Wireless Sennheiser EW 300 randomly drops signal

[Radagasthebrown]

Hi all,

So I've been having a really strange RF problem with one of my Sennheiser evo series mics. I've got six total EW 300 G3 series rack receiver/transmitter pack combos the transmitters are connected to countryman E6s and B3s depending on the actor. Pack three has been presenting with a really strange RF drop out for a couple weeks now. It's never a constant problem but once or twice a week the pack will just drop all its signal and I'll get a bad RF interference noise from the open channel. This would make sense if the actor was passing behind some big metal object but they're doing nothing different from any other actor on stage. The pack is on 555.125mhz and the closest other pack is on 518.200 so im not mucking with another pack. The infuriating thing is that when i then watch the RF meter as the actor walks off stage and around through our crossover under/behind the audience it stays at full (ARRRRRGGGGHHHH!!!!!!). If anyone has any advice on how to deal with this problem i'd greatly appreciate it. My temporary solution is to just swap the pack with another actor who has significantly fewer lines and therefore less chances to cause a problem.

 

[Chris15]

Sounds to me like you're trying to sit on top of an active TV station or something like that...

 

[Radagasthebrown]

Sounds to me like you're trying to sit on top of an active TV station or something like that...

Thats what I thought it must have been at first, some kind of other station interference, but its still happening after changing signal frequencies by 80+mhz(630s to 550s).

 

[AudJ]

I had a similar issue a few years ago. All day long it was fine, but dropped erratically in the evening hours. After a lot of research, it turned out I was in a tv band. Recalculated frequencies and everything has been great since. Do you have a list of all the tv stations and frequencies they use in your area? They will be scattered throughout the bands you are using.

What are the 6 frequencies you are using?

 

[2mojo2]

The DC metro area has a disturbing number of unlisted (don't ask) transient radio sources that can play h*ll with wireless microphones.
You may be bumping into that sort of problem.
Where are you working?

 

[Radagasthebrown]

What are the 6 frequencies you are using? -AudJ

Other than the two listed above I don't know them off hand but i'll look into the tv stations in the area.

Where are you working? -2mojo2

MetroStage in Alexandria. Like I said we're stupid close to DCA and close to the pentagram, no hexagon, no... oh what is it again?

 

[2mojo2]

The Pentagram, that is rich.
Alexandria would be a great place to pick up unlisted radio sources.
Some military/intelligence/don't-ask operations send out data in bursts of high intensity and broad frequency band transmissions.
I know one theater in Maryland that has been hamstrung by interference with the Sennheisers, and I have had problems in several locations myself.

 

[Radagasthebrown]

Out of curiosity which space in MD? Also if you do a fair amount of work in the area we may have actually met before, just sayin.

 

[2mojo2]

Out of curiosity which space in MD? Also if you do a fair amount of work in the area we may have actually met before, just sayin.

That space is at a private school in Potomac.

 

[FMEng]

This could be an intermod problem, caused by mixes of the all of the frequencies in use. Use a software program, like Shure Wireless Workbench, to determine frequencies for all of the systems, based on both intermod reduction and channels free of TV carriers.

 

[StradivariusBone]

The DC metro area has a disturbing number of unlisted (don't ask) transient radio sources that can play h*ll with wireless microphones.

My vote is this, I've had similar experiences with the same hardware in Brevard County and we've got no shortage of interference from Harris' RF division to KSC and Patrick AFB. I've never been sure how to determine the most populated areas on the spectrum without having lots of black vans park outside my house.

 

[TimmyP1955]

You need an RF spectrum analizer to tell you what's coming at you from elsewhere.

 

[AudJ]

You need an RF spectrum analizer to tell you what's coming at you from elsewhere.

I sort of did this myself one afternoon by turning off all of the receivers but one. I programmed many different frequencies until I narrowed down where the usable space was by keeping a grid of frequencies that showed any interference. Then tried the good ones with the transmitter on. Then I compared to local tv stations and white space. Ended up locating the bulk of my problem was coming from a Canadian TV station not on my local list. I used a free frequency software program to determine the frequencies I should use, but blocked out the interference frequencies before calculating. Definitely not the best way to do this, but it worked, and no problems in 2 years.

 

[Chris15]

If I'm remembering my details right, then you already have spectrum analysis capability built in to the EW300G3 receiver.
Download Sennheiser's Wireless Syetsm Manager, connect up the ethernet and you should be able to scan within the tuning bandwidth of the receiver...

 

[mbenonis]

Could you post a list of all six frequencies you're using? I can run the numbers, compare it against local TV, and take a quick look with a spectrum analyzer if you'd like.

 

[Michael Grimaila]

I use the Sennheiser Wireless Systems Manager with my EW 300 G3 IEMs and it does a great job of identifying low interference frequencies. I don't know if it it works with wireless mics though.