ProSoundWeb Community

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: Lee Douglas on December 17, 2017, 03:30:14 pm

Title: Transmitters in bread pans
Post by: Lee Douglas on December 17, 2017, 03:30:14 pm
I was reading through the thread (linked below) and didn't want to derail the experiment in progress, but can someone explain the practice of putting transmitters in bread pans? Links welcome!

http://forums.prosoundweb.com/index.php/topic,165731.0.html
Title: Re: Transmitters in bread pans
Post by: Samuel Rees on December 17, 2017, 03:31:49 pm
Same link, still good.

https://www.rfvenue.com/blog/2016/05/13/whats-up-with-the-tin-bins


Sent from my iPhone using Tapatalk
Title: Re: Transmitters in bread pans
Post by: Lee Douglas on December 17, 2017, 04:24:10 pm
Thanks for that.  I was so concerned about cluttering up the other thread with my lack of knowledge on the subject, I presumed that link was specifically and only addressing the battery anomaly that was the subject of the thread.
Title: Re: Transmitters in bread pans
Post by: Keith Broughton on December 17, 2017, 04:29:42 pm
I did my own testing with 6 transmitters within about 10' of the receiver antennas and watched the receivers that were turned on but did not have a transmitter associated with them.
Watched as the RF showing meters on the open receivers dropped away to nothing as the transmitters were put in the trays.
As others have found out, it really works to reduce intermod problems with multiple transmitters in a relatively close space.
2 major mistakes I see all the time are...
1-transmitters on a table too close to receive antennas
2-transmitters that are lined up in a row on a table. (use the pans Luke...)
Title: Re: Transmitters in bread pans
Post by: Dan Mortensen on December 17, 2017, 05:46:10 pm
Thanks for that.  I was so concerned about cluttering up the other thread with my lack of knowledge on the subject, I presumed that link was specifically and only addressing the battery anomaly that was the subject of the thread.

Hi Lee,

FWIW I don't think you would have cluttered up the thread due to your lack of knowledge, because I don't know anything either and am asking questions to try to learn.
Title: Re: Transmitters in bread pans
Post by: Lee Douglas on December 17, 2017, 06:57:28 pm
I appreciate that.  I started this thread so that those of who know nothing about the technique could get sufficiently caught up and make intelligent posts in the other thread! 
Title: Re: Transmitters in bread pans
Post by: Lee Douglas on December 17, 2017, 07:04:00 pm
FWIW I don't think you would have cluttered up the thread due to your lack of knowledge, because I don't know anything either and am asking questions to try to learn.

Then I just realized you're the guy doing the testing! 
Title: Re: Transmitters in bread pans
Post by: Dan Currie on December 18, 2017, 11:46:18 am
4x UHFR in tins
(https://i.imgur.com/E6PIlXL.png)

4x UHFR clustered on table
(https://i.imgur.com/yKnm3MW.png)
Title: Re: Transmitters in bread pans
Post by: Dan Mortensen on December 18, 2017, 02:19:50 pm
4x UHFR in tins
(https://i.imgur.com/E6PIlXL.png)

4x UHFR clustered on table
(https://i.imgur.com/yKnm3MW.png)

Thanks, Dan, those are nicely behaved. The ones I'm using in the experiment are quite nasty, and I'll post some pics in the other thread later this afternoon showing just how nasty they are. Still, they are going to serve a purpose in my world and I'm happy to have them.
Title: Re: Transmitters in bread pans
Post by: Dan Currie on December 18, 2017, 02:44:07 pm
Thanks, Dan, those are nicely behaved. The ones I'm using in the experiment are quite nasty, and I'll post some pics in the other thread later this afternoon showing just how nasty they are. Still, they are going to serve a purpose in my world and I'm happy to have them.

Those are at 10mw.  These are 4 mics in close proximity at 50 mw

(https://i.imgur.com/1dQ3DME.png)
Title: Re: Transmitters in bread pans
Post by: Keith Broughton on December 18, 2017, 04:37:47 pm
Those are at 10mw.  These are 4 mics in close proximity at 50 mw

(https://i.imgur.com/1dQ3DME.png)
A very clear demonstration that "more is better" may not be better!
Title: Re: Transmitters in bread pans
Post by: John Sulek on December 18, 2017, 04:39:19 pm
Those are at 10mw.  These are 4 mics in close proximity at 50 mw

(https://i.imgur.com/1dQ3DME.png)

