Follow Slashdot blog updates by subscribing to our blog RSS feed

 


Forgot your password?
Close
typodupeerror
×
Wireless Networking Hardware Technology

Rolling Your Own Wireless Communications System? 254

Posted by Cliff from the keeping-in-touch dept.
nuggetman asks: "My high school, like most others, has a theater program. One critical element of the show is the tech crew - the group of people behind the scenes who keep it all running. Communication between the stage manager (myself) and crew members (as well as between crew members) is critical. For this job right now, we're using standard hand-held walkie-talkies. They get the job done, but they're susceptible to dead batteries, incompatibility between VOX headsets, and interference from janitors, the office, hall monitors, and even the local McDonald's. We've been wanting to invest in a theater-communication system, but they can run extremely expensive. Is there any hardware out there that could use a standard PC (Linux or Windows) and some wireless headsets to roll your own communication system that could cover a long enough range (say the theater which is the size of a gym plus a decent range outside it) at a low enough cost? Our school just installed 802.11b/g throughout the hallways, so we could tap into that if necessary and add our own router near the stage if we had to."
This discussion has been archived. No new comments can be posted.

Rolling Your Own Wireless Communications System? More

Rolling Your Own Wireless Communications System?

Comments Filter:

  • This is easy! (Score:5, Funny)

    by bc90021 ( 43730 ) * <bc90021 AT bc90021 DOT net> on Friday January 23, 2004 @07:54PM (#8071352) Homepage
    1) Set up a private Counter Strike Server [counter-strike.net] somewhere on the school LAN.

    2) Get a laptop (with an 802.11g card in it, of course) and backpack for each crewmember.

    3) Every crew member joins the game on their laptop, sets the laptop to never suspend, throws it in their backpack, and uses headsets [csnation.net] to communicate with their team members!

    Other than the sound of an explosion every three minutes or so, and the occasional "Terrorists Win!" all your communications problems are solved!
    • Don't forget to turn sv_alltalk on
    • Hes got a point. Have you thought about seeing if cheep palm-based or winCE based pdas have audio/netmeeting type support?

      • Not PDAs (Score:4, Insightful)

        by homer_ca ( 144738 ) on Friday January 23, 2004 @08:48PM (#8071806)
        Forget about Wifi PDAs. Since Wifi is an always-on data connection, it's inefficient with power. Battery life sucks and you can't get headsets for them. Most have headphone jacks but no microphone jacks.

        Still, if you want to try it XTEN makes a SIP softphone for PocketPC. There's probably ones for Palm OS too.
    • Actually, I think you're on the right track. How about TeamSpeak [teamspeak.org]? I don't think you need to be playing a game to use it. If the crew will be relatively stationary, just put in a cheap networked computer running either Windows or Linux and a headset for every person. If they need to move farther than a cord will let them, see if wireless headsets exist. Make the fastest computer the server and you'll be all set.
      • Of course, what I mentioned above is what I'd use if I had to use computers. A good set of two-way radios with headsets, plus some rechargeable batteries and enough chargers to do all at once would be better and last a long time. I have some Motorolas I take skiing that can last a few days on alkaline AA batteries. Even with rechargeables, headsets, and more talking, they should still last at least the few hours required for a show. Just make sure to charge all the batteries between shows, and have some

    • Re:This is easy! (Score:5, Informative)

      by BenFranske ( 646563 ) on Friday January 23, 2004 @08:34PM (#8071715) Homepage
      You obviously have no experiance in theater. Techs are expected to do anything from crawling out over suspended ceilings to crawling under a stage or running up and down stairs during a performance a laptop in any sort of arrangement would get in the way and be easily broken, nevermind that for the price of a few laptops you could buy a real system from someone like Telex or Clear-Com. I would suggest visiting ControlBooth.com [controlbooth.com] and asking this question in their forums to get some practical suggestions. These are people who actually work with this day in and day out so they have real life experiance. Here's my idea to do this on the really cheap. It's not that hard to build a private phone network that doesn't actually dial but works like a party line, just put some voltage on the line. Get yourself a bunch of cheap cordless phones that allow headset use and lock the phones on so the line is always open. It's far from perfect but is the closest thing I can come up with off the top of my head. Don't take my word for it visit ControlBooth.com [controlbooth.com] and ask in the forums, they're good people and know what they're doing.

      • Clearcom (Score:2, Informative)

        by n1ugl ( 744812 )
        My school always used Clear-com's. They're not incredibly cheap, but certainly better than a PC. You also don't need to go all out and get a real base station...the portable one does nicely. BenFranske is right that people need to be all over the place, but they don't always have to be connected. We had someone on each side of the stage, the people running the boards, and the stage manager all connected. The stations are wired together, but it shouldn't be hard to find someone to run the XLR for you,
      • "You obviously have no experiance in theater"

        You obviously have no sense of humor. Or spelling. :P

  • Easy solution (Score:5, Funny)

    by Anonymous Coward on Friday January 23, 2004 @07:56PM (#8071375)
    Use yelling. Everyone comes equiped with all the right hardware. No sweat.

