BigYinUK Posted February 25, 2014 Share Posted February 25, 2014 Hi all I was looking at a document on the PMSE website today which clearly showed that Channel 69 was still available for wireless microphones and IEMs - My understanding (and Shures document http://www.shure.co.uk/support_download/frequencies confirms this) that its not the case and that CH69 is no longer available. In a nutshell my understanding is that CH70 is still free, CH38 is available on a shared annual/bi-annual licence basis. CH39&40 have become part of the interleaved spectrum along with CH21-30 and CH41-60 so co-ordinated daily site specific licence required. All the other UHF channels are now no go. Is this about right? Regards Link to comment Share on other sites More sharing options...
sam.spoons Posted February 25, 2014 Share Posted February 25, 2014 This page http://www.pmse.co.uk/pmse-spectrum.aspx from Arquiva (or jfmg as was) the company who administer these licences on behalf of Offcom basically copies the Shure chart. As you say CH69 became unavailable for PMSE use on Jan 1st 2013. Link to comment Share on other sites More sharing options...
laolu Posted February 26, 2014 Share Posted February 26, 2014 Am I lucky or what? Here in Taiwan there is no limitation on any channels, VHF or UHF or GHz, everything is possible and – as far as I know – allowed and license-free. On the other hand, radio mics have such a limited range, that I don't completely grasp the problem some people seem to have with those frequencies. In our theatre I am using our locals (Mipro and JTS) and find that even walking backstage can already give me dropouts. Outside the walls of the theatre there is no more signal. So I am rather sure that I will not be disturbing anyone. The same is btw true for the Walkie-Talkies we sometimes use and which are also somewhere in the UHF band. Another story would be open-air, but I hardly ever do that. Maybe I'm just lucky. B-) Norbert Link to comment Share on other sites More sharing options...
azlan Posted February 26, 2014 Share Posted February 26, 2014 the big advantage of the co-ordinated frequency system that we use in the UK is that we can be reasonably sure that the local minicab office etc.. will not be broadcasting on one of our frequencies in the middle of the big finale number of our show, and obliterating all our hard work. also, in areas like the west end, or round my way (embassies and hotels aplenty) there are simply so many users on top of each other, that even if there is not enough interference to put their voices through our speakers, havoc can still be played without some control over who is using what. we also do it to ensure that we do not ruin some unfortunate local's TV picture, or get in the way of emergency services, air traffic control, or other safety critical wireless infrastructure Link to comment Share on other sites More sharing options...
Bobbsy Posted February 27, 2014 Share Posted February 27, 2014 Am I lucky or what? Here in Taiwan there is no limitation on any channels, VHF or UHF or GHz, everything is possible and – as far as I know – allowed and license-free. On the other hand, radio mics have such a limited range, that I don't completely grasp the problem some people seem to have with those frequencies. In our theatre I am using our locals (Mipro and JTS) and find that even walking backstage can already give me dropouts. Outside the walls of the theatre there is no more signal. So I am rather sure that I will not be disturbing anyone. The same is btw true for the Walkie-Talkies we sometimes use and which are also somewhere in the UHF band. Another story would be open-air, but I hardly ever do that. Maybe I'm just lucky. B-) Norbert Radio mics interfering with others is something to watch out for but not usually the biggest issue for reasons you mention. The far bigger problem is interference with your mics from very high power broadcast channels. With the move to digital and the "digital dividend" frequency sell off, the spare frequencies available for radio mic use is severely reduced. Don't forget that it's not just the local transmitters that can cause interference. As an example, when I lived in Leighton Buzzard, my "local" TV transmitter was Sandy Heath but, in certain locations, I had to also avoid frequencies in use from Crystal Palace in London and from Oxford. (Obviously I'm talking about temporary licences on coordinated frequencies--I wasn't cheating, honest!). Making things even worse is the way the digital TV signals are modulated--they tend to fill pretty much the entire channel without the usual spare space top and bottom. The good thing about JFMG (at least was I was in the UK) was that they'd work all of this out for you and suggest interference free frequencies when issuing your licence. On balance, I prefer the more bureaucratic system in the UK to the free for all I've encountered in other countries. Link to comment Share on other sites More sharing options...
paulears Posted February 28, 2014 Share Posted February 28, 2014 Has anyone ever really found minicab companies operating on radio mic channels? This is often mentioned in chat about radio mic systems, but two way radio would occasionally be a problem with VHF systems because the operating frequencies were quite close, but now most users are on UHF business radio is nowhere near PSME or channel 70. My summer venue is surrounded by taxi ranks and loads of two way radio users and marine radio and we've never experienced this at all. As most theatres run their own radio systems often on stage, interference from your own people would be much more common. A theatre old wives tale, I suspect. Every bit of noise and interference blamed on 2 way radio! Link to comment Share on other sites More sharing options...