The higher RBW and VBW settings are affecting the resolution in this screen shot compared to the previous examples.
There will undoubtedly be many more intermod spurs at the higher power setting, but the lower resolution could make them appear much wider than they might be.
Thank you for putting in the time to do these tests and post the results.
Title: Re: Transmitters in bread pans
Post by: Kevin Maxwell on December 18, 2017, 07:00:06 pm
I have been thinking of using steal loaf pans for the wireless body packs. The last show I did in November we were using 30 and when we lined them up to test them before putting them on the actors I noticed more interference (intermods) than ever before. To get enough channels working together in WWB (Wireless Work Bench) I had to use the “More Frequencies” settings. I assume that possibly made them more susceptible to audible interference. It was extremely minor but it was there. I am really just testing them at this point to make sure all the mics hooked up to the transmitters are still working properly. We had a lot of cable problems for this show. It was very rough on the mics. We always test them before every show just to help catch any problem ones early.

Once the mics are on everyone there aren’t any intermod problems that I have ever noticed. But due to mic swaps that are needed, there might be times during the show when there are enough mics back stage waiting to get put on a different actor that I am a little bit concerned that some intermods may be created when they are sitting waiting. But they are far enough away from the stage that they aren’t usually picked up on the receivers from back there. So I would assume that if they are creating intermods from sitting too close they probably aren’t strong enough to cause a real problem. But being paranoid isn’t always a bad thing.

I was wondering about maybe coating the inside of the pan with some sort of rubber material. Maybe just to keep things from clanking around or to help keep the packs from getting scratched up. But with the possible problems that started these recent threads, it got me wondering if with the pans were lined would that in any way affect it. Especially if there is a bare spot on the end of the antenna, like can happen with the Shure’s if they lose their antenna cap.     

This past weekend I did a show where I had 6 wireless handheld mics on the leftover frequencies from the 30 mic show and when monitoring the receivers on my computer running WWB I noticed that when the mics were on stands sitting pretty close together waiting to get put on stage, I saw an overload light on the RF meters on the B antenna on one of the receivers. I went down and readjusted where the mics were sitting and the light went off. This got me thinking more about the inference that the wireless can cause when too close to each other. The receivers and receive antenna weren’t too close. The antennas were up in the air about 20 feet away. I thought that maybe the gain switch on the paddle antenna was set too high, it was set to +6 and I changed it to 0, but I still got the overload light when the mics were arranged in a certain way. This was with 50 feet of cable to reach from the antenna to the antenna distro.

Title: Re: Transmitters in bread pans
Post by: Stephen Swaffer on December 18, 2017, 07:23:03 pm
I have used the same set of 8 MiPro wireless in conjunction with some Shure SLX Receivers for several years-and always fought intereference on the MiPro's.  We wind up doing mutiple mic changes and mics are together quite often-though nowhere near FOH.  I have a helper tending to the mics-use an iPad connected to the QU to view the metering to make sure mics are at least getting a signal.   This year I asked her to use a metal pan for the mics-it made a world of difference almost no mic issues-other than a broken cable or 2 (on rentals so to be expected I guess).

The MiPros have insane battery life anyway-so any degradation due to the pan is a non-issue with them.
Title: Re: Transmitters in bread pans
Post by: Ike Zimbel on December 18, 2017, 08:55:53 pm
I have been thinking of using steal loaf pans for the wireless body packs. The last show I did in November we were using 30 and when we lined them up to test them before putting them on the actors I noticed more interference (intermods) than ever before. To get enough channels working together in WWB (Wireless Work Bench) I had to use the “More Frequencies” settings. I assume that possibly made them more susceptible to audible interference. It was extremely minor but it was there. I am really just testing them at this point to make sure all the mics hooked up to the transmitters are still working properly. We had a lot of cable problems for this show. It was very rough on the mics. We always test them before every show just to help catch any problem ones early.

Once the mics are on everyone there aren’t any intermod problems that I have ever noticed. But due to mic swaps that are needed, there might be times during the show when there are enough mics back stage waiting to get put on a different actor that I am a little bit concerned that some intermods may be created when they are sitting waiting. But they are far enough away from the stage that they aren’t usually picked up on the receivers from back there. So I would assume that if they are creating intermods from sitting too close they probably aren’t strong enough to cause a real problem. But being paranoid isn’t always a bad thing.

