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Please make sure this will work together

Discussion in 'Sound, Music, and Intercom' started by zac850, Mar 5, 2008.

  1. zac850

    zac850 Well-Known Member

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    Hey all,
    I know I normally stick to my lampie area, but I was looking for suggestions and advice for a wireless system I am putting together. So, I'm looking at:

    8 SLX14W microphones (the SLX system, includes the SLX4 receivers)
    2 directional antennas (PA805) would run through around 10 feet of BNC to a a UA221 splitter/combiner which would split the antennas between two UA844 antenna distribution systems. Each UA844 would feed 4 of the SLX receivers. The entire system would be rack mounted in a 6U case.

    I want to be able to mount the antennas on the front of the booth, and be able to have the actual receivers off to the side of the booth where they would not have a good line-of-sight to the stage, hence me wanting to get the external antennas.


    The SLX system seems to be a good mid-level system. It is about 80' from the back of the stage to the back of the house in the balcony where the sound/lighting booth is, and it seems like the SLX system will be able to do this no problem. In the pas the space has rented lower quality wireless mics and had issues with interference and mics dropping out, so I am trying very hard to make the system as robust as possible for the money.

    This install/improvement is also involving flying 3 speakers in a center cluster. I'll post more about that as things develop.

    So, I'd love any suggestions or corrections to my system.

    Thanks guys and gals!
    Zac
     
  2. DaveySimps

    DaveySimps CBMod CB Mods Premium Member

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    This should work out well for you. We have 12 Shure SLX systems rack mounted with UA844 DA/Combiners with helical antennas, and the WL93 mic elements. They have worked out great for us for over three years now (7 musicals and many individual events later). You will probable need to fine tune some of the settings for the antennas (via the 844 units) to make sure the signal strength is there. This is usually what needs to happen when your antennas are located away from the receivers themselves.

    Something to keep in mind, make sure your specify the frequency range so that the systems match. For example, we have 12 units on the H5 frequency set. If we expand we will need to to the the J series set. Of course, that is spicific to our area and wireless frequencies we have to compete with. Although they are frequency agile systems, it is something you will want to look out for so you can leave yourself in a good position for future expansion, and so you will have the greatest number of options for choosing reliable frequencies.

    ~Dave
     
  3. zac850

    zac850 Well-Known Member

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    Thanks.

    I was going to get all 8 in the J frequency range, which is the stock frequency the supplier I was looking to use. The only other wireless device in the space is a wireless hearing assist system, I hadn't thought of that causing interference, but now that you mention it I will check what that frequency is and make sure I don't have issues there.
     
  4. DaveySimps

    DaveySimps CBMod CB Mods Premium Member

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    Dont forget to check the local TV stations in your area. With the new HD switch in broadcasting, they are causing problems in many areas. About a year after we opened our new space, we had to retune our hearing assisted devices because a local stataion went digital. Their frequencies changed, and they were broadcasting on our channel. This was not a frequency agile system (Telex Sound Mate), so it was not cheap to have them retuned.

    You can download Shure's Wireless Work Bench software for free on their website. This would be a good start to see what frequencies are broadcast in your area.


    ~Dave
     
  5. zac850

    zac850 Well-Known Member

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    Wow, thats a really nice piece of software! Need to figure out what frequency the hearing assist system is on, but besides that it looks like the system should work fine.

    Thanks!
     
  6. mbenonis

    mbenonis Wireless Guy Administrator

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    Please take a few minutes to read my wireless FAQ in the Sound forum.

    The most important thing you can do to ensure your system works it to coordinate your frequencies properly. The IAS software (see the FAQ) allows you to use it for 30 days for a limited number of systems (less than 20, I think), so take advantage of it and use it to generate a list of frequencies specific to your location.

    Also, all of the current Shure systems offer a "Master List" mode - this allows you to directly input an operating frequency by code (the lookup table is in the manual). If you use IAS, you'll want to use this mode to input the frequencies it gives you. Don't worry about the fact that you're not using the built-in groups and channels - the frequencies IAS gives you will work without any problems.

    Feel free to ask any questions that come to mind - I'll add them to the FAQ.
     
  7. museav

    museav CBMod CB Mods Departed Member

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    The following is from the United States Access Board regarding the ADA Accessibility Guidelines for Buildings and Facilities (ADAAG):
    The vast majority of RF ALS systems operate in these reserved bands with the majority of those in the 72MHz band.

    Also keep in mind that with the upcoming broadcast frequency allocation changes, wireless mics operating on UHF frequencies above 698MHz will no longer be available and you should probably best avoid any wireless systems at those frequencies.
     
  8. zac850

    zac850 Well-Known Member

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    Good to know. The assisted hearing system is on 74.700mhz, I suppose that makes sense now.

    The frequencies I'm looking to use are between 529.5 and 593.5. I believe that is still low enough to avoid issues in the upcoming years? Can someone confirm this? (I can list the frequencies I am using (by that I mean the frequencies Shures program told me would work well for me).

    Thanks,
    Zac
     
  9. museav

    museav CBMod CB Mods Departed Member

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    There's no way to know, this is the whole "White Space" issue for UHF frequencies below 698MHz. You will probably be fine for some time, but there may be a lot fewer open frequencies and they may be much more difficult to predict.

    Unless you are a licensed broadcaster, then if you are operating a UHF (FCC Part 74) wireless mic, you are technically operating illegally. The FCC and broadcasters have simply accepted UHF wireless mics operating in unused bandwidth as long as they don't interfere with broadcasts. Since analog broadcast channels required some separation, there were plenty of 'holes' available in most areas that this wasn't an issue. The conversion to digital broadcasting and new technology is changing this in two ways.

    First, digital broadcasts may not have any separation between channels and may use all the allotted bandwidth for each channel, thus there may be fewre holes in the bandwidth or "white space". Second, some big players want to make any "white space" available for new consumer wireless services to be developed. The currently proposed legislation requires that these devices detect and avoid interfering with licensed broadcasters, but since the vast majority of wireless mics are not licensed, that would not apply to them. The result could be a very crowded spectrum with devices almost randomly appearing and changing frequency.

    This is not to say that this will happen overnight come February 17, 2009. Many people using UHF wireless mics may be able to continue as they are for some unknown time. However, if the consumer wireless devices proliferate in areas with a large number of digital broadcasters, then finding open frequencies may become a challenge. Shure and other manufacturers are fighting to have the related legislation address the use of wireless mics, but it is an uphill battle. Although widely accepted by all involved, most UHF wireless mic users have technically been operating illegally all along and the simple fact is that because of this, weren't really considered in future bandwidth and frequency planning. With companies like Microsoft and Motorola fighting to gain access to the bandwidth UHF mics use in order to support new consumer wireless devices, this being a 'non-entity' becomes a factor.

    Added:
    The short answer is simply that no one really knows what will happen. Some UHF wireless mic users may go years and never notice a difference, others may run into frquent problems. One of the biggest unknowns in all of the frequency allocation effort is that much of it relates to development of future technology and it is thus impossible to know what that will be or when its use will be common, if ever.
     
    Last edited: Mar 10, 2008
  10. mbenonis

    mbenonis Wireless Guy Administrator

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    Brad, your analysis is spot-on. :-D
     

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