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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: Pete Erskine on October 18, 2016, 02:39:02 PM
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These BBQ Pizza trays eliminated the fluttering we got when initially setting up here at the UNLV Thomas & Mack Center. The roof here is a dome and, while not excessively high, does reflect back down to the floor all RF. The aluminum screen is not grounded, just mounted above the antenna. I'm thinking about suspending another 8" below to make essentially a doughnut pattern and keep reflections from going down when the antenna is mounted higher than 20' from floor. The fluttering mostly would have gone away once an audience fills the arena but on this show there is virtually no audience -- most of the stadium is empty.
https://www.amazon.com/gp/product/B00EAXW1VY/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
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How high off the floor was the final position?
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How high off the floor was the final position?
all 5 were about 15-20' up
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all 5 were about 15-20' up
Very interesting Pete, similar strategy to a 'black wrap' solution I've tried previously when encountering a metal concave roof. I've been musing further about creating a reflection blocker for these situations again by covering RF Blocking Material on a similar structure. I've looking at this material in particular:
http://www.aaronia.com/products/shielding-screening/Aaronia-X-Dream-100dB-shielding-fleece/ (http://www.aaronia.com/products/shielding-screening/Aaronia-X-Dream-100dB-shielding-fleece/)
Marc
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Very interesting Pete, similar strategy to a 'black wrap' solution I've tried previously when encountering a metal concave roof. I've been musing further about creating a reflection blocker for these situations again by covering RF Blocking Material on a similar structure. I've looking at this material in particular:
http://www.aaronia.com/products/shielding-screening/Aaronia-X-Dream-100dB-shielding-fleece/ (http://www.aaronia.com/products/shielding-screening/Aaronia-X-Dream-100dB-shielding-fleece/)
Marc
interesting material but for the price and convenience the pizza trays are easier, I think.
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So, this week the FSII and Base2 are at a conference at the T-Mobile Arena. The ceiling here is 190', 160' to the bottom of the steel so it's large.
Our stage is in the round, 36" high. We knew it would be a challenge due to reflections. 1 Antenna in each of the 4 voms about 1-2' back from the entrance made them work well. Coverage did not extend to the center of the arena. On 4 corners of the round stage (use your imagination) we put an antenna at about 5'. As is the dropout was serious and unusable, even for just listening. Placing a pizza screen on top of each antenna made it almost usable but the breakup was still very annoying. Ultimately we had to move our main ASM and Stage crew to a BTR.
When off the floor the coverage is perfect, just not in the house. Hopefully CC will come up with a solution.
In first pix you can see the FSII, the Mic antenna and on the railing behind, the white box, one of the 100+ wifi access points. The last pix is one of the AP located around the stage. We negotiated with the IT dept to keep them as far away as possible from our antennas.
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Thanks for sharing your experience. I had a very similar experience with FSII at the Anaheim Convention Center Arena, which although not as large as T-Mobile, does have a unique curved ceiling. In the hallways outside of the arena, quality was excellent. Inside, the breakup was pretty bad once you were about 20' from a transceiver. We experimented quite a bit with antenna placement inside the arena, with minimal improvement.
After the show, Clear-Com came out to the arena to do some tests and confirmed that the system was having trouble due to the ceiling reflections. We also demoed the 2.4 GHz version of FSII, which sounded great - zero dropouts. Apparently the 2.4 software deals with "errors" (reflections) differently than the 1.9 system. Hopefully, improvements can be made to the 1.9 software to better handle the reflections. It's a pretty great system aside from this issue.
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Hi Pete, great information.
I'm doing a corporate type show in the San Diego CC. Using Freespeak II, latest version. Having the same audio stutter problem as you describe. I've used Freespeak on 3 other shows in very different environments and it worked great. Expected the same here.
It's a large space,not really square, more like a square next to a triangle. 500' x 300' with lots of hard surfaces, concrete floor. Most of the walls have a 8' high concrete finish on them. The air wall between Halls seems to be made of metal.
There are also 56 directional wifi emitters in this space transmitting a,c band at 5.3Ghz straight down as described by the Smart City techs we summoned for a conversation. These are probably at about 45'. Very nice people happy to help in any way as long as they didn't have to change the power, configuration of their perfectly working system. Which this particular high tech show would rely on for their 8000 attendees who surely would have at least 3 wifi hungry devices each.
