radio mic frewuency help

I

irishcamera

New member
Dear all

I need to get a radio mic to use with my canon 5d MK II.

Does anyone know if you can use them in different countries?

I live in the uk but a lot of work in North America. i have seen one for sale but need to be sure i can use it outside the uk – ie. the sennheiser EW 112-p g2. Range 830 – 866 MHz.

any advice welcome

adam
 
That range will not be usable in the US (don't know about anywhere else). The only valid G2 frequency blocks for the US are A (518 - 554) & B (626 - 662). G3 added a third block that they call G (566 - 608).
 
irishcamera said:
and also why wouldn't it work if there are no activities in that frequency?
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From a physical standpoint, it will work. But whether it's legal or not and whether other powerful users might already be sitting in that band that would interfere with your mic is another story. The radio spectrum is really pretty crowded. AFAIK there is no overlap on the legal frequencies between North America and the UK. Your best bet will probably be to rent a US legal unit from a vendor there. I'm not positive but I think a good part of that frequency range is used by TDMA cell phone systems in NA.
 
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irishcamera said:
and also why wouldn't it work if there are no activities in that frequency?
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The US has Magic Jammer(tm) towers everywhere...

Of course it will work, it is just illegal to operate in the US on those frequencies...

I don't know what the FCC does to 'patrol' these sorts of things, so you could very well use these frequencies and 'get away' with it... sort of like speeding on the highway... until something comes along, like someone complaining about RF interference, and someone from the FCC having nothing better to do than go out and look into the matter...

In the case of 'pirate radio', that is operating on an AM or FM band without a license, it does turn into a police action...

If it is Saint Vitus Church of the Refractured Christ, operating unlicensed mics on Sundays... who knows...

The question is, do you feel lucky???
 
It's more a case of legality rather than practicality. An empty channel is quite able to be used - however, the powers that be could be unhappy - and worse still, using an apparently empty channel could make you very unpopular if some other important and protected service are the authorised one, and you just blast away unaware you just wiped out something critical. Radio mic receivers are wideband devices, and may blissfully ignore a narrow band user. They, on the other hand, could be totally out of action. This is pretty unlikely due to the very low powers we're talking about, but you'd be guilty if caught.

In the UK, loads of people operate radio microphone systems illegally - taking the manufacturer's designed in ability to tune like a broadcast radio receiver to mean that they can use them anywhere in this range - which of course they cannot - but non-technical people cannot be expected to know this. I've never heard of any prosecutions for using radio mics on unlicensed channels, but it's possible.

A Brit, taking in radio systems to the US will probably have no issues with the items - I packed walkie talkies, chargers, stickypod car attachments, UK mains adaptors and 4 way sockets into my baggage and nobody seemed interested - even though an X-ray would have shown up some very strange looking things. The radios had US channels in them, but were not type approved for one, or a license held for the other, and nobody checked. This, however, was luck. If the security people want to object, then it's their right. Taking in a non-US spec product could be tricky, the same as bringing in one here. Our system is a little different - strictly speaking it's illegal here to have in your possession radio transmitting equipment for which a license is not available - so at the very least, it could be confiscated (seized) just because you have it - not because you're using it. However, this would be very, very unlikely.
 
paulears said:
In the UK, loads of people operate radio microphone systems illegally - taking the manufacturer's designed in ability to tune like a broadcast radio receiver to mean that they can use them anywhere in this range - which of course they cannot - but non-technical people cannot be expected to know this. I've never heard of any prosecutions for using radio mics on unlicensed channels, but it's possible.
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This is true in the US as well. While in some places like Las Vegas, for conventions, things may be a bit more controlled, the facility may require that you only use their approved people and devices... but perhaps a donation to the Italian Fisherman's Fund of Lake Mead, may assist in overcoming any minor infraction...

In places like churches, and other event locations where there's perhaps a maintenance person doing the setup, anyone's guess as to the state of the wireless mics relative to regulations.
 
irishcamera said:
if this is the case, is there a wireless radio mic you can buy that is usable in both the USA and UK??
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There will be in a few months.

You will need G3 range "GB" - This starts at the top end of band "G" and finishes at the bottom end of range "B". It will cover TV channels 38, 39, 40 and 41 (that's European 8MHz channel numbers).

You will require a licence in the UK as it uses the new Ch.38 mobile frequencies (the old Ch.69 frequencies will go in 2012), but this should also be well usable in the USA.

Frequencies will be 604 to 646 MHz I think.

Otherwise 2000 series version "Gw" (558 to 626 MHz) is available now, but is more expensive.
 
paulears said:
In the UK, loads of people operate radio microphone systems illegally - taking the manufacturer's designed in ability to tune like a broadcast radio receiver to mean that they can use them anywhere in this range - which of course they cannot - but non-technical people cannot be expected to know this. I've never heard of any prosecutions for using radio mics on unlicensed channels, but it's possible.
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Don't rely on this continuing.