I was wondering about maybe coating the inside of the pan with some sort of rubber material. Maybe just to keep things from clanking around or to help keep the packs from getting scratched up. But with the possible problems that started these recent threads, it got me wondering if with the pans were lined would that in any way affect it. Especially if there is a bare spot on the end of the antenna, like can happen with the Shure’s if they lose their antenna cap.     

This past weekend I did a show where I had 6 wireless handheld mics on the leftover frequencies from the 30 mic show and when monitoring the receivers on my computer running WWB I noticed that when the mics were on stands sitting pretty close together waiting to get put on stage, I saw an overload light on the RF meters on the B antenna on one of the receivers. I went down and readjusted where the mics were sitting and the light went off. This got me thinking more about the inference that the wireless can cause when too close to each other. The receivers and receive antenna weren’t too close. The antennas were up in the air about 20 feet away. I thought that maybe the gain switch on the paddle antenna was set too high, it was set to +6 and I changed it to 0, but I still got the overload light when the mics were arranged in a certain way. This was with 50 feet of cable to reach from the antenna to the antenna distro.
Good idea to use the tins. With belt packs, any loaf tin from the super market will work. For hand-helds, or stick mics as they're called in the broadcast world, the Weber 6417 drip pan is just the ticket. I find very often, when working with A-2's, they think that the head of the mic goes in the pan and they put them in with the antenna end resting on one end of the pan, which defeats the purpose. Takes a bit of explaining but they usually get it.
Title: Re: Transmitters in bread pans
Post by: Mac Kerr on December 18, 2017, 09:00:50 pm
I find very often, when working with A-2's, they think that the head of the mic goes in the pan and they put them in with the antenna end resting on one end of the pan, which defeats the purpose. Takes a bit of explaining but they usually get it.

You need to hang out with a better class of A2s.

Mac
Title: Re: Transmitters in bread pans
Post by: Ike Zimbel on December 18, 2017, 09:06:09 pm
You need to hang out with a better class of A2s.

Mac
True enough! To be fair, a lot of them are really young kids, just getting started in the biz.
Title: Re: Transmitters in bread pans
Post by: John Sulek on December 18, 2017, 11:26:47 pm
True enough! To be fair, a lot of them are really young kids, just getting started in the biz.

One day I will be available...lol.
Title: Re: Transmitters in bread pans
Post by: Mark Cadwallader on December 18, 2017, 11:38:03 pm
Good idea to use the tins. With belt packs, any loaf tin from the super market will work. For hand-helds, or stick mics as they're called in the broadcast world, the Weber 6417 drip pan is just the ticket. I find very often, when working with A-2's, they think that the head of the mic goes in the pan and they put them in with the antenna end resting on one end of the pan, which defeats the purpose. Takes a bit of explaining but they usually get it.

Thank you for the specific model number of the longer aluminum pans. Saves me a bunch of research time!
Title: Re: Transmitters in bread pans
Post by: John Sulek on December 18, 2017, 11:44:34 pm
I have been thinking of using steal loaf pans for the wireless body packs. The last show I did in November we were using 30 and when we lined them up to test them before putting them on the actors I noticed more interference (intermods) than ever before. To get enough channels working together in WWB (Wireless Work Bench) I had to use the “More Frequencies” settings. I assume that possibly made them more susceptible to audible interference. It was extremely minor but it was there. I am really just testing them at this point to make sure all the mics hooked up to the transmitters are still working properly. We had a lot of cable problems for this show. It was very rough on the mics. We always test them before every show just to help catch any problem ones early.

Once the mics are on everyone there aren’t any intermod problems that I have ever noticed. But due to mic swaps that are needed, there might be times during the show when there are enough mics back stage waiting to get put on a different actor that I am a little bit concerned that some intermods may be created when they are sitting waiting. But they are far enough away from the stage that they aren’t usually picked up on the receivers from back there. So I would assume that if they are creating intermods from sitting too close they probably aren’t strong enough to cause a real problem. But being paranoid isn’t always a bad thing.

I was wondering about maybe coating the inside of the pan with some sort of rubber material. Maybe just to keep things from clanking around or to help keep the packs from getting scratched up. But with the possible problems that started these recent threads, it got me wondering if with the pans were lined would that in any way affect it. Especially if there is a bare spot on the end of the antenna, like can happen with the Shure’s if they lose their antenna cap.     

