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[Bob Charest]

Haven't posted in a while, but we're still dealing with these random zaps/interference.  I have coordinated frequencies, did scans at offending venues, and still no relief.  Would a directional paddle help vs the omni I'm using?   Could it be the combiner going/is bad?   Appreciate all the advice. 


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Hi Terry,

You've gotten help from those on this forum far more knowledgeable and experienced than I am, but I feel your pain!

Would you mind answering a few questions for me?
1.) The zip code for your shows (one where this situation happens frequently)
2.) The frequencies that you currently have for your Sennheiser G2 IEM gear (we still use these...)
3.) Any other wireless gear and those frequencies.
4.) Can you get the same result with only one transmitter/receiver pair not in the rack?
5.) What software are you using for your coordination?

I believe in your 1st post you mentioned a combiner - am I remembering that correctly?

I had trouble on my IEM channel a couple of years ago, and testing revealed it to be the cable to my IEM transmitter from the Shure AC300, but your experience shows that it's not just one cable.

Our current setup (usually in the Portland, ME area, zip 04101 through 04103) is 7 Sennheiser G2 transmitters (518-554Mhz), one Sennheiser EW365 and one SKP100 (both 518-554) and 12 Shure ULXD mics (470-534Mhz)

We use a Shure PA821A combiner for the IEMs (got that after our old Sennheiser AC300 went down)

One thing that might be important is the plane of the transmitter antenna versus the orientation of the bodypack antenna. We ended up going with the PWS helical antenna to ensure that, no matter which orientation the body pack is in, it still has optimal alignment with the transmitted signal. It has worked wonderfully for us. If you were able to rent one, you could see if it made the difference you're in need of.

Anyway, for my own understanding (and maybe to your benefit) I'd love to get at the root of this one!

Best regards,
Bob Charest

[Robert Lofgren]

I made a mistake in my early days thinking that it didn’t matter how I mounted an omni antenna since it’s omni, right?

I got to learn that antennas are omni in the horizontal plane but not in the vertical plane, where it becomes more directional, as the antenna signal is doughnut shaped.

[Terry Martin]

Mine is mounted in this configuration, without fail.

I made a mistake in my early days thinking that it didn’t matter how I mounted an omni antenna since it’s omni, right?

I got to learn that antennas are omni in the horizontal plane but not in the vertical plane, where it becomes more directional, as the antenna signal is doughnut shaped.

[Terry Martin]

Thanks Bob.  I get the most interference in a mall nightclub (yes, they took over approximately 4-5 stores, took down the walls, and have the biggest nightclub in a 100 mile radius).  The zip is 47715. 

But this past weekend, we were in 40108 - and got the same condition.  Some locales, we get no RF hits / others make the system almost unusable.

I will have to get back to you on the frequencies.  I've done some many scans over the past couple of weeks, I have no idea where I'm at the moment.

I've used WWB in the past to coordinate.

I've not tried to take 1 transmitter out of the rack yet - we primarily get the RF hits on the road, and there is little time to troubleshoot.  ...other than freq scans.

Yes, I use the AC2 combiner. 

I'm wondering if it is going bad - cables are built into the chassis - or if I have a transmitter that is leaking some stray RF??

I wish I'd written everything down I've tried - I'm not sure there is anything left to try.  LOL

Hi Terry,

You've gotten help from those on this forum far more knowledgeable and experienced than I am, but I feel your pain!

Would you mind answering a few questions for me?
1.) The zip code for your shows (one where this situation happens frequently)
2.) The frequencies that you currently have for your Sennheiser G2 IEM gear (we still use these...)
3.) Any other wireless gear and those frequencies.
4.) Can you get the same result with only one transmitter/receiver pair not in the rack?
5.) What software are you using for your coordination?

I believe in your 1st post you mentioned a combiner - am I remembering that correctly?

I had trouble on my IEM channel a couple of years ago, and testing revealed it to be the cable to my IEM transmitter from the Shure AC300, but your experience shows that it's not just one cable.

Our current setup (usually in the Portland, ME area, zip 04101 through 04103) is 7 Sennheiser G2 transmitters (518-554Mhz), one Sennheiser EW365 and one SKP100 (both 518-554) and 12 Shure ULXD mics (470-534Mhz)

We use a Shure PA821A combiner for the IEMs (got that after our old Sennheiser AC300 went down)

One thing that might be important is the plane of the transmitter antenna versus the orientation of the bodypack antenna. We ended up going with the PWS helical antenna to ensure that, no matter which orientation the body pack is in, it still has optimal alignment with the transmitted signal. It has worked wonderfully for us. If you were able to rent one, you could see if it made the difference you're in need of.

