Live Sound & Production

[Tomm Williams]

An opportunity has presented itself to start renting wireless units for theatre. I've picked up several AT 2000 and 3000 series units in preparation. AT has a pretty nice set of articles concerning succesfull use of wireless gear that I've learned a lot from. However, a few questions have popped up as I have seen (or heard from reliable sources) of folks doing much the opposite of AT's suggestions, and doing just fine.

1--Casing the receivers. AT speaks about the problems of the metal parts of the case causing interference issues. I can't see these things NOT being in a case, they wouldn't last a minute as a rental. 

2--Touching or parrallel antenna causing interference. I can see touching being a problem but if you have a stack of 4-6 of these units, how should the all the antennas be pointed?

3--What is the suggested span of frequency seperation from unit to unit? at one point they suggest 1 mhz and then show a chart that (in some cases) is only 500 khz.

4--Antenna splitters--------------is there such a thing as a "generic" splitter or do I have to use an AT product? I know they are frequency-range specific but are there other issues at stake?     

Any other pearls of wisdom are welcome

[RoadRanger]

Spacing is more complicated than that - start here:

http://ff.audiotechnica.com/cgi-bin/tvfreqcheck/tvfreqcheck2.cgi

[Tomm Williams]

Yeah, I saw that chart and ran some samples. That is partly where I'm getting the confusion. I see suggested multiple channels that are closer than 1mhz

[RoadRanger]

Maybe read and understand this too:

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.167.5478&rep=rep1&type=pdf

If you are running more than a couple wireless mics you need to understand intermod and why the frequencies are spaced the way they are.

[agedhorse]

If you use an antenna combining amplifier (or distribution amp) and a proper remote located antenna, it not a problem at all. I do this all the time, and many (most) pro providers have figured out how to make this work well.

IF you are trying to poor boy it, without usinjg the proper tools then yes, there can be problems.

[Tomm Williams]

Concerning the antenna distributer, must I use an AT or if I come across another maker rated for the same frequency range, would that work as well?

[agedhorse]

I prefer to stick with the same manufacturer, in part because of the integrated power distribution that they provide. I haven't tried it, but shure and AT use the same power supply scheme so provided the rf bandwidth was the same they should work ok. Disclaimer.... Not tested