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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 => Wireless and Communications => Topic started by: Pete Erskine on November 23, 2016, 08:49:03 AM

Title: Freespeak fiber antenna splitter latency
Post by: Pete Erskine on November 23, 2016, 08:49:03 AM
On the Macys parade at 34th street we are using almost 40 Freespeak beltpacks.  20 on a 1.9GHz system and 20 on a 2.4GHz.  5 antennas for each line the street from mid block east to 6th avenue on a cat5 connected splitter.  The remaining 5 for each, are in the TV compound and up 6th avenue via a fiber connected splitter.

Initially with all antenna cable lengths at minimum, BP could roam from the stage on 34th street into the TV compound and up 6th ave.  However they could not go back...the BP stayed connected to the TV compound and the only way to get them back on the 34th st stage was to cycle power on the bp.

at first I adjusted the various antenna cable lengths as high as 300 M with no results.  I did notice that setting a fiber antenna at 1540 would evict it back to the stage.  I set all the fiber splitter antennas at 1000M and then they began to sync properly with the cat5 splitter.  The fiber conversion probably introduces a lot more latency than a cat5 cable would.

Notes from Clearcom:  We measured the sync/data latency in the lab and found no real difference between the new/old splitters and fiber/cat cabling just to isolate that from the equation.
Title: Re: Freespeak fiber antenna splitter latency
Post by: Riley Casey on November 23, 2016, 10:30:14 AM
Not really familiar with the Freespeak gear but this does make me curious about how the difference between copper and fiber translate to possible Dante issues.  Was the fiber conversion taking place in a dedicated Freespeak piece of hardware or some generic Ethernet switch with a fiber port?
Title: Re: Freespeak fiber antenna splitter latency
Post by: Mac Kerr on November 23, 2016, 11:20:12 AM
Not really familiar with the Freespeak gear but this does make me curious about how the difference between copper and fiber translate to possible Dante issues.  Was the fiber conversion taking place in a dedicated Freespeak piece of hardware or some generic Ethernet switch with a fiber port?

Freespeak antennas use a proprietary splitter. It is not RF over IP. It is still analog signals, just via light instead of EM signals, so latency can cause phase errors if not corrected for. Dante is digital, and the timing signal within Dante keeps everything in sync, so while overall latency can be greater, it does not impede the transmission.

Mac
Title: Re: Freespeak fiber antenna splitter latency
Post by: Pete Erskine on November 23, 2016, 02:55:37 PM
(currently) Freespeak antennas use a proprietary splitter. It is not RF over IP. It is still analog signals, just via light instead of EM signals, so latency can cause phase errors if not corrected for. Dante is digital, and the timing signal within Dante keeps everything in sync, so while overall latency can be greater, it does not impede the transmission.

Mac

CC announced that FSII antennas will soon be IP Based and will operate on a normal network with other data like Dante.  This will eliminate the need for a special splitter.  Not sure if the antennas themselves will be fiber but switches could be fiber while distributing to the antennas.
Title: Re: Freespeak fiber antenna splitter latency
Post by: Ross Goldman (2) on November 23, 2016, 03:49:23 PM
CC announced that FSII antennas will soon be IP Based and will operate on a normal network with other data like Dante.  This will eliminate the need for a special splitter.  Not sure if the antennas themselves will be fiber but switches could be fiber while distributing to the antennas.

Wow, that's great news. Is that a software update for existing transceivers, or new hardware?
Title: Re: Freespeak fiber antenna splitter latency
Post by: Pete Erskine on November 24, 2016, 03:27:44 AM
Wow, that's great news. Is that a software update for existing transceivers, or new hardware?

Don't know yet.
Title: Re: Freespeak fiber antenna splitter latency
Post by: brian maddox on November 30, 2016, 02:32:02 PM
CC announced that FSII antennas will soon be IP Based and will operate on a normal network with other data like Dante.  This will eliminate the need for a special splitter.  Not sure if the antennas themselves will be fiber but switches could be fiber while distributing to the antennas.

Best news i've heard all week.  I'll be watching for this....
Title: Re: Freespeak fiber antenna splitter latency
Post by: Chris Johnson [UK] on December 02, 2016, 05:40:56 AM
Wow, that's great news. Is that a software update for existing transceivers, or new hardware?

The latter, I believe.

I once did a gig with some loaner antennae from CC, and one of them had a POE jack...
Title: Re: Freespeak fiber antenna splitter latency
Post by: Pete Erskine on December 02, 2016, 09:28:29 AM
CC announced that FSII antennas will soon be IP Based and will operate on a normal network with other data like Dante.  This will eliminate the need for a special splitter.  Not sure if the antennas themselves will be fiber but switches could be fiber while distributing to the antennas.

Sorry for perpetuating a rumor.  This networkable antenna was hinted at at NAB/NYC by some salesman at CC and in reality, although it can be done, there is no plan currently to make the antennas IP networkable such that the antennas are all in sync.  There has always been notes in the manyal about extending an antenna over a network or fiber with certain limitations, namely that the remote antenna location is not a roaming connection and it is in another rv zone away from the other non networked antennas.

The fiber connection currently offered to the splitter has not only the ethernet E3 audio data but a 422 Sync pulse.  We have previously used 2 divverent media converters, 1 for E3 and 1 for 422 to extend the splitter.  Read more and see a video of the method on my  Freespeak page (http://www.bestaudio.com/helixnet/)


Title: Re: Freespeak fiber antenna splitter latency
Post by: brian maddox on December 02, 2016, 01:12:19 PM
Sorry for perpetuating a rumor.  This networkable antenna was hinted at at NAB/NYC by some salesman at CC and in reality, although it can be done, there is no plan currently to make the antennas IP networkable such that the antennas are all in sync.  There has always been notes in the manyal about extending an antenna over a network or fiber with certain limitations, namely that the remote antenna location is not a roaming connection and it is in another rv zone away from the other non networked antennas.

The fiber connection currently offered to the splitter has not only the ethernet E3 audio data but a 422 Sync pulse.  We have previously used 2 divverent media converters, 1 for E3 and 1 for 422 to extend the splitter.  Read more and see a video of the method on my  Freespeak page (http://www.bestaudio.com/helixnet/)

Well bummer, but thanks for the followup.

Just to make sure i fully understand this...  In this non networked scenario, a user could travel to the remote location and speak to folks in the local location,  but would need to 'resync' their beltpack to do so.  It would not just seamlessly move from one antenna to another?

And just to be really pedantic.  'resync' would mean a power cycle AND a change/reselection of BP Role?  Or just a power cycle?
Title: Re: Freespeak fiber antenna splitter latency
Post by: Pete Erskine on December 02, 2016, 01:25:10 PM
Well bummer, but thanks for the followup.

Just to make sure i fully understand this...  In this non networked scenario, a user could travel to the remote location and speak to folks in the local location,  but would need to 'resync' their beltpack to do so.  It would not just seamlessly move from one antenna to another?

And just to be really pedantic.  'resync' would mean a power cycle AND a change/reselection of BP Role?  Or just a power cycle?

Beltpack would loose connection and then reacquire it when in range of the other antennas.  If the remote antennas were in an overlapping area it might roam but probably would need a power cycle.
Title: Re: Freespeak fiber antenna splitter latency
Post by: brian maddox on December 02, 2016, 01:41:32 PM
Beltpack would loose connection and then reacquire it when in range of the other antennas.  If the remote antennas were in an overlapping area it might roam but probably would need a power cycle.

Gotcha.  So the real issue is if the asychronous antennas overlap.  That makes perfect sense.

Thanks for the info.