Anyway, for my own understanding (and maybe to your benefit) I'd love to get at the root of this one!

Best regards,
Bob Charest

[Bob Charest]

Thanks Bob.  I get the most interference in a mall nightclub (yes, they took over approximately 4-5 stores, took down the walls, and have the biggest nightclub in a 100 mile radius).  The zip is 47715.

Chasing this stuff down can be a royal PITA, for sure.

This is what I get for available frequencies from IAS for zip 47715:

Senn EW300IEM A Bank-Chan 1.01    518.400    
Senn EW300IEM A Bank-Chan 6.02    518.900
Senn EW300IEM A Bank-Chan 8.01    520.525    
Senn EW300IEM A Bank-Chan 3.02    522.400
Senn EW300IEM A Bank-Chan 7.04    523.900    
Senn EW300IEM A Bank-Chan 7.05    525.100
Senn EW300IEM A Bank-Chan 7.08    535.100    
Senn EW300IEM A Bank-Chan 7.09    536.900
Senn EW300IEM A Bank-Chan 7.10    541.100    
Senn EW300IEM A Bank-Chan 7.11    541.700
Senn EW300IEM A Bank-Chan 5.08    546.025    
Senn EW300IEM A Bank-Chan 1.10    546.800
Senn EW300IEM A Bank-Chan 2.10    548.800    
Senn EW300IEM A Bank-Chan 4.09    550.100
Senn EW300IEM A Bank-Chan 1.12    552.400 

But this past weekend, we were in 40108 - and got the same condition.  Some locales, we get no RF hits / others make the system almost unusable.

And for 40108:

Senn EW300IEM A Bank-Chan 5.01 & 7.01    518.300    
Senn EW300IEM A Bank-Chan 6.02    518.900
Senn EW300IEM A Bank-Chan 5.02    520.975    
Senn EW300IEM A Bank-Chan 3.01    521.800
Senn EW300IEM A Bank-Chan 5.04 & 7.06    525.500    
Senn EW300IEM A Bank-Chan 5.05    532.000
Senn EW300IEM A Bank-Chan 3.05    533.400    
Senn EW300IEM A Bank-Chan 5.06    533.900
Senn EW300IEM A Bank-Chan 5.07    540.700    
Senn EW300IEM A Bank-Chan 5.09    549.900
Senn EW300IEM A Bank-Chan 5.10    550.300    
Senn EW300IEM A Bank-Chan 5.11    551.000
Senn EW300IEM A Bank-Chan 4.11    553.500

So, the RF coordination for these two zip codes is completely different - The only frequency that works in both locations is 518.900

I will have to get back to you on the frequencies.  I've done some many scans over the past couple of weeks, I have no idea where I'm at the moment.

I've used WWB in the past to coordinate.

I've not tried to take 1 transmitter out of the rack yet - we primarily get the RF hits on the road, and there is little time to troubleshoot.  ...other than freq scans.

I think that maybe the only way to get ahead of the game involves a few items.

First, use software before you head out for the particular zip code. That way, you've at least got a valid coordination before you get there.

The 2nd item is to have a frequency scanner like the TTi, so when you arrive, you can see if there are rogue RF sources  in the venue. I've had situations where everything was coordinated and had massive interference. My TTi showed a bunch of activity with all my transmitters off. It turned out that the venue had a number of 600Khz devices on - they weren't need, and, when they were turned off, everything was good.

If when you turn on your IEM packs without anything else on and they show RF, that's a telltale sign for sure...

Lastly, I think you're going to have to take things apart and test... A major PITA, I know, but sometimes, you cost yourself more time and aggravation than just doing it.

Yes, I use the AC2 combiner. 

I'm wondering if it is going bad - cables are built into the chassis - or if I have a transmitter that is leaking some stray RF??

Either of those things are certainly possible.

I wish I'd written everything down I've tried - I'm not sure there is anything left to try.  LOL

I've been in that boat! I think starting with a known good coordination for each zip code is likely to yield the most immediate positive results.

