Wireless receiver location

[rriley84]

Hey all! My church runs seven Shure PGX24/SM58 wireless sets. The problem we are having is constant drop out and loss of signal from 60 feet away. Currently, the receivers are nestled between the mixer and the video switcher, stacked on top of each other in the booth at the back of the sanctuary. It is roughly waist hight from the ground and sit behind a ledge. I keep thinking we need to mount them over our heads and give them some space. Any thoughts?

Ryan

[bpalermini]

Yes, bodies in the way can impact your signal. There are a number of things you could do.
- Put the receivers in a higher location as you said.
- Get a antenna distribution system so that you can use two antennas to feed all of your receivers then mount just the antennas higher.
- Move the receivers to the stage so there is less opportunity for things or people getting between the transmitter and receiver.

[[Admin] osborn4]

We got antenna distribution system and are about 60; away and it works great.

[waynehoskins]

Some receivers will desense each other when too many are closely stacked like that without an antenna distribution system. I don't know if PGX does this or not, but it's my first guess, presuming that RF coordination isn't the problem. If this is the case, increasing the spacing between the receivers will help. A local theatre has this problem with closely-spaced receivers from brand A leaking and desensing receivers from brand B; putting a piece of 2x4 between them solved the problem.

The distance is short enough, and the receivers in-the-clear enough, that path obstruction isn't a likely problem. I've run systems at similar or greater distances, with worse path conditions, with far better results.

PGX doesn't have removable antennas, I don't think, so antenna distribution isn't an option.

Do check your RF coordination, both with the wireless systems you're using and with the list of nearby TV stations. You could very well have two systems interfering with each other, or you could be co-channel with a TV station.

[bobbycito]

to check ur freqs you can use the shure freq finder on their website http://www.shure.com/americas/suppor...nder/index.htm

also do you you see issues when they have freash batteries or as they are draining down to end of life?

are the mics spread out or are there some on and close together in a tray?

[rriley84]

Originally Posted by bobbycito

to check ur freqs you can use the shure freq finder on their website

also do you you see issues when they have freash batteries or as they are draining down to end of life?

are the mics spread out or are there some on and close together in a tray?

Issues are with fresh batteries and they are spread out along the stage when being used. The Shure site says to use group 8 which I will try next week during rehearsal. Right now they are spread all over the groups.

[rriley84]

Originally Posted by waynehoskins

Some receivers will desense each other when too many are closely stacked like that without an antenna distribution system. I don't know if PGX does this or not, but it's my first guess, presuming that RF coordination isn't the problem. If this is the case, increasing the spacing between the receivers will help. A local theatre has this problem with closely-spaced receivers from brand A leaking and desensing receivers from brand B; putting a piece of 2x4 between them solved the problem.

The distance is short enough, and the receivers in-the-clear enough, that path obstruction isn't a likely problem. I've run systems at similar or greater distances, with worse path conditions, with far better results.

PGX doesn't have removable antennas, I don't think, so antenna distribution isn't an option.

Do check your RF coordination, both with the wireless systems you're using and with the list of nearby TV stations. You could very well have two systems interfering with each other, or you could be co-channel with a TV station.

Unfortunatly, the PGX systems do not have an antenna distributuion option as far as I can tell. I will try spacing them out more across the booth and see what happens.

[waynehoskins]

Originally Posted by rriley84

Right now they are spread all over the groups.

There's part of your problem, potentially. Those groups are intermod-free sets of frequencies that are calculated to not interfere with others in the same group. The short version of intermod (short for intermodulation distortion, also IMD, IM) is that when two transmitters are on within close proximity to each other, they mix to create additional distortion products that interfere with radios on other frequencies. By doing the math carefully, you can come up with a set of frequencies that don't interfere with each other, as the manufacturers do, but unless you know what you're doing, you need to stay within one group.

And again, be aware of frequencies to avoid, like those occupied by TV stations, as you will be fighting a losing battle with interference.