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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 => Wireless and Communications => Topic started by: Nate Zifra on December 11, 2015, 09:29:39 AM
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I'm sure the answer to this depends. Our band is now looking at Shure PSM300 units. At the most, we would have 3 transmitters. Uses would be mainly on small stages and bars, and would travel with the band. The idea is to rack them side stage. Other wireless in use would be 3 Line 6 instrument units (G30), and two older Shure PGX mic units.
With three transmitters for IEM, would the combiner be a necessity? Thank you for help, and please excuse my ignorance.
Nathan
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Cost, The rack the transmitters are mounted into. Height is your friend in Wireless, getting the combiner in the rack and sending up one antenna on a stand will spead up the setup and tear down.
Transmitters need to be away from other receivers and computer or digital gear. Using the remote antenna and a cable to connect will make your system more reliable. 20 to 30 inchs between transmitters and receiver antenna. Digital effects, Digital mixers and other devices can cause interference. So the remote getting antennae high and separated some would say yes very smart move.
Looks good to have one antenna. Transmit, two more for the receivers. But Your receivers for the instruments and mics may not have removable antenna with a distribution amp. This can make the stage area look cluttered. If the receivers can be connected to an antenna distribution and you can use two antenna connected tot he distribution to give to each receiver than you will be making the setup and tear down quicker, along with a cleaner stage by having just the three antennae.
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Cost, The rack the transmitters are mounted into. Height is your friend in Wireless, getting the combiner in the rack and sending up one antenna on a stand will spead up the setup and tear down.
Transmitters need to be away from other receivers and computer or digital gear. Using the remote antenna and a cable to connect will make your system more reliable. 20 to 30 inchs between transmitters and receiver antenna. Digital effects, Digital mixers and other devices can cause interference. So the remote getting antennae high and separated some would say yes very smart move.
Looks good to have one antenna. Transmit, two more for the receivers. But Your receivers for the instruments and mics may not have removable antenna with a distribution amp. This can make the stage area look cluttered. If the receivers can be connected to an antenna distribution and you can use two antenna connected tot he distribution to give to each receiver than you will be making the setup and tear down quicker, along with a cleaner stage by having just the three antennae.
All very good points!
Keep your transmitter and receiver antennas apart.
And remember that antennae may only work on insects ;-)
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And remember that antennae may only work on insects ;-)
Give that man a cheroot!
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Digital effects, Digital mixers and other devices can cause interference. So the remote getting antennae high and separated some would say yes very smart move.
Interference is an issue at the receiver, not the transmitter.
Another factor to keep in mind is that a properly designed and built combiner will reduce transmitter intermodulation products by significantly reducing the amount of RF energy from any two of the transmitters getting into the third's final power amplifier through its antenna.
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All very good points!
Keep your transmitter and receiver antennas apart.
And remember that antennae may only work on insects ;-)
And don't point the transmit antenna at the receiver antenna(s).
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http://grammarist.com/usage/antennae-antennas/
In the U.S. and Canada, the plural of the noun antenna is antennae when the word denotes the flexible sensory appendages on insects and other animals. But when the word refers to a metallic apparatus for sending or receiving electromagnetic signals, American and Canadian writers usually use antennas. British writers tend to use antennae for both purposes. Australian and New Zealand writers are split on the matter, using both plurals for the metallic devices.
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http://grammarist.com/usage/antennae-antennas/
In the U.S. and Canada, the plural of the noun antenna is antennae when the word denotes the flexible sensory appendages on insects and other animals. But when the word refers to a metallic apparatus for sending or receiving electromagnetic signals, American and Canadian writers usually use antennas. British writers tend to use antennae for both purposes. Australian and New Zealand writers are split on the matter, using both plurals for the metallic devices.
The United States, the United Kingdom, Australia, and Canada continue to be divided by a common language.
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http://grammarist.com/usage/antennae-antennas/
In the U.S. and Canada, the plural of the noun antenna is antennae when the word denotes the flexible sensory appendages on insects and other animals. But when the word refers to a metallic apparatus for sending or receiving electromagnetic signals, American and Canadian writers usually use antennas. British writers tend to use antennae for both purposes. Australian and New Zealand writers are split on the matter, using both plurals for the metallic devices.
Interesting! It makes sense but as has been the case, the Americans tend to ...er..."adjust" the language to suit them.
Here in Canada we kind of have to go along to some extent to keep the peace ;D
Now don't get me started on Lectern vs Podium
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Now don't get me started on Lectern vs Podium
The O.E.D. lists both as correct for that thing you stand behind to speak. The thing you stand on to conduct an orchestra is only a podium.
