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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Installed Sound/Contracting => Topic started by: Joseph D. Macry on May 16, 2016, 01:48:09 pm

Title: 2.4GHz intercom through glass window
Post by: Joseph D. Macry on May 16, 2016, 01:48:09 pm
A high school football field has a press box in which the windows are all sealed (cannot open the windows). Coach wants to buy CoachComm brand intercom. Wants to keep the system portable. System includes 2.4GHz antenna. Manufacturer says the antenna will not always work well through glass window, depending upon glass composition, thickness, tinting, etc.

I'm surprised to hear the 2.4GHz won't go through glass well. My cell phone (Verizon) works around 1.9GHz, and goes through all kindsa stuff.

What's your opinion on this antenna working through glass window? The specific antenna is "CP Beam" by CoachComm. (So far, they don't want to spring for extra antennas to have both mounted and portable option.)
Title: Re: 2.4GHz intercom through glass window
Post by: Keith Broughton on May 16, 2016, 02:06:10 pm
A high school football field has a press box in which the windows are all sealed (cannot open the windows). Coach wants to buy CoachComm brand intercom. Wants to keep the system portable. System includes 2.4GHz antenna. Manufacturer says the antenna will not always work well through glass window, depending upon glass composition, thickness, tinting, etc.

I'm surprised to hear the 2.4GHz won't go through glass well. My cell phone (Verizon) works around 1.9GHz, and goes through all kindsa stuff.

What's your opinion on this antenna working through glass window? The specific antenna is "CP Beam" by CoachComm. (So far, they don't want to spring for extra antennas to have both mounted and portable option.)
It should work through glass that doesn't have metal (copper)tinting or metal mesh.
Title: Re: 2.4GHz intercom through glass window
Post by: Cailen Waddell on May 17, 2016, 07:50:34 am
Why not get the 900 MHz series?  Has a bit more range and goes through things better


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Title: Re: 2.4GHz intercom through glass window
Post by: Joseph D. Macry on May 17, 2016, 09:24:18 am
Why not get the 900 MHz series?  Has a bit more range and goes through things better

The Connex system is only available in 2.4GHz.
Got an opinion on 2.4 GHz through glass?
Title: Re: 2.4GHz intercom through glass window
Post by: Cailen Waddell on May 17, 2016, 09:58:04 am
The Connex system is only available in 2.4GHz.
Got an opinion on 2.4 GHz through glass?

Was thinking of tempest...

Same as above on 2.4 through glass.  Metallic tints are no good.  We have external antennas around the press box at our 10,000 seat stadium for this reason.  Without the window tint, we'd bake everyone in the room.
Title: Re: 2.4GHz intercom through glass window
Post by: Jason Glass on May 17, 2016, 10:53:47 am
Manufacturer says the antenna will not always work well through glass window, depending upon glass composition, thickness, tinting, etc.

Hi Joseph,

You could easily test the press box window attenuation @2.4GHz with a WIFI access point and a smart phone.

Set up a typical wireless access point and its antennas just outside of the press box.  If possible, set up its parameters to use a fixed RF output level.  Walk around the venue with your phone connected to the access point via WIFI and note the locations where the signal drops below usable levels.  You can also get free phone apps that read out the RF signal level in dB, which you could note at fixed points around the venue.

Set up the access point and its antennas just inside one of the press box windows and repeat the walk test.  Compare the walk test results between the two setups to determine the attenuation.
Title: Re: 2.4GHz intercom through glass window
Post by: Rob Spence on May 17, 2016, 11:43:56 am
If you have an I thing (iPad, iPhone ), the airport utility can be used to get good readings.


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Title: Re: 2.4GHz intercom through glass window
Post by: Joseph D. Macry on May 17, 2016, 12:19:39 pm
Here's a picture of the corner of the window glass. Wish I had a measure tape then, but it gives an idea of thickness by comparing to my dirty fingernails.
If there is tinting here, it sure is subtle. I think there is none.
You can see the bleachers outside the window.
Around these parts, they know to put the Press Box on the west side of the field. A: Your coaches, cameras and announcers are not facing into the sun. B: At least for early season games, the visitor team gets to sit on to hot, sunny side of the field. In August, this can be a game-changer.