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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 => Wireless and Communications => Topic started by: Stephen Swaffer on November 10, 2017, 12:49:27 PM

Title: Basic antenna distribution
Post by: Stephen Swaffer on November 10, 2017, 12:49:27 PM
I'v e read several thread about antenna distribution but I have a couple of outstanding questions-this is completely new territory for me.

I am using 6 Shure SLX systems in the J3 band.  We also have 5 Line 6 on 2.4 Ghz-along with a router in the media booth.  Not really worried aboout the Line 6's and the router-they seem to be playing well.  The Shure's work better than I have a right to expect given our rather ugly RF setup.  Our booth is a purpose built corner balcony in an old (1860's) brick building.  It is stick built-plywood and lumber with the floor about 10' above the main floor.  My thought is to mount antenna's under the floor on the ceiling below-should be about 50' line of sight to platform with no obstructions.

The Shure UA844 says I can do 5 (or is it just 4?) receivers.  What do I do about 5 & 6?  Do I spring for another amp?  Can I just run 5 and a second pair of antenns for #6?  If so, what kind of separation do I need for these antennas?  The booth is about 22' wide-how far would you spread the antenna's-do I need to be concerned about proximity to the brick walls on either end? 

The main problem I currently have is an occasional very brief drop out-almost sounds like a bad cable but it is persisting an a complete separate system (different rx/tx/mic).  Usually right handed speakers wear the belt pack on their right putting their body between rx and tx antennas.  I think that is the main problem-or I could just be hearing things :).
Title: Re: Basic antenna distribution
Post by: Keith Broughton on November 10, 2017, 02:36:42 PM
I'v e read several thread about antenna distribution but I have a couple of outstanding questions-this is completely new territory for me.

I am using 6 Shure SLX systems in the J3 band.  We also have 5 Line 6 on 2.4 Ghz-along with a router in the media booth.  Not really worried aboout the Line 6's and the router-they seem to be playing well.  The Shure's work better than I have a right to expect given our rather ugly RF setup.  Our booth is a purpose built corner balcony in an old (1860's) brick building.  It is stick built-plywood and lumber with the floor about 10' above the main floor.  My thought is to mount antenna's under the floor on the ceiling below-should be about 50' line of sight to platform with no obstructions.

The Shure UA844 says I can do 5 (or is it just 4?) receivers.  What do I do about 5 & 6?  Do I spring for another amp?  Can I just run 5 and a second pair of antenns for #6?  If so, what kind of separation do I need for these antennas?  The booth is about 22' wide-how far would you spread the antenna's-do I need to be concerned about proximity to the brick walls on either end? 

The main problem I currently have is an occasional very brief drop out-almost sounds like a bad cable but it is persisting an a complete separate system (different rx/tx/mic).  Usually right handed speakers wear the belt pack on their right putting their body between rx and tx antennas.  I think that is the main problem-or I could just be hearing things :).

The RF Venue DISTRO4 can connect to 4 receivers and has a "cascade" ports that (I think) you could connect to  passive (RF Venue 2X1SPLIT) splitters for the last 2 receivers.
There will be some loss in that passive split but at 50' to the transmitters, may not pose an issue with the use of "paddle" antennas.
Others will chime in, I'm sure.
You could contact RF Venue for advice.

Tel: 800.795.0817
Email: [email protected]
Title: Re: Basic antenna distribution
Post by: Jean-Pierre Coetzee on November 10, 2017, 02:53:36 PM
The RF Venue DISTRO4 can connect to 4 receivers and has a "cascade" ports that (I think) you could connect to  passive (RF Venue 2X1SPLIT) splitters for the last 2 receivers.
There will be some loss in that passive split but at 50' to the transmitters, may not pose an issue with the use of "paddle" antennas.
Others will chime in, I'm sure.
You could contact RF Venue for advice.

Tel: 800.795.0817
Email: [email protected]
This pretty much.

I would honestly just push for 2 DISTRO4 units though, looks neater in a rack.

Regarding separation, given this is all RX antennas 1 wavelength is enough more will start yo be a coverage thing more then diversity thing.