Mac
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The O.E.D. lists both as correct for that thing you stand behind to speak. The thing you stand on to conduct an orchestra is only a podium.
Mac
See, that's what doesn't make sense.
If one can be both, then both can be both.
Er...or sumthin like that ;D
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See, that's what doesn't make sense.
If one can be both, then both can be both.
Er...or sumthin like that ;D
You can discuss that with the editors of the Oxford English Dictionary. As for as I'm concerned antennae only appear on bugs.
Mac
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As for as I'm concerned antennae only appear on bugs.
Mac
And as far as I have seen , they have 2 so must be diversity antennae :)
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As for as I'm concerned antennae only appear on bugs.
Didn't know lobster was a bug. Crawfish on the other hand . . . :)
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Didn't know lobster was a bug. Crawfish on the other hand . . . :)
Sorry, I still think lobsters are big water bugs... Ewwwww
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Didn't know lobster was a bug. Crawfish on the other hand . . . :)
They're both mud bugs. I'd rather eat lobster though. I've never developed a taste for Crawfish.
Mac
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Lol, love how this has digressed. :)
So as to the original question, seems like once you have more than one transmitter for iem, it is a good time to start looking at combiners? I can see in some instances how an external antenna on a mic stand could help with setup. Nothing is as easy as just popping the lids off the rack though. The PSM300 have a 4 channel combiner specific to that model. The mic units and guitar wireless units we have do not have external antennas.
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The United Kingdom, the United States, Australia, and Canada continue to be divided by the latter 3 butchering the english language.
FTFY. Antennae is the plural of antenna. This encompasses its many zoological and technical usages. The difference between various english speaking nations is really down to the demise of latin in schools and grammatical laziness :)
On topic though, you raise an interesting point Henry about combiners reducing 3Tx IM products. Would it be fair to say then that 3 antennae, on 3 Tx units, and each was fitted with a circulator, would this have similar 3Tx IM suppression performance to a combiner?
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On topic though, you raise an interesting point Henry about combiners reducing 3Tx IM products. Would it be fair to say then that 3 antennae, on 3 Tx units, and each was fitted with a circulator, would this have similar 3Tx IM suppression performance to a combiner?
Absolutely, but in this application it's an isolator (third port is terminated). This is in fact a major design feature of much of Lectrosonics mic and IFB transmitters. and why they have been of relatively limited frequency range per block.
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FTFY. Antennae is the plural of antenna. This encompasses its many zoological and technical usages. The difference between various english speaking nations is really down to the demise of latin in schools and grammatical laziness :)
On topic though, you raise an interesting point Henry about combiners reducing 3Tx IM products. Would it be fair to say then that 3 antennae, on 3 Tx units, and each was fitted with a circulator, would this have similar 3Tx IM suppression performance to a combiner?
If a spy planted a bug that was disguised as an insect, it would have real antennas that looked like real antennae.
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Thanks again everyone for the replies. I will definitely be getting the combiner. I'm also strongly considering the Shure PA805 paddle. I have a couple questions with regard to some scenarios we may face.
1. The wireless may be all side stage. Considering some places are very small (bar corner), is a paddle antenna not a good solution in that case? I've read it is possible to be to close to the transmitting antenna. In that case, would it be best to stack the rack of iems on top of some equipment and use the standard 1/4 wave?
2. IEMs may have to be located at FOH at times, usually no more than 50 feet in front. Paddle antenna should be ok on a mic stand up high over the crowd in this case. Any concerns?
3. We may at some point update the wireless mics to the BLX rack, two units, which would most likely end up racked with the iems. To remote the antenna for these, I was thinking of purchasing two 1/2 wave omni's and mounting them on a stereo mount mic stand. Would this method be ok when also using the paddle antenna for the iems?
3(a) To save setup time, could the 1/2 wave omni's and paddle antenna be mounted on one mic stand? Paddle mounted in between the two omni's?
Thanks again.
Cost, The rack the transmitters are mounted into. Height is your friend in Wireless, getting the combiner in the rack and sending up one antenna on a stand will spead up the setup and tear down.
Transmitters need to be away from other receivers and computer or digital gear. Using the remote antenna and a cable to connect will make your system more reliable. 20 to 30 inchs between transmitters and receiver antenna. Digital effects, Digital mixers and other devices can cause interference. So the remote getting antennae high and separated some would say yes very smart move.
Looks good to have one antenna. Transmit, two more for the receivers. But Your receivers for the instruments and mics may not have removable antenna with a distribution amp. This can make the stage area look cluttered. If the receivers can be connected to an antenna distribution and you can use two antenna connected tot he distribution to give to each receiver than you will be making the setup and tear down quicker, along with a cleaner stage by having just the three antennae.
