mrg198 Posted November 29, 2010 Share Posted November 29, 2010 I'm working on our plans for the switchover at the moment, but I'm wondering if anyone has any experience on squeezing the maximum number of channels into ch.38? At the moment we can get 12 out of our shared ch69 plus ch70 863-865 region without requiring specific licences for other frequencies. I'm planning on using Sennheiser 500 G3 kit and have done a quick check using the SFIM software, but it looks like only 11 channels will fit. Does anyone have any experience of more? I could potentially save some kit on E band and use 4 sets in Ch.70 plus 11 on Ch.38 but I'd rather not have to and use all ch.38 if possible. Link to comment Share on other sites More sharing options...
Ynot Posted November 29, 2010 Share Posted November 29, 2010 Talk to JFMG. Oh, and our current CH69 licence gives me 14 channels, not 12... Link to comment Share on other sites More sharing options...
J Pearce Posted November 29, 2010 Share Posted November 29, 2010 It does Tony, but you can't use them all without intermodulation issues. Incidentally, on Ch69 we have to stick to prescribed frequencies, but I believe in Ch38 we can use anything in the range. This might be useful if you have more expensive systems with a smaller radio bandwidth, as you may be able to squeeze more mics in the range. Link to comment Share on other sites More sharing options...
Ian Cunningham Posted November 29, 2010 Share Posted November 29, 2010 I'm working on our plans for the switchover at the moment, but I'm wondering if anyone has any experience on squeezing the maximum number of channels into ch.38? At the moment we can get 12 out of our shared ch69 plus ch70 863-865 region without requiring specific licences for other frequencies. I'm planning on using Sennheiser 500 G3 kit and have done a quick check using the SFIM software, but it looks like only 11 channels will fit. Does anyone have any experience of more? I could potentially save some kit on E band and use 4 sets in Ch.70 plus 11 on Ch.38 but I'd rather not have to and use all ch.38 if possible. I was looking into this as well - Sennheiser haven't yet put the frequency lists for the G3-GB version of the Evolutions. I had to get a local dealer to photocopy the manual from a unit to get the lists. From memory I think there was a set of 12 freqs that worked in ch38 Link to comment Share on other sites More sharing options...
chelgrian Posted November 29, 2010 Share Posted November 29, 2010 It does Tony, but you can't use them all without intermodulation issues. Incidentally, on Ch69 we have to stick to prescribed frequencies, but I believe in Ch38 we can use anything in the range. This might be useful if you have more expensive systems with a smaller radio bandwidth, as you may be able to squeeze more mics in the range. Channel 38 is indeed a range. I think that Sennheiser currently can get 10 Evolution G3s into channel 38 without problems. Link to comment Share on other sites More sharing options...
StevieR Posted November 29, 2010 Share Posted November 29, 2010 ... but I believe in Ch38 we can use anything in the range. Correct. Which offers a little more flexibility than previously. We've certainly had 12 channels working with the new Trantec kit but haven't tried with the Sennheiser systems as yet. Steve Link to comment Share on other sites More sharing options...
Ynot Posted November 29, 2010 Share Posted November 29, 2010 It does Tony, but you can't use them all without intermodulation issues.Well, whilst that's true in theory, in practice we HAVE been able to successfully use all 14 frequencies on more than one occasion. It does need to be given due consideration and planning to make sure those frequencies which MAY suffer intermod are kept separated when on stage, but even when that's not always possible we've not experienced many major issues. It's not something that's encouraged as a rule - we have 11 sets in-house at present (with access to 3 more when needed), which is quite honestly more than enough for the majority of shows. Link to comment Share on other sites More sharing options...
northernaudioman Posted November 30, 2010 Share Posted November 30, 2010 On a Sennheiser 500 Series in GB range there are 12 compatible frequencies in channel 38, these are Bank 1 channel 1 to 12. No issues with using all 12 together. Link to comment Share on other sites More sharing options...
Bobbsy Posted November 30, 2010 Share Posted November 30, 2010 In the UK, each UHF television channel has an 8MHz bandwidth so you should be able to get exactly the same number of radio mic channels on 38 as you currently do on 69. The exact number will vary among makes and model of your system, depending on the quality of their filtering and intermod rejection. As Ynot points out, calculations will often suggest that you MIGHT get problems with certain frequencies that, in the real world, seem to work okay. This is because the calculations have to be conservative and point out every potential problem. The big difference of Channel 38, of course, is that the frequencies aren't contiguous with the license-free channels so you can't "mix and match" on the same RF gear. Bob Link to comment Share on other sites More sharing options...
Shez Posted November 30, 2010 Share Posted November 30, 2010 I'm slightly surprised the G3s can only manage 12 in ch.38. I recall them having a frequency set that could squeeze six in to the dereg part of ch.70, rather than than the four that were manageable previously so the filtering is obviously improved. But Sennheiser's official line was that you could only get eight G2s working together in ch.69, although in the real world, 12 is usually quite possible. I suspect it's quite possible that you can get a couple more than 12 G3s in ch.38 but I imagine that needs someone with access to some clever software to work out what freqs they would be. Link to comment Share on other sites More sharing options...
mrg198 Posted November 30, 2010 Author Share Posted November 30, 2010 Just spoke to Sennheiser Tech support - on a terrible line I might add but I'm fairly sure he said you could get 12 of the working in the ch.38 range. Moderation: Edited to remove double posting. Bob/mods Link to comment Share on other sites More sharing options...
pattonaudio Posted November 30, 2010 Share Posted November 30, 2010 Just spoke to Sennheiser Tech support - on a terrible line I might add but I'm fairly sure he said you could get 12 of the working in the ch.38 range. Moderation: Edited to remove double posting. Bob/mods I have very good reason to beleive that you can get 19 Trantec S5.3 working with out any issues within Channel 38/39. I have them running fine with no issues 19 intermod free frequencies that will operate in the channel 38/39 bands of a s5.3 system.606.500607.600608.250609.875610.275611.025612.425612.800613.375614.225614.725615.450617.850618.925619.450619.750620.425620.750621.300 Link to comment Share on other sites More sharing options...
revbobuk Posted November 30, 2010 Share Posted November 30, 2010 But Channel 38 is only 606 - 614 MHz? Why are you including Ch 39? Link to comment Share on other sites More sharing options...
Lamplighter Posted November 30, 2010 Share Posted November 30, 2010 There is also a problem that the 1st channel is on the band edge , the modulation would intrude into the guard band, and the maths do not support this combination of 9 frequencies in channel 38 being intermod free, the 10 frequencies suggested by JFMG are on a much firmer footing. Brian Link to comment Share on other sites More sharing options...
pattonaudio Posted December 1, 2010 Share Posted December 1, 2010 But Channel 38 is only 606 - 614 MHz? Why are you including Ch 39? Sorry yeah I was Link to comment Share on other sites More sharing options...
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