The initial antennae design had 5 in the catwalk and 4 on the ground.
We implemented this original design and when we finally got to do some tests late on day two, realized the complete system had the audio stutter symptom. We tried moving antennas closer to the users. We raised the antennas higher for better line of sight and nothing seemed to help.
I came back to the hotel with BTR's on an early morning order and very frustrated. And then I found this post. It encouraged me to try a few more things. I had not used this system in an arena and I saw the mention about deploying the antennas in the voms to shield from the reflections and multi path issues.
We basically put 4 antennas under the 45' x 200' stage near the areas that had the heaviest user traffic. 2 under tables that were needed in the main production tables, 1 under a table at FOH 300' from the stage but where a couple users would ultimately sit for the show and 1 under a table in front of the stage where a temporary tech table has been set for rehearsals. We left one in the catwalk, somewhere in the middle of this space between the stage and FOH and even put a screen as Mr. Erskine shows to try to shield the antennae from the wifi emitters closest to it. This was just to get users to FOH.
This has dramatically upgraded our system, using the additional shielding of the stage and tables it brought our system usability up by 70%. It has probably decreased our range a bit but seems to be working.
My question after all of this is, based on this scenario, what should I expect on show day when 8,000 attendees arrive with 24,000 + wifi devices. How will my quality of service change and what improvements can I make to keep the integrity of what I already have.
Thanks so much,
Ryan Trefethen
Sent from my iPad using Tapatalk
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We basically put 4 antennas under the 45' x 200' stage near the areas that had the heaviest user traffic. 2 under tables that were needed in the main production tables, 1 under a table at FOH 300' from the stage but where a couple users would ultimately sit for the show and 1 under a table in front of the stage where a temporary tech table has been set for rehearsals. We left one in the catwalk, somewhere in the middle of this space between the stage and FOH and even put a screen as Mr. Erskine shows to try to shield the antennae from the wifi emitters closest to it. This was just to get users to FOH.
This has dramatically upgraded our system, using the additional shielding of the stage and tables it brought our system usability up by 70%. It has probably decreased our range a bit but seems to be working.
My question after all of this is, based on this scenario, what should I expect on show day when 8,000 attendees arrive with 24,000 + wifi devices. How will my quality of service change and what improvements can I make to keep the integrity of what I already have.
Thanks so much,
Ryan Trefethen
Sent from my iPad using Tapatalk
You didn't say if you were using 1.9 or 2.4 FSII. Neither should be affected by the audience.
In either case keep the antennas 15+' away from cell or WiFi antennas. It's just good antenna practice.
The shielding I used was not to avoid antennas but to limit the reflection off of the ceiling which was almost 190' up.
is your catwalk antenna as high as the ceiling or how much room is above it?
I, too, went from a totally unusable system to one which was 70% with lots of dropout but mostly intelligible.
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What is actually causing the "stuttering"?
Do I take it these systems are not diversity and as such, the RF signals are subject to (partial) cancellation due to the out of phase signals reflected signal from the ceiling?
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You didn't say if you were using 1.9 or 2.4 FSII. Neither should be affected by the audience.
In either case keep the antennas 15+' away from cell or WiFi antennas. It's just good antenna practice.
The shielding I used was not to avoid antennas but to limit the reflection off of the ceiling which was almost 190' up.
is your catwalk antenna as high as the ceiling or how much room is above it?
I, too, went from a totally unusable system to one which was 70% with lots of dropout but mostly intelligible.
Hi Pete,
This is a 1.9Ghz system. And that multi path reflection is the original reason I tried the shields. But ultimately using the stage itself which is about 36" high has been the most effective to avoid the reflections that seem to be causing my problems.
I would say the antennas in the air were suspended about 4' above the WIFI antennas that are every 30' and about 15' below the ceiling in this hall. We did try just one catwalk antennae and had the same unusable audio stutter while standing below it which is probably 35' up.
We are successfully using the Freespeak on our second day of rehearsals. And while the com guy and myself(A2) feel like it could be much better no one has mentioned a thing about the now occasional stutters on the com system.
