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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 => LAB Lounge => Topic started by: John Luty on December 30, 2018, 07:29:17 PM

Title: rf interference
Post by: John Luty on December 30, 2018, 07:29:17 PM
I'm having a problem with rf interference with my AVG  wireless mics . What if anything can I do to stop it  ?
Title: Re: rf interference
Post by: Jerome Malsack on December 30, 2018, 07:35:07 PM
It will depend on the location your at, The frequencies being used, and did you get height for line of site along with 1/4 wave spacing on the antenna receiving. 
1/4 wave rule says you will space the antenna to prevent problems.  Receiver one needs to have about 4 to 8 inchs separating it from receiver 2.  The antenna should be the 4 to 8 inchs for a UHF frequency.  VHF is 2 to 5 feet. 
Title: Re: rf interference
Post by: Ryan Trefethen on December 30, 2018, 07:35:19 PM
Hi John,

We’d will need to know a bit more info before we can help.

1. AVG must be AKG brand microphone
2. Model
3. Frequency range
4. Description of the problem. If you don’t know technical jargon just a laymen description of what’s happening will suffice.
5. Your location in the world (City,State, Country)
6. Environment you are in (Church, warehouse, club, theater, etc.)

Ryan


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Title: Re: rf interference
Post by: John Luty on December 30, 2018, 07:58:57 PM
Hi John,

We’d will need to know a bit more info before we can help.

1. AVG must be AKG brand microphone
2. Model
3. Frequency range
4. Description of the problem. If you don’t know technical jargon just a laymen description of what’s happening will suffice.
5. Your location in the world (City,State, Country)
6. Environment you are in (Church, warehouse, club, theater, etc.)

Ryan


Sent from my iPhone using Tapatalk
yes AKG WMS40 MINI2 Dual Vocal Handheld Microphone Wireless System
both freg. bands537.5 539.3 ,537.9 540.4 so 4 mics total
the problem is occasional popping
I live in western new York state  pretty rural small town pop 13000
in a small neighborhood bar
thanks for taking the time to help
Title: Re: rf interference
Post by: Ryan Trefethen on December 30, 2018, 08:18:04 PM
Those are fixed frequency models.

Does the popping happen on all 4 at the same time? 

Popping on all of them but at different times?

Ryan


Sent from my iPhone using Tapatalk
Title: Re: rf interference
Post by: John Luty on December 30, 2018, 09:19:19 PM
Those are fixed frequency models.

Does the popping happen on all 4 at the same time? 

Popping on all of them but at different times?

Ryan
Can't say with 100% certainty but I think it is all of them at different times but it could just be one I will try to pay attention when I use them tomorrow night

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Title: Re: rf interference
Post by: John Sulek on December 30, 2018, 10:05:34 PM


The zip code of the venue where this is happening would enable a check of your frequencies in Wireless Workbench or IAS software.
Title: Re: rf interference
Post by: John Luty on December 30, 2018, 10:08:22 PM
The zip code of the venue where this is happening would enable a check of your frequencies in Wireless Workbench or IAS software.
14760
Title: Re: rf interference
Post by: John Sulek on December 31, 2018, 10:39:30 AM
14760

Looks good in IAS but without an actual scan from the venue, hard to know what is happening on site.
With all your mics powered off, do the receivers show no rf level?
Then turn each mic on by itself and make sure all the other receiver channels show no rf.

When the popping happens, are the mics deployed on the stage or grouped together side stage or at FOH?

Also check for a loose mic capsule, or loose contacts in a battery compartment. Not rf related but could cause a popping noise.
Title: Re: rf interference
Post by: Jerome Malsack on December 31, 2018, 10:55:26 AM
The popping possibly could be static discharge.  If the pop is when changing hands and picking it up ? 
Title: Re: rf interference
Post by: Jean-Pierre Coetzee on December 31, 2018, 11:38:32 AM
Is there a his followed by a pop or just a random pop every now and then?

If I remember those have fixed antennas on the receivers, try to have them closer to the performers and also try to get them higher up, preferably above peoples heads.
Title: Re: rf interference
Post by: Mike Caldwell on December 31, 2018, 04:41:15 PM
How are they connected to your mixer, XLR or 1/4 plugs into line inputs?

If using XLR connections do you have phantom power turned on to those inputs? If you are using/need phantom power and your mixer only has global phantom power as in all on or off to all channels use the 1/4 inch line inputs if your mixer has them.

What I'm getting at is that some active equipment like mic receivers don't like having their outputs hit with phantom power.
Title: Re: rf interference
Post by: John Luty on January 03, 2019, 07:09:59 PM
update the main problem was my mixer the right channel was going add that to the mic frequencies at 537.500 and 537.900and it was a recipe for disaster , spent some money today hopefully no more problems
Title: Re: rf interference
Post by: Mike Caldwell on January 03, 2019, 07:56:33 PM
update the main problem was my mixer the right channel was going add that to the mic frequencies at 537.500 and 537.900and it was a recipe for disaster , spent some money today hopefully no more problems

What was your "fix" to the problem, not sure I completely understand
your post.
Title: Re: rf interference
Post by: Marc Sibilia on January 04, 2019, 01:38:27 PM
... not sure I completely understand
your post.

Punctuation and capitalization enable communication:

Quote
Update. The main problem was my mixer.  The right channel was going.  Add that to the mic frequencies at 537.500 and 537.900 and it was a recipe for disaster.  Spent some money today.  Hopefully no more problems.
Title: Re: rf interference
Post by: John Luty on January 05, 2019, 05:33:36 AM
What was your "fix" to the problem, not sure I completely understand
your post.
the "fix " was a new mixer and mics
Title: Re: rf interference
Post by: Mike Caldwell on January 05, 2019, 08:24:25 AM
the "fix " was a new mixer and mics

What did you get?

That may have been a broad "shotgun" approach to the problem, but if it worked for you.
Title: Re: rf interference
Post by: John Luty on January 05, 2019, 02:17:22 PM
What did you get?

That may have been a broad "shotgun" approach to the problem, but if it worked for you.
I picked up a Yamaha mg10xu mixer and 2 sets of Shure BLX288/PG58 mics , I run a small karaoke show so I didn't need a large mixer and I didn't want to go too expensive on the mics knowing drunks will be using them but at the same time wanted something fairly good
I'm planning on sending my other mixer Peavey PV10 at in to get it fixed giving mea decent backup
Title: Re: rf interference
Post by: Roland Clarke on January 06, 2019, 02:34:43 PM
update the main problem was my mixer the right channel was going add that to the mic frequencies at 537.500 and 537.900and it was a recipe for disaster , spent some money today hopefully no more problems

Those frequencies are quite close.  Often if you read the manual, you will find that they will advise you to use one or the other with frequencies this close.  Glad to hear you found a fix, whilst not what any of us want, it sounds that you have learnt a lot from the experience.