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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Rick Scofield on March 06, 2014, 02:31:52 PM

Title: Best Practice for antenna separation btwn Rx & Tx (IEM and MICs in same rack
Post by: Rick Scofield on March 06, 2014, 02:31:52 PM
I'm putting together a small wireless rack with two Sennheiser IEM transmitters and one mic reciever.

I know that there should be separation between the two sets of antennae(?) and could use some advice.

I currently have a 2 RU rack with one IEM transmitter and one Mic reciever mounted side-by-side, along with a rack panel with inputs/outputs, antennas and powercon. 

I'm getting one additional IEM transmitter, and would like to incorporate the new unit into the existing rack, adding two more inputs etc, but not sure if that's feasible/desireable.

Mic transmitter comes with 2 antennas, and each IEM transmitter has one.  I don't think I need to go with a combiner at this point, but I am interested in your experience.

Thanks,

Rick
Title: Re: Best Practice for antenna separation btwn Rx & Tx (IEM and MICs in same rack
Post by: Steve Alves on March 06, 2014, 03:18:48 PM
Similar setup, I am using two Shure SLX Mics and Three Sennheiser G3 ears with a combiner. I purchased an external paddle for the ears that I usually put about 10 feet from the rack.
Title: Re: Best Practice for antenna separation btwn Rx & Tx (IEM and MICs in same rack
Post by: Tim McCulloch on March 06, 2014, 06:38:57 PM
I'm putting together a small wireless rack with two Sennheiser IEM transmitters and one mic reciever.

I know that there should be separation between the two sets of antennae(?) and could use some advice.

I currently have a 2 RU rack with one IEM transmitter and one Mic reciever mounted side-by-side, along with a rack panel with inputs/outputs, antennas and powercon. 

I'm getting one additional IEM transmitter, and would like to incorporate the new unit into the existing rack, adding two more inputs etc, but not sure if that's feasible/desireable.

Mic transmitter comes with 2 antennas, and each IEM transmitter has one.  I don't think I need to go with a combiner at this point, but I am interested in your experience.

Thanks,

Rick

4 meters between TX and RX.
Title: Re: Best Practice for antenna separation btwn Rx & Tx (IEM and MICs in same rack
Post by: Jerome Malsack on March 06, 2014, 07:42:57 PM
So Tim, 

To add some clarification, He is adding a second transiting antenna so should this be

TX  4m  RX   4m  TX.   

having two 4 meter cables one to each side keeps them short as possible and provide the distribution.
Title: Re: Best Practice for antenna separation btwn Rx & Tx (IEM and MICs in same rack
Post by: Cameron Stuckey on March 06, 2014, 07:53:10 PM
TX  4m  RX   4m  TX
TXTX 4m RX 4m RX is the ideal solution in my opinion. You want your diversity receive antennas to be separated from each other and to both be separated from your transmit antennas. To add, directional antennas will be superior to omnis and spacing out your mic and IEMs frequency wise is a good idea. Ideally there is zero overlap between the two ranges and your antennas are physically separated.
Title: Re: Best Practice for antenna separation btwn Rx & Tx (IEM and MICs in same rack
Post by: Lyle Williams on March 07, 2014, 05:24:49 AM
If it were me, I'd try and work my tx and rx in different bands.

Make sure your tx and rx are well grounded together.

FM is pretty forgiving.
Title: Re: Best Practice for antenna separation btwn Rx & Tx (IEM and MICs in same rack
Post by: Rick Scofield on March 07, 2014, 11:33:09 AM
A little clarification.  I'm talking about a small rack that will be located on-stage with the performers, that will have Two IEM transmitters and One Mic reciever.  Performers will be no more than 20 feet from the rack, and expected to have decent placement of IEM bodypacks.  Small <20'x20' stages in small <150 punters halls/bars etc.

I know I asked for "Best Practices", but I guess I'm hoping that there's a way to rack these 3 devices together and have the four total antennas attached to the rack.   4 meters of separation would put one of those antennas out in the trailer in some of these places... ;)
Title: Re: Best Practice for antenna separation btwn Rx & Tx (IEM and MICs in same rack
Post by: Andrew Makinson on March 07, 2014, 01:04:45 PM
A little clarification.  I'm talking about a small rack that will be located on-stage with the performers, that will have Two IEM transmitters and One Mic reciever.  Performers will be no more than 20 feet from the rack, and expected to have decent placement of IEM bodypacks.  Small <20'x20' stages in small <150 punters halls/bars etc.

I know I asked for "Best Practices", but I guess I'm hoping that there's a way to rack these 3 devices together and have the four total antennas attached to the rack.   4 meters of separation would put one of those antennas out in the trailer in some of these places... ;)

Rick, Not best practice, but I've been happy running my 9 wireless mics and 4 wireless IEMs (5 antennas total) all in one rack for the past 2 years.  The rack sits at FOH about 50' from the stage typically.  My mic antennas have about 6' of separation (it's a big custom case...), but my IEM antenna is about 6" from one if the mic antennas.  I am using LPDA antennas.
--Andrew
Title: Re: Best Practice for antenna separation btwn Rx & Tx (IEM and MICs in same rack
Post by: Cameron Stuckey on March 07, 2014, 01:11:52 PM
I know I asked for "Best Practices", but I guess I'm hoping that there's a way to rack these 3 devices together and have the four total antennas attached to the rack.   4 meters of separation would put one of those antennas out in the trailer in some of these places... ;)

Fair enough. But that's not asking for best practices, that's asking for cheats. Nothing wrong with that either, but let's be real about the limitations. Having both transmitters and receivers in the same rack using only the provided whips will be doable but not recommended. Like mentioned before, try to make sure that your two ranges are as far apart as possible for both the racked gear and the body packs. Try to separate the TX frequencies from the RX frequencies as much as your location will allow, and have your IEM transmitters at their lowest useable transmitting power setting.