Linking BTR-800 base stations

[vcuchris]

We just added a new BTR-800 base station to link to another one we've had a few years. The first one (and the 4 wireless headsets) work great.
One base station is on E88 frequency range, the other on A2.

The two stations are connected in the back with XLR cables, and with a Cat6 cable, per the manual.
Both stations are in RTS Mode, with 2-wire setting.

The comm boxes are all TR-800.
The original 4 boxes (with the first base station) were 4-pin male.
The new boxes, while still TR-800, are 6-pin female boxes (A2R5).

The original base station has two paddle antennas, one to send & one to receive.
The new base station only has one antenna, as we were led to believe we didn't need a second.

The communication with the new, 6-pin boxes, is one way. Everyone on the original base station can hear them, but they are unable to hear anything, including themselves.

I'm no engineer, and this whole process is way more advanced than I'm capable of. Any help would be greatly appreciated!

 

[themuzicman]

We just added a new BTR-800 base station to link to another one we've had a few years. The first one (and the 4 wireless headsets) work great.
One base station is on E88 frequency range, the other on A2.

Are you US based? E88 is fine (Base Station Tx @ 590-608, Rx @ 470-488) however A2 is no longer a valid frequency band (Base Station Tx @ 518-536, Rx @ 632-650). The Rx side of the base station will be consistently hit by interference from cell phones, but you can still use those packs as listen-only packs.

The two stations are connected in the back with XLR cables, and with a Cat6 cable, per the manual.
Both stations are in RTS Mode, with 2-wire setting.

The XLR is for intercom, the RJ-45 links are for WTA (Wireless Talk-About) channel, the little round button on the beltpacks no one ever touches. The RJ-45 is non-essential for link to happen unless folks actually use WTA.

The comm boxes are all TR-800.
The original 4 boxes (with the first base station) were 4-pin male.
The new boxes, while still TR-800, are 6-pin female boxes (A2R5).

Your E88 beltpacks use Clearcom compatible headsets, are you sure it's actually a 6-pin headset and not a 5-pin headset? RTS headsets are 5-pin stereo headsets and that's the only other variant of BTR I've seen. You can easily make 5-pin to 4-pin adapters.

The original base station has two paddle antennas, one to send & one to receive.
The new base station only has one antenna, as we were led to believe we didn't need a second.

The communication with the new, 6-pin boxes, is one way. Everyone on the original base station can hear them, but they are unable to hear anything, including themselves.

With BTR systems, you can only get away with a single antenna on the second unit if they are both in the same operating band. You let Unit #1 handle base station transmit, disabling transmit on Unit #2, and then both units get their own receive antennas for a total fo 3 antennas. When you have BTR units in separate bands you need 2 antennas per unit. It seems like this is how you have things set up, as folks can hear them but they can't hear anything.

The ability for a user to hear themselves in intercom is called sidetone. In BTR systems sidetone is not generated locally, it is generated in the base station and is an indicator that 2-way communication is happening from beltpack to base station. Without a transmit antenna on your second unit, you will not get side tone.

 

[vcuchris]

Are you US based? E88 is fine (Base Station Tx @ 590-608, Rx @ 470-488) however A2 is no longer a valid frequency band (Base Station Tx @ 518-536, Rx @ 632-650). The Rx side of the base station will be consistently hit by interference from cell phones, but you can still use those packs as listen-only packs.



The XLR is for intercom, the RJ-45 links are for WTA (Wireless Talk-About) channel, the little round button on the beltpacks no one ever touches. The RJ-45 is non-essential for link to happen unless folks actually use WTA.



Your E88 beltpacks use Clearcom compatible headsets, are you sure it's actually a 6-pin headset and not a 5-pin headset? RTS headsets are 5-pin stereo headsets and that's the only other variant of BTR I've seen. You can easily make 5-pin to 4-pin adapters.



With BTR systems, you can only get away with a single antenna on the second unit if they are both in the same operating band. You let Unit #1 handle base station transmit, disabling transmit on Unit #2, and then both units get their own receive antennas for a total fo 3 antennas. When you have BTR units in separate bands you need 2 antennas per unit. It seems like this is how you have things set up, as folks can hear them but they can't hear anything.

The ability for a user to hear themselves in intercom is called sidetone. In BTR systems sidetone is not generated locally, it is generated in the base station and is an indicator that 2-way communication is happening from beltpack to base station. Without a transmit antenna on your second unit, you will not get side tone.

Thank you for all this - it's more info than I've been given over the past month or so. A couple follow up questions, if you don't mind:

The Rx side of the base station will be consistently hit by interference from cell phones, but you can still use those packs as listen-only packs.

