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[Debbie Dunkley]

My first thought - was the problem ever *definitively* determined?

If so, then Debbie's most recent problem may well be something else or an indication that we didn't get it 100% right the first time around... or that there is a new problem related the venue she was in (didn't say if it was the same or different place).

You have a point Tim.
Originally when I tested the mic receiver at home and found it was that top iem unit antenna messing with the mic receiver antenna, that is when I simply switched off the top unit, and with the other 3 iem systems on and working, I got no issues so I figured I was set for now at least until I go the extra mile  ( antennas moved to back of rack, remote antenna etc).
At the show, everything worked great together keeping that top iem unit switched off and I thought we had a temporary solution. Then I left the stage area and as I walked away, the RF started to become noisy and intermittent again - just like before.
Normally I would spend the time checking out different frequencies but after trying a couple different ones selected by the auto freq select, with the same problem as last time, I just used my back up that I took with me this time which took all of 30 secs to set up and it sounded great even 30- 40 ft from the stage.
Could the problems have been caused by the venue? Perhaps -  but it's time I got this to work as well as it can regardless of any RF issues caused by venue/environment.

[Rob Spence]

You have a point Tim.
Originally when I tested the mic receiver at home and found it was that top iem unit antenna messing with the mic receiver antenna, that is when I simply switched off the top unit, and with the other 3 iem systems on and working, I got no issues so I figured I was set for now at least until I go the extra mile  ( antennas moved to back of rack, remote antenna etc).
At the show, everything worked great together keeping that top iem unit switched off and I thought we had a temporary solution. Then I left the stage area and as I walked away, the RF started to become noisy and intermittent again - just like before.
Normally I would spend the time checking out different frequencies but after trying a couple different ones selected by the auto freq select, with the same problem as last time, I just used my back up that I took with me this time which took all of 30 secs to set up and it sounded great even 30- 40 ft from the stage.
Could the problems have been caused by the venue? Perhaps -  but it's time I got this to work as well as it can regardless of any RF issues caused by venue/environment.

Short answer, yes. All additional rf in the room makes it harder. The 3 iem transmitters are hammering your mic receiver. Transmitters and receivers in close proximity are a bad thing.

Debbie, something for you to know. Multiple transmitters near each other generate intermod spurs. Two performers with wireless mics near each other can cause intermod that may screw up some other mic.

When you coordinate your wireless, you do the items and your headset, right?


Sent from my iPad using Tapatalk Pro

[Debbie Dunkley]

When you coordinate your wireless, you do the items and your headset, right?


Sent from my iPad using Tapatalk Pro

Every show.

[Debbie Dunkley]

After having searched online for a couple of half wave antennas to remotely position on stage, I haven't been able to find reasonably priced generic ones that cover my frequency band.
However, I am seeing mainly Shure, Audio Technica and Sennheiser.
I need 2 and saw this ad on eBay. Good price so would these work for me?
I am H9 band 512- 542mhz.
The rest is easy and I am going to go ahead and do as Rob suggested here.

https://www.ebay.com/itm/2-PCS-1-2-Wave-UHF-Antennas-BNC-Connectors-for-Sennheiser-2000-3000-5000-Series-/331868570313?_trksid=p2385738.m4383.l4275.c10

[Tim McCulloch]

Debbie, I still think you should try removing the mic receiver from the rack and set it up a few feet away from the IEM transmitters.... just as an experiment.

That this seems to happen in only 1 venue tells me there is more going on than just physical proximity and antenna position, though.

[Debbie Dunkley]

And one more thing for clarification:

I will get a good long pair of 50 ohm coax cables with BNC's - maybe 25ft?
Would I be able to bring the antenna connections out from the back of the receiver to a 1 space panel with BNC's fitted on the back of the rack, connect the extension coax cables to that - then to the remote BNCs ?
It adds one more connector per antenna and I wanted to make sure it wouldn't affect the reception in any way. It's just easier and quicker to do this at shows than having to connect the extension coax cords directly to the back of the receiver - and connecting to the front of the receiver will look messy.

I am excited to put this together and stop the madness - LOL !!

[Debbie Dunkley]

Debbie, I still think you should try removing the mic receiver from the rack and set it up a few feet away from the IEM transmitters.... just as an experiment.

That this seems to happen in only 1 venue tells me there is more going on than just physical proximity and antenna position, though.