If you have any TX antennas up then you need to take those into account, generally same rules as a mic, point the null on the RX antenna to the TX antenna.

Make sure you buy good quality cables and connectors and get terminators for the extra ports if you go the 2x DISTRO4 or whatever route. Any open port needs to be terminated.

Also try to keep the antennas away from large metal objects, that tends to cause issues with them.

Don't power on your belt packs up in close proximity to each other and if you need to lay them next to each other while on then invest in some aluminium pans, will greatly reduce your IM.

Hopefully Henry or one of the other guys will chip in and help you out a bit more but this topic has been discussed before just go back a few pages in this forum.

Sent from my 2014817 using Tapatalk

Title: Re: Basic antenna distribution
Post by: Mark Cadwallader on November 10, 2017, 03:15:01 PM
Stephen, did you mean to post this in Wireless & Comm instead of AC power?
Title: Re: Basic antenna distribution
Post by: Stephen Swaffer on November 10, 2017, 05:06:02 PM
Stephen, did you mean to post this in Wireless & Comm instead of AC power?

Yes.  I don't multitask very well. :-[  I thought I had clicked on that forum.
Title: Re: Basic antenna distribution
Post by: Don Boomer on November 13, 2017, 08:07:00 PM
The RF Venue DISTRO4 can connect to 4 receivers and has a "cascade" ports that (I think) you could connect to  passive (RF Venue 2X1SPLIT) splitters for the last 2 receivers.
There will be some loss in that passive split ...

Should work fine in most instances. But you might wanna run the cascade output to a single receiver and do the split from one of the regular 4 outputs as they have 3dB gain and the cascade out is unity. Again, it probably wont make much difference for most users ... Depends how close you are living to the edge.

Don Boomer
RF Venue, Inc.
Title: Re: Basic antenna distribution
Post by: Keith Broughton on November 14, 2017, 06:14:08 AM
Should work fine in most instances. But you might wanna run the cascade output to a single receiver and do the split from one of the regular 4 outputs as they have 3dB gain and the cascade out is unity. Again, it probably wont make much difference for most users ... Depends how close you are living to the edge.

Don Boomer
RF Venue, Inc.
Good idea Don :)
Title: Re: Basic antenna distribution
Post by: Jerome Malsack on November 22, 2017, 09:41:55 AM
Stephen,  When working with my 12 channels, I like to place my receivers close to the stage and use a snake to bring the audio back to the mixer.  I place one antenna in the far back right and the second antenna on the left but out in front or in the audience.  This gets one or the other in direct line of site usually.  The spacing of the antennae for the various systems is a big help also.  I run an X32 rack with wifi to Ipad to mix.  12 vhf wireless mics. and one IEM for myself 530 Mhz.  wifi stays with the mixer but he IEM is 5 ft from the wifi.  vhf is 20 ft or more on the snake.   Wireless DMX lighting in 2.4 also.  2 transmitters, 3 rec, and 4 rec.     
Title: Re: Basic antenna distribution
Post by: Stephen Swaffer on November 22, 2017, 01:11:33 PM
So, bonehead mistake #1, I have my Shure systems on the wrong group for my zipcode.  Obviously a zero cost fix, so will do that.  That said, the nearest TV transmitting antenna is 60+ miles away.

Going forward, I would like to clean up the media booth and get the receivers in racks.  I like Jerome's idea-but I think my antenna's would wind up in a less desireable RF space just knowing the way the building and platform area is laid out.  Plus, once I get "backstage" there is an 18" thick brick wall that is not very RF friendly-pretty sure it has wire mesh for the plaster too. 

Am I wasting money with a distro?  I have plenty of real estate on the ceiling below the booth to put individual antennas and space them.  They would be hidden from view for the most part by a 6" lip of 1/2" plywood-that is the only thing that would be between them and the platform.  I have an experinced HAM in the church that would likely gladly make all my cables the longest of which would be maybe 14'.

Title: Re: Basic antenna distribution
Post by: Keith Broughton on November 22, 2017, 02:14:45 PM

Going forward, I would like to clean up the media booth and get the receivers in racks.
Why not get the distro now, save the work of mounting those antennas and be ready for your rack mounting scenario?