When you say "listen-only" packs, you mean the A2 belt packs should be able to hear the E88 communication, but cannot talk to it? Currently, it's the opposite of that.

Your E88 beltpacks use Clearcom compatible headsets, are you sure it's actually a 6-pin headset and not a 5-pin headset?

The E88 beltpacks are 4-pin males. The A2 beltpacks are 6-pin females. Attached to this reply is a photo of the beltpack.
I did manage to get someone from Telex to tell me that the 6th pin is not used.

With BTR systems, you can only get away with a single antenna on the second unit if they are both in the same operating band.

It sounds like these two BTR units won't communicate with each other at all, regardless of the number of antennas. Would adding a second transmit antenna really matter?
Again, if these A2 beltpacks/headsets could at least hear the director on E88, that would be sufficient.
Talkback, while ideal, isn't totally necessary.

Thanks again for all your help!

 

[themuzicman]

I say listen-only in that your A2 isn't a valid range for use in the US. Flip your A2 receive antenna to the transmit side and you'll have a unit that's fit for operation.

It's the opposite of that at the moment because you only have one antenna on the A2 base station and it's plugged into the Rx side because you're set up in the way I described to have 2 base stations in the same range operating, where 1 station handles transmit for both stations and each station gets its own receive.

Just because things are stable now doesn't mean it isn't both illegal to use and won't hit issues later - as is the nature of cell phones because they are portable.

As for the 6-pin female, that's wild, that's not even on the TR-800 spec sheet as a model.
If I had to guess the pinout, it may follow the older KP panels (1. Mic - 2. Mic + 3. Speaker - 4. Speaker L 5. Speaker R 6. Mic On/Off) which would mean 6 won't work on the TR-800. Still, easy enough to adapt that to Clearcom compatible headsets as the BTR's are mono and Speaker R is just a duplicate of Speaker L.

It sounds like these two BTR units won't communicate with each other at all, regardless of the number of antennas. Would adding a second transmit antenna really matter?
Again, if these A2 beltpacks/headsets could at least hear the director on E88, that would be sufficient.
Talkback, while ideal, isn't totally necessary.

BTR units never actually communicate with each other ever, they are dumb devices in all senses of the word. The XLR linking is literally just looping the PL's and the RJ-45 is literally just another 4-wire interface for WTA - even Stage Announce isn't transferred between units. There is no data exchanged, there is nothing going on to force a link. The only thing transferred is audio from WTA. If you want your A2 range to fully work, again assuming you are in a location where they are legal for use, you would indeed require a second antenna and you would need to hit the "transmit power" switch to On and that would fix your issues. Also the packs in your photos had no antennas, so you'd need antennas on the packs.

 

[vcuchris]

Thanks again. Sorry I didn't clarify before - yes this is in the US and we're using this for production in a sports venue. Operating within the bounds of the law is always a positive.
The beltpacks do have antennas, they just weren't screwed in when the photo was taken.

So to wrap this up, would purchasing a matching BTR base station in the E88 spectrum allow us to add additional headsets? Such as this used one.
Would any other frequency ranges be functional?

And any other suggestions/tips you can think of that might allow us to expand beyond our original 4 wireless headsets.
Thank you!

 

[Jay Ashworth]

> And any other suggestions/tips you can think of that might allow us to expand beyond our original 4 wireless headsets.

[ Just to put it out there, not because I necessarily think it's in your budget. ]

BTR-800s are *really* old. Almost no matter what you're communicating, things will go bad if that breaks.

ClearCom FreeSpeak II is the gold standard in midrange wireless comm (that is: it's not Riedel , but for as great as it is, it is in no way cheap. But the 5 seats of it my theatre bought 5 years ago (for $25K) is easily the best money we've ever spent.

Separately, you might find it useful to grab the Intercom Engineering Handbook, and sit down with it over a frosty beverage some quiet day; it'll teach you a lot. If you can't google up the PDF, I can send you a link.

 

[vcuchris]

> And any other suggestions/tips you can think of that might allow us to expand beyond our original 4 wireless headsets.

[ Just to put it out there, not because I necessarily think it's in your budget. ]

BTR-800s are *really* old. Almost no matter what you're communicating, things will go bad if that breaks.

ClearCom FreeSpeak II is the gold standard in midrange wireless comm (that is: it's not Riedel , but for as great as it is, it is in no way cheap. But the 5 seats of it my theatre bought 5 years ago (for $25K) is easily the best money we've ever spent.

Separately, you might find it useful to grab the Intercom Engineering Handbook, and sit down with it over a frosty beverage some quