henny Posted January 13, 2013 Share Posted January 13, 2013 Just a quick question . I have the option to buy some wireless talkback/coms at a verry good price , but they ate ex tv and are currentley tuned to something like 425 MHz what I want to know is aslong as they respect the rules as to power output is there any reason why they can't be used in ch38 on our current pmse lincence ??? Link to comment Share on other sites More sharing options...
Jivemaster Posted January 13, 2013 Share Posted January 13, 2013 Talk to the makers/distributors and ask them whether the units can be used or retuned for use, or not. Link to comment Share on other sites More sharing options...
StevieR Posted January 13, 2013 Share Posted January 13, 2013 As far as I understand things, Talkback requires separate licensing and is not covered by a PMSE license. According to the JFMG website, it is possible to license talkback 'in-band' so long as it is a fixed site and subject to location availability. I would speak to JFMG before doing anything to see what the current situation is. Steve Link to comment Share on other sites More sharing options...
henny Posted January 13, 2013 Author Share Posted January 13, 2013 The units can be retuned anywhere between ch 10 and 70 apparently Link to comment Share on other sites More sharing options...
paulears Posted January 13, 2013 Share Posted January 13, 2013 I doubt it! If it's on 425MHz then it's narrow band comms, and the current band will be in the 454-456 area if you take out a new license. PMR generally covers the full range of 420-470MHz, but nowhere near channel 38 - and even then, the ch38 band is for wideband operation, not narrow band comms use. Comms kit also exceeds the permitted power output too. It is possible to tune comms radios to wideband channels, but the audio is very unpleasant if it works, and some (Icom notably) will not lift the squelch on a wideband transmission. I suspect that the units are confusing you by their use of the word channel - which is different from the TV channel allocations. Link to comment Share on other sites More sharing options...
henny Posted January 14, 2013 Author Share Posted January 14, 2013 These are the units http://www.woodanddouglas.co.uk/wireless-telemetry/duo-wireless-intercom Duo operates in the 400 to 900MHz frequency range Link to comment Share on other sites More sharing options...
paulears Posted January 14, 2013 Share Posted January 14, 2013 No it doesn't. It works in a very small section of it, which Wood and Douglas will need to set. I think they will probably be doing their usual thing and using modules, which are swapped to give operational capability in the desired band, and then you get switched channels in that particular sector - pretty much the same as radio mics that must be bought in the right band version. They are narrow band devices, as we guessed, so the results with a proper bases station will be pretty good. We're using one of their base stations at the moment with comms radios and they do make excellent kit and are well established in the industry. These are handy devices - but the base station is a bit expensive. If you have this, then they'll be fine - and simplest is to establish their current operating channel and see if OFCOM will license it. If they can't then JFMG may be able to on one of the broadcast comms channels. I doubt very much if there's any point considering channel 38 because they are not compatible with radio mics - bandwidth totally wrong, so no point wreck a radio mic channel when there's not much space for them anyway. These devices only need a small amount of spectrum, so a comms channel makes much more sense. What you have is essentially a walkie-talkie with a push to talk button on the top. You could use any business radio the other end - repeaters/base stations come up on ebay from time to time if you need to interface with a normal comms system. The ones I'm using at the moment are licensed to transmit on 459MHz and receive just under 5MHz lower. The base station has a small cavity filter to enable transmit and receive on one aerial at the same time. If you buy them without the base station, they won't work - they're duplex, not simplex, so they can't talk directly to each other - they need the bit of kit the other end! Link to comment Share on other sites More sharing options...
henny Posted January 14, 2013 Author Share Posted January 14, 2013 The sake is for3 x duplex beltpacks3 x duplex base2 x tx only rack 6 x rx only beltpacks I now have a note of current frequencys so will call Jmfg tommrow Link to comment Share on other sites More sharing options...
paulears Posted January 14, 2013 Share Posted January 14, 2013 If the price is good - I'd buy it. Wood and Douglas duplex base stations in working order go for around £600+. I've seen some in the £800s. The system looks complete. Personally, I'd check the frequency (W&D often write it on the back of the base station) and if it's in the OFCOM business UHF1 range (420-450) or UHF2 (453-466) band, then just contact them to license it - price wise, not too expensive and licenses last 5 years. JFMG look after the broadcasters for their comms, so probably won't be interested in your comms system as it's not really their remit. If you can get this kit cheap - it's very saleable. The base stations need a bit of ventilation as they get a bit hot! EDIT - the W&D spec also means that you can also use plain ordinary walkie talkies bought from places like ebay for £40 or so. Handy of you need to expand. These often have the deviation set a little low, but do go into the system quite well. If it helps the W&D audio is less nasty on the ears - using audio frequency limited Motorolas, for instance, means the audio is a bit thin and tinny - so gives me ear ache. The W&D with in ears sounds a bit nicer. Link to comment Share on other sites More sharing options...
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