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Thanks again everyone for the replies. I will definitely be getting the combiner. I'm also strongly considering the Shure PA805 paddle. I have a couple questions with regard to some scenarios we may face.
1. The wireless may be all side stage. Considering some places are very small (bar corner), is a paddle antenna not a good solution in that case? I've read it is possible to be to close to the transmitting antenna. In that case, would it be best to stack the rack of iems on top of some equipment and use the standard 1/4 wave?
Often in small venues I switch to whips for my mics and Comms.
2. IEMs may have to be located at FOH at times, usually no more than 50 feet in front. Paddle antenna should be ok on a mic stand up high over the crowd in this case. Any concerns?
50' is not so bad. Line of sight is paramount. a mic stand, even on top of a rack may not be enough. Bodies suck up a lot of RF.
3. We may at some point update the wireless mics to the BLX rack, two units, which would most likely end up racked with the iems. To remote the antenna for these, I was thinking of purchasing two 1/2 wave omni's and mounting them on a stereo mount mic stand. Would this method be ok when also using the paddle antenna for the iems?
I never recommend mounting IEM in the same rack as mics. The TX can radiate even within the rack and will affect the sensitivity of the wireless systems. If you must, place them at opposite ends of the rack with a metal shelf or drawer between them.
3(a) To save setup time, could the 1/2 wave omni's and paddle antenna be mounted on one mic stand? Paddle mounted in between the two omni's?
Make sure your TX antennas are at least 6-8' away from the RX antennas and if possible in the null of the RX antenna. RX antennas need to be at least 3-4' apart to take advantage of diversity.
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The difference between various english speaking nations is really down to the demise of latin in schools and grammatical laziness :)
Agreed.
Latin is where the lectern (to read)and podium (raised platform)has the root of their names and their use gets blurred.
So, if someone is at the lectern with an RF mic, you might want to have your antennas(e) on a podium to get them up higher ;D ;D
I worked with a major band once where the monitor tech had the IEM TX antenna on the same stand within 12" of the receiving antennas. ::)
Had to show him how many more freqs his receivers would find if the TX antenna was farther away.
"Well, it's been working so far" Yes, but it doesn't make it right.
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I worked with a major band once where the monitor tech had the IEM TX antenna on the same stand within 12" of the receiving antennas. ::)
Had to show him how many more freqs his receivers would find if the TX antenna was farther away.
"Well, it's been working so far" Yes, but it doesn't make it right.
Here is a major artists monitor antenna setup...mics and 16 channels of ears. "It's worked everywhere!"
I will admit that in this venue the furthest musician was 20' away.....
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Thank you again for the replies.
Do you get a little more leeway with placement if the mics are a different band than the iems?
Thanks.
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Thank you again for the replies.
Do you get a little more leeway with placement if the mics are a different band than the iems?
Thanks.
Not really. The degradation of the RX is in the overload of the front end of the RX before frequency takes part. If the higher power IEM system is radiating into the RX at a greater power than the Mics which are further away and lower power, the RX will try to protect itself or limit the RF in and therefore make the correct frequency harder to receive.
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I will be using 9 IEM (PSM-900) transmitters soon. I plan to rack them in one rack but I would like to mount the antenna's on the back of the rack. At this time I cant afford to do the distros. If i mount all 9 on a 2U rack plate, what problems will I have ? The spacing between them would be about 2" ...
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I will be using 9 IEM (PSM-900) transmitters soon. I plan to rack them in one rack but I would like to mount the antenna's on the back of the rack. At this time I cant afford to do the distros. If i mount all 9 on a 2U rack plate, what problems will I have ? The spacing between them would be about 2" ...
Nine transmitter antenna that close is going to create intermod problems. The RF gurus will surely jump in here.
When you have more than a couple of iem transmitters, a combiner is a necessary item. You should have bought 8 and the combiner.
Sent from my iPad using Tapatalk HD
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Nine transmitter antenna that close is going to create intermod problems.
I had expected the reply on this... So until i can afford the distro, I'm guessing the best thing i can do is spread the transmitters out... humm Thanks for the reply tho.
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You should strongly consider renting an 8 input combiner if you don't have the budget to purchase one now. The time and annoyance factor in running 8 remote antennas to appropriate locations alone will make it worth it, not to mention the cost for the coax runs (don't skimp on the coax; it'll bite you hard), antennas (don't skimp on this either) and mic stands may be a significant contribution toward the price of a combiner.
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Not really. The degradation of the RX is in the overload of the front end of the RX before frequency takes part. If the higher power IEM system is radiating into the RX at a greater power than the Mics which are further away and lower power, the RX will try to protect itself or limit the RF in and therefore make the correct frequency harder to receive.
