Curtis
Curtis UltimaDork
9/9/18 5:11 p.m.

I'm looking for an inexpensive way to communicate with crew, stage managers, and house managers at the theater during shows.  The industry standard is a wired "clearcom" box with a headset (which is expensive), but we can't do wired stuff here because of the fact that we're all wearing multiple hats both backstage and in the house/lobby.  I can't trail 100' of XLR through a lobby with 100 patrons in it.  The other option is wireless clearcom, but those are monstrously expensive... as in each box costs about $1500 and still requires an amp and a central installation.  Since we would need up to 10 comms, that aint happenin.

What about FRS with headsets?  We would have the learning curve factor... each night our ushers and box office is staffed by different volunteers (often times they fall into a particular white-haired demographic).

The staff at a larger theater downtown went the whole FCC route and bought expensive motorola units with an assigned and licensed frequency.  Why couldn't I just get some FRS talkabouts for a couple hundred bucks?  Is there an FCC problem doing that?  They're UHF in the high 400s mHz, so I can't see them disturbing (or being disturbed by) any wireless stuff as everything I have here is 2.4gHz and 5gHz.

TheMagicRatchet
TheMagicRatchet New Reader
9/9/18 7:26 p.m.

I would think FRS would work fine for your intended use. The radios are 1/2 watt which means there should be plenty of power and the short wavelength of the 460 mHz signals should "bounce" around inside the building well enough to provide decent coverage. The batteries will last through several hours of heavy use. If you use them a lot, you may want to switch to rechargeable batteries to save money. I have a few of these radios and like the Motorola the best. In your situation, I'd make sure to purchase the radios with the most useful accessories (headsets, etc.). I would suggest you try 2 or 3 and see how they work for you before building an entire system. 

I checked the FCC rules, it looks like your assignment would be within the regulations. You can look here for more information: https://www.fcc.gov/wireless/bureau-divisions/mobility-division/family-radio-service-frs

Stay away from the combination GMRS units as you'll be wildly illegal if you accidentally happen to operate on one of the higher power GMRS frequencies. It is almost a given that the licensed operators in that band will immediately report you if you interfere with their operations.

The other "license by rule" service available is MURS but it is VHF and may not suit your indoor usage as well. 

Good luck with it. 

Lou

 

 

 

oldopelguy
oldopelguy UberDork
9/10/18 6:22 a.m.

The free frequencies are generally considered to be for amateur use and use by a "business" would be frowned on.  As a ham, I'd probably file a complaint if I ran across Bob's pizza or the like using FRS. 

That said,  you mentioned volunteers,  and I specifically wouldn't report someone who uses volunteers. Not all hams would be so generous, but most would,  and worst case is you eventually get a letter telling you to stop.

One concern is going to be interference from your lighting system.  Inexpensive radios plus the lights themselves and their control systems in particular being radio "noisy" is a recipe for crummy reception.  The Strand boards we had at one theater I worked at were so noisy that you could pick it up with a car stereo in the parking lot during a show.

Ian F
Ian F MegaDork
9/10/18 6:39 a.m.

I've used both cheap FRS radios and the high-dollar Motorola versions. The one problem I've had with the FRS radios is their inability to go through a lot of walls.  Something the Moto units can easily do. About 10 years ago I was part of a team commissioning a generator I had designed. I was in the control room next to two big boilers in the basement about 500 feet and dozens of concrete walls from where the generator was running. Talking to the guy at the other end wasn't an issue.  With FRS radios, my ex- and I had trouble communicating between her house and garage, 50 feet and a handful of residential walls away.

My suggestion would be to risk $50, get a pair of FRS radios and see if they can work in your building, making sure you can communicate from every location needed.

The other issue is FRS frequencies are public, which means anyone nearby who has one can hear and chime in on your discussions.  Sometimes by accident, other times on purpose.

ultraclyde
ultraclyde PowerDork
9/10/18 7:23 a.m.

As of the changes in may 2017, FRS radios are legal for 2 watts on channels 1-7, so that should help the through-wall propagation. Some. BUt it is partly a frequency issue. Most of them also support sub- audible squelch "privacy" tones too, so it's a little easier to have a private channel. Well, more accurately it's harder for someone to stumble on your broadcast. FRS is legal for "facilitating family and group operations" so you might be considered legal for that operation, particularly with a volunteer staff. If you are for-profit operation though, it probably puts you out even using volunteers. FCC page on FRS usage

You might want to get in touch with a shop like "buytwowayradios.com" and discuss your options. They sound hokey but they do a lot of business, ham, and consumer system setups. They're in south carolina and I just bought a dual band mobile unit from them. The staff was personable and knowledgable, and shipping was fast and free.

GameboyRMH
GameboyRMH MegaDork
9/10/18 8:42 a.m.

From my experience FRS/GMRS will work as long as there are no sheet metal walls in the way. Another option could be some kind of VoIP system, there are plenty of options there that could work if everyone has a smartphone.

Curtis
Curtis UltimaDork
9/10/18 8:57 a.m.

I honestly think a 1/2 watt handset would work.  It's a small theater.  There is a 50' x 60' black box theater space separated by a curtain from a 30 x 75 lobby, then a short hallway to the box office.  Nearly everything is open and darn near line of sight.