Pete, Do you think the wifi antennas, multi path from the hard surfaces or a combination of the two are affecting our system?
As always appreciate your help.
Ryan
Sent from my iPad using Tapatalk
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What is actually causing the "stuttering"?
Do I take it these systems are not diversity and as such, the RF signals are subject to (partial) cancellation due to the out of phase signals reflected signal from the ceiling?
the problem is a very high domed ceiling where the signal bounces back and the receiver cant tell what is the signal or a reflection so it stutters and disconnects. two rooms 1 with flat ceiling and 1 with domed ceiling will be very different.
I do not know if they are diversity. The antenna consists of 2 elements on a PC Board near the top of the unit. Whether it is diversity or RX/TX is not known. I infer from statements made by CC in other forums that this is a software defined radio and may be adjustable with further software changes. We'll hope for the best.
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Sorry to wake up a dead thread...
I am currently sitting in Lucas Oil Stadium with a couple FSII packs giving me this exact issue. Show in 2 days.
Has anyone found a better solution than a pizza pan?
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Sorry to wake up a dead thread...
I am currently sitting in Lucas Oil Stadium with a couple FSII packs giving me this exact issue. Show in 2 days.
Has anyone found a better solution than a pizza pan?
Hi Sean,
My solution for the show I mentioned in the post worked out fine after I did the following.
- Hide all of the freespeak antennas under the stage and tables(this seemed to shield it from the interference)
- Another suggestion from Pete that seems like it would do the same thing is to put your antennas in the voms to shield them.
- That's it!
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Hi Sean,
My solution for the show I mentioned in the post worked out fine after I did the following.
- Hide all of the freespeak antennas under the stage and tables(this seemed to shield it from the interference)
- Another suggestion from Pete that seems like it would do the same thing is to put your antennas in the voms to shield them.
- That's it!
I fought this issue and lost at a convention center a few months back [don't remember which one... i travel too much...]. IIRC i actually put the antennas under the stage and still had issues. What was your stage made of? Metal? Wood decking with metal frame? Just curious....
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No stage, expo. The floor is sportcourt covering a football field. Roof is steel, 300' up.
I'll try the pizza pan idea tomorrow.
Thanks!
I fought this issue and lost at a convention center a few months back [don't remember which one... i travel too much...]. IIRC i actually put the antennas under the stage and still had issues. What was your stage made of? Metal? Wood decking with metal frame? Just curious....
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I fought this issue and lost at a convention center a few months back [don't remember which one... i travel too much...]. IIRC i actually put the antennas under the stage and still had issues. What was your stage made of? Metal? Wood decking with metal frame? Just curious....
Hi Brian,
I believe it was wood deck with metal locking frames. It made the system from unusable to 70% which, unfortunately these days was enough to receive zero comments from the users. I could hear a drop out now and again but not a peep otherwise. One interesting psychological aspect is that since the talking user gets side tone locally they don't notice themselves dropping out now and again and no one else seems to notice the other users as much as themselves. I found this interesting and maybe is just my opinion but seemed consistent the couple times I used this system in less than ideal environments.
Sent from my iPhone using Tapatalk
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Hi Brian,
I believe it was wood deck with metal locking frames. It made the system from unusable to 70% which, unfortunately these days was enough to receive zero comments from the users. I could hear a drop out now and again but not a peep otherwise. One interesting psychological aspect is that since the talking user gets side tone locally they don't notice themselves dropping out now and again and no one else seems to notice the other users as much as themselves. I found this interesting and maybe is just my opinion but seemed consistent the couple times I used this system in less than ideal environments.
Sent from my iPhone using Tapatalk
That was absolutely my experience as well. My client was also the producer and she did most of the talking. Since she could hear herself fine, she never said a peep. But since she talked a LOT, everyone else heard the breakups. Thankfully they weren't the ones paying the bills. :)
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That was absolutely my experience as well. My client was also the producer and she did most of the talking. Since she could hear herself fine, she never said a peep. But since she talked a LOT, everyone else heard the breakups. Thankfully they weren't the ones paying the bills. :)
Ryan and Brian, I agree with your assessments about local sidetone. Another phenomenon that I've observed is that when most users notice the breakup, they say something like, "I think John needs a new battery," or "I think I need a new battery." It's better than "Hey A2, I notice some errors resulting from multipath interference, did you spec the wrong com system for this venue?"
