Rax Posted November 13, 2008 Share Posted November 13, 2008 Out of interest, have any UHF radio mic users noticed an increased level of problems and interference over the last week or two? Symptoms may include unexpected and drastic reduction in range, or breakthrough from high speed data. There is a possibility that this could be a national rather than a local phenomenon. Channel 69 does not appear to be affected. Thanks. Link to comment Share on other sites More sharing options...
SoLiEn Posted November 13, 2008 Share Posted November 13, 2008 I Had major intereference problems begining of this month/end of last month. had to put my recievers on stage because I didnt have the range, was only 20m or so back and this set have done nearly double that with no problems at all!!! Link to comment Share on other sites More sharing options...
Bobbsy Posted November 13, 2008 Share Posted November 13, 2008 Assuming you have radio mics in a conventional range for the UK, your competition for bandwidth is still television transmitters (analogue and digital) and other users of radio mics/IEMs. Those would both be a local phenomenon. If I can venture a guess, I've read in a broadcast forum that, in many areas, they're playing with the EIRPs of digital TV transmitters trying to get as much out of them as possible to encourage people to convert to DTV before the analogue switchoff. JFMG should be aware of such things when issuing your licences for non Channel 69, non de-regulated bandwidth. You do have licenses don't you? Bob Link to comment Share on other sites More sharing options...
paulears Posted November 13, 2008 Share Posted November 13, 2008 Have you calculated the power required to generate an interference problem on a national scale? Don't forget that UHF propagation is also mostly groundwave, so unless the source of any interference is either flying very high or there is some unreported sporadic E style refractive phenomenon - or tropospheric ducting (unusual with the current weather) taking place, you're left with local interference. The clue is that you are hearing data. Are you sure you haven't got a data link just been installed near where you are working? These are often working in the low UHF band, and doubling the frequency does come out quite close to many of the radio mic channels. Even if suppressed, the 2nd harmonic of a data transmission could still quite troublesome. Have a good look around for aerials - usually long yagi types with the elements vertical. Link to comment Share on other sites More sharing options...
boswell Posted November 13, 2008 Share Posted November 13, 2008 Channel 69 does not appear to be affected. Thanks. Which channels are affected?? Link to comment Share on other sites More sharing options...
AndyL Posted November 13, 2008 Share Posted November 13, 2008 Channel 69 does not appear to be affected. Thanks. Which channels are affected?? My thoughts too! Also what locations? As a previous poster has said, the chances of truly "national" UHF interference are as close to zero as makes no difference. Also consider that if the interference is everywhere that you go then maybe it is something that travels with you or with the show. Has anybody, or any department, recently aquired any new "toys" however unlikely a source of RF it seems? Link to comment Share on other sites More sharing options...
Rax Posted November 13, 2008 Author Share Posted November 13, 2008 Many thanks to everyone who is contributing. The sound of the data interference is like "GSM on Acid". A reptitition frequency of a hundred or so pulses per second. We once traced similar interference to an iphone user on a local wi-fi connection but the studio was dark and devoid when we carried out tests to try and locate the interference this morning. A national network of ground based transmitters is one possibility, others are that the transmitter is in a satellite, or a powerful OTH radar. This has been happening over the last two weeks with different trucks, channels and studio locations. A colleague has a call in with JFMG, but there is no reply yet. Link to comment Share on other sites More sharing options...
AndyL Posted November 13, 2008 Share Posted November 13, 2008 The sound of the data interference is like "GSM on Acid". A reptitition frequency of a hundred or so pulses per second. Based on that description I would look for a Blackberry user. Or possibly a Tetra handset as used by the emergency services (380 / 390MHz) amongst others? A national network of ground based transmitters is one possibility, others are that the transmitter is in a satellite, or a powerful OTH radar. Sorry, not buying any of the suggested interference sources. Believe me, if this were a national problem over the last two weeks my phone would be red hot by now... No, not ringing that much at the moment. :unsure: I think you are hearing hoofbeats and looking for zebras. From what you say you have so far eliminated the trucks, the radio channels and the locations, so you need to look for what all the occurrences do have in common in the widest sense; people, equipment, etc., not what is different. Link to comment Share on other sites More sharing options...
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