Radar rfi????

Shot news on a military base yesterday.
really bad audio....had this twanging sound throughout the audio. Its the sort of thing that occurs sometimes with wireless mics...but this was with all wired sure m58, sony lavs, tram lavs, wired Senn boom. Different mics different cables. i tried everything. even the camera mic had it.

Today I recalled the gig in palm springs where i couldn't get it out of my lectrosonic wireless mics, all three. Even the main conference stage where a panel of 8 speakers were all on wired lavs and they had it too. all wired lavs. This was the Lodge at RAncho Mirage.

Someone on a user board suggested that it was the radar from military or commercial airlines. They said Palm Springs is a seathing network of overamped radar. The same could be said of the military site i was shooting yesterday. Tons of communication presence.

Thus i'm thinking that the radar IS the culprit.

Have any of you experienced this before and what do you do to prevent it?

<<< even the camera mic had it. >>>

But it went away when you disconnected all the mics?

I always wondered why this doesn't happen more. There is a lot of stuff inside a CamCorder that runs at microwave frequencies.

The obvious choice is a Copper Faraday Shield over the camera while it's running, but failing that, Aluminum Foil will do. Wrap the camera with one long piece of foil leaving the lens sticking out and an opening for the mic cable.

I think ElectroVoice had plug-in microphone adapters that featured RF suppression inside.

Is all this fancy sound work done with full balanced XLR3 cables, or are you adapting down to 1/8"mini and going into the side of the camera. Balanced work tends to suppress a lot of this stuff, if you're running six or more feet of unbalanced mic cable (one conductor and shield), you're just begging for trouble.

There are serious magic things you can do with ferromagnetic beads around the mic wires, and .01uFd bypass caps, but those only work if the interference is coming down the cable. If it's coming through the CamCorder case, you have other problems.

How many different cameras has this happened to? I note you don't say in the post.

Koz

Darn, disconnecting the mics was the only alternative I didn't try. It was the "heat of battle" so to speak.... and I didn't have the guts to unplug everything!! during the shoot! Should have tried after the event.

Since writing the post, I've been told that the area where I shot on Sunday is covered in very intense wirless activity via military tx.

I also wondered if a full sized cam, i.e. betacam, betaSP, etc would have had better luck because of better shielding....but the Palm Springs rfi existed without cameras (the large venue with the 8 wired lavs).
I have only experienced this rfi using Sony PD150's and 170's. I'm currently attempting to contact other shooters who have worked the same military area with BetaSp cams.

BTW, all audio is XLR3.

I'm curious about these filters, etc.

Thanks for the comments.