J Pearce Posted February 28, 2014 Share Posted February 28, 2014 I think it is a tale hanging on from the bad old days of poorly maintained fixed frequency VHF mics and dodgy poorly maintained taxi radios. UHF range is too short (without big power broadcast/telecomms style) to be of much use to taxi ranks. Link to comment Share on other sites More sharing options...
Grum Posted February 28, 2014 Share Posted February 28, 2014 Has anyone ever really found minicab companies operating on radio mic channels? This is often mentioned in chat about radio mic systems, but two way radio would occasionally be a problem with VHF systems because the operating frequencies were quite close, but now most users are on UHF business radio is nowhere near PSME or channel 70. My summer venue is surrounded by taxi ranks and loads of two way radio users and marine radio and we've never experienced this at all. As most theatres run their own radio systems often on stage, interference from your own people would be much more common. A theatre old wives tale, I suspect. Every bit of noise and interference blamed on 2 way radio! But we have had the show playing on the bowling green PA after they left their equipment on at the end of the night, treating everyone on the seafront to a free audio version of the Cannon & Ball show. Link to comment Share on other sites More sharing options...
kerry davies Posted February 28, 2014 Share Posted February 28, 2014 In the sixties, before we learned about earthing and safety (and not pouring beer over guitar amps) it used to happen near taxi offices running over-powerful transmitters and later, in the late 70's, on the illegal AM CB radios imported from the US which, when boosted, swamped emergency military frequencies. It may be that these cases made people over-sensitive but PO Telephones and Customs and Excise had draconian powers and it scared a lot of people. My link If the "old wive's tales" make people act responsibly and legally then they serve a purpose. Bobbsy and Ynot probably have their own horror stories from those halcyon days of the CB "wars". Link to comment Share on other sites More sharing options...
Bobbsy Posted February 28, 2014 Share Posted February 28, 2014 Has anyone ever really found minicab companies operating on radio mic channels? This is often mentioned in chat about radio mic systems, but two way radio would occasionally be a problem with VHF systems because the operating frequencies were quite close, but now most users are on UHF business radio is nowhere near PSME or channel 70. My summer venue is surrounded by taxi ranks and loads of two way radio users and marine radio and we've never experienced this at all. As most theatres run their own radio systems often on stage, interference from your own people would be much more common. A theatre old wives tale, I suspect. Every bit of noise and interference blamed on 2 way radio! Never heard a minicab on my radio mic channels but, many years ago during a production of Cabaret, I had the opposite. Late during tech the director decided she wanted an extra radio mic and handed me a old Nady VHF unit she'd owned for years. I turned it on with trepidation and was surprised (and worried) to find I could pick it up on EVERY receiver I had active--a real accomplishment since the rest of the channels were on UHF 67 (with a temp site licence) and 69. I later heard that the minicab company over the road was also hearing that mic--I can't remember what frequency the were on but it was also UHF. No, I didn't use that mic. Link to comment Share on other sites More sharing options...
themadhippy Posted February 28, 2014 Share Posted February 28, 2014 No taxis here,although did get to listen to the fire brigades walkie talkys once,and also had someone asking about the best way to look after there petunias half way through a panto tech. kerry cheers for the link,it would apear the uk maybe getting AM and SSB in the near future,might just have to get myself a rig Link to comment Share on other sites More sharing options...