Best regards,
Bob

[Jason Glass]

Thanks Bob.  I get the most interference in a mall nightclub

Aah. The honky-tonks of the new millennium​. Did these clubs happen to have neon lights on the walls?

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[Terry Martin]

Aah. The honky-tonks of the new millennium​. Did these clubs happen to have neon lights on the walls?

Sent from my Nexus 5 using Tapatalk

Not so much neon - a few beer/whiskey lights - but a $hit ton of TVs. 

[Jason Glass]

Not so much neon - a few beer/whiskey lights - but a $hit ton of TVs.

Hi Terry,

Just be aware that even a single neon light charger in the venue can splatter RF noise badly.

Sent from my Nexus 5 using Tapatalk

[Tim McCulloch]

Not so much neon - a few beer/whiskey lights - but a $hit ton of TVs.

So Terry.... I remember a problem that someone else (Ike Z?) had when the video dept had to set up very close to the SL monitor world and the RF dept had a terrible time.  Never happened before but VDO was usually on the other side of a wall or in a vomitory 50 ft or more away.  Use of an RF spectrum analyzer showed a big RF spike from a bad cable or termination of a cable connecting to an SDI device.

This seemed like a 1 in a lifetime thing to me but I had a very similar experience RF problem but didn't have the RF instrumentation to track down the source.  I had only 8 transmitters but would get random RF hits on at least 3 of 4 receivers that were at FOH with me; the 4 receivers for the audience Q&A mics were back stage.  All Shure UHF-R... I'd come in early & fire up the Q&A mics one at a time, each receiver doing a freq scan, then move to the lavaliere mics and do the same.  The video guys were arriving and going through their pre-show checks.  I'd complete the scans and programming and turn off transmitters only to observe RF levels on the receivers that were significantly higher than when I started... and not in any predictable way.  I'd turn the transmitters on again and things seemed to work, until the didn't.

I'd repeat the process during a break but it was a crap shoot.  At the end of the day when VDO was powering stuff down, things got better.  At the time I didn't put this all together.

FWD to a repeat of this event a couple weeks ago (same video gear and wireless mics) and I put ALL receivers back stage and had 100% reliability.  There could be any number of things that changed and without an RF spectrum analyzer I can't say it's 100% that RF leakage in VDO land was the problem but it's consistent, in retrospect.

All of this gets me to wonder if you're getting a blanket of spurious RF from the video distribution in the places you play.

[Terry Martin]

Very well could be video.  I bet there are 15-20 big screens in the mall o'rama nightclub.  He gets many semi-nationals in there about once a quarter.  Unfortunately, we're always somewhere else, so I can speak with the TM, etc.

I guess I could try to reach out to some of them -but a cold call/email will probably get me nowhere (from a regional cover band).

Anyone know the (right) guy to speak with from LoCash, Pop Evil, Saliva, Drowning Pool, Adelta's Way??


 

So Terry.... I remember a problem that someone else (Ike Z?) had when the video dept had to set up very close to the SL monitor world and the RF dept had a terrible time.  Never happened before but VDO was usually on the other side of a wall or in a vomitory 50 ft or more away.  Use of an RF spectrum analyzer showed a big RF spike from a bad cable or termination of a cable connecting to an SDI device.

This seemed like a 1 in a lifetime thing to me but I had a very similar experience RF problem but didn't have the RF instrumentation to track down the source.  I had only 8 transmitters but would get random RF hits on at least 3 of 4 receivers that were at FOH with me; the 4 receivers for the audience Q&A mics were back stage.  All Shure UHF-R... I'd come in early & fire up the Q&A mics one at a time, each receiver doing a freq scan, then move to the lavaliere mics and do the same.  The video guys were arriving and going through their pre-show checks.  I'd complete the scans and programming and turn off transmitters only to observe RF levels on the receivers that were significantly higher than when I started... and not in any predictable way.  I'd turn the transmitters on again and things seemed to work, until the didn't.

I'd repeat the process during a break but it was a crap shoot.  At the end of the day when VDO was powering stuff down, things got better.  At the time I didn't put this all together.

FWD to a repeat of this event a couple weeks ago (same video gear and wireless mics) and I put ALL receivers back stage and had 100% reliability.  There could be any number of things that changed and without an RF spectrum analyzer I can't say it's 100% that RF leakage in VDO land was the problem but it's consistent, in retrospect.

All of this gets me to wonder if you're getting a blanket of spurious RF from the video distribution in the places you play.

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