  • Back when I was doing this at school (Score:5, Insightful)

    by Space cowboy ( 13680 ) on Friday January 23, 2004 @07:57PM (#8071377) Journal
    ... which was admittedly about 18 years ago, we were happy to have the very latest technology... microphones and headphones (well, it was on a school-sized budget :-)

    To be honest, I'd be surprised if WiFi would help you very much - it'd have to be a VoIP network, which isn't an obvious use of WiFi (the range is too short - most people would simply shout!)

    Bluetooth might be an option, but they're basically clever walkie-talkies. Buy some rechargeable batteries and carry them. Sometimes the "clever" solution is the low-tech one...

    Simon.
    • I don't see how bluetooth is any better. The range is certainly far too limited.

      Regardless, any brew-it-yourself solution would probably be far too large, anyway. I doubt you could run VoIP on anything short of a small laptop anyway, and you certainly can't go buying those for every student.

      Probably best, as you said, to stick with the older tried-and-true methods. Get newer walkie-talkies with multiple channels and keep 'em charged.

      Or you could get Nextels for all the crewmembers.

    • Just use the goddamn cellphones everybody has anyway. You can even send SMSes if you need silent communications sometimes.
    • To be honest, I'd be surprised if WiFi would help you very much - it'd have to be a VoIP network, which isn't an obvious use of WiFi (the range is too short - most people would simply shout!)

      Actually, I want VOIP on my zaurus handheld.

      Let me explain why: cordless phones (not cell phones, the kind that connect a base station to the wall phone jack) are easily intercepted with consumer equipment. Tin-foil hat aside, there have been several cases of weirdos tapping their neighbors' conversations just for ki
      • Channel-based systems are easy to tap. Spread-spectrum is much harder. (It'd be basically impossible, except that US eavesdropping laws limit the frequency-hopping rates to something the Feds can tap, but that's still beyond your average advanced hobbyist.)
    • Blue tooth range is shorter then wi-fi. You can get Voip enabled cellphones but your school would have to pitch out about $500 a handset. You can build something similar with certain pda's. If you want more info just reply with your email addy and i'll hook you up.

  • A solution (Score:5, Funny)

    by The Human Cow ( 646609 ) on Friday January 23, 2004 @07:57PM (#8071378) Homepage
    Some of my friends and I make up the A/V crew at my school, and I came up with an ingenious solution yet to be implemented: a zipline. The A/V booth is about 20 feet higher than the stage and a good 75 feet away, and we decided that a zipline would be the best way to get down to the stage to tell somebody something important.

    I guess if you need to tell somebody something who's level with you then you'd have to invest in some model rocket engines or something.
  • www.vonage.com

  • problems (Score:3, Insightful)

    by Mieckowski ( 741243 ) <mieckowski@@@berkeley...edu> on Friday January 23, 2004 @07:58PM (#8071394)
    I'm sure there are probably a lot of problems with interference, but shouldn't it be possible to just get better walkie-talkies? Computers have their own problems too, and I'd imagine that any device you are using to communicate will have dead battery problems (unless you want to have 20 ft cords running all over the place).

  • I wonder how... (Score:5, Funny)

    by moehoward ( 668736 ) on Friday January 23, 2004 @07:58PM (#8071395)
    Makes you wonder how in the hell Shakespear ever got by without a Slashdot subscription.

    Sheesh. It's high school, dude.

  • Get some cups and string (Score:2, Funny)

    by Anonymous Coward
    And you can build a great communication system. It's easy to do, even my 5 year old nephew can do it.
  • a few pairs of decent quality digital walkie talkies (im assuming u are using analog at present) would probably be a simpler, if not cheaper solution in the long-run.

  • Every problem looking like a nail. (Score:3, Interesting)

    by normal_guy ( 676813 ) on Friday January 23, 2004 @08:01PM (#8071433)
    Sounds like a battery-management issue more than something requiring a complex software solution.

  • ClearCom? (Score:5, Insightful)

    by Arcady13 ( 656165 ) on Friday January 23, 2004 @08:02PM (#8071435) Homepage
    Just buy a few ClearCom [clearcom.com] headsets. If wireless costs too much for you, get the old-style models and some lengths of XLR cable. Why waste time with all this computer stuff? It just complicates things. Use the simplest solution.

    • Re:ClearCom? (Score:5, Informative)

      by elsilver ( 85140 ) on Friday January 23, 2004 @08:20PM (#8071588) Homepage
      Just buy a few ClearCom headsets. If wireless costs too much for you, get the old-style models and some lengths of XLR cable. Why waste time with all this computer stuff? It just complicates things. Use the simplest solution.

      I'll second this suggestion.

      When I was in high school, we used RadioShack walkie-talkie type headsets, with both press-to-talk (PTT) and voice activated mikes. We were always dealing with dead batteries, dropouts, and the voice activated took turns being either too sensitive, or not sensitive enough for volume the stage manager neeed to speak at (fairly quiet, sitting just off stage in the wings).

      We even had interference from a Fischer-Price baby monitor, and spent an afternoon walking around the neighbourhood near the school, knocking on doors and asking people if they had any babies. I don't want to know what they thought.

      The next year, we got a set of wired ClearCom headsets, and all was good in the world.

      The signal was clear, and reliable.

      Because they were "the" standard brand, we were able to borrow extra equipment from the local theatre company when we needed an extra headset or something.

      They are also good, 'cause unlike the walkie-talkies, they come either with 1 or 2 earmuffs and do a good job of cutting down on outside noise (useful if you do bands or concerts).

