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RF signature [message #321092]

Fri, 09 May 2008 00:04

Steve Weiss
Messages: 342
Registered: July 2004
Location: Las Vegas

Has No Life

RF signature

1. what does that term mean exactly?

2. How do we measure it?

Thanks

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Re: RF signature [message #321100 is a reply to message #321092 ]

Fri, 09 May 2008 00:38

Michael 'Bink' Knowles
Messages: 3861
Registered: April 2004
Location: Oakland, CA

Has No Life

Steve Weiss wrote on Thu, 08 May 2008 22:04

RF signature

1. what does that term mean exactly?

2. How do we measure it?

Thanks

I can think of five meanings for "RF signature":

1: General shape and characteristics of the RF output of a device that transmits RF. An analog wireless microphone would have a large spike at one frequency and then some small bumps at specific steps on either side. Measured with an RF spectrograph.

2: General shape and characteristic of the RF status of a location that has multiple RF sources. For instance, a city has RF spikes and mesas and noise in a complex changing pattern that varies over time and by specific location. Measured with an RF spectrograph over a number of time periods.

3: Radar return signal. An aircraft can be said to have an RF signature on a radar screen.

4: RFID. An identification scheme using a microchip transponder to return a unique data packet when polled. Needs an RFID reader.

5: Coded packet sent over RF along with main RF message. Needs a decoder of some sort.

Good luck!

-Bink

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Re: RF signature [message #321101 is a reply to message #321100 ]

Fri, 09 May 2008 00:41

Steve Weiss
Messages: 342
Registered: July 2004
Location: Las Vegas

Has No Life

The question was posed to me by the LCS guys. Seems we have had some dodgey faders. They are searching for every answer but the simple one of maybe there are some bad apples. So the question was do we know the Operational RF signature of the theatre? Well hell there is a buttload of RF flying through this joint.

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Re: RF signature [message #321122 is a reply to message #321100 ]

Fri, 09 May 2008 05:45

Henry Cohen
Messages: 644
Registered: January 2006
Location: Westchester Co., NY

Has No Life

Michael 'Bink' Knowles wrote on Fri, 09 May 2008 01:38

Steve Weiss wrote on Thu, 08 May 2008 22:04

RF signature

1. what does that term mean exactly?

2. How do we measure it?

"RF Signature" can also refer to the unique transmission characteristics of an individual transmitter, analogous to a fingerprint. Measured with a highly sensitive network vector spectrum analyzer.

Quote:

2: General shape and characteristic of the RF status of a location that has multiple RF sources. For instance, a city has RF spikes and mesas and noise in a complex changing pattern that varies over time and by specific location. Measured with an RF spectrograph over a number of time periods.

AKA 'RF environment', and which I suspect the original inquiry intended.

Henry Cohen
Production Radio Rentals
----------------------------------
"Every new [intentional] radio emitter since Marconi’s 2nd transmitter has caused interference to other systems!" - Michael Marcus, Oct '07

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Re: RF signature [message #321180 is a reply to message #321101 ]

Fri, 09 May 2008 11:23

Charlie Zureki
Messages: 266
Registered: April 2008
Location: Detroit Area

Has No Life

As Harry stated they're looking for RF that's possibly interfering with their equipment. Tell them to get a spectrum analyzer and sweep for peaks. If they're getting interferance through the faders... they're probably worn with a lot of slop.
Old Equipment?
It's most likely a problem with their wireless mics.

Hammer

Be prepared, you'll need it!

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Re: RF signature [message #321201 is a reply to message #321180 ]

Fri, 09 May 2008 12:11

Steve Weiss
Messages: 342
Registered: July 2004
Location: Las Vegas

Has No Life

No wireless mics.We do have a ton of wireless com.

The gear is brand new. Except these are the same brand faders, made by Alps, that is in the Pm1D. We have had every fader in our less than 1 year old PM1D replaced because they were bad. Both the LCS faders and Yamaha faders had the same issue. SLOP. Just seems like a bad batch from the factory.

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Re: RF signature [message #321206 is a reply to message #321201 ]

Fri, 09 May 2008 12:15

Charlie Zureki
Messages: 266
Registered: April 2008
Location: Detroit Area

Has No Life

Steve,
I remember having problems some years ago with a Mic Cable picking up a Fire Dept. Radio.

What are you picking up?

Hammer

Be prepared, you'll need it!

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Re: RF signature [message #321227 is a reply to message #321206 ]

Fri, 09 May 2008 13:01

Mac Kerr
Messages: 5806
Registered: April 2004
Location: Westchester County, NY

Has No Life

Charlie Zureki wrote on Fri, 09 May 2008 13:15

Steve,
I remember having problems some years ago with a Mic Cable picking up a Fire Dept. Radio.

What are you picking up?

Hammer

I don't think they are picking up anything. The faders in an LCS Cue Console, as well as in a PM1D, are digital encoders. There is no audio in them. I think the problem is that the motorized faders are misbehaving.

Mac

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Re: RF signature [message #321273 is a reply to message #321227 ]

Fri, 09 May 2008 15:20

Steve Weiss
Messages: 342
Registered: July 2004
Location: Las Vegas

Has No Life

Bingo Mac.

When the 1D faders were pulled the belt was sort of stretched. It had a bulge in it at the point where the down position would be. Like it had been stored that way for years. The LCS faders showed the same except they had a bulge at the unity point. The faders behaved by moving without being touched. I have heard some similar reports from a company in Nashville of M7 faders doing it as well.

I should revisit the thread about the 1D faders and post the pics. I just need to find them now.

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