This past weekend I did a show where I had 6 wireless handheld mics on the leftover frequencies from the 30 mic show and when monitoring the receivers on my computer running WWB I noticed that when the mics were on stands sitting pretty close together waiting to get put on stage, I saw an overload light on the RF meters on the B antenna on one of the receivers. I went down and readjusted where the mics were sitting and the light went off. This got me thinking more about the inference that the wireless can cause when too close to each other. The receivers and receive antenna weren’t too close. The antennas were up in the air about 20 feet away. I thought that maybe the gain switch on the paddle antenna was set too high, it was set to +6 and I changed it to 0, but I still got the overload light when the mics were arranged in a certain way. This was with 50 feet of cable to reach from the antenna to the antenna distro.

Use the pans and these intermod problems at the rf table will not be such a huge issue.
You can lay a piece of towel, rubber mat or duvetyn in the bottom if you are worried about scratches. It won't affect the shielding properties as long as you keep the antenna portion of the mic or body pack inside the pan.

Mics close together on stands can interact same as they do stacked up on a table...you could "wargame" your coordination by turning off one transmitter at a time to make sure the rf meters go dark.
Or alternate the position of the antenna portion if they must remain on stands.

I don't usually use any gain on the rx antenna for only 50 feet of quality cable. You are raising the rf noise floor which can get you closer to rf overload faster.

That's my 2 cents but there are many others way more knowledgeable than myself on this site freely sharing their wisdom.


Title: Re: Transmitters in bread pans
Post by: Keith Broughton on December 19, 2017, 07:13:26 am
As for pan liners, a piece of the rubber matting used as household drawer liners works great.
Title: Re: Transmitters in bread pans
Post by: Scott Helmke on December 19, 2017, 10:02:05 am
I don't usually use any gain on the rx antenna for only 50 feet of quality cable. You are raising the rf noise floor which can get you closer to rf overload faster.

+1.  Antenna or in-line amplifiers are only there if you need to compensate for running long cable.
Title: Re: Transmitters in bread pans
Post by: Keith Broughton on December 19, 2017, 12:04:19 pm
+1.  Antenna or in-line amplifiers are only there if you need to compensate for running long cable.
Using antenna gain for "better mic reception" is another common mistake.
In fact, the new Shure antennas have a -3 db setting  along with the usual +gain settings.
Title: Re: Transmitters in bread pans
Post by: boburtz on December 23, 2017, 02:12:58 pm
I bought a wooden flatware organizer from one of the department stores and covered it in foil tape. It works as well as the breadpans and can be kept in the wireless drawer for transport and brought out onto a table for the show. It only holds four handheld mics, though.
Title: Re: Transmitters in bread pans
Post by: Ike Zimbel on December 27, 2017, 03:13:08 pm
I bought a wooden flatware organizer from one of the department stores and covered it in foil tape. It works as well as the breadpans and can be kept in the wireless drawer for transport and brought out onto a table for the show. It only holds four handheld mics, though.
This points to another solution I have seen: If you already have foam fitted trays in a work trunk (or other road case...) to carry your mics in, you can just fit some heavy foil (I've seen black wrap used a lot) in the antenna end of the cutout. The downside of this is if your transmitters fit snugly in the foam, it can slow the ins-and-outs of the mics. On some shows, they move pretty fast...
Title: Re: Transmitters in bread pans
Post by: Dan Mortensen on December 27, 2017, 07:48:26 pm
This points to another solution I have seen: If you already have foam fitted trays in a work trunk (or other road case...) to carry your mics in, you can just fit some heavy foil (I've seen black wrap used a lot) in the antenna end of the cutout. The downside of this is if your transmitters fit snugly in the foam, it can slow the ins-and-outs of the mics. On some shows, they move pretty fast...

It's interesting you brought this up, as I've been trying to figure out a variation on this.

There was a vendor on the NAB side of the last NY AES Convention selling cut foam inserts with or without cases.  mycasebuilder.com (https://www.mycasebuilder.com)

The sweet thing about it was that you can have literally any cutout or combination of cutouts in the foam, an unlimited number. You use the app on their site to create new or use predefined shapes that meet your need (FYI Safari on laptop or old iPad are crap for the app, Chrome on a laptop works great) and their computer cutters make them. There was a now-expired convention discount which made it a sweeter deal. And if you are not sure of your exactitude, you can get do-over insurance for something like $10.