      Spend the money. It's not that much, espcially when you consider (1) that they'll still be chugging along in 20 years, when the RadioShack stuff is lucky to make it through 20 weeks, and (2)over those 20 years, how much are you going to be spending on batteries which you need to replace each show (you are using a fresh set each show right?)

      Also, we rented them out to other groups occassionally, so you get a source of income.

      Do it the right way, you won't regret it.

      E.

      • Re:ClearCom? (Score:5, Informative)

        by mu_wtfo ( 224511 ) * on Friday January 23, 2004 @08:58PM (#8071871) Homepage
        Damn, I already commented, and thus lost my ability to mod, so I guess I'll just add a "Me too!" post, to support the parent and grandparent's posts. Backstage communication is really, really, not a complex issue anymore. It's been solved, and solved well. Clear-Com, Telex, and Production Intercom all make extraordinarily reliable products just for this purpose. Yes, they're expensive, and yes, they're worth it.
        Having a cue get missed because your batteries died, or because someone is DDOS-ing your 'intercom server' is just plain unacceptable.
        If money is really tight, check ebay - I wouldn't be the slightest bit surprised to find used intercom gear on there. And really, all you need is a base station and a couple of beltpacks and headsets. If you're really cheap, buy raw 2-conductor shielded cable and 3-pin XLR connectors and build your own cables (that's what I do :) )

      • Re:ClearCom? (Score:4, Informative)

        by mu_wtfo ( 224511 ) * on Friday January 23, 2004 @09:04PM (#8071923) Homepage
        I used to work at a theatre which had those Radio Shack wireless headsets. What pieces of crap. They were actually *worse* than nothing. Completely unreliable - I'd have no clue whether the person I was trying to talk to was there or not. They also really, really, liked to break. Usually at the 9v-battery connector, since the batteries died so quickly and had to be replaced so often. You can only solder those things back on so many times...

      • ClearCom Third (Score:2, Informative)

        by glk572 ( 599902 )
        I actually really like the wired clear com. There are no batterys to buy, and no interfearance.

        The audio quality is as good as anything out there, the system is full duplex, so you can talk over each other. It uses standard xlr cable, so if you have a house snake you can just run it along that.

        Try to get a used system, the equipment lasts forever.

        My only warning about clearcom is to make shure that you don't have any short's in you cables, they can bring down the whold system. Also be cautious running it

      • Re:ClearCom? (Score:3, Informative)

        by Huogo ( 544272 )
        I do tech at my HS (sound), and we have both clearcoms and those cheap radio shack things. The radio shack wireless system sits in the boxes, unless we absolutely need another headset. The clearcoms work excelently, no interference. Only thing is they're like $500 per beltpack & headset, so it can get costly. Our sound system was installed with one in the sound booth, light booth, and stage left. I later added one for stage right/pit (in a musical). Right now I'm working on getting the school to s
      • I have to second (third? fourth?) this -- Clear-Com units are THE way to go. There's a reson the pro's use these units. On the other hand, they're WAY expensive for such (relatively) simple devices.

        If your school can't afford to buy a bunch, you should consider renting them, or perhaps trying to convince a local theatre group to let you borrow theirs. If you have a professionally installed PA system, the folks who supplied you with that can usually supply the belt-packs as well. Note that most of your
    • Why waste time with all this computer stuff? It just complicates things. Use the simplest solution.

      Yes, it does complicate things. And complication is a very bad thing in theater: if something CAN go wrong, it will. And theres enough that can already go wrong when you're doing a show.. if your communications goes wrong, it makes all those other problems that much more difficult to solve.

      We used to use private-band UHF radios with headsets, or at least headphones. My dad's company had a pair of these, a

  • Encryption? (Score:3, Insightful)

    by Manip ( 656104 ) on Friday January 23, 2004 @08:02PM (#8071437)
    Why not buy some new handheld walki-talkies that have built in encryption (digital), wouldn't that be cheaper/easier than any computer network?

  • That's simple... (Score:4, Funny)

    by Mieckowski ( 741243 ) <mieckowski@@@berkeley...edu> on Friday January 23, 2004 @08:03PM (#8071443)
    All you need is some tin cans and some stri-
    Wait, does string count as "wireless?"
  • I'm confused, what would the PC accomplish? You can't possibly consider trying to do a VOIP solution for a highschool theator. You may know how it works but when you graduate no one else will. Save the cash and buy clearcom or telex. They're really not that expensive once you consider just how long they last. I've seen clearcom systems that have been installed for atleast 15 years, and telex for even longer. Instead of posting this to slashdot, write up a proposal to send to your school board or even

    • Re:No PC (Score:4, Insightful)

      by pirodude ( 54707 ) on Friday January 23, 2004 @08:11PM (#8071513)
      More information for my original post.

      Consider the cost of your solution vs the cost of a regular system.

      CS-222 Clearcom 2 channel base station: $876
      Belt pack: $238
      Headset: $149

      Now you'll need a headset for the base station (which is a station by its self). So say you need 1 stage left, 1 stage right, and your base station will be at FOH for sound/lighting. That takes a basic solution to $1799 without XLR cables. Buying used you could probably save even more. Remember, not every single person needs a headset. You basically need someone stage left, stage right and FOH to give messages and give cues. I was in highschool theator and I know how much everyone loves to wear the headset to sound important. I can also remember how many cues people missed because they were messing around on them.

