Simple (I hope) question re wireless systems

[Jim Andrada]

@Chris

I don't worry too much about not seeing what still I've shot on the display - I mostly use film:<) Large film at that (and so does Greg - we're both on the Large Format Photography Forum!) and don't actually see the result for days to weeks. Digital for video, film for pictures (although I do have an original Canon 5D as well)

It's great fun when I'm out with a group and ask the waiter/waitress to take a photo and hand them a 4 x 5 Graphic with a huge flash gun (flashbulbs) The reactions can be priceless. I've seen people stare at the back of the camera looking for the display!

[Paul R Johnson]

Originally Posted by Greg Miller

I've never performed a scientific test of this (thank God) but I suspect that the effect of surface sweat is minuscule compared to the effect of all the salt water contained inside the body. After all, we are not placing two conductive electrodes in electrical contact with the surface sweat. The effect here is one of absorption of the electromagnetic field radiated by the [insulated] antenna.

I too have seen no data on the effect of sweat, but in practical terms, sweaty people increase the nulls. I can't say it's the salt content and could just be the water, but so undies in theatre try all sorts of things to get the packs away from them. The linen bags most of us use to attach them get pretty nasty on the sweaty people, and one. Olleague swears by sandwich bags with the pack in tucked inside the pouch.

Design wise I suspect the output tuning is always less than optimum. Very little point aligning for optimum when the aerial system is rarely going to be close to 1 to 1.

Too many people simply try to run systems with tx and rx too far apart, expecting too much. After saying all this, the odd thing is that I have never had a dropout with my digital systems in the same space my G3s do occasionally have problems with.

[Steve House]

Originally Posted by Jim Andrada

@Chris

I...

It's great fun when I'm out with a group and ask the waiter/waitress to take a photo and hand them a 4 x 5 Graphic with a huge flash gun (flashbulbs) The reactions can be priceless. I've seen people stare at the back of the camera looking for the display!

Images of Weegee at work or the opening of the old Bob Cummings TV show flashing in my head

[John Willett]

Originally Posted by Chris Harding

I'm certainly no audio engineer but I have noticed the I get better performance if the antennas are in free air ..

This is essential - if an antenna touches the body you can get about 70dB of signal attenuation.

Getting the antenna just 1cm off the body will give you back most of this, with just minimal attenuation.

This is why transmitters are often put on with the antenna facing down, to get it away from the body.

[Greg Miller]

Originally Posted by Jim Andrada

I've seen people stare at the back of the camera looking for the display!

That won't work too well once the sheet film holder has been slid into place.

Maybe someone should make an app that rotates the image on a cellphone display by 180º to simulate using a cut film camera. At the very least it would drive most people crazy.

[Jim Andrada]

Progress report - declaration of success!

I had the good folks at Markertek make up a cable to go from XLR to the input of the AT System 10 transmitter, and got a Switchcraft box to take the 1/8 stereo Tape Out of the 702 to Balanced Mono XLR.

Started something playing on my monitors, hooked the mics up to the 702 and Tape Out to the transmitter via the Switchcraft box and the Markertek cable, and Voila!!! I have a nice clean track 100 feet away without running cable.

Remembering that all I'm looking for is a sync track to three balcony cameras, I think it will work. We'll see how it goes 6/6 at the concert. (And just in case I'll use the clapper board before the show starts.)

By the way, I'll take the output from the receiver into a Motu interface and distribute it to all the cams, so I only need a single wireless channel

[Jim Andrada]

Just reporting back on results

I recorded a 2 hour concert today. The System 10 worked flawlessly and I never heard a dropout or a Snap Crackle or Pop. It just worked

[Chris Harding]

Great Jim

It's my next purchase for the new wedding season without a doubt! I'm treading on dangerous ground using my UHF units on frequencies that have been re-allocated ...very soon I will get a digital radio station coming thru load and clear instead of bridal vows!!

Chris

[Paul R Johnson]

Jim - never fall into the mind set that a system is bomb proof. None of them are. They all work brilliantly until they don't. Location is critical. When I used to do theatrical touring shows, we'd have the same system every night, in similar capacity venues - usually 800-1500 seat size. One night all would be perfect, the next night, pops, hisses, warbling sounds, major dead spots. The best you can do is mount aerials in the clear - split receive aerials apart if possible, and cross your fingers. I suspect that if we could see RF (like Geordie in Star Trek) we could solve many problems instantly, but all solutions or reductions in severity are down to experience and witchcraft!

[Jim Andrada]

I was pretty happy with the way it all worked - up to the point where SOMEONE seated near the 702 managed to switch it off mid-concert! I've never had anything remotely like that happen. I always have someone guarding the recorder, but yesterday I was REALLY all by myself. I usually have a backup mic/recorder set running but of course this was the day the janitor didn't open the hall until 30 minutes before the start of the program and I barely had enough time to get one pair of mics in place before the doors opened - I was still cabling things together as people started coming down the aisles.

One of the orchestra members had a recorder running so we'll have at least SOME audio for the whole concert.

All things considered, I'm more worried about something like this than a few dropouts in a sync track.

[Jay Massengill]

Did they inadvertently knock the power loose or did they literally switch it off? If the latter, that's pretty astounding... Perhaps the ultra-bright Sound Devices LED's made them go temporarily insane!

[Jim Andrada]

Well - when I saw it was off I just hit the power button and it woke up so power wasn't an issue - it was running on battery and the battery looks good for another hour or more. CF card had enough room for a couple of more concerts left so it wasn't the card filling up.

The 702 is pretty well designed to protect against truly inadvertent on-off button pushes - you have to want to power it off to make it stop. Haven't updated firmware recently and I've used the recorder for enough years to trust it. I "always" mount a Sony PCM D50 on the mic stand "just in case" but the thundering herd was on me before I could get it set up.

Could it have been a glitch of some kind? Of course, anything is possible. But, statistically, why would a glitch hit precisely in the applause between two pieces instead of in the middle of a piece. Sort of like dropping a dime and having it land in the crack between two sections of pavement. Possible, yes, likely, no.

The final file is only 1.3GB so it wouldn't have been trying to do a file "split"

It's a mystery.

One thing I know for sure is that I need more than 30 minutes between the doors being unlocked and the "start of festivities." They keep adding new events before the main concert - like a children's 30 minute concert and most recently an instrumental "petting zoo" for the kiddies. Nice idea - they have a bunch of players with their instruments and the kids are encouraged to touch, blow, whatever. The Timpani were the most popular because 4 year-olds like to make noise. I think it's actually a really good idea, but it's impossible to set up when a horde of kiddies and parents is milling around underfoot right where the mics need to be placed.