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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 => Pro AV Forum => Topic started by: Kellen Tyburski on November 18, 2012, 10:35:48 am

Title: Multiple antennas + WL mics
Post by: Kellen Tyburski on November 18, 2012, 10:35:48 am
Hey all,

I have a gig tomorrow with 16 Wireless Shure UHF-R's, and I am brainstorming on the Best Practice for setting up my antenna's.
The racks I will be using are broken up into (2) 10 Packs, each with a UA845 antenna distro. 12 of these mics will be scattered throughout the audience, and 4 will be used as stage mics for talking heads. The Antenna's are the full range uni-directional "shark fins"...

I'm considering 2 options:
1.) Using 4 antennas (2 from each separate DA) as 2 independent systems....but I hesitate to just put all 4 of them on sticks in a line, or in pairs.

2.) Using 2 antennas only and daisy chaining the 2 DA's. I can eliminate 1 dual receiver from the first rack of 10, and use my 2 free DA outputs to hop to the DA in rack #2. This leaves me with 18 total receiver's, which is 2 more than I need.

Curious what you would do, and if either option is a "no-no" and why. I am doing some presetting today so any quick tips would be MUCH appreciated...

Thanks for any help!!

Kellen

 
Title: Re: Multiple antennas + WL mics
Post by: Mac Kerr on November 18, 2012, 11:03:23 am
Hey all,

I have a gig tomorrow with 16 Wireless Shure UHF-R's, and I am brainstorming on the Best Practice for setting up my antenna's.
The racks I will be using are broken up into (2) 10 Packs, each with a UA845 antenna distro. 12 of these mics will be scattered throughout the audience, and 4 will be used as stage mics for talking heads. The Antenna's are the full range uni-directional "shark fins"...

I'm considering 2 options:
1.) Using 4 antennas (2 from each separate DA) as 2 independent systems....but I hesitate to just put all 4 of them on sticks in a line, or in pairs.

2.) Using 2 antennas only and daisy chaining the 2 DA's. I can eliminate 1 dual receiver from the first rack of 10, and use my 2 free DA outputs to hop to the DA in rack #2. This leaves me with 18 total receiver's, which is 2 more than I need.

Curious what you would do, and if either option is a "no-no" and why. I am doing some presetting today so any quick tips would be MUCH appreciated...

Thanks for any help!!

Kellen

If the setup is in a wide room, like the Conrad, you may want to use 4 antennas and keep the stage mics and the center of house Q&A mics in 1 rack with the antennas aimed at the stage, and the wide Q&A mics in the other rack with the antennas aimed out toward the ends of the room. You lose much of the advantage of diversity, but may gain better coverage.

If it is a deep ballroom, like the Marquis, either way should be fine.

In either case, I hope both racks are not the same band split. You will have a hard time getting 16 J5s to work in one place, particularly the Marriot Marquis. ;-)

Mac
Title: Re: Multiple antennas + WL mics
Post by: Kellen Tyburski on November 18, 2012, 11:21:55 am
If the setup is in a wide room, like the Conrad, you may want to use 4 antennas and keep the stage mics and the center of house Q&A mics in 1 rack with the antennas aimed at the stage, and the wide Q&A mics in the other rack with the antennas aimed out toward the ends of the room. You lose much of the advantage of diversity, but may gain better coverage.

If it is a deep ballroom, like the Marquis, either way should be fine.

In either case, I hope both racks are not the same band split. You will have a hard time getting 16 J5s to work in one place, particularly the Marriot Marquis. ;-)

Mac

Hey Mac, thanks for the quick response...
All 20 are all on the H4 band. I'm thinking it would be better to go grab some loose dual units and just stack em to make the other 6, all on a different band than H4. Now that I hear that using the 4 antenna's is do-able, I'll try sectioning off the room into 2 chunks and use 1 DA per chunk, pointing the antennas in that direction like you said.   
Title: Re: Multiple antennas + WL mics
Post by: Mac Kerr on November 18, 2012, 11:29:35 am
All 20 are all on the H4 band.

Sorry. If these are rented, you need to make sure not to get that many units in the same bandsplit in the future. Finding good frequencies would be easier with 10 J5s and 10 H4s, or better yet 3 bandsplits. With multiple bandsplits you do have to do your own frequency coordination because you can't rely on the manufacturer's groups, but that is the price of doing business with 20 RF mics. You can use WWB, or IAS (or others) to do the coord.

Mac
Title: Re: Multiple antennas + WL mics
Post by: Kellen Tyburski on November 18, 2012, 12:04:25 pm
Sorry. If these are rented, you need to make sure not to get that many units in the same bandsplit in the future. Finding good frequencies would be easier with 10 J5s and 10 H4s, or better yet 3 bandsplits. With multiple bandsplits you do have to do your own frequency coordination because you can't rely on the manufacturer's groups, but that is the price of doing business with 20 RF mics. You can use WWB, or IAS (or others) to do the coord.

Mac

Nope, they are not rented. When I went back to go find some loose dual units there were about 16 more singles on the H4 band. I guess whoever purchased them did not know, or was not thinking straight! I found 4 on J5, and a dual unit on the L3 band so I should be set. I will probably use those for the stage mics to keep them separate. I am going to sit down with WWB 6 today and give it a go!
Title: Re: Multiple antennas + WL mics
Post by: Henry Cohen on November 18, 2012, 05:35:35 pm
Another option, if the room isn't terribly deep AND wide, and this is merely a talking head event with a backdrop or projection screen about mid-stage, is to place two directional antennas directly behind the backdrop just on stage left and right and cross aim them to the diagonal corners at the back of the house.

