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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 October 08, 2016, 04:02:38 pm

Title: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Pete Erskine on October 08, 2016, 04:02:38 pm
We are using Shure ULXD VHF wireless for Pre show at the debates.  While the mics were off. we noticed that there was another carrier on the P1 mic at its freq of 196.6mHz.  Called Henry to come and track down the offender and he discovered it was strongest when near the Digico Mix engines.....

We moved.....
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Jens Palm Bacher on October 08, 2016, 07:39:21 pm
We are using Shure ULXD VHF wireless for Pre show at the debates.  While the mics were off. we noticed that there was another carrier on the P1 mic at its freq of 196.6mHz.  Called Henry to come and track down the offender and he discovered it was strongest when near the Digico Mix engines.....

We moved.....
Digico's can't run 192kHz, only 48 and 96 kHz :-)
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Henry Cohen on October 09, 2016, 09:22:00 am
We are using Shure ULXD VHF wireless for Pre show at the debates.  While the mics were off. we noticed that there was another carrier on the P1 mic at its freq of 196.6mHz.  Called Henry to come and track down the offender and he discovered it was strongest when near the Digico Mix engines.....

We moved.....

The more exact frequency turned out to be 196.605MHz, which I then found is a common spur from a lot of digital equipment.
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Pete Erskine on October 09, 2016, 09:36:53 am
Digico's can't run 192kHz, only 48 and 96 kHz :-)


What I said was the NAME of the console is Digico 192 kHz
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Ike Zimbel on October 09, 2016, 11:32:45 am
The more exact frequency turned out to be 196.605MHz, which I then found is a common spur from a lot of digital equipment.
Hmmm...sounds like that might be worth plugging into a coordination before allocating any VHF gear. I hear this digital stuff is popular... :P
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Diogo Nunes Pereira on October 09, 2016, 04:18:33 pm
We are using Shure ULXD VHF wireless for Pre show at the debates. 

So the VHF band systems are out already?

Can't seem to find any info on band name in Shure website... WWB version 6.11 doesn't seem to be able to coordinate nothing below 470MHz.

Cheers,

D
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Pete Erskine on October 09, 2016, 04:59:53 pm
So the VHF band systems are out already?

Can't seem to find any info on band name in Shure website... WWB version 6.11 doesn't seem to be able to coordinate nothing below 470MHz.

Cheers,

D

WWB ver 12 soon to come.....
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Riley Casey on October 09, 2016, 05:46:13 pm
8 db above the noise floor, tsk,tsk.  How close did you have to get to the engine to get that reading?  I'd be curious to see what a high voltage class D amp like a Lab Gruppen looks like on your scanner.
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Henry Cohen on October 09, 2016, 05:52:38 pm
So the VHF band systems are out already?

Can't seem to find any info on band name in Shure website... WWB version 6.11 doesn't seem to be able to coordinate nothing below 470MHz.

Lectrosonics VHF IFB
RAD intercom
And there are a number of beta ULXD VHF units in the wild, one of which is on our little tour.
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Henry Cohen on October 09, 2016, 05:54:36 pm
8 db above the noise floor, tsk,tsk.  How close did you have to get to the engine to get that reading?  I'd be curious to see what a high voltage class D amp like a Lab Gruppen looks like on your scanner.

Pete's antenna is about 10' above and over from the front of the Digico rack. When I did near field measurements I could get -70dBm about a foot away from the rear of the engine.
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Jason Glass on October 09, 2016, 11:44:42 pm
Pete's antenna is about 10' above and over from the front of the Digico rack. When I did near field measurements I could get -70dBm about a foot away from the rear of the engine.

Ouch.  Perhaps it might be a good idea for RF guys to start instituting a "Clock LO" zone with a 192.605 assignment in our advance coordinations.  Hmm.  Henry, Pete, Ike, and Vinny, what do you think?
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Henry Cohen on October 10, 2016, 11:55:40 am
Ouch.  Perhaps it might be a good idea for RF guys to start instituting a "Clock LO" zone with a 196.605 assignment in our advance coordinations.  Hmm.  Henry, Pete, Ike, and Vinny, what do you think?

I always have at least an "NFG" zone and many times a zone for house/venue and/or video wall spurs.
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Pete Erskine on October 10, 2016, 10:34:19 pm
Digico's can't run 192kHz, only 48 and 96 kHz :-)

It will run at 192kHz although for the life of me I can't imagine why you would want to.
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Neil White on October 11, 2016, 01:46:11 am
It will run at 192kHz although for the life of me I can't imagine why you would want to.

It's interesting that this is in the Digico Sd-Rack for I/O. It is very common for us to have a large quantity of these (sometimes 8+) all located together with our active splits and RF world on our biggest shows. I assume there would be a cumulative effect for multiple racks. Is the same spur also measurable near the actual processing engine in the surface of the consoles?
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Ike Zimbel on October 11, 2016, 08:20:44 pm
Ouch.  Perhaps it might be a good idea for RF guys to start instituting a "Clock LO" zone with a 192.605 assignment in our advance coordinations.  Hmm.  Henry, Pete, Ike, and Vinny, what do you think?
I'm in. Absolutely...going into my next coord. It's worth it just to keep a RadCom belt pack from ending up on that frequency.
iz
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Jens Palm Bacher on October 13, 2016, 03:03:05 pm
It's interesting that this is in the Digico Sd-Rack for I/O. It is very common for us to have a large quantity of these (sometimes 8+) all located together with our active splits and RF world on our biggest shows. I assume there would be a cumulative effect for multiple racks. Is the same spur also measurable near the actual processing engine in the surface of the consoles?
As long as your performers and receive antennas are not there, i would not worry too much. Compared to LED/movinhead emission on the stage itself, this is a very minor issue in my experience.
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Ike Zimbel on November 02, 2016, 10:31:31 am
I'm in. Absolutely...going into my next coord. It's worth it just to keep a RadCom belt pack from ending up on that frequency.
iz
Further to this: I took some measurements on my most recent show, and this signal is definitely present around the processing engines. I measured the DigiDesign stage and FOH racks and a Calrec Hydra i/o. Can't remember if I got close enough to the Yamaha traffic mixer (a 5D, I think) to measure it or not. It's definitely there, even if I had to go looking for it with a high gain antenna and my TTI gain wide-open. One thing that I checked, and this is very good news, is that it's NOT coming from switch-mode power supplies. I would say that this is a very low level source of potential interference.
That said, for the time it takes to plug in as an "avoid" frequency in a coordination it's worth doing. Easier to avoid it than spend the time chasing it on a job.
Title: Re: Digico 192 kHz console causing 192.6mHz carrier.
Post by: Keith Broughton on November 02, 2016, 11:39:04 am
Good to know.
Thanks for the confirmation test Ike :)