  • Stupid technology tricks (Score:4, Insightful)

    by DocJohn ( 81319 ) on Friday January 23, 2004 @08:05PM (#8071465) Homepage
    No, this is just silly. A laptop is going to be far more expensive than some high-quality two-way radios from Motorola or the like. Even if you already had the laptop, there's nothing that allows you to easily tap into VOIP via independent headsets. I'm not sure why regular, quality two-way radios (at $40 for a pair with rechargeable batteries) isn't good enough for this simple application?
  • Everyone is deriding the topic poster, but perhaps he's going to /. high school... It would be interesting to hear someone's cost effective solution for home brewed VOIP.
    • Exactly, whether or not it makes sense to actually implement, I'd love to see how this could be accomplished... Haven't any of you done something ridiculously overcomplicated just for fun? Rube Goldberg? Not only that, but if this kid is in highschool, maybe he actually wants to learn something (as opposed to just learn how to do busy work).

      I am definitely not a network engineer or a wireless expert, but possibly a very simple solution might be a Roger Wilco server with some bluetooth headsets. VoIP is

  • ClearCom (Score:3, Informative)

    by zachlipton ( 448206 ) on Friday January 23, 2004 @08:09PM (#8071501)
    While you could probably roll your own system with a lot of work, you are better off going with a real Clearcom system for theater use. They do both wired (cheaper, but it's really all you need for high school) and wireless (quite expensive). eBay often has some used eqipment you can buy as well. These systems are what are actually used in the field, and in many schools as well and are quite less likely to fail than a home-grown solution (rebooting the communications computer in the middle of a show so the SM can talk to a board-op is a very very bad idea). It may seem easier to put together a free system than buying the Real Thing, but by the time you purchase wireless eqipment and setup a custom system you have spent more in time and money than you would with a real system.

    $800 for a CS-222 ClearCom 2 Channel Main Station is a lot of money, so another thing you may want to try are Motorola TalkAbout radios with headsets (not in VOX mode though, you don't want that in a theatre since you want to avoid unintentional chatter on the comms system). They tend to have fairly good range in my experience and if you take the time to pick out clear channels there isn't an issue with interference).
    • I have to agree with this. Among the various other things I do, I run a youth circus program called Simply Circus (www.simplycircus.com). We use 8 of the talkabout 2 way radios, and have not had any problem with them.

      Before a show we will use the pair of T5710's we have to scan for others in the area and to find a pair of clear channels. Once we find a pair of channels that works (primary and backup), we set the rest of the radios to the same channel, and make sure every one knows he backup. The system

  • Walkie Talkies (Score:3, Insightful)

    by BrookHarty ( 9119 ) on Friday January 23, 2004 @08:11PM (#8071510) Journal
    Use the money and buy more rechargeable batteries for the Walkie Talkies. Using batteries as an excuse to go VoIP, which also uses batteries, doesn't make sense.

    If interference is the real issue, look into low frequency radios with a 5 watt range.

    Sounds like someone wants a project.

    • Re:Walkie Talkies (Score:4, Insightful)

      by dougmc ( 70836 ) <dougmc+slashdot@frenzied.us> on Friday January 23, 2004 @08:17PM (#8071564) Homepage
      Using batteries as an excuse to go VoIP, which also uses batteries, doesn't make sense.
      The voice of reason.
      If interference is the real issue, look into low frequency radios with a 5 watt range.
      The school ought to be able to have a 20 khz or so chunk of frequency allocated to it. In fact, it may already have such a frequency allocated to it -- certainly there's a lot of schools listed in the scanner lists. This frequency should be mostly free from interference (as opposed to FRS or stuff on 27 mhz, 49 mhz, 900 mhz or any of the other unlicensed bands.) If you are picking up intereference, either your radios are just crappy or somebody's causing interference. If it's the latter, get your local ham radio club (perhaps the school has one?) to track it down for you, and the FCC may require them (the source of the interference) to fix it.

      • Re:Walkie Talkies (Score:5, Informative)

        by mu_wtfo ( 224511 ) * on Friday January 23, 2004 @08:50PM (#8071825) Homepage
        Gaaah!!! No, no, no!!! 5 watt transmitters in a backstage environment?!? I recently had to completely ban our Motorola 2-watt radios from the booths in both of our theatres [ardentheatre.org], because when someone tried to talk on them, it would often induce RFI into the sound equipment, headset system, and, worst of all, the light board. You key up one of those things next to an unbalanced signal line, and *everyone*'s gonna know it.
        In a theatre, nearly everything is temporary - speakers need to be in this spot for this show, then, six weeks later, completely across the room - hence, most cabling and playback/processing equipment is portable, and certainly not run in nice steel conduit - which, sadly, leaves it susceptible to RFI.
        Yes, I've also banned the use of cell phones. :)

        (Master Electrician, Arden Theatre Company, Philadelphia, PA.)

        • Gaaah!!! No, no, no!!! 5 watt transmitters in a backstage environment?!?

          I did not mention a power range -- that was the parent of my post. 5 watts is enough power to talk across town (or across country with the right antenna and frequencies, but I digress...) I imagine that even 100 mW would be plenty for these people's needs.

