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Wireless question, antenna stuff

Discussion in 'Sound, Music, and Intercom' started by gabe, Feb 28, 2008.

  1. gabe

    gabe Member

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    Hey,
    Currently installed in our theater are 4 ULX wireless receivers and one Shure UA844 wireless combiner. We are looking to expand what were in the original specs for the building by going to 12 wireless channels. We would like to stick with the ULX because that is what is already installed. Ideally we would order 8 more ULX systems and 3 more UA844's, we can't currently afford all of this however. But we do have some Sennheiser EW112G2 receivers sitting around from our old building. So can we order the 3 UA844's and as many of the ULX receivers as we can afford, and supplement what we don't buy with the Sennheisers? Will the Sennheiser receivers function along side the ULX receivers with the UA844 combiners?
     
  2. BNBSound

    BNBSound Active Member

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    The answer should be yes. As long as the Sennies have a BNC connector for an antenna input. I can't think off the top of my head of a UHF wireless that still uses the SO-239 connectors. You might just want to give a brief check to the spec page of all the gear and make sure that you won't be giving the Sennies a case of front end overload with too hot a signal from the Shure gear. The frequency range of the combiners is from the mid 400's up through 900 MHz so you should be good on that front.

    Never mind, got bored, did it for you...

    Shure UA844 Distributed RF Output Level (Gain)
    -0.5 to 3 dB, 1 dB typical, from antenna input (unused ports terminated
    with 50 Ω)

    What that basically means is that whatever comes in on the antenna could possibly go back out anywhere from being reduced slightly in power to being doubled in power, but usually goes through neither amplified nor diminished, just split up. If you're using the Shure paddles and you're overloading any of the units, check and see if the pre-amp is on. Otherwise, there shouldn't be any reason that I can see for the Sennie receivers to play nice with the Shure combiners. P.S. they do have BNC's on the back.
     
  3. avkid

    avkid Not a New User Fight Leukemia

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    It appears that you can also use the power supply combiner for the Sennheiser units.
    The UA844 supplies 14-18 volts D.C. and the Sennheiser units will accept 10.6-16 volts.
     
  4. mbenonis

    mbenonis Wireless Guy Administrator

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    The answer is yes, you can connect the Sennheiser receivers to the UA844 antenna distribution amplifier. However, the critical part of the equation here is the type of antenna you're using. If you're using a half-wave whip antenna, you'll want to make sure all of your receivers operate in roughly the same range (a 50 MHz range is probably fine). However, if you're using paddle (really a Log-Periodic Dipole Array), you'll be fine any which way you do it since it's a wideband antenna.

    Just a note, be sure to connect the splitters in a "tree" formation - that is, three of the splitters connected to one splitter, which is connected to the antenna. Be sure to terminate the fourth, unused port with a 50 load (should be able to buy these online). Use as short a coax cable as possible to connect everything up - you don't want any excess cable coiled up back there. Also use low loss coax cable (RG-8U or LMR400) for runs to the antenna if you need coax longer than 25' or so to get to the antennas.
     
  5. BNBSound

    BNBSound Active Member

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    Make sure you check the polarity before you plug in those Sennheisers to the Shure power supply.
     
  6. mbenonis

    mbenonis Wireless Guy Administrator

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    You're right, I didn't think about the power issues - only the RF side. Yes, do make sure you check the polarity and desired voltage for the Sennheiser units.

    At least nobody does what Vega used to do, and put power on the output RF connectors...
     
  7. avkid

    avkid Not a New User Fight Leukemia

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    Geez guys, do you think I was trying to sabotage Gabe's wireless plans?
    I checked the back panels and diagrams.
     

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