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[Steve Bunting]

Here's some observations that I've made recently, that maybe useful to someone, or is common knowledge, but has never come up in my world as a problem before. I've been having problems with an SD7 giving off quite a lot of RF energy. Looking back, it probably has affected me before and I haven't looked into it enough to ascertain what the problem was specifically.

The problem came about by cue pack interference, and a general dissatisfaction with the performance of my RF system which I couldn't put my finger on. It wasn't terrible, just not as good as I would expect. The output is repeatable and stable, the same on 2 different SD7s. Having spoken to DiGiCo about it, the console itself is within FCC part 15 emissions specs and completely without fault.

I have got around this by using the scan to generate exclusions and factor it into the co-ordination. Also by moving my antennas further away from the console.

Here is a scan of the background spectrum and the console spectrum. It is worse case, the scan was taken sitting on the fader bank. I also took a scan of an SD10, but it is much reduced, presumably due to fewer screens and fewer internal high-speed data flows.

[Jordan Wolf]

Here's some observations that I've made recently...

Interesting! I know I've seen hash from bad SDI and unshielded network connections. Guess I have some more things to consider measuring now.

[Pete Erskine]

Here is a scan of the background spectrum and the console spectrum. It is worse case, the scan was taken sitting on the fader bank. I also took a scan of an SD10, but it is much reduced, presumably due to fewer screens and fewer internal high-speed data flows.

I also have seen rfi from digital console engines.  Some with strong peaks as well as BG RFI

[Dan Currie]

How far away were the measurements taken from?  I have seen some a little bit of hash in the vhf range with Digico but nothing uhf.

[Pete Erskine]

How far away were the measurements taken from?  I have seen some a little bit of hash in the vhf range with Digico but nothing uhf.

RFI extended 10' from console.  Had to move wireless mic RX further away.

[Luke Geis]

You can get RF noise from HDMI as well. I am not surprised really. The mixers these days technically are computers and video devices with hardware controls. 

[Steve Bunting]

How far away were the measurements taken from?  I have seen some a little bit of hash in the vhf range with Digico but nothing uhf.

My measurements were taken with the scanner sitting on the console, so were worst case, but they do extend around 3-5m from the console.

[Ike Zimbel]

My measurements were taken with the scanner sitting on the console, so were worst case, but they do extend around 3-5m from the console.

Interesting stuff, Steve. One question: By "console" we are talking about the control surface, yes? Have you taken any measurements around the engines?

[Steve Bunting]

Interesting stuff, Steve. One question: By "console" we are talking about the control surface, yes? Have you taken any measurements around the engines?

Yes, the scanner was sitting on the fader bay of the control surface. As the engines for the SD7 are internal to the console, we did some troubleshooting by removing each engine and the RFI was reduced with each engine we took out. However, with no engines in the console, there was still significant, but reduced, emissions. We also tested each of the PSUs individually but there were of no consequence.

I have not tested the SD-Rack specifically, but in our situation, where it is underneath the console, turning the console off while leaving the SD-Rack on caused such a huge drop in emissions that I would not suspect it to be a significant contributor. I could test it if I get time tomorrow though.

[Ike Zimbel]

Yes, the scanner was sitting on the fader bay of the control surface. As the engines for the SD7 are internal to the console, we did some troubleshooting by removing each engine and the RFI was reduced with each engine we took out. However, with no engines in the console, there was still significant, but reduced, emissions. We also tested each of the PSUs individually but there were of no consequence.

I have not tested the SD-Rack specifically, but in our situation, where it is underneath the console, turning the console off while leaving the SD-Rack on caused such a huge drop in emissions that I would not suspect it to be a significant contributor. I could test it if I get time tomorrow though.

Well, I'll know soon enough. On my next adventure, my RF gear is sharing a double-wide rack with a pair of Digico 192 KHz engines

[ProSoundWeb Community]