The different band models should have some front end selectivity. Otherwise they might have well have made a single radio tuneable across all bands.
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The different band models should have some front end selectivity. Otherwise they might have well have made a single radio tuneable across all bands.
The selectivity happens at the first filter stage. Prior to that most RX have an input protection limiter which prevents overload on a broadband basis. RF of any frequency if too strong will lower the gain some.
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You should strongly consider renting an 8 input combiner if you don't have the budget to purchase one now. The time and annoyance factor in running 8 remote antennas to appropriate locations alone will make it worth it, not to mention the cost for the coax runs (don't skimp on the coax; it'll bite you hard), antennas (don't skimp on this either) and mic stands may be a significant contribution toward the price of a combiner.
Thanks for the reply. Although the whole project is overwhelming. I'm plugging along. I have asked for the combiners but you all know how that goes. What I have done so far is laid out the antenna's 12" apart and have 5 working. So far No problems. With limited amount of Freq's in the area, no RF interference yet. I wish it was just IEM's being installed on this project. If a used or great priced combiner shows up on E-bay or such, I will prolly buy it out of my own pocket. (overwhelmed again)
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Check out RFVenue's gear; they seem fairly solid.
- Jordan Wolf
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Here is a major artists monitor antenna setup...mics and 16 channels of ears. "It's worked everywhere!"
I will admit that in this venue the furthest musician was 20' away.....
Don't the paddles have RX preamp's in them? If they do, the amp is before the loss of the cable. Basically a preamp in the paddle enclosure makes up for cable and splitting losses.
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Don't the paddles have RX preamp's in them? If they do, the amp is before the loss of the cable. Basically a preamp in the paddle enclosure makes up for cable and splitting losses.
In that example, quoted the don't. I always shy away from preamps in antenna cable unless the cable is over 150', particularly in heavy DTV towns and we are outside or in line of sight to the TV towers. The preamp will just amplify everything, including the high noise floor and often just overload itself and distort the RF. Shure's UA874 has an interesting "amp". The options include -6dB. Also it has an overload light which almost always goes on at the +6dB level so it shows how easily the antenna amp can overload. If I feel that a long run needs a little boost to match other antennas I use the Shure UA830 and put it at the end of the coax - the RF and noise floor attenuated by the coax lessening the possible overload of the amp but giving the cleanest RF.
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In that example, quoted the don't. I always shy away from preamps in antenna cable unless the cable is over 150', particularly in heavy DTV towns and we are outside or in line of sight to the TV towers. The preamp will just amplify everything, including the high noise floor and often just overload itself and distort the RF. Shure's UA874 has an interesting "amp". The options include -6dB. Also it has an overload light which almost always goes on at the +6dB level so it shows how easily the antenna amp can overload. If I feel that a long run needs a little boost to match other antennas I use the Shure UA830 and put it at the end of the coax - the RF and noise floor attenuated by the coax lessening the possible overload of the amp but giving the cleanest RF.
Hi Pete
Did you know that the UA874 rf amp is "always on", even when the switch is in the "passive" -6 og 0 db position? See this interesting page: http://shure.custhelp.com/app/answers/detail/a_id/4115/~/will-the-shure-ua874-or-ua870-antenna-work-if-dc-power-is-not-supplied%3F
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Hi Pete
Did you know that the UA874 rf amp is "always on", even when the switch is in the "passive" -6 og 0 db position? See this interesting page: http://shure.custhelp.com/app/answers/detail/a_id/4115/~/will-the-shure-ua874-or-ua870-antenna-work-if-dc-power-is-not-supplied%3F
Since it is a software switch the antenna needs power in any setting.
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In that example, quoted the don't. I always shy away from preamps in antenna cable unless the cable is over 150', particularly in heavy DTV towns and we are outside or in line of sight to the TV towers. The preamp will just amplify everything, including the high noise floor and often just overload itself and distort the RF. Shure's UA874 has an interesting "amp". The options include -6dB. Also it has an overload light which almost always goes on at the +6dB level so it shows how easily the antenna amp can overload. If I feel that a long run needs a little boost to match other antennas I use the Shure UA830 and put it at the end of the coax - the RF and noise floor attenuated by the coax lessening the possible overload of the amp but giving the cleanest RF.
Intersting, if the noise is broadband and in the bandpass of the what you trying to pickup and/or the preamp lacked a preselector filter you could create more harm than good. It is also dissapointing to hear the front ends of the rx's are that easy to overload.
I was simply quoting a general RF design principle and did not take in account application specific issues.
I will refrain from commenting in the future unless I have direct operational experience with the hardware in question.
My apologies.
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