Wireless Lost RF on all on stage mics at once, trying to determine why?

B

BobHealey

Active Member
Last night was the second performance of a community production of The Rocky Horror Show (you may all wince in sympathy), and I had an odd RF issue I've never seen before. During the second to last number of Act 1, all the SLX receivers for the mics on stage at the time all lost RF at the same time. I don't think the rented Lectrosonics SMV lost reception, but that mic was not live and I was more interested in the receiver for the soloist. The channels in question are all between 475 and 515 MHz. Nothing's change since tech rehearsals started a week ago, other than a touring production of Newsies opening last night a city block away. But I wouldn't expect that show to cause all the mics to drop in and out over a 1-3 minute period and then behave as if nothing has happened.

Anyone ever seen anything odd like that before?
 
Are you using an antenna distribution system? How many receivers and what type? How do you know it was an RF problem? We can't help without more details.
 
Was there any power surges that night? Might not be RF. I've had an experience where my receivers went out for 2 seconds due to a power jump. By sound board that was connected to the same power source was fine but the receivers didn't like those 2 seconds.
 
It could be a number of things as stated by others, power going out at the receivers and no one having eyes on that rack is the most likely culprit if they came back on and behaved as if nothing happened. Is the rented Lectro stuff on the same circuit?

The next thing to look at is your antenna placements and cable. Are you running two antennas into a distributor or are you running with the OEM quarter-wave antennas on each receiver? If you are using a distributor there is a chance that could have had something go wrong internally and caused BOTH antennas to go out which would kill the ability to use those mics.

I don't think their show would do too much to affect you, they most likely have low-powered Sennheiser transmitters on everyone (SK5212's) and the most high-power part of their system is most likely their RF Intercom. You would have had constant overlapping issues if you and Newsies weren't playing nice, not one chunk where a lot of stuff didn't work.

Also keep in mind that you can only have 12 SLX packs running at once from the same frequency band, 20 if you have a mix of bands. This is a Shure imposed limit.

While this is unrelated, please consider the effect you may have on Newsies especially because you have rented Lectrosonics SMV, and either turn down the Lectro to low power, or go pay Newsies a visit and coordinate wireless between your shows. Lectrosonics SMV can be set to 250mW high-power and it can wreak havoc on a system without coordination. The Newsies folks have the ability to give you freqs that will play well with their system. I had a system this summer comprised of 45 SK5212's and SK5012's that started taking massive hits when 8 Lectrosonics SMV transmitters were turned on close to 3/4 of a mile away. It was a perfect mix of them being in almost line-of-site to our directional antennas, and us all being outdoors, and their Lectro packs tuned a few mHz away, but it blasted through our system. No good at all, and they had no clue at all.
 
To reply to everything posted while I was at today's matinee, which had no wireless issues.


All wireless receivers, off board processing (DBX 166, 166XL, 266XL), Soundcraft K2, and an old Dell PC that is the interface to the RPM 88 system processor are all on the same circuit/power strip. Nothing else had issues last night. There were no issues today that could not be tracked down to actors doing things with the SLX antennas I've asked them not to do, suck as coiling them up and jamming them in the belt clip. I'm using 10 of the 16 installed SLX, 6 each in G4 and L4 (thought I was in H5 too, but those 4 aren't being used).

Each receiver is using 1/4 wave OEM since the funds were not there at the DTV switchover to get the distribution system (or even 1:1 replace the old mics). Receivers are slightly above and to the right of the sound board.

First thing I did with the SMV was dial it down from 100 mW it was shipped to me at to 50 mW for better battery life. I can actually get a full show on one AA now instead of changing each act. On the plus side, all the buildings are old brick buildings (we're in a former church built in 1830s) and it goes from north to south my stage, my recievers, street, parking lot, newish/renovated office building, street, roadhouse foh, roadhouse stage. Both facilities know of each other, and I dropped the Lectro where SLX [HASHTAG]#3[/HASHTAG] would normally fall (exact freq). I'm being a bit vague to avoid implicating any venues by name, but it shouldn't be too hard for folks in the area I say I'm in to figure out which facilities I'm referring.

I'd blame one of the bars nearby, but the issue went away within a minute or two, as opposed to persisting rest of show.
 
BobHealey said:
First thing I did with the SMV was dial it down from 100 mW it was shipped to me at to 50 mW for better battery life. I can actually get a full show on one AA now instead of changing each act.
Click to expand...

If you switch from Alkalines to NiMH rechargeables, you will more than double the usable On time on the SMV's. My vote goes to the Powerex batteries, at 2,700mAh you will be more than good on run time.
 
themuzicman said:
If you switch from Alkalines to NiMH rechargeables, you will more than double the usable On time on the SMV's. My vote goes to the Powerex batteries, at 2,700mAh you will be more than good on run time.
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Using the Powerex 2700's. I end up burning 2h of run time before curtain though. 100 mW made it just iffy enough to justify an intermission swap.
 
Fun how small of a world theatre can be sometimes (ok, most times). I've seen pics of this production on Facebook because I've worked with the girl playing Janet before in Ohio.

I've had issues with the SLX line before where I placed the the receivers (using the stock antennas) next to a wall that turned out to have a giant steel plate in it. They built these plates into the building in case they ever wanted to add lighting positions and needed to spread the load out, or so I was told. It would always drop all signal once or twice a run. Moved the receivers to the other side of the console and the problem stopped.
 
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