          You key up one of those things next to an unbalanced signal line, and *everyone*'s gonna know it.

          Unshielded lines? There's your problem. Let's hope nobody decides to use t

          • That's what coax is for. Very RFI resistant, and pretty cheap as well.
            To followup to my own post, if this wire is going to something that handles only low frequencies, like a power line or a speaker wire, there's no need for even coax -- low-pass filters at both ends (some simple ferrite beads might do it) should cover that nicely, keeping the RF signal out of the electronics connected to it.

            Of course, you probably already know all this :)

  • Convince a local cell provider to donate phones and air time.

  • Easy fix, FRS Radios (Score:4, Informative)

    by Jtheletter ( 686279 ) on Friday January 23, 2004 @08:14PM (#8071536)
    Your best bet for cost and effectiveness is to get nicer walkie-talkies. At $40/pair Motorola FRS/GMRS radios have 22 channels, and a 2-mile range, plus you can get headset/microphones to go with em. I own a couple pairs and they're durable as hell (you shouldn't drop them in a lake, but mine came back to life anyway) and have 12+ continuous hrs on a couple AAs. Plus now you can multichannel your crew - Ch 1 is Lights/sound Ch 2 is backstage crew.... ~J >-- I'm not a pessimist, I'm a realist. It's not my fault that life sucks so much. --

    • License required (Score:2, Insightful)

      by jim_deane ( 63059 )
      You can use FRS frequencies with FCC-approved FRS walkie talkies.

      To use any GMRS-exclusive frequencies, you MUST purchase a license from the FCC and use the appropriate call sign and operating procedures.

      GMRS radios are /not/ license free.

      Jim
    • FRS radios would be illegal. They are regualted and are only allowed to be used for individual purposes. If the FCC catches your school using them you can end up with a hefty fine, and don't think the FCC won't I know several schools that it's happened to.
      • They are regualted and are only allowed to be used for individual purposes.

        FRS is not restricted in purpose. 47CFR95.193 defines the use of FRS, and the only mention of "individual" is:

        (a) You may use an FRS unit to conduct two-way voice communications with another person.

        There is no limitation as to the purpose of this communications with another person, other than a blanket prohibition on use in connection with a violation of federal, state, or local law. Assuming the stage crew is not supporting

      • My appologies, FRS-only then, jim deane has it right. FRS-only radios should be fine however and not susceptible to FCC fines. From the FCC FRS Page [fcc.gov]:

        "You may use your FRS unit for business-related communications.
        License documents are neither needed nor issued. You are provided authority to operate a FRS unit in places where the FCC regulates radio communications as long as you use only an unmodified FCC certified FRS unit. An FCC certified FRS unit has an identifying label placed on it by the manufacturer

      • The rules are different when it comes to indoor, contained usage. As long as you're not in competition with ATT, you're legal :)

  • Better question...digitial microphones? (Score:5, Interesting)

    by JoeShmoe ( 90109 ) <askjoeshmoe@hotmail.com> on Friday January 23, 2004 @08:17PM (#8071568)
    I work with a lot of presentations and lectures and I'm dying to know if there is any consumer or prosumer level digital microphone systems out there? Everything that you can find both at cheap ass Radio Shack and even high end audio stores is varying degrees of wireless. 900Mhz or 2.4Ghz just like cordless phones. Some through the word "digital" around but are still susceptible to interference and static.

    What I'm dreaming of is something that is purely digital, from the device the speaker wears all the way to the speaker. I envision something like a Bluetooth wireless microphone similar to the bluetooth headsets that some cellular phones use. This bluetooth microphone would relay to either a box in the speaker's pocket or inside the lecturn. This box would then use CAT-5 or 802.11 to transmit the stream as a WAV or MP3 so that it could be played on a SlimMP3 or Shuttle connected directly to the speaker system. In theory the speaker could roam freely and speak clearly and sound crystal clear.

    Is there anythign like this? One place that I work for is about 100 feet from high power lines. The resulting RF interference renders even the most expensive $600-800 wireless microphone solutions worthless. Wired microphone even have a problem, even with grounding wires you still pick up pops clicks and hums over fifty feet.

    So, how about it? There are plenty of devices that can take an audio stream off a network and output a sound wave? How about a device that can record the sound wave and output an audio stream?

    FYI - consumer or prosumer means less than four digits...I'm sure studios and recording studios have plenty of expensive options available.

    -JoeShmoe
    .
    • Less than 4 digits doesn't even really get you a good conventional wired mike.

      Plenty of pros are using wireless SM58's, I guess that's UT24/58. But you've already gone there I guess, and your power lines won't move huh?

      A hundred bucks can go a long way towards damned good low-Z cables. Just use real mic's! (The expensive options that the studios is still the good old wired Telefunken).

      Foley guys won't touch wireless. TV news folks use AKG's and Shure's, and deal with RF issues just like you. You are
    • You're hearing pops and clicks on wired mics and you expect to use digital???

      Give me a break! As opposed to pops, clicks, hums and static when digital gets interference you just loose the signal completly!

      So ..t ..ound.. som..ing l..ke this.