I more or less replicated an SKB micbox layout in a deeper case, with deeper holes for ULX-D size handhelds, and was wondering about having them slice squares around each hole, then wrap that square with aluminum foil, putting the transmitter end down into the hole, with a layer of foil on the interior bottom of the entire case. The foil would be protected by foam on each side, and you could do a checkerboard foil/no foil for the interior holes to take up a little less space.

Their foams are either expanded polyethylene in white (special order) or gray, or the normal case soft foam that works great but deteriorates over time. There is also a premium foam that is about 20% more than those, which looked and felt nice but wasn't needed for this project.

Prices seemed to be not a whole lot more than buying a big chunk of foam and spending hours trying to figure out how to make nice even holes/shapes in it.

The cases came just after Thanksgiving, and look really good and work well so far, although I didn't do the foil thing since the loaf pan discussion happened subsequent to order placement. Also, I didn't realize foil would work as well as solid metal. Did get the do-over insurance, though...

Questions:

It seems like just putting foil in the holes would wear the foil quickly. Did you notice that?

Does the foil/metal need to be contiguous (like a loaf pan) to be effective, or are isolated bits as described above just as good? I was going to try it to see before calling about re-ordering the foam.

Regarding deterioration of the foil, it seems like a mesh would be just as effective as solid up to a point, since the wavelengths are quite a bit longer than the bread pans/foil, so some holes don't matter?
Title: Re: Transmitters in bread pans
Post by: John Sulek on December 27, 2017, 11:16:46 pm
Does the foil/metal need to be contiguous (like a loaf pan) to be effective, or are isolated bits as described above just as good? I was going to try it to see before calling about re-ordering the foam.

Regarding deterioration of the foil, it seems like a mesh would be just as effective as solid up to a point, since the wavelengths are quite a bit longer than the bread pans/foil, so some holes don't matter?

This is from Tim Vear of Shure in their "Operation and Selection of Wireless Microphones". Lots of good non brand specific info.

Interestingly, a reflecting metal object can be porous,
that is, it can have holes or spaces in it. As long as the
holes are much smaller than the wavelength, the metal
surface will behave as if it were solid. This means that
screens, grids, bars, or other metal arrays can reflect radio
waves whose wavelength is greater than the space
between the array elements and less than the overall array
size. If the space between elements is larger than the
wavelength, the radio waves will pass through the array.
For example, the metal grid on the glass door of a microwave
oven reflects microwaves back into the oven but
allows light waves to pass through so that the inside is visible.
This is because microwaves have a wavelength of at
least one centimeter while visible light has a wavelength of
only one-millionth of a meter.
Title: Re: Transmitters in bread pans
Post by: Henry Cohen on December 28, 2017, 11:34:22 am
This is from Tim Vear of Shure in their "Operation and Selection of Wireless Microphones". Lots of good non brand specific info.

Interestingly, a reflecting metal object can be porous,
that is, it can have holes or spaces in it. As long as the
holes are much smaller than the wavelength, the metal
surface will behave as if it were solid. This means that
screens, grids, bars, or other metal arrays can reflect radio
waves whose wavelength is greater than the space
between the array elements and less than the overall array
size. If the space between elements is larger than the
wavelength, the radio waves will pass through the array.
For example, the metal grid on the glass door of a microwave
oven reflects microwaves back into the oven but
allows light waves to pass through so that the inside is visible.
This is because microwaves have a wavelength of at
least one centimeter while visible light has a wavelength of
only one-millionth of a meter.

As long as the holes or openings in the screen or mesh material are 1/20th of a wavelength or smaller, the material will be 99.9% effective as a shield or reflector for that frequency and lower.
Title: Re: Transmitters in bread pans
Post by: John Sulek on December 28, 2017, 11:41:36 am
As long as the holes or openings in the screen or mesh material are 1/20th of a wavelength or smaller, the material will be 99.9% effective as a shield or reflector for that frequency and lower.

Thanks Henry!
Title: Re: Transmitters in bread pans
Post by: Mac Kerr on December 28, 2017, 03:36:37 pm
As long as the holes or openings in the screen or mesh material are 1/20th of a wavelength or smaller, the material will be 99.9% effective as a shield or reflector for that frequency and lower.

A very rough back of napkin calculation (actually mostly in my head) puts the wavelength of 700MHz at about 450mm. 1/20th of 450 is 22.5mm, or just under an inch to mix notation standards. That seems to say any common metallic window screen should be an adequate RF shield. Have i lost a decimal somewhere?

