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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 => LAB: The Classic Live Audio Board => Topic started by: Jason Glass on March 05, 2014, 02:17:48 PM

Title: FCC Chipping Away at The 2.4GHz Mic Spectrum
Post by: Jason Glass on March 05, 2014, 02:17:48 PM
It was inevitable with the "spectrum crunch" that the commission is grappling with.  The FCC has proposed allowing another service to share 10.5MHz of the 2.4GHz ISM band with WiFi, Bluetooth, your brand new mics, etc.  :(

http://www.commlawblog.com/2014/03/articles/unlicensed-operations-and-emer/fcc-proposal-intrudes-on-unlicensed-spectrum/ (http://www.commlawblog.com/2014/03/articles/unlicensed-operations-and-emer/fcc-proposal-intrudes-on-unlicensed-spectrum/)

(http://www.commlawblog.com/uploads/image/globalstar-ml%20chart-1.JPG)
Title: Re: FCC Chipping Away at The 2.4GHz Mic Spectrum
Post by: Cameron Stuckey on March 05, 2014, 03:19:56 PM
Looks like we all read the same blogs.

My understanding is that the FCC is considering allowing Globstar to utilize the adjacent 2.4GHz space to WIFI channel 11; Channel 14. Line6's XD line tunes through the full unlicensed ISM band and Q5X's control frequency exist in that channel but when compared to the utilization of Channels 1-11 it's empty. If you cannot guarantee a clean 20MHz channel for wireless mics in the 2.4GHz range I wouldn't recommend using them anyway.
Title: Re: FCC Chipping Away at The 2.4GHz Mic Spectrum
Post by: Don Boomer on March 06, 2014, 12:10:14 AM
Line6's XD line tunes through the full unlicensed ISM band

Actually only up through ch 11.  That keeps us legal worldwide
Title: Re: FCC Chipping Away at The 2.4GHz Mic Spectrum
Post by: Cameron Stuckey on March 06, 2014, 12:53:08 AM
Actually only up through ch 11.

I read off of page 29 in the XD-V75 User Manual that shows Frequency B for XD Channel 1, 2, and 4 within WIFI Channel 14. Have I misunderstood the operation of the system?
Title: Re: FCC Chipping Away at The 2.4GHz Mic Spectrum
Post by: Jason Glass on March 06, 2014, 06:58:50 PM
Actually only up through ch 11.  That keeps us legal worldwide

Hi Don,

That is good news!

My concern lies with the fact that channel 14 is not used for WiFi because the IEEE concluded that they need a self-imposed 10.5MHz guard band at the top of their spectrum to protect 802.11 protocol from adjacent-channel interference caused by satellite uplinks, and to protect adjacent licensed satlink channels from spurious 802.11 emissions.  Even Bluetooth stays a few MHz away.  The satellite guys got wise to this and now want to utilize the guard band for themselves.  Although the commission is considering an unprecedented lifting of the requirements that nonlicensed users do not interfere with licensed in the new adjacent band, physics will again force nonlicensed users down away from the new satlink frequencies to maintain their own robust performance.
Title: Re: FCC Chipping Away at The 2.4GHz Mic Spectrum
Post by: Don Boomer on March 06, 2014, 07:34:25 PM
Hey Cameron

Sorry, my bad.  We do go up to 2478.  But remember that's only one of the four carriers.  We don't need to collect all the data to create audio.