      As someone else told you either spend some serious dough on a real wireless system top of the line Shure or the new Audio-Technicas. Or if you're really in a high line noise envronment get a good wired mic and some super shielded cable.
      • Digital is all or nothing, but there's no way interference should wipe out the signal completely...especially considering it would not be very hard to overtransmit (send more stream information than needed in case some gets lost). There should be more than enough bandwidth available for a digital solution. Hell, voice sounds fine on a 128kbps MP3, I could send dozens of those on a computer network and play the best one. It shouldn't be that hard to do...remember, plenty of digital solutions exist to play
    • Any microphone is going to be vulnerable to interference from a big magnetic field near it. Microphones use magnets to convert sound into electrical impulses, so the only thing that might save you is microphones designed to deal with high RF interference.

      The same thing goes for the RF interference to a wireless setup. Digital isn't a magic solution that eliminates RF problems. The better solution as far as the wireless is to just go to a frequency that the power lines aren't putting out, which probbably
    • The first problem they were having is that the most expensive $600-$800 wireless audio systems are the cheapest. If you're not willing to drop $3000 per channel on sennheiser transmitters [sennheiser.com] and receivers [sennheiser.com], where squelch, sensitivity, frequency, and a zillion other things can be set at the venue, you'll have problems. Also, you won't find any serious show using VHF. To much interferance. Most cheepo units are VHF.

  • Now just wait a minute... (Score:5, Funny)

    by Phexro ( 9814 ) on Friday January 23, 2004 @08:18PM (#8071573)
    You're a high school kid with walkie-talkies that can be used in pranks on McDonalds customers, janitors, and hall monitors, and you want to get rid of them?

    The U.S. education system must be going downhill fast.

  • The very latest in technology (Score:5, Funny)

    by Pedrito ( 94783 ) on Friday January 23, 2004 @08:20PM (#8071593)
    For something this "critical", you need technology that won't fail, but will also work in the kind of vast distances you're talking about. I suggest tin cans and string. Of course, you'll have to make sure nobody in the audience brought scissors, but with all the hi-tech anit-terrorism stuff they throw in schools these days, surely nobody can get in with sharp objects.

  • Does it have to be wireless? (Score:2, Informative)

    by Anonymous Coward
    Been there, both in HS and college. Is there a particular reason it has to be a wireless system? We used wired ClearCom systems at both. Sometimes the cord was anoying, but usually it was not a problem, and it eliminates the VOX, noise, dead spots, etc. problems. A quick search found this
    http://springtree.net/pi/econocom.html
    whi c h has some packages by Production Intercom that arn't too bad price wise, and you can probably find used equipment out there for less (eBay had some real ClearCom gear last time I
    • Here! Here! All the posts in the story are crap about WinCE devices and wireless laptops in backpacks! Get a grip! That will just be heavy, unreliable, expensive, hard to set up and a pain in the ass to maintain.

      Get a low-cost clone of the industry-standard ClearCom party-line intercom system. It's the tried-and-true method for theatres worldwide. There is a reason: IT WORKS! Simple setup and excellent intelligibility in noisy environments. Lots of accessories are available, such as call lights to

  • Any communications systems needs maintenance (Score:3, Insightful)

    by zapster ( 39411 ) on Friday January 23, 2004 @08:23PM (#8071612)
    The problems you cite are universal for portable communications systems. Batteries going dead, bad headsets etc. The key is planning and maintenance. If it is critical to the show then make darn sure the batteries are charged before the show starts and if one doesn't last the entire show then dispose of it. (Nicads and nickel-metal hydride need to be disposed of properly, Radio Shack does this for free) Keep a couple of spare radios ready to go and charge some extra batteries as well.

    The better route to go is to get a license for your own radio channel and use higher end radios like police and firemen do. Schools often have a business band license for buses or maintenance that you could use on the off hours, this keeps other people off your frequency. The radios cost more but you are paying for reliability.

    Don't whine that you don't have the money, get a system designed by your local radio (Motorola) dealer and then start getting the money through grants and donations. I get solicited all the time for free stuff and sometimes the dealers can hook you up with a corporation that is changing systems out and looking for a place to donate the old (but good) equipment too.

    The main thing is plan ahead, and plan for things not going perfectly.

  • Ok, i'll roll up the network in one, but I'm sure as hell not sparking it.
  • Seriously, you know NexTel lives for these kinds of situations. Get a bunch of NexTels with ample walkie-talkie minutes and then get some headsets. Put the phones on your belt and then either use voice activated talk mode, or the old push-button style. Frankly, I hate half-duplex stuff but it's what you are already used to. The advantage is that you can roam anywhere (not just the gym) and have instant communication. It shouldn't be all that pricey either. They have pay-as-you-go prepaid plans. The s
  • If by walkie talkies you mean the standard 49 mhz AM kind, I can understand why you have problems. Go with an FM UHF solution. It will be much clearer and you'll be able to communicate over longer distances.

    To solve the interference problem you could use FRS or GMRS radios with CTCSS. As long as you pick a tone no one else in the area is using, you should not hear interference even from others using the same frequency.

    If you go with GMRS, someone will have to get a GMRS license. This is easy to do (no

  • Find you local church(es) (Score:3, Informative)

    by bluGill ( 862 ) on Friday January 23, 2004 @08:29PM (#8071664)

    I'll bet there is more than one large church in your town, and each one has wireless gear that they use for services sunday morning, and no other time. Just talk to them in advance and borrow their gear. Most would be more than willing if you ask correctly. (and take care of the equipment)

    Note that there is an art to asking. Best is to have someone in the production (actor, teacher, think outside of tech crew) ask. I'm not sure about much else because as a tech guy I don't know how to ask.

