RADIO-LATEST-MODOL-12KM-/280764458374?pt=UK_ConsumerElectronics_SpecialistRadioEquipment_SM&hash=item415edda586#ht_500wt_1362there are other that are speced for 400-450 MHz

author: oliver602
author_rank: Regular Contributor
timestamp: November 13, 2011, 03:56:40 pm
content: '12KM range' advertised on those is total BS(i had a quick check on amazon reviews) PMR446 radios are limited to 500mW

author: Simon
author_rank: Unknown
timestamp: November 13, 2011, 04:01:42 pm
content: oh, maybe i should go for a set of the others at £40ish they are advertised as 5W

author: Simon
author_rank: Unknown
timestamp: November 13, 2011, 04:26:43 pm
content: what sort of range will this have ? it is advertised as 5Whttp://www.ebay.co.uk/itm/Dual-Band-UHF-VHF-FM-transceiver-radio-walkie-talkie-/250889937616?pt=UK_MP3_Player_Accessories_AudioDocks_Speakers&hash=item3a6a34a2d0#ht_3203wt_1134

author: oliver602
author_rank: Regular Contributor
timestamp: November 13, 2011, 05:35:24 pm
content: I'd suspect you would need a licence for those 5W radios. I managed between 1 - 2 Km on my set of Oregon Scientific PMR446 radios in the country across a valley with some obstructions. Wasn't a very scientific experiment. Range reduced dramatically in built up areas. I'm not into radio so I'll leave that question to someone else.

author: FreeThinker
author_rank: Frequent Contributor
timestamp: November 13, 2011, 06:56:33 pm
content: Quote from: Simon on November 13, 2011, 04:26:43 pmWell according to the spec sheet they are 2W @ 5km range. Wouldn't put too much credence in those though

author: PetrosA
author_rank: Frequent Contributor
timestamp: November 13, 2011, 08:53:58 pm
content: If your cell phones won't do the trick (that would be the cheapest option) and you're going to be in vehicles, I'd recommend a simple CB with rooftop antenna. Handhelds will put you at a disadvantage right at the start because you'll lose antenna height and have all the steel of the vehicle around you. Whatever radios you end up getting, you'll probably need licenses for.

author: Balaur
author_rank: Unknown
timestamp: November 13, 2011, 09:41:13 pm
content: Quote from: PetrosA on November 13, 2011, 08:53:58 pmNot quite. The446 MHzband is free to use in Europe.I'm also using walkie talkies with my friends when travelling, trekking or skiing. They can be very useful.Cheers,Dan

author: Unknown
author_rank: Unknown
timestamp: November 13, 2011, 10:06:05 pm
content: Quote from: Simon on November 13, 2011, 04:26:43 pmA: What sort of environment will it be used in? In ideal conditions a few kilometres, in damp conditions from within the Faraday cage of a motor vehicle traversing hilly well vegetated terrain, maybe a few hundred metres.First thing to realise is that while transmit power helps (helps discharge batteries too) 5W does not equate to 5 times the range of 1W.For your application some half watt to 2W sets should suffice once you get over the expectation that they will be able to absolutely contact each other any time within a geographical range.You can spend a fortune on Antennas and just legal sets and not be too much better off in the circumstances you describe. Your biggest problem on CB of any time will be finding a channel free of pre and post pubescant knobs shrieking expletives and talking illiterate bollocks.You may pay by the minute for the mobile phone system, but with any decent plan you get a hell of a lot of talk time for the cost of some eBay CBs. Best thing there is someone with some clues about RF propagation has sorted out most of the black spot transmission issues for you.

author: Simon
author_rank: Unknown
timestamp: November 14, 2011, 06:49:29 am
content: err complicated CB stuff is out of the question, it has to be operated by a layman or laywoman, the vehicles should not be more than a few hundred metres apart. Mobile phones are a pain in the back side and well if it is an hour journey that is quite a chunk out of anyone that is not on an unlimited plan plus you have to dial the phone, My idea was to make it as easy as pressing a button and talking. I'm working on the fact that any specified range will be greatly diminished in a car.There was a review on amazon for a 0.5W set that was rated for 3 Km and this was noted to be about 200 metres when used in cars which is why i wanted to go for something more powerful just to be safe. There are sets that are listed as dual band as they work at the 136~174 MHz and 400~470 MHz ranges. maybe the lower frequency band will have more range - is it a licence free band in the UK ?An example of use is that next week we have to go somewhere about 30 miles away. i will have my satnav and the other driver does not use a satnav. So she could go ahead and I can follow and give her directions over the radio that was we don't loose each other and she knows where we are going. If we are out in two cars then there will be at least four of us in the group so passengers can man the radios

author: tnt
author_rank: Regular Contributor
timestamp: November 14, 2011, 11:52:02 am
content: You could use TETRA handsets in DMO mode. Works greatNot cheap tough ... like 300-400$ for a MTH800.

author: sonicj
author_rank: Frequent Contributor
timestamp: November 14, 2011, 11:54:07 am
content: PMR446 should easily be adequate for a convoy a few hundred meters apart.-sj

author: vk6zgo
author_rank: Super Contributor
timestamp: November 15, 2011, 03:27:45 am
content: Basically,the legal UHF radios are fairly limited in range,as you can't legally put gain antennas on them,& there are no repeaters for these things in the UK.Contrast that to the situation in Australia,where there is a network of UHF CB repeaters which can be used by handheld UHF CB radios to radically increase the effective range (of course, allowing for the possibility that the repeater may be monopolised by one of the people that think profanity is the new free speech).Back in dear old Blighty,you are stuck with direct communications,which as others have said can be very limited car to car,.DO NOTbuy anything that is not a legal device for you ,in your country!!The things advertised as dual band 136-174MHz & 400-470MHz areNOT!legal for you to use!Don't be tempted by these things,as you could end up in big excrement with your licencing authorities.HMG is very jealous of her position of arbiter of who uses what frequency allocation in the UK,& the aforesaid excrement could range from a"slap on the wrist" & having your radios taken away,to a "sell your car to pay it" type fine.It seems that the only things legal in the UK are PMR446 & oldtimey 27MHz CB,unless you,& all of your mates get an Amateur Foundation licence,when you could use equipment for that service-----Again,don't even fantasise about using "Ham" equipment without a licence!!Another point,to a Police Officer,these little handheld radios look a lot like cellphones,& cops don't like you usingthemwithout a "hands free" setup.VK6ZGO

author: Zad
author_rank: Super Contributor
timestamp: November 15, 2011, 04:42:30 am
content: I would have thought old style CB would be better, at least it allows you to have an external antenna on the car. Easy to put on and remove with a magnetic mount.

author: sonicj
author_rank: Frequent Contributor
timestamp: November 15, 2011, 11:49:57 am
content: whats the UK equivalent to TracFone? for less than $10, you get a phone with 20min pre-paid. im sure yo guys have something similar...-sj