I'll add that I purchased the pizza pans recommended by Pete and did a quick A/B test with and without them in the Santa Clara Convention Center exhibit halls. They did not improve the breakup for me in that room, but it was very minimal to begin with.
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Ryan and Brian, I agree with your assessments about local sidetone. Another phenomenon that I've observed is that when most users notice the breakup, they say something like, "I think John needs a new battery," or "I think I need a new battery." It's better than "Hey A2, I notice some errors resulting from multipath interference, did you spec the wrong com system for this venue?"
Ha this is very funny. Yes getting a battery replaced is akin to leaning over the monitor desk and "making" the adjustment. 60% of the time it works every time.
I'll add that I purchased the pizza pans recommended by Pete and did a quick A/B test with and without them in the Santa Clara Convention Center exhibit halls. They did not improve the breakup for me in that room, but it was very minimal to begin with.
Yes Ross, I too tried the trays at my event and that did not help my particular problem. I believe my problem was not multipath but just noise floor issues. Which the stage shielding the antennas seemed to help. Wonder if you tried something silly like putting them in a closed road case on a short stand. Putting mine under the stage and under tables near the users most likely reduced my range but I was lucky to have 10 antennas in that system and I used them all to account for this.
Sent from my iPhone using Tapatalk
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What is actually causing the "stuttering"?
Do I take it these systems are not diversity and as such, the RF signals are subject to (partial) cancellation due to the out of phase signals reflected signal from the ceiling?
The multipath reflections cause out of time reception of several signals to the extent that the 1s and 0s cannot be distinguished anymore. They are not diversity - this wouldn't fix the issue anyway. Two solutions are better RX circuits and changing the kind of data which is sent. The data type is fixed because of the licence to use DECT and cannot be changed, Adding diversity as well as polarity diversity and extensive processing would probably help.
The new Bolero from Riedel does that and may work better (I have yet to try it myself). Crewcom from Plyant (Coachcom) deals with it in a different way. They made the data word be 3X linger with sane no if bits, Now the multipath distortion is smaller in relation to the direct signal. See the diagram below.
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The multipath reflections cause out of time reception of several signals to the extent that the 1s and 0s cannot be distinguished anymore. They are not diversity - this wouldn't fix the issue anyway. Two solutions are better RX circuits and changing the kind of data which is sent. The data type is fixed because of the licence to use DECT and cannot be changed, Adding diversity as well as polarity diversity and extensive processing would probably help.
The new Bolero from Riedel does that and may work better (I have yet to try it myself). Crewcom from Plyant (Coachcom) deals with it in a different way. They made the data word be 3X linger with sane no if bits, Now the multipath distortion is smaller in relation to the direct signal. See the diagram below.
But Crewcom is not running on DECT if i understand correctly? It's running in 2.4Ghz and/or 900Ghz? Still a very cool idea for interference reduction, especially in that crowded space.
I'm assuming that in order to use something other than a legitimate DECT transmission within the 1.9GHz space would require approval from the FCC for a completely new use of that spectrum; something i am also assuming is slightly less likely than a sudden outbreak of aeronautical swine...
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But Crewcom is not running on DECT if i understand correctly? It's running in 2.4Ghz and/or 900Ghz? Still a very cool idea for interference reduction, especially in that crowded space.
I'm assuming that in order to use something other than a legitimate DECT transmission within the 1.9GHz space would require approval from the FCC for a completely new use of that spectrum; something i am also assuming is slightly less likely than a sudden outbreak of aeronautical swine...
This is not up to the FCC. DECT standard is an international standard and cannot be substantially altered. Advanced digital processing, both on the RF side and AF side is the only solution to make it work. Possibly Riedel has solved it but I have not actually tried their system yet.
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This is not up to the FCC. DECT standard is an international standard and cannot be substantially altered. Advanced digital processing, both on the RF side and AF side is the only solution to make it work. Possibly Riedel has solved it but I have not actually tried their system yet.