  • An excellent wired/wireless solution (Score:5, Informative)

    by mdkemp ( 720790 ) on Friday January 23, 2004 @08:29PM (#8071667)
    For a theater group with which I work, I built an inexpensive intercom system that uses standard corded or cordless telephones. The [simple] schematics I used can be found at http://www.epanorama.net/documents/telecom/telepho ne_intercom.html [epanorama.net] -- just scroll down to the "Theatre intercom circuit".

    Basically, it mimics a standard phone line, and any telephone device you plug in can communicate with the others. You can run long cables and use splitters [nearly] to your heart's content. For about $30-$50 per station (hundreds less than a real, however superior, Clear-Com system), you can purchase corded or cordless headset telephones which work nearly as well.

    If you do that, be sure to get phones with mute capability; and if you go cordless, be sure to check on battery life and try to get phones that don't beep too loudly. You might even need to disassemble the cordless phone and disable the internal beeper to make it silent.

    Two things that are really nice about true Clear-Com systems is that (1) they can be operated silently (i.e., without beeping), and (2) their mute/talk controls can be operated by feel alone -- you don't need to look at a mute LED to determine whether or not you're muted. Those features are hard to come by on unmodified corded and cordless phones.

    In general, a theater intercom system needs to be absolutely reliable, and should also be full-duplex (which walkie-talkies are not, but telephones are). I'd shy away from creating a custom wireless soultion with unproven technology -- it will take much more time to develop and won't be as reliable. If anything goes wrong during a show, or if reception isn't good enough, you've got big trouble.

    • Use the old phone trick. The parts are cheaply obtained, and not likely to get stolen. Plus, it works very well. The only downside is that you have to hold onto the handset. But there are solutions to that problem, as well.

  • get cellphones that have unlimited sprint to sprint calls. makes sure you get decent signal in the auditorium. get the smallest plan available in your area.
  • In my experience all professional theaters use telex or clear com systems. Wired ones are quite expensive, and prefered as you can get headsets powered from the jack. However, both also make wireless systems that use FM and have quite good quality and range. The wireless systems are not nearly as cheap as walkie talkies, but they are far cheaper than wired systems and will last for years. It may be worth the time and effort to get some approved, or do a fund raiser.
  • Cisco sells wireless VoIP handsets [cisco.com].

  • Better Yet. (Score:5, Insightful)

    by dracocat ( 554744 ) on Friday January 23, 2004 @09:02PM (#8071905)
    Don't buy anything. Work on sharing the football team's headsets. They probably have a bigger budget than your theatre department anyways. This should work out as long as you never have a performance during a game, which you should never do anyways!!

    If they don't have one, perhaps its a good time to talk about splitting the cost of one.
  • I would have to say that your best option would be to invest in the system

    Think about it
    1) The computer crashes.
    2) PortabilityWill you be able to use this everywhere? You probably aren't going to take computers with you if you travel for competitions, and if you do that takes up your setup time.
    3) Lag, you need real time conferencing behind the stage and can't wait even for a second of lag time if something goes wrong.
    4) InterferenceMost people in the audience probably have a cell phone which operate
  • If you're already experiencing interference from the local McDs then it sounds like you're already using FRS radios, but did you realize they offer FRS radios with security channels? That should solve the interference problem.

    Best part about FRS: they're extremely cheap. Walmart has several brands for less than $10 each.

    If battery life is a problem I'd recommend getting FRS radios that use as many batteries as possible. 4 AA would obviously last the longest, with 3 AA followed by 4 AAA.

    If that's not

  • FRS? (Score:3, Interesting)

    by anethema ( 99553 ) on Friday January 23, 2004 @11:12PM (#8072627) Homepage
    I'm assuming that you people in the USA dont have a band allocated to the FRS?

    Here in Canada, we have something called (you guessed it) FRS. Stands for Family Radio Service. The handsets run for around 25-40 bux canadian. You can usually get them in a pair for 50 dollars. They put out a half watt on vhf(get about a mile of range), and operate in a band allocated ONLY to the frs. There are..14 channels?

    Hm, some quick googling turns up the fact that you DO have frs down there. Other than intermod, there isnt really much interference on the band. If you are using normal walkie-talkies, try some FRS radios. If the channel you are on has interference..switch to one of the others.

    Here is the bandplan from the fcc [fcc.gov].

    Here are the radios at Best buy [bestbuy.com].
  • First off, let me preface this by saying that i have worked building large-scale theater shows, and as a lighting designer for 7 years. I have worked on shows including the Lion King, Cher, Phanton of the Opera, Miss Saigon, Tim McGraw, the Pan American Games, as well as numerous regional and touring theater shows and outdoor festivals.

    Quite literally the only thing these shows have in common is the need for clear, reliable crew communications. During setup/strike (installation/teardown), crews usually have portable radios (Motorola Walkie-talkies generally), so everyone can keep in touch without shouting or running around looking for each other. Essential for big shows, unnecessary but nice for small one. However, for all shows, only "Clearcom" communications are used.

