RTs, UHF Radio, CB ...communication help please

[Oakie]

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 http://www.dse.co.nz/cgi-bin/dse.storefront/479527e000ba51762740c0a87f3306ed/Product/View/D1804 will cut the mustard or if we should look at something like this http://www.dse.co.nz/cgi-bin/dse.storefront/479527e000ba51762740c0a87f3306ed/Product/View/D1895 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?

[sir.taz]

We began to use therse at our worksite and found them really good, but the batteries were a pain. We now have ones with rechargable bases. Not that much more expensive, think they were 450 for six but that was a few years ago. We find the distance is good for them. I can hear work if I forget to take my radio off at the end of the day and take it home. We have a large hill between home and work. Straight line distance in that case is around 500-700m. We have a large number of wooden buildings at work spread out over a large area, and the radios work fine

[wofman]

hi the cheap ones in most cases work well in side buildings as well as about 2to 3 klm range. if you would like to try some give me a call i have some we use when we go out in the 4x4s.
ph 072265781
cheers wayne

[ManDownUnder]

Where's Biff when you need him? He's DA MAN with this stuff...

[Virago]

Always ignore the quoted "line of sight range" - reception is only possible at those ranges under the most ideal circumstances. The best rule of thumb is "watts equal kms".

We use PRS radios in our business under similar circumstances to yours, carrying out annual checks on fire alarms etc. The big killer for radio reception is concrete and steel - some of the bigger buildings we service will defeat even the most powerful (5 watt) radios, costing $400-$500 each.

However, a 50 metre range, blocked by a wooden building, should not be a problem for even the cheaper (0.5 watt) units from Dick Smith, although the more expensive (2 watt) units would be more reliable. The 2 watt units have NiMH rechargeable batteries and come with a desktop charger, whereas the cheaper ones require AA batteries (which will chew out fast).

[Oakie]

I finished up buying a rechargable pair for $99 (down from $149) with a '7 km range'. I thought that should at least guarantee reception on our site. That has turned out to be correct. Great reception on site and walking around the large block to where another our other houses is (600 metres away as the crow flies?) still gave good reception. Demonstrated these today at work and much happiness was evident.