paulears Posted February 28, 2014 Share Posted February 28, 2014 Tut tut! We're still promoting disinformation and that wiki link is extremely skewed in it's history. Back in the late 1970s into the 80s, When I'd got my newly printed City & Guilds piece of paper that said I was fit to talk into a radio, and the panic of going from Lowestoft to Mablethorpe to take a Morse code exam had passed, I became quite ware of the illegal CB underground and helped a few of them out. Remember that back then the Home Office ran radio licensing, and they took it very seriously. We were at that time not at all friendly with the Russians, and back then the only people who had radios in their vehicles were the very obvious ones, and radios in the pocket would be deeply suspicious to any passing policeman. Even with a license, I got taken to the Police Station and had to convince them it was legal. The CB people hid radios in their cars, and were very aware that if they were caught with one, then the consequences were pretty serious. Kerry's comment about wiping out military radio is a little extreme, because although the military were the owners (and still are today) of huge swadges of RF bandwidth, occupancy was very low. Clansman radio kit, which I think was just in service when illegal CB took off was capable of operating on CB frequencies, but as they had thousands of channels to choose from, most well away from CB - the CB people with 100W 'Burner' amplifiers didn't really cause any issues. Mainly because groundwave propagation doesn't increase very much if you pile on the output power. Skywave of course does, but interference from other countries INTO the UK meant that the military steered clear of 27MHz as an operating frequency because not much use trying to use it with hundreds of Americans trying to talk to each other being heard here. Back then, it didn't take much for the Radio Invstigation Branch to bring out the spinning roofracks and track people down - but the only time I was aware of any action in my own area was when commisioning new PMR systems, where the equipment was tested for frequency, power output and deviation. They tracked down pirate radio stations and accidental interference to essential services. For the main part, they acted as advisory bodies, and rarely enforced the considerable powers they had (have). From my dealings with the CB fraternity at that time, they were a pretty enthusiastic bunch, who often just could not cope with the maths side of the amateur exam - I still remember having to do the resonance calculations 1/2pifc or whatever it was. Clearly it was a qualification designed to limit access to radio transmission to people who were aware how it worked and would be able to avoid interference. The CB people were users - perfectly OK, I always thought. Some were a bit, er, odd - but I guess many of us are too. The Government killed it by making it available in shops - it killed the enthusiasts hobby when every kid got one for christmas. Now the amateur license has been split, so people can use radios with much less electronics background. I've had a listen to the people around here, and I still have the license as it's perpetual now, as long as every few years you tick a box - and amateur radio is now like CB radio was in 1980 or so. There was on CB guy in Lowestoft who tried to attach a 20ft aerial to his car - didn't last long, but I think I saw him a few months ago with an amateur aerial on his car - just as huge, clamped to the towbar! Link to comment Share on other sites More sharing options...
chelgrian Posted February 28, 2014 Share Posted February 28, 2014 Has anyone ever really found minicab companies operating on radio mic channels? This is often mentioned in chat about radio mic systems, but two way radio would occasionally be a problem with VHF systems because the operating frequencies were quite close, but now most users are on UHF business radio is nowhere near PSME or channel 70. My summer venue is surrounded by taxi ranks and loads of two way radio users and marine radio and we've never experienced this at all. As most theatres run their own radio systems often on stage, interference from your own people would be much more common. A theatre old wives tale, I suspect. Every bit of noise and interference blamed on 2 way radio! I have picked up bar link (system used in by pubs to warn the next one along the road when trouble is on its way) two way radios on channel 69 radio mics. I suspect what they were using wasn't even legal to operate. Most theatres would either be using PMR446 or co-ordinated licensed frequencies so their own two way radios are going to be no where near their radio mics. The majority of radio mics issues I've had to deal in the past have come from: - Other users in adjacent buildings- TV transmissions in adjacent bands- Neon signs and other such devices emitting broad spectrum interference Link to comment Share on other sites More sharing options...
althemusicwizard Posted March 25, 2014 Share Posted March 25, 2014 As a newbie I wonder if someone with years of experience with radio mics could give me their thoughts. I own 4 Sennheiser EW100 / 300 systems running on Channel 70 (863-865Mhz). I've just acquired another two and know that getting six to work is about the maximum you could expect. As has been mentioned here and elsewhere, what is the likelyhood of interfering with external signals within a building such as a theatre (where if there was the chance of external sound getting in or out of the building it would be disastrous for the show being performed). Has anybody ever strayed outside Channel 70 after say doing an external sweep of the building they're in. Would I be right or wrong in thinking that if you got someone to take a mic out of the building that you're in, and the receiver inside couldn't pick up that mic, then vice versa, the mic once inside the building wouldn't be transmitted outside of the building during performance? Is this logic flawed? I sometimes work with another singer who has a G3 system operating on the same free channel making the number of systems 7.........but the question is more to do with the reality of the situation, rather than just that. Al Link to comment Share on other sites More sharing options...
sleah Posted March 25, 2014 Share Posted March 25, 2014 Staying away from the legalities for a moment....Your logic isn't exactly flawed as such, however in my limited experience there are few constants when it comes to rf, in particular range.There is in theory a maximum range, but there are too many variables and other factors to give an exact or even close answer.You can have a mic and receiver in the exact same places on two seperate occasions and with no other apparent difference, and can get different results. Atmospherics can play a big part in addition to solid objects or the tolerance of the components used in the rf kit. You could do the perimiter walk as you suggest and pick up nothing but then do it again following the exact route and might find something breaking through. Someone with more experience will explain how to overcome these problems or avoid them in the first place. Link to comment Share on other sites More sharing options...
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