So in order to alter DECT basically Old McDonald's entire farm would have to go airborne first. Understood... :)
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This is not up to the FCC. DECT standard is an international standard and cannot be substantially altered. Advanced digital processing, both on the RF side and AF side is the only solution to make it work. Possibly Riedel has solved it but I have not actually tried their system yet.
You'll get your chance soon, no doubt.
But yes, this is the key, and something we've spent years looking at.
Interestingly, this is something that makers of mobile phones implicitly understand and they have been dealing with this for a lot longer than us lowly comms folk! If you think the multipath issues are bad getting 50m to your DECT antenna, wait until you try and go 250m to the nearest cell tower...
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These BBQ Pizza trays eliminated the fluttering we got when initially setting up here at the UNLV Thomas & Mack Center. The roof here is a dome and, while not excessively high, does reflect back down to the floor all RF. The aluminum screen is not grounded, just mounted above the antenna. I'm thinking about suspending another 8" below to make essentially a doughnut pattern and keep reflections from going down when the antenna is mounted higher than 20' from floor. The fluttering mostly would have gone away once an audience fills the arena but on this show there is virtually no audience -- most of the stadium is empty.
Hello, I am going to set up a Freespeak II system in NRG stadium for a large event in March, All I need is coverage around the stage and surrounding floor area. The Stage moves to the center of the arena for the performance. Should I place these ants possibly under the Metal stage? We will still have BTR and RAD there for other facets of the show and I want to do some experimentation. Any hints are certainly appreciated.
Thanks,
DC
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Just a quick little revival to this thread... I'm curious if anyone has tried putting antennas up near the ceiling of an arena? In other words, if given access to catwalks in an arena, would putting the antennas within 20-30' of the ceiling in a venue with a 120' ceiling do any good? Yes, there is real potential for signal loss just due to the distance, but would putting the antennas as close to the ceiling as possible be a solution? We have a show in a few months where I'd much rather use our FS2 system, rather than wrangle 4 BTR systems. We've got a couple of network switches with fiber modules, so using house fiber to get the signal up there shouldn't be an issue... at this point it's just a matter of reducing the reflection issues.
So... antennas approximately 100' up, approximately 120' ceiling, and all users on the floor.
Thoughts?
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We've got a couple of network switches with fiber modules, so using house fiber to get the signal up there shouldn't be an issue...
Will FS transceivers work through a network switch? My understanding is that they will not.
Mac
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Will FS transceivers work through a network switch? My understanding is that they will not.
Correct; the currently shipping FSII transceiver is not IP and will not work with Ethernet equipment. The new IP transceiver will work over standard Ethernet switches but requires the IVC-32 card and an Eclipse HX frame. Should be shipping in the very near future.
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Just a quick little revival to this thread... I'm curious if anyone has tried putting antennas up near the ceiling of an arena? In other words, if given access to catwalks in an arena, would putting the antennas within 20-30' of the ceiling in a venue with a 120' ceiling do any good? Yes, there is real potential for signal loss just due to the distance, but would putting the antennas as close to the ceiling as possible be a solution? We have a show in a few months where I'd much rather use our FS2 system, rather than wrangle 4 BTR systems. We've got a couple of network switches with fiber modules, so using house fiber to get the signal up there shouldn't be an issue... at this point it's just a matter of reducing the reflection issues.
So... antennas approximately 100' up, approximately 120' ceiling, and all users on the floor.
Thoughts?
We tried ceiling antennas in a venue with bad multipath. Made no difference because now the signal was bouncing off of the floor, For venues with slight dropped packets the new firmware V1.07 is truly magic. Even in good venues people talking while moving are jittery... this 1.07 fixes that totally.
The firmware is not officially released.
For fiber remote antennas use a combination of 2 media converters. The antenna connection is not actually only network-it is a combination of network and 422 data.
Using this kluge of media converters you can remote antennas over fiber.. (https://static1.squarespace.com/static/53062f8de4b09e63a23ce552/t/58418861be6594f57213dd4a/1480689761746/Microsoft+Word+-+FreeSpeakII+via+fiber+-+Version+3.docx.pdf)
Another way:
Using FSII-SPL splitters you can use 2 splitters and split the 5 antennas between two locations. Cat5 to 1st FS-SPL (outputs 1-2-3-4 turned on) and fiber to second FSII-SPL (only output 5 turned on)
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We tried ceiling antennas in a venue with bad multipath. Made no difference because now the signal was bouncing off of the floor, For venues with slight dropped packets the new firmware V1.07 is truly magic. Even in good venues people talking while moving are jittery... this 1.07 fixes that totally.