    Clearcom is a brand-name of wired "party-line" communications sets. It's used generically for other brand systems, like Telex, HME, etc. It's the same thing you see camera operators on TV shoots wearing. Everyone has a headset and beltpac, and can talk to one another on a common "channel". Everything is hard-wired, and everything works, all the time, every time. The systems is used for calling show cues, as well as any other necessary communication during showtime.

    However, the "wired" issue becomes a problem for some people. While audio and lighting techs can often stay put (they sit behind a board), stagehand/stage managers have to be mobile, often on stage. Usually they need to be able to communicate in a high-noise environment, and it must work reliably.

    The only way to do this is via a wireless clearcom system. Telex [telex.com], HME [telex.com], and Clearcom [clearcom.com] are the big three, and all of their systems are inter-operable. I personally like HME's RadioComm, but all systems have their own benefits. Simply put, these systems are expensive but necessary. For a school situation, you can probably get away with 2 wireless stations, and 4 wired. But you can't cheap out on this. You need great headsets, and equally good beltpacs to go with them. When you're midshow, and you can't hear your cue, you'll know why.

    I hope this helps. I realize that you were looking for a cheap way around the problem, but there isn't one. You'll find that with 95% of things in theater, cheaping-out never works. You buy a crappy light, or sound equipment, or cleacom, and life sux but things go on. You cheap out on rigging or construction, and people die. It's as simple as that.

    -Michael Roy

  • A few notes (Score:2, Interesting)

    by reidab ( 230724 )
    In my high school theatre we have a clear-com system that we use for general communication but there are times on our larger productions in which it simply will not do. To remedy this, a friend and I hacked together a system by which to patch our clear-com output into our assisted listening devices. After completing this, we could give our stage crew boxes which would allow them to hear anything that went on on headset. We have two wireless microphones (1 lav, 1 handheld) which we gave to important crew

  • Slight misappliance of science. (Score:3, Insightful)

    by vik ( 17857 ) on Saturday January 24, 2004 @01:29AM (#8073193) Homepage Journal
    While I'm fairly sure that some variant or successor to 802.11* will be the norm for wireless phone handsets one day, I don't think now is a good time to solve that problem with it.

    Soon there will be 802.11-enabled mobiles in common use and all those base stations will make an awesome ad hoc network, but until then I'd suggest PRS handsets and headsets with VOX to save power.

    If anyone is interested, I've developed a concept for sharing browser caches over LANs to speed up the access of all members here [family.gen.nz].

    Vik :v)
  • The technical director at my college just switched us from a 15 year old clear com system starting to show its age to a set of Motorola talkabouts. All of us hate them and use the clear coms when he is not around since we prefer them for the headsets and the fact that we don't have to worry about batteries . Full duplex is also a great feature except when everyone is trying to shout each other down.

  • My Idea (Score:2, Informative)

    by concordeonetwo ( 644570 )
    I work on my schools television station. Anything big like recording the school plays we usually do FRS radios. I've seen other setups use the unused 2-pairs of wire in the CAT5 network ports in the school as the local loop in a homebrew intercom system.

  • Motorola talkabouts (Score:3, Informative)

    by Ryan Amos ( 16972 ) on Saturday January 24, 2004 @04:53AM (#8073862)
    Use those Motorola radios that get like 1 mile range. They're like $50 for a pair plus $10 for some headsets to plug in. That's what most high school theaters use, cause they're cheap, work well and are simple to operate.

  • PTT Cell phones? (Score:2, Interesting)

    by halo1982 ( 679554 ) *
    Get your school on a multiline phone plan with low minutes but unlimited push to talk...long distance walkie talkie that no one can look in on and you won't pick up anyone else's stuff...maybe you could do 4 phones for around $100 a month? That still might be too much, but with free or discounted equipment the initial cost shouldn't be too much, maybe around $600, with a monthly fee. Sprint, Verizon, and Nextel all offer unlimited PTT...(that is if phones would even work in your theatre)

  • Challenge (Score:3, Insightful)

    by ONOIML8 ( 23262 ) on Saturday January 24, 2004 @11:40AM (#8074908) Homepage
    Being a geek is a good thing. But it doesn't mean that you have to make things more complicated than they need to be.

    You obviously need voice communication without (expensive) signalling. So analog voice will do just fine. Forget computer or networking based ideas, going there is only going to sidetrack you from your goal. Remember that this is about getting your theater group to communicate, not about playing with geek toys.

    Someone here has already mentioned 49 MHz headsets. Radio Shack and Maxon are common brands and those should work great for you. But if you need something with a little less interference then......

    FRS, or Family Radio Service is another option. The radios are fairly inexpensive and can be had for $30 each or so. They offer multiple channels and CTCSS tones (if you don't know what that means either RTFM or get back to me, it's worth your time to understand it). Those should give you the range you're looking for. You won't get interference from businesses there, that frequency band is for non-commercial use. And if you do find someone interfering then gather information and turn them in to the FCC and your interference problem is gone.

    Beyond that you could go for commercial land mobile gear. It works like FRS but you have to license a channel. You do get a lot more power and range. The drawback is that the school will have to apply for a license and that takes time. You'll have to budget $300 on up for each radio with the accessories you'll want.

    If it were me I would try FRS first, a trial run with a couple of borrowed radios.

Slashdot Top Deals

He has not acquired a fortune; the fortune has acquired him. -- Bion

Close