These 2 shows I have had problems with have been different venues.
I never had any issues using just one space gap between the closest iem unit and the mic receiver for well over a year till I changed out the rack itself. ...Same material and size yet the problems arose after the change.
So, 2 weeks ago when the problem occurred after the rack switch out, I did remove the mic receiver from the rack at the show, placed it next to the rack and it worked fine all night. So I know it would work if not in the rack but I really would like to keep it in there if possible.
I have a patch bay in the rack and everything is nicely wired in for ease of connection to the mixer. .....so I will try anything within reason to get it to work in situ.
My last resort would be removal from the rack.

[Keith Broughton]

And one more thing for clarification:

I will get a good long pair of 50 ohm coax cables with BNC's - maybe 25ft?
Would I be able to bring the antenna connections out from the back of the receiver to a 1 space panel with BNC's fitted on the back of the rack, connect the extension coax cables to that - then to the remote BNCs ?
It adds one more connector per antenna and I wanted to make sure it wouldn't affect the reception in any way.

As I recall, technically, each connection can count as a .5 db loss.
You need 1 connection from the receiver to the coax cable, another to the coaxial "barrel" at the antenna and another from the "barrel" to the antenna.
Counts for 1.5 db loss,plus cable loss which in practice may not be an issue.
I think the gains (pun...) you will get from remote antennas up in the air will FAR outweigh any inline losses.

[Tim McCulloch]

These 2 shows I have had problems with have been different venues.
I never had any issues using just one space gap between the closest iem unit and the mic receiver for well over a year till I changed out the rack itself. ...Same material and size yet the problems arose after the change.
So, 2 weeks ago when the problem occurred after the rack switch out, I did remove the mic receiver from the rack at the show, placed it next to the rack and it worked fine all night. So I know it would work if not in the rack but I really would like to keep it in there if possible.
I have a patch bay in the rack and everything is nicely wired in for ease of connection to the mixer. .....so I will try anything within reason to get it to work in situ.
My last resort would be removal from the rack.

My observations have been with bands that carry their own RF/IEM rack - a small mixer of some flavor on top, with the wireless mic (& often instrument wireless) receivers mounted under the mixer, then the splitter or i/o panel, with the IEM transmitters clear down at the bottom of the rack.

I understand you want to keep this all in one rack but Reality is telling you a different story.

Now that all said, I contend your symptoms are more consistent with broadband RF interference.  I had a similar problem several years ago with a fixed frequency wireless system owned by a youth musical theater company.  Their mic #2 was almost always assigned to the male lead and for several years it was all fine and dandy.  Then the DTV transition and 700mHz auction came about and the #2 mic started having issues that cropped up when the actor faced stage left, putting his body between the transmitter and receiver.  The RF level at the receiver didn't seem to change but his voice would fade out quickly and if he turned to face stage right or downstage, it would feed back briefly before the level stabilized.

That mic transmitter was square in the middle of a re-aligned TV stations new digital TV channel and it was desensitizing the receiver, and overwhelming the front end of the receiver when the mic transmitter RF level dropped due to the salt water bag it was attached to.

I suspect you have a source of interference in those locations that is either direct, or creating an intermodulation product that cannot be predicted because the source of the interference is not in the FCC data base (we have that problem at a venue near our airport, but that's another matter).

[Debbie Dunkley]

My observations have been with bands that carry their own RF/IEM rack - a small mixer of some flavor on top, with the wireless mic (& often instrument wireless) receivers mounted under the mixer, then the splitter or i/o panel, with the IEM transmitters clear down at the bottom of the rack.

I understand you want to keep this all in one rack but Reality is telling you a different story.

Now that all said, I contend your symptoms are more consistent with broadband RF interference.  I had a similar problem several years ago with a fixed frequency wireless system owned by a youth musical theater company.  Their mic #2 was almost always assigned to the male lead and for several years it was all fine and dandy.  Then the DTV transition and 700mHz auction came about and the #2 mic started having issues that cropped up when the actor faced stage left, putting his body between the transmitter and receiver.  The RF level at the receiver didn't seem to change but his voice would fade out quickly and if he turned to face stage right or downstage, it would feed back briefly before the level stabilized.

That mic transmitter was square in the middle of a re-aligned TV stations new digital TV channel and it was desensitizing the receiver, and overwhelming the front end of the receiver when the mic transmitter RF level dropped due to the salt water bag it was attached to.

I suspect you have a source of interference in those locations that is either direct, or creating an intermodulation product that cannot be predicted because the source of the interference is not in the FCC data base (we have that problem at a venue near our airport, but that's another matter).

It is all very strange. The last time we played the same venues as these 2  shows in question was 6 - 8  weeks earlier with no problems using the old rack, same iem units, same mic unit - same everything in exactly the same position and configuration. The rack is the only difference.

[ProSoundWeb Community]