Theatrical lighting should be pretty quiet.  It is all LED fixtures so there are no dimmers except for occasional small Edison dimmer packs for things like controlling lamps on the set.  This show for instance has some street lights with 40w incandescent bulbs and I use a dimmer pack with wireless DMX to control those.

FCC site says the FRS is OK for business use.  So I just have to choose a radio that can't transmit the higher wattage on certain frequencies?

I was thinking about getting some of the cheap chinese programmable radios to try and then figuring out how to program them for legal use.

ultraclyde
ultraclyde PowerDork
9/10/18 9:16 a.m.

I was thinking about getting some of the cheap chinese programmable radios to try and then figuring out how to program them for legal use.

You can't. They aren't tested as Part 97 (or is it 95?) devices by the manufacturer, and therefore will never be legal to use on those frequencies. They can easily be programmed to do so however using a freely available software like CHiRP.

How does someone on the other end of your signal know if it's a correctly typed device? Well...they can't. Take that as you will.

Any of the radios sold as FRS radios should be correctly typed and the FCC won't approve one within the correct type that is over wattage, so no worries if you just buy FRS radios.

ThatsNoUsername
ThatsNoUsername HalfDork
9/10/18 9:20 a.m.

Marco Polo app?

eastsideTim
eastsideTim UltraDork
9/10/18 9:47 a.m.

Is there any WiFi/Bluetooth headset option you could look into!

Curtis
Curtis UltimaDork
9/10/18 9:57 a.m.
ThatsNoUsername said:

Marco Polo app?

We tried a similar app, but it's a bit clumsy and relies on the use of a network (which is currently terrible at the theater.  It drops frequently and it's cheap and slow)

Also... white-haired volunteers often don't have smartphones, nor would they be savvy enough to use the app.  The lady in the box office last night was in her 90s, has a hearing aid, and struggles with the credit card machine.

I was thinking a walkie talkie thing is pretty universally understood, wouldn't require equipment that works on different phone hardware, it's standalone, and pretty bulletproof operation.

Curtis
Curtis UltimaDork
9/10/18 9:58 a.m.
eastsideTim said:

Is there any WiFi/Bluetooth headset option you could look into!

I have no idea, actually.  Let's brainstorm it.  I'm planning on an AirPort some day for using ipads to control lights and sound.

Curtis
Curtis UltimaDork
9/10/18 10:05 a.m.
ultraclyde said:

I was thinking about getting some of the cheap chinese programmable radios to try and then figuring out how to program them for legal use.

You can't. They aren't tested as Part 97 (or is it 95?) devices by the manufacturer, and therefore will never be legal to use on those frequencies. They can easily be programmed to do so however using a freely available software like CHiRP.

How does someone on the other end of your signal know if it's a correctly typed device? Well...they can't. Take that as you will.

Any of the radios sold as FRS radios should be correctly typed and the FCC won't approve one within the correct type that is over wattage, so no worries if you just buy FRS radios.

So basically you're saying the chinese ones could Tx legally, but they won't be technically legal because they don't have an FCC sticker on them?  Did I get that right?  So the only trouble I would be in is if a person reported it and the FCC showed up and looked at the radios?

The chinese ones I was looking at comes with the software and cord.  I realize that I'm trying to do this on a public frequency and anyone can hear it, but honestly I think with all the channels and sub codes I can find one that isn't really used.  The plan would be to more or less put them on as a scanner for a week and listen for any broadcasts and note the channel, then pick one that doesn't ping anything.

Curtis
Curtis UltimaDork
9/10/18 10:15 a.m.

Also thought of something else... I better check the frequencies of my wireless mics.  It would be embarrassing if I keyed the radio and disrupted a show with "Dammit the berkeleying fog machine broke again."

ultraclyde
ultraclyde PowerDork
9/10/18 10:23 a.m.
Curtis said:
ultraclyde said:

I was thinking about getting some of the cheap chinese programmable radios to try and then figuring out how to program them for legal use.

You can't. They aren't tested as Part 97 (or is it 95?) devices by the manufacturer, and therefore will never be legal to use on those frequencies. They can easily be programmed to do so however using a freely available software like CHiRP.

How does someone on the other end of your signal know if it's a correctly typed device? Well...they can't. Take that as you will.

Any of the radios sold as FRS radios should be correctly typed and the FCC won't approve one within the correct type that is over wattage, so no worries if you just buy FRS radios.

So basically you're saying the chinese ones could Tx legally, but they won't be technically legal because they don't have an FCC sticker on them?  Did I get that right?  So the only trouble I would be in is if a person reported it and the FCC showed up and looked at the radios?

 

ahh...no.  They are ABLE to transmit and receive on FRS frequencies. They cannot LEGALLY TRANSMIT on those freqs because of they aren't certified under the correct testing as required by the FCC. Receiving is legal of course, or at least isn't technically regulated under the law. But you are right about being in trouble if someone rats you out to the FCC which is how that usually goes down. Like $10,000 and up per violation trouble in a real worst-case scenario.

 

Curtis
Curtis UltimaDork
9/10/18 11:19 a.m.

Just learned my wireless mics are in the 500 mhz spectrum.  460 mhz for FRS seems a little close to me.

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