Mac
Title: Re: Transmitters in bread pans
Post by: John Roberts {JR} on December 28, 2017, 03:59:12 pm
A very rough back of napkin calculation (actually mostly in my head) puts the wavelength of 700MHz at about 450mm. 1/20th of 450 is 22.5mm, or just under an inch to mix notation standards. That seems to say any common metallic window screen should be an adequate RF shield. Have i lost a decimal somewhere?

Mac
according to google wavelength of 700MHz is 42.9 CM.   1/20= 2.14 cm  = 0.84"

Close enough for government work...

JR

Title: Re: Transmitters in bread pans
Post by: Henry Cohen on December 28, 2017, 04:04:18 pm
A very rough back of napkin calculation (actually mostly in my head) puts the wavelength of 700MHz at about 450mm. 1/20th of 450 is 22.5mm, or just under an inch to mix notation standards. That seems to say any common metallic window screen should be an adequate RF shield. Have i lost a decimal somewhere?

You've not lost a decimal place; 700MHz is 428.27mm, 1/20th being 21.4mm. And yes, window screen works well up to about 1GHz. (Just ensure the screen material is in fact metal, and not nylon  :-\ )
Title: Re: Transmitters in bread pans
Post by: Dan Mortensen on December 28, 2017, 04:33:42 pm
Good info, thanks, guys.

One other thing about bread pans vs. tubes (as in an SKB type mic box with wrapped holes):

I get the impression that using bread pans allows you to still see the active frequencies but specifically cuts the intermod products. At least that's what I see when using them vs just setting on the table. And seeing those active frequencies allows you to observe something valuable in real time (what? The fact that something competing hasn't kicked in?) so that you can maintain the integrity of your coordination. This is why you just don't have the talent turn the transmitters off in between uses, in addition to not letting them forget to turn them on.

Is that right?

The bread pans have one whole side open to allow the RF out, a tube would only have a hole on top, opposite the antenna. If used as a holding pen for active but unused mics, it seems like the tubes would limit the ability to monitor the mics while in them. Yes?

If the mesh works just as well as bread pans, something like this (https://smile.amazon.com/KD-Organizers-5-Slot-Drawer-Organizer/dp/B01D1QZ6NU/ref=sr_1_10?ie=UTF8&qid=1514495695&sr=8-10&keywords=metal+mesh+drawer+organizer) or this (https://smile.amazon.com/Honey-Can-Do-KCH-02158-Drawer-Organizer-Silver/dp/B007NC307I/ref=pd_sbs_201_3?_encoding=UTF8&refRID=9FR4W0DGBS5FCCNTMCGG&th=1) might be the better option. These are cheaper than new bread pans, too, although it looks like only the second one will nest like bread pans for travel.

Thanks again for the great info.
Title: Re: Transmitters in bread pans
Post by: Henry Cohen on December 28, 2017, 04:52:15 pm
Good info, thanks, guys.

One other thing about bread pans vs. tubes (as in an SKB type mic box with wrapped holes):

I get the impression that using bread pans allows you to still see the active frequencies but specifically cuts the intermod products. At least that's what I see when using them vs just setting on the table. And seeing those active frequencies allows you to observe something valuable in real time (what? The fact that something competing hasn't kicked in?) so that you can maintain the integrity of your coordination. This is why you just don't have the talent turn the transmitters off in between uses, in addition to not letting them forget to turn them on.

Is that right?

I think you're overthinking this. Bread pans were initially chosen because they were readily available and cheap. Yes, they do have the advantage of permitting one to see the transmitter's display in real time and readily tell the frequency, battery life and whether the unit is on.


Quote
The bread pans have one whole side open to allow the RF out, a tube would only have a hole on top, opposite the antenna. If used as a holding pen for active but unused mics, it seems like the tubes would limit the ability to monitor the mics while in them. Yes?

You may need another [attenuated] RX antenna by your mic staging area if your metal tube will attenuate the RF significantly.



Quote
If the mesh works just as well as bread pans, something like this (https://smile.amazon.com/KD-Organizers-5-Slot-Drawer-Organizer/dp/B01D1QZ6NU/ref=sr_1_10?ie=UTF8&qid=1514495695&sr=8-10&keywords=metal+mesh+drawer+organizer) or this (https://smile.amazon.com/Honey-Can-Do-KCH-02158-Drawer-Organizer-Silver/dp/B007NC307I/ref=pd_sbs_201_3?_encoding=UTF8&refRID=9FR4W0DGBS5FCCNTMCGG&th=1) might be the better option. These are cheaper than new bread pans, too, although it looks like only the second one will nest like bread pans for travel.