Position above [talking] head level and give a slight downtilt.
Title: Re: Multiple antennas + WL mics
Post by: brian maddox on November 18, 2012, 11:12:51 pm
Another option, if the room isn't terribly deep AND wide, and this is merely a talking head event with a backdrop or projection screen about mid-stage, is to place two directional antennas directly behind the backdrop just on stage left and right and cross aim them to the diagonal corners at the back of the house.

Position above [talking] head level and give a slight downtilt.

Which is exactly what I used to do.  Nice to see a real pro actually confirm the validity of my approach.
Title: Multiple antennas + WL mics
Post by: Patrick Moore on November 19, 2012, 01:19:23 am
Which is exactly what I used to do.  Nice to see a real pro actually confirm the validity of my approach.

Yes, same here.  Put them on desks stands and hide them behind the fast fold screen skirt.  Works really well and is virtually invisible.  :)

Title: Re: Multiple antennas + WL mics
Post by: Mac Kerr on November 19, 2012, 10:42:45 am
Yes, same here.  Put them on desks stands and hide them behind the fast fold screen skirt.  Works really well and is virtually invisible.  :)

Unless of course the mic receivers are at FOH. He didn't say so specifically, but my guess is that in Kellen's case they are.

Mac
Title: Re: Multiple antennas + WL mics
Post by: Kellen Tyburski on November 19, 2012, 09:31:04 pm
Unless of course the mic receivers are at FOH. He didn't say so specifically, but my guess is that in Kellen's case they are.

Mac

Correct, my receiver's were @ FOH. In this case having the antenna's behind the stage might not have been ideal, but I will definitely consider that in the future. I ended up using something along the lines of Mac's first suggestion, which worked perfectly.

I used WWB6 for the first time and it worked really well.. I didn't have any trouble finding clean frequencies on 10 H4's, 4 J5's, and 2 L3's.
The gig went really well, thanks for the tips guys...

KT

Title: Re: Multiple antennas + WL mics
Post by: Kellen Tyburski on November 23, 2012, 08:47:01 pm
I did have one more question I was hoping you guys could shine some light on for me.

Right when the first speaker went on stage I experienced some static on his mic that I am convinced came from an RF issue. I have heard this sound before when using WL mics.. Best way I can describe it is "static", similar to the sound you would get if you were using a transistor radio to cut through different stations.

I chopped the piece out of the recording so you guys could hear.

http://www.kellent.biz/drops/static_recording.mp3

The sound in questions comes in right at the beginning, @ 13s, 23s, and 54s. It's best heard with a pair of cans on. In the room it wasn't loud, but enough for me to prep a backup lav in case it became worse. The lav was not rubbing against the speakers clothes...
the RF meters on the receiver were locked solid, so were all other 15 in use.. According to WL workbench all frequencies were spaced properly, etc. This particular mic was the only one that had this issue the entire time, luckily he only spoke for about 5-6 mins in the beginning.

Any ideas on what this could be?? 
Title: Re: Multiple antennas + WL mics
Post by: Jerome Malsack on December 28, 2012, 12:24:26 pm
Yes but do the receivers need to be at FOH? 

Could you use a snake to take the receivers behind the screen and leave the antennas in a location to hide and better support the room. 

I plan to place my antennas this way for a future conference that I had trouble with an Airport Radar sweeping the antennas and killing the signal.  by using 20 foot cables to the antennas I have a 40 foot wide span so the radar sweep will kill one antenna at a time that way I have signal all the time. 
Title: Re: Multiple antennas + WL mics
Post by: Henry Cohen on December 29, 2012, 01:26:18 pm
Yes but do the receivers need to be at FOH? 

Could you use a snake to take the receivers behind the screen and leave the antennas in a location to hide and better support the room. 

I plan to place my antennas this way for a future conference that I had trouble with an Airport Radar sweeping the antennas and killing the signal.  by using 20 foot cables to the antennas I have a 40 foot wide span so the radar sweep will kill one antenna at a time that way I have signal all the time.

Are you using active antennas?
Title: Re: Multiple antennas + WL mics
Post by: Pete Erskine on December 29, 2012, 02:40:23 pm
I did have one more question I was hoping you guys could shine some light on for me.

Right when the first speaker went on stage I experienced some static on his mic that I am convinced came from an RF issue.

With the TX off, do your RX show any RF?  If so find another freq for those.  If you are using active antennas and your antenna cable is low loss like LMR400 or RG8, set their gain on 3db.  10 db tends to just raise the noise floor.

Do yu have a SA?  What does the freq look like when TX is off?
Title: Re: Multiple antennas + WL mics
Post by: Kellen Tyburski on January 23, 2013, 11:34:42 am
With the TX off, do your RX show any RF?  If so find another freq for those.  If you are using active antennas and your antenna cable is low loss like LMR400 or RG8, set their gain on 3db.  10 db tends to just raise the noise floor.

Do yu have a SA?  What does the freq look like when TX is off?

Hey Pete,
When TX is off, no RF showed on any receivers. Gain on both active antenna's was set @ 3dB.
And you will have to forgive but what does SA stand for?
Title: Re: Multiple antennas + WL mics
Post by: Mac Kerr on January 23, 2013, 11:49:23 am
And you will have to forgive but what does SA stand for?

Spectrum Analyzer, like This One (http://www.tti-test.com/products-tti/rf/spectrum-analyzer.htm).

Mac

Title: Re: Multiple antennas + WL mics
Post by: Kellen Tyburski on January 23, 2013, 12:01:16 pm
Spectrum Analyzer, like This One (http://www.tti-test.com/products-tti/rf/spectrum-analyzer.htm).

Mac

Ok- Pete - No SA  was used :)