The firmware is not officially released.
For fiber remote antennas use a combination of 2 media converters. The antenna connection is not actually only network-it is a combination of network and 422 data.
Using this kluge of media converters you can remote antennas over fiber.. (https://static1.squarespace.com/static/53062f8de4b09e63a23ce552/t/58418861be6594f57213dd4a/1480689761746/Microsoft+Word+-+FreeSpeakII+via+fiber+-+Version+3.docx.pdf)
Another way:
Using FSII-SPL splitters you can use 2 splitters and split the 5 antennas between two locations. Cat5 to 1st FS-SPL (outputs 1-2-3-4 turned on) and fiber to second FSII-SPL (only output 5 turned on)
Has there been a new devolpment in the last two years on the bad multipathing??? Any work arounds??? Seems like we are running into more and more in arenas now as well not just stadiums.
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Has there been a new devolpment in the last two years on the bad multipathing??? Any work arounds??? Seems like we are running into more and more in arenas now as well not just stadiums.
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Mac
admin
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Has there been a new devolpment [sic] in the last two years on the bad multipathing??? Any work arounds??? Seems like we are running into more and more in arenas now as well not just stadiums.
Presuming you're referring to FreeSpeak E1 transceivers (non-IP), the last several iterations of firmwares for the base, transceivers and packs have resulted in a decent reduction of multipath issues. Additionally, any type of metallic shielding on the side of the transceiver facing the ceiling, and aiming the corner of the transceiver where the antenna traces are located (corner opposite the CC logo) downward, helps further.
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Going higher may help too. We put in a temporary FS II system in an ice arena last fall, getting bad multipathing with the antenna on a mic stand for initial test. Putting the antennas up in the catwalks, which are about 2/3 of the height of the roof, worked really well.
So well, in fact, that the "temporary" system is still in place until Clear-Com gets past all their backorders.
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Presuming you're referring to FreeSpeak E1 transceivers (non-IP), the last several iterations of firmwares for the base, transceivers and packs have resulted in a decent reduction of multipath issues. Additionally, any type of metallic shielding on the side of the transceiver facing the ceiling, and aiming the corner of the transceiver where the antenna traces are located (corner opposite the CC logo) downward, helps further.
Hi Henry. I wonder if you mean this way of pointing the corner down? Ur just top down (connectors facing up)?
I'm having multipath issues in the arena I'm at right now (Trade Fair Hall 1 in Valencia, Spain), so I thought of going back to this thread for counsel...
edit: I've never seemed to understand the 'proper' way of mounting this tranceivers: vertical with connectors up or down? Horizontal with logo up or down? I understand they are supposed to be omni, but even omni antennas have blind spots, right?
Cheers.
Diogo
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edit: I've never seemed to understand the 'proper' way of mounting this tranceivers: vertical with connectors up or down? Horizontal with logo up or down? I understand they are supposed to be omni, but even omni antennas have blind spots, right?
Cheers.
Diogo
ANTENNA IS BASICALLY OMNI...slight dip out connector (bottom) side) .... use pizza screens and mount 6" above antenna
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ANTENNA IS BASICALLY OMNI...slight dip out connector (bottom) side) .... use pizza screens and mount 6" above antenna
Thanks. I've mounted them many ways, but always wondered...
We've stuck Rosco Cinefoil on the ones on stands and it definitely helps.
Cheers
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Also...
is grouping a couple of transceivers like this a bad idea? I was short on Manfrotto clamps and the XY-bar was available, so I went with it.
This piece of truss is 5m above my comms station backstage. I need some TCVR concentration in this area as there a lot of users roaming around here and it's also where I power most of the packs every morning. I have another 6 transceivers spread around the venue...
Cheers,
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Also...
is grouping a couple of transceivers like this a bad idea?
Not necessarily. It’s a little close for my liking (probably just me, lol), but colocating transceivers yields higher capacity vs extended coverage.