The government is selling off tons of spectrum and I would expect, that with big bucks floating around, that in the future that things will get very much tougher for illegal users.

I have known the Radiocommunications Agency Investigation Division to turn up unannounced at a theatre and demand to see the radiomic. licenses!

And that was *before* the sell-off.

And - in the UK - the penalty for illegal use can be up to 5 (maybe 10 now) years in prison, plus a fine of up to £10,000 and confiscation of equipment (and that's everything, not just the transmitter, it includes camera and everything).

Why so tough? It's the same law that covers pirate radio stations.

Ignorance of the law is no excuse, and radiomic. companies do normally make all the legal channels clear (Sennheiser UK certainly do on their price lists) for the users.
 
The trouble as I see it, is that people very often don't realise they actually need a license - I always wondered why Sennheiser, Shure and the others didn't put a slip in each box with the jfmg website details on it - kind of "Get your license here".

The Old Radio Investigation Service lost their vehicles with spinning roof racks many years ago, and I strongly suspect that when they tackle interference to protected services, as in the owners of our old channels - it won't really be us that interferes with them - the field strength from a radio microphone is highly unlikely to cause them any harm at all - even if it's even noticed. I suppose the most likely areas where problems could occur would be where installations are perhaps on the roof of a building containing the 'illegal' radio microphone - but I doubt it's really going to be an issue.

John's penalities are worst case scenario. Confiscation of equipment is pretty certain, but the fines will be scaled by the magistrate to suit the perceived severity of the crime. Examples get made of Pirate Radio broadcasters, and this is good.

Fine wise - the Wireless Telegraphy Act is obviously concerned about broadcasting illegally - so fines for pirate radio broadcasting are quite tough, as Johns states - they are not quite that bad. Two years and a Level 5 fine (£5000) as the maximum. Pleading guilty gives the same fine max, but a year as maxiumum imprisonment.

However - radio microphone systems do not broadcast - they are a specific point to point system, so Section 35.2 doesn't apply - and subsection (5) reduces the prison element to 51 weeks - but keeps the fine maximum.

There is also a potentially troublesome section that is about keeping equipment. Let's say you have a system that can be used on the license free channels, but it's easily tunable to the 'illegal' ones. It's possible that if you know this, and suspect your hire customer may be planning to retune it, then you've broken the law - the actual wording being if you "know, or has reasonable cause to believe, that another person intends to use it in" - so your technically innocent customer finds the free channels full, tunes down a bit and uses it, then if you knew he might do this, you could also get the fine and clink!

Obviously, this is unlikely to happen, but it's possible.

A while back there was some consultation on if a fixed penalty system for non-broadcast illegal radio usage would be appropriate. The Government proposal at that time was a fixed £100 fine, with forfeiture only appropriate if decided by the court on conviction. Much of the focus of this exercise was down to illegal use of maritime radio - something that again people can buy and not realise should be licensed.

I'd consider that the potential safety risk of maritime radio interference is hugely greater than a radio mic transgression - so if £100 is fair for VHF radio, then I doubt a court would see our problem as any more serious.

Quite interesting, though. The fixed penalty idea seems to have vanished. I can't find it becoming law!
 
paulears said:
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However - radio microphone systems do not broadcast - they are a specific point to point system, so Section 35.2 doesn't apply - and subsection (5) reduces the prison element to 51 weeks - but keeps the fine maximum.
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Of course they broadcast, their signal goes out in all directions. The fact that they're intended for only one receiver doesn't mean that anyone else close enough and on the right frequency won't pick them up. As for being low power, cell phones don't have much power either but make it to the closest tower a few blocks or a mile away just fine.
 
Steve House said:
Of course they broadcast, their signal goes out in all directions. The fact that they're intended for only one receiver doesn't mean that anyone else close enough and on the right frequency won't piclk them up. As for being low power, cell phones don't have much power either but make it to the closest tower a few blocks or a mile away just fine.
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I don't know what has been developed in the area of the 'dreaded' white space devices, but one of the issues is dealing with wireless mics, which would have priority in the band being analyzed for 'white space'.

One idea was to require of the wireless mic some sort of PN code which if detected would count as 'not-white-space'. If there was an FM pilot, but no PN code, then depending on signal strength, etc, the band could be declared 'white-space'.

Illegal mics would cause spectrum to be 'wasted', or alternatively, if it wasn't listed in the Grand RF Allcations Bible In the Sky, then the 'white-space' device could operate, and interfer with the mic.

Depending on power, and location, mics and the 'white-space' device are on similar levels, so they have a much higher likelihood of mutual interference.

A TV signal is not going to be interfered with by a mic, except in fringe areas...
 
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