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Author Topic: Wireless Mic Antenna Distrubution  (Read 4233 times)

Joseph Monarch

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Wireless Mic Antenna Distrubution
« on: February 09, 2014, 03:51:14 PM »

I have been working a/v equipment for some time now in small churches and never had to deal with much interference in the wireless mics.  I have recently taken a position in a bigger church that is in the process of upgrading all the a/v equipment.  While I have no issue with our wireless system during mic checks, when people start arriving and the seats fill up we start having a little interference.  Sometimes it gets to the point what all my mics on different frequencies are having issues with the signal and completely cutting out during the service.  But it doesn't always happen.  Sometimes we can go an entire service without any interference and other services I am tempted to go back to wired mics.

I have been looking into antenna distribution but really I am not sure how they work or how they will work with our mics.

Here is what we currently have:
G-787H Diversity UHF 4x800 Channel Wireless Microphone System
http://www.gtdaudio.net/product_info.php?cPath=31&products_id=121

When there is no interference these mics sound and operate great.  Plus we will be getting 2 more of these for a total of 12 mics.  It will include handheld mics and body packs.

What I am needing to know is the who, what, where, when and why of distribution systems.
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Jerome Malsack

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Re: Wireless Mic Antenna Distrubution
« Reply #1 on: February 10, 2014, 01:28:30 PM »

One thing you can try is work your way threw some online training. 

http://www.shure.com/americas/support/training/advanced-wireless-seminars

Where is the receivers and antennae mounted in relation to the stage area. 

Height is your friend. 

Seems the people and their wireless may be creating a lot of RF noise for the mic's to compete with.   Seeing that the document shows a Freq 610 to 680 mhz  you should not be having interference from wifi. 

Lighting, do you have florescent that are off during rehearsals.
Sometimes Lights or dimmers can cause problems. 
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Thomas Le

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Re: Wireless Mic Antenna Distrubution
« Reply #2 on: February 10, 2014, 01:30:47 PM »

Hmm, with this brand, they don't even make a distribution system AFAIK. So you can't do one anyway.
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Mac Kerr

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Re: Wireless Mic Antenna Distrubution
« Reply #3 on: February 10, 2014, 01:44:14 PM »

Hmm, with this brand, they don't even make a distribution system AFAIK. So you can't do one anyway.

No. There is nothing brand specific about RF. If you can attach external antennas you can use an antenna distribution system from any of several manufacturers.

Mac
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Jordan Wolf

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Re: Wireless Mic Antenna Distrubution
« Reply #4 on: February 11, 2014, 09:40:21 AM »

No. There is nothing brand specific about RF. If you can attach external antennas you can use an antenna distribution system from any of several manufacturers.

Mac
Just be careful - some output bias voltage and some receivers don't like that...
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Jordan Wolf
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Jason Glass

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Re: Wireless Mic Antenna Distrubution
« Reply #5 on: February 11, 2014, 12:50:39 PM »

I have been working a/v equipment for some time now in small churches and never had to deal with much interference in the wireless mics.  I have recently taken a position in a bigger church that is in the process of upgrading all the a/v equipment.  While I have no issue with our wireless system during mic checks, when people start arriving and the seats fill up we start having a little interference.  Sometimes it gets to the point what all my mics on different frequencies are having issues with the signal and completely cutting out during the service.  But it doesn't always happen.  Sometimes we can go an entire service without any interference and other services I am tempted to go back to wired mics.

I have been looking into antenna distribution but really I am not sure how they work or how they will work with our mics.

Here is what we currently have:
G-787H Diversity UHF 4x800 Channel Wireless Microphone System
http://www.gtdaudio.net/product_info.php?cPath=31&products_id=121

When there is no interference these mics sound and operate great.  Plus we will be getting 2 more of these for a total of 12 mics.  It will include handheld mics and body packs.

What I am needing to know is the who, what, where, when and why of distribution systems.

We usually assume that systems operating in the broadcast TV band will not have interference problems caused by cellular phones, but it can occur when cheap receivers' front ends do not have adequate bandpass filtering to reject out-of-band signals (like cellular).  When these signals enter the receiver, they can drive the front end into non-linear operation and generate lots of intermodulation products and severely desensitize the receiver.

A super-inexpensive system like yours, where you get four channels, each having 70MHz tuning bandwidth, for $329.00, is extremely unlikely to have adequate bandpass filtering to prevent this type of problem.  You will have much more success if you upgrade your system by actually upgrading to higher quality (and price) equipment rather than trying to put an antenna splitter system band-aid on poorly performing receivers.

If your budget prohibits stepping up to better receivers, and the "powers that be" insist on throwing away good money after bad, you might try an antenna distribution unit in conjunction with appropriately tuned external bandpass filters inserted on the antenna input lines.  These could work well for you if you do your homework and find which bands are best for your location and equipment: https://lectrosonics.com/186-PF50-Specify-Blocks/View-details.html or https://lectrosonics.com/176-PF25-Specify-Block/View-details.html.

Karl Winkler

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Re: Wireless Mic Antenna Distrubution
« Reply #6 on: February 11, 2014, 03:41:56 PM »


A super-inexpensive system like yours, where you get four channels, each having 70MHz tuning bandwidth, for $329.00, is extremely unlikely to have adequate bandpass filtering to prevent this type of problem.  You will have much more success if you upgrade your system by actually upgrading to higher quality (and price) equipment rather than trying to put an antenna splitter system band-aid on poorly performing receivers.

Jason makes some good points and all I want to add is that with the system you have there, an antenna distro setup is more likely to make the problem worse than it is to make it better. But as Jason said, IF you do your homework and IF you get a distro system made with good components, it is possible to see improvements. By that point, in my opinion, you'll have spent quite a bit of money. One of the issues you are likely facing is that people are coming into your services with cell phones and other electronics, perhaps silenced, but all of which are emitting RF on different bands. Getting receiver antennas closer to your mics might help, but only be degree. Again, the problem is very likely the issue of poor component/system quality.

A modest investment of perhaps $600 or more per channel of wireless along with decent antennas placed properly and a proper frequency coordination for your site would likely make the problems to go away.
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ProSoundWeb Community

Re: Wireless Mic Antenna Distrubution
« Reply #6 on: February 11, 2014, 03:41:56 PM »


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