I'd avoid the multiple slot version (the first link) as that would present a common wall between any two TX and is an overall common conductor within the reactive near fields of all TX's: I suspect this would not mitigate the IM's as much as individual receptacles.  But since you're in the testing groove, try it and let us know  ;D
Title: Re: Transmitters in bread pans
Post by: Dan Mortensen on December 28, 2017, 05:48:03 pm
I think you're overthinking this.

Unquestionably, but there's a lot to think about and it's hard to tell wheat from chaff when there's so much wheat.


I'd avoid the multiple slot version (the first link) as that would present a common wall between any two TX and is an overall common conductor within the reactive near fields of all TX's: I suspect this would not mitigate the IM's as much as individual receptacles. 

And that's why I'm overthinking. That wouldn't have occurred to me.

But since you're in the testing groove, try it and let us know  ;D

I ordered a used (cheaper yet) version of the second one to do that. The common wall one doesn't lend itself to packing easily, so probably not.

Like I said somewhere else, the student should be willing to put in some serious time, and I am. I've made what seems like a lot of progress in understanding these new mics, both good and ill.
Title: Re: Transmitters in bread pans
Post by: John Roberts {JR} on December 28, 2017, 07:18:31 pm
I still think this is an opportunity for microphone mfrs (should one be lurking around here.  ::)  )... If the loading from a nearby ground plane shorting the RF field increases antenna load, maybe sense for that and turn it off when I detects that it is "ground(plane)ed". Of course if the mechanism does not draw that much more current then it really doesn't matter.

JR
Title: Re: Transmitters in bread pans
Post by: Dan Mortensen on December 28, 2017, 08:27:25 pm

I'd avoid the multiple slot version (the first link) as that would present a common wall between any two TX and is an overall common conductor within the reactive near fields of all TX's: I suspect this would not mitigate the IM's as much as individual receptacles.

In overthinking about this for a little while during packing for a show, does the quoted text mean that the individual bread pans can't touch each other, since if they did, they'd be creating a single wall due to conductivity of the metal? Or do the two sides of metal, even if touching,  do something different than the single wall of mesh or solid? I can certainly test touching vs. non-touching for intermod display...

Regardless, the slots in that common wall mesh container are too short for ULX-D-sized mics, so I definitely won't be getting one.
Title: Re: Transmitters in bread pans
Post by: Rob Spence on December 28, 2017, 10:05:43 pm
Tubes would be fine for hand held mics (given you can’t look at it, might as well turn it off). Not so much for belt packs and accessories.



Sent from my iPad using Tapatalk Pro
Title: Re: Transmitters in bread pans
Post by: Ike Zimbel on December 29, 2017, 06:21:40 pm
In overthinking about this for a little while during packing for a show, does the quoted text mean that the individual bread pans can't touch each other, since if they did, they'd be creating a single wall due to conductivity of the metal? Or do the two sides of metal, even if touching,  do something different than the single wall of mesh or solid? I can certainly test touching vs. non-touching for intermod display...
It's probably better that they don't touch...but they often do. I can tell you from my experience wearing a BTR pack while wrangling mics that when the pans are touching, I can hear lots of "static" in my headset when the pans get bumped. Is this a problem for other RF devices nearby? Not that I've been able to see. Sometimes when you need to get 14 mics on a table, in a line, the pans are going to touch. On another note, when I'm short pans, I put every other mic in a pan, so between the added distance between tx, and the sides of the pans, you still reap a benefit.
Title: Re: Transmitters in bread pans
Post by: Dave Garoutte on December 30, 2017, 02:28:54 pm
A little gaff tape on the outside of the pans will insulate them.
Title: Re: Transmitters in bread pans
Post by: Stephen Swaffer on January 01, 2018, 12:07:27 am
I still think this is an opportunity for microphone mfrs (should one be lurking around here.  ::)  )... If the loading from a nearby ground plane shorting the RF field increases antenna load, maybe sense for that and turn it off when I detects that it is "ground(plane)ed". Of course if the mechanism does not draw that much more current then it really doesn't matter.

JR

Hmmmm, until the "ground plane" of a performer's hand around the mic shuts it off?  I'm not a huge fan of "smart devices"-they too often turn dumb at the wrong time!