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Thread ID: 86628	2008-01-23 02:51:00	UHF radios, RTs, walkie talkies ... help needed	Oggy (5399)	PC World Chat

Post ID	Timestamp	Content	User
633033	2008-01-23 02:51:00	I've been doing a bit of a project at work on our fire evacuation procedure and Civil Defence emergency procedure. (We run a complex for adults with an intellectual disability) I've identified that in those circumstances it would be good to have access to a set of RTs .. Radio Telephones .. UHF radios call them what you will, as that will help the person in charge of evacuation communicate with his deputy who will be in another part of our large complex. I basically want to know if the units that typically go for about $70/$80 like this www.dse.co.nz will cut the mustard or if we should look at something like this www.dse.co.nz at about $200? I realise that the ranges quoted are probably only obtainable if you have a line of sight situation and a few other variable are perfect and I also believe that a good rule of thumb is that you will get about 1km range for each watt of power output. My immediate problem is that in a fire evac, the chief warden and his deputy stand 50 metres from each other but on opposite sides of a large two story wooden building, hence no 'line of sight'. Would one of those smaller units cope with that or should we just go to the more powerful model? Secondary to that, we have a couple of houses a few hundred metres from our main site that fit within the theoretical range of the smaller units but in the real world may not be reachable. Anyone got any real world experience of working with these units in an urban situation that you'd like to share?	Oggy (5399)
633034	2008-01-23 03:10:00	From the way you spelled "defence" I will guess you are not in the US . . but I have some really powerful handheld radios . They are Cobra Micro-Talk units, use the FRS freqs and as far as being legal . . well if it's just for emergencies, I bet that NZ has a non-limiting law that allows one to use ANY form of communication in times of peril to life or private property . Here's a NZ site for you to see ( . com/index . cfm?currentpage=1&fuseaction=category . display&category_id=29" target="_blank">cobra . com) . . . and Cobra has a really good name in the US .	SurferJoe46 (51)
633035	2008-01-23 05:06:00	Hey Oggy, Your DSE links are not working. A couple of years ago me and a mate bought a pair of radios for $100 each just for mucking around with. They had a rated line of sight range of 1km, i cannot recall what their wattage was. They do work very well, there range is good, even through buildings - we would test them out around Waikato Uni. One thing i can recommend is that you get a pair with a headset jack, otherwise it justs comes out the speaker which makes it much harder to hear.	noone (22)
633036	2008-01-23 05:28:00	the small ones are quite good, I have had about 150M around the streets. DSE have a good exchange policy..... get the small ones and give then a shot , if you dont get what you want from them , just go back up swap/upgrade to the bigg ones :-)	robsonde (120)
633037	2008-01-23 06:54:00	All good to know. Thanks.	Oggy (5399)
633038	2008-01-23 20:35:00	From the way you spelled "defence" I will guess you are not in the US . . but I have some really powerful handheld radios . They are Cobra Micro-Talk units, use the FRS freqs and as far as being legal . . well if it's just for emergencies, I bet that NZ has a non-limiting law that allows one to use ANY form of communication in times of peril to life or private property . Here's a NZ site for you to see ( . com/index . cfm?currentpage=1&fuseaction=category . display&category_id=29" target="_blank">cobra . com) . . . and Cobra has a really good name in the US . Those are quite interesting - claim up to 27 mile range! But they do not list the frequencies (MHz), nor the power (RF watts output) . And are you sure thats a NZ site because the Contact Us does not list NZ . Have you used the Cobra units, SJ?	Morpheus1 (186)
633039	2008-01-23 23:25:00	As far as knowledge goes, I can't offer much, but www.dse.co.nz looks quite good (albeit a bit pricey). Comes with rechargeable batteries, cradles, and headsets, and it's 2-watt, with a range of up to 10 k's (line of site). So it should be somewhat clear within 1-2 k's without line of site (vital when everyone is yelling and everything is happening at once and the chaos theory has decided to visit you personally). Or, for more units for less money, try www.uniden.co.nz (four pack). While it has a lesser range, and not so many bonuses, the price-per-unit is around $30. How many units would you need anyway?	ubergeek85 (131)
633040	2008-01-24 01:54:00	Those are quite interesting - claim up to 27 mile range! But they do not list the frequencies (MHz), nor the power (RF watts output) . And are you sure thats a NZ site because the Contact Us does not list NZ . Have you used the Cobra units, SJ? I have a pair of the Cobras right here on my desk on full-time charge . They work very well, although I have not seen the 27 miles range, I can get at least 17-20 miles . Here's a link for the freqs for both the FRS and the GMRS systems . (Pssst: we don't really bother with licensing them here . . . it's like the old days of CB-radio and skip and 50,000 watt linear amps and directional beam antennas . Your results may be different and there may be goons at your door to show you the rules if you try that in NZ) . The original site was on the Worldwide Cobra site and that link was for their Australia/New Zealand page . Like I say, Cobra is a very very good product here in the US . Here's the homepage for Cobra ( . com/index . cfm" target="_blank">cobra . com) . . and click on the link WHERE TO BUY for your local distributer .	SurferJoe46 (51)
633041	2008-01-24 04:05:00	I can get at least 17-20 miles. That is a long way and I am impressed ! Did not see a link in your post, SJ, but I found this one: www.ba-marc.org It looks like 462 MHz. I did not think the range for a small hand held transceiver in UHF frequencies would be more than around 5 miles.	Morpheus1 (186)
633042	2008-01-24 04:38:00	Here's Radio Shack's 18 mile range versions: . radioshack . com/family/index . jsp?categoryId=2032071&cp=2032052&allCount=18&fbc=1&f=PAD%2FMax+Talk+Range%2F18+Miles&fbn=Max+talk+range+%28miles%29%2F18+Miles" target="_blank">www . radioshack . com And here's the Cobra MicroTALK® LI 7200-2 WX 27-Mile Radio ( . com/index . cfm?currentpage=1&fuseaction=category . display&category_id=29" target="_blank">cobra . com) Here's the next one . . the model after the ones I bought . . . without the NOAA Weather reception: MicroTALK® LI 5600-2 DX 22-Mile Radio ( . com/index . cfm?fuseaction=product . display&Product_ID=396&category_ID=29" target="_blank">cobra . com) Typically . . . they all have 142 Privacy Codes; 38 CTCSS (Continuous Tone Coded Squelch System) codes and 104 DCS (Digitally Coded Squelch) codes provide a total of 142 privacy codes . 3,124 privacy combinations are possible when the 22 channels are combined with the 142 privacy codes Hopefully, you can see those links . Any licensing would be required if you want to use the legal repeaters that are all over the place . . but I typically get from Lake Hemet to Idyllwild (16 miles) over hills and thru trees . . but also over a larger body of water too . . . . to help the propagation . I can usually hit my house from the same side of the mountain when I get a line-of-sight fix on my home . Once I can actually see San Jacinto, I can get connected OK . So the range is pretty accurate . . and the battery life on HIGH power is about 8 hours . . . on LOW power, it is twice as long before they go flat . . . but I have a mobile charger and the home unit can be left in the charger-base and it will receive when it's there . . so there isn't any real dead battery condition to worry about .	SurferJoe46 (51)
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