- Posts: 334
- Joined: Tue Sep 26, 2017 10:13 am
- Location: Norway
I found out something new yesterday. As part of most mini-rigs I've been a part of building (4-12U), we've put in an Apple Airport Express to do service as a router to interface with the local LAN/WAN on location. In one of these rigs, we've been getting reports of blinking inputs during production, and so we thought "oh, are they using too long/bad cables, are they using cheap cameras with bad SDI outputs, +++", the whole spiel.
Every component of the system checked out fine individually though, including having BMD check out the switcher and us verifying the cables with a known good system.
After some serious fault finding when the system finally ended up in our hands, it seems the issue is related to the use of fairly long (but within spec!) cables, and keeping the Apple Airport too close to the mixer.
Typical symptoms are heavy blinking of an input signal and popping and peaking on the audio line of that input, in time with Wi-Fi usage. Connecting a new laptop to the wifi, for instance, made the blinking occur extremely often.
We pulled power to every unit in the rack individually, and when the Airport was out, the signal became rock solid. As such, I guess the added EMI of Wi-Fi decreased the noise margin of the input chips to be just too bad.
Just a hint for the other system integrators out there
We're also doing this in several systems with an old 1M/E, where we've registered no problems, so I guess this is more apparent in the newer units.
Every component of the system checked out fine individually though, including having BMD check out the switcher and us verifying the cables with a known good system.
After some serious fault finding when the system finally ended up in our hands, it seems the issue is related to the use of fairly long (but within spec!) cables, and keeping the Apple Airport too close to the mixer.
Typical symptoms are heavy blinking of an input signal and popping and peaking on the audio line of that input, in time with Wi-Fi usage. Connecting a new laptop to the wifi, for instance, made the blinking occur extremely often.
We pulled power to every unit in the rack individually, and when the Airport was out, the signal became rock solid. As such, I guess the added EMI of Wi-Fi decreased the noise margin of the input chips to be just too bad.
Just a hint for the other system integrators out there
We're also doing this in several systems with an old 1M/E, where we've registered no problems, so I guess this is more apparent in the newer units.