ceecrb1 Posted May 16, 2011 Share Posted May 16, 2011 Yeah various manufacturers use 2.4ghz systems for RC.I have the Futaba version and it is absolutely ROCK solid, we've flown VERY large gliders (4meter wing span) as high as we could... they were a tiny spot straight up and still landed with 100% connection during the flight.We can tell this as the receivers flash an LED when there has been a signal loss be it blackout or the more commonly appearing term "brown out" for just a "hickup" rather than a complete loss... One day we actually set about trying to make it fail.. we couldnt. we tried everything.. microwaves, laptops/wifi, phones, covering the TX antenna and EVEN cutting the antenna off the receiver.... it just keeps going. The main thing that makes me want to try these new 2.4ghz mics is that we have also had days were a VERY large number of pilots have been flying all at once, all with the same system and there were ZERO Faults. Again.. would be interesded to see LOTS of these mics used at once.. Plus: I dont know the system.. but in RC we have to link an RX to a TX. To do so, no other TX's can be transmitting.... so everyone has to stop flying etc.Are the mics the same? This could be fun in a large corporate event when you ahve to halt a speach so that the techs in the next room can link a mic to the receiver rather than just retune link is the current option. http://imageshack.us/photo/my-images/860/9284q.jpg/ Link to comment Share on other sites More sharing options...
dboomer Posted May 17, 2011 Share Posted May 17, 2011 End result is that the microphones, with which the dropped packets are not necessarily needed, work fine, but the wifi is impeded.. Correct, loss of a little data does not result in the loss of audio ... we just correct/conceal it. As far as Wi-Fi ... lots of things interfere with Wi-Fi, slowing it down. Link to comment Share on other sites More sharing options...
paulears Posted June 2, 2011 Share Posted June 2, 2011 Moderation: Interesting OT discussion - so I moved it to it's own home. Link to comment Share on other sites More sharing options...
Just Some Bloke Posted June 5, 2011 Share Posted June 5, 2011 Moderation: And another OT discussion split off to its own thread. Link to comment Share on other sites More sharing options...
Quincy Posted July 16, 2011 Share Posted July 16, 2011 Hi Boswell, Just wondering if you ever got to the bottom of which resistor to use with the CPC MP33750 mics when connecting them to the XD-V70 beltpacks?I have just ordered a couple to make some headsets for the kids school, as the adult sizes just won't stay put!!Thanks in advanceAndrew Link to comment Share on other sites More sharing options...
boswell Posted July 16, 2011 Author Share Posted July 16, 2011 No, never got to the bottom of how to calculate the best value but 2k2 seems to work fine.HTH Link to comment Share on other sites More sharing options...
Quincy Posted July 17, 2011 Share Posted July 17, 2011 Thanks for that, will give it a try. Link to comment Share on other sites More sharing options...
dboomer Posted July 18, 2011 Share Posted July 18, 2011 Sorry, I guess I missed the question. Are you asking for a pull-up resistor value? It's not terribly critical. I'd try between 4k7 and 10k. Also make sure you short pins 3 & 4 together as that sets the input impedance for 20k (instead of 1.3 meg) Link to comment Share on other sites More sharing options...
Quincy Posted July 18, 2011 Share Posted July 18, 2011 Thanks for that, the bits arrive tomorrow so can give it a try. Just out of interest, do you know what the pad config / register values are to allow a line level input, ie straight out of the back of a cd player etc, using a pair of belt packs to make a wireless stereo link to save a cable run when its all that's required could be very handy. Thanks Andrew. Link to comment Share on other sites More sharing options...
dboomer Posted July 19, 2011 Share Posted July 19, 2011 The transmitters can handle a 6Vp-p input signal without clipping (aprox +8 dBu). If your source's output is under that then no pad is necessary. Beyond that you would need to know how much you want to pad. A simple L-pad should work fine. The values will depend on output level and impedance. There are many design tools free online. Link to comment Share on other sites More sharing options...
paulears Posted August 9, 2011 Share Posted August 9, 2011 First Line 6 problem today. 4 70 series handhelds in use. Normally they are fine, and maximum distance from the furthest part of the stage area to the rack aerials is around 12m worst case, usually 6-7m, line of sight, no obstructions. Today for some reason, with two on stage at one time, frequent drop outs where the audio would cut out for a second or two then come back - no clicks or pops, but silence. Signal strength full on the meters, no red lights. In the interval, the only thing I figured I could do seemed a bit pointless - a very cheap VHF system - an AKG single channel diversity receiver brought in by one of the turns, was sitting on top. I removed the receiver and moved it away from the Line 6 rack and the 'dropouts' vanished. For the second half the show, with four mics on stage, no dropouts at all. All I can assume is the receiver has some kind of spurious output that manages to kill the line 6 audio, without any signs of problems on the meters. Very odd! Link to comment Share on other sites More sharing options...
cedd Posted August 9, 2011 Share Posted August 9, 2011 I seen a (old) VHF receiver wipe out an entire channel 69 setup. Have a feeling something was going stray in the first mixer section. Never did get to the bottom of it and only tracked it down with a spectrum analyser and the old dipole null trick. We never thought to look to the receivers as the source of interference! I was incredibly surprised at the level the thing was capable of generating. Certainly above mute level on the G2's. Still not sure if it was getting in through the aerials (a good way away) or was getting straight in to the receivers. Slightly worrying if it is the case. That seems like a pretty "simple" source of interference for the things to deal with. I've no idea of the internal architecture of the things, and at these frequencies it's all a bit magic anyway. Probably falling on an IF frequency rather than the carrier? Might bypass some of the filtering if it did. No idea how many stages they'll use, or if they're using standard IF's and local oscillator frequencies. Link to comment Share on other sites More sharing options...
Bobbsy Posted August 10, 2011 Share Posted August 10, 2011 Snap. I've had the same thing happen. I was once working a show where somebody brought in a cheap Nady radio mic. As soon as I turned on the receiver I lost just about every other radio mic I was using, both VHF and UHF. Bob Link to comment Share on other sites More sharing options...
paulears Posted August 10, 2011 Share Posted August 10, 2011 Somewhat annoying that it seems to negate the interference proof selling point on these digital mics. The fact the RF indications suggest the interference is not geting in on the operating frequency suggests a filtering problem with the design - and totally unpredicatble as the metering system doesn't show it! Link to comment Share on other sites More sharing options...
pritch Posted August 10, 2011 Share Posted August 10, 2011 Has anyone used these at a venue or gig where VHF PMR radios are in use? Would be interesting to see what happens if someone gets a bit close while transmitting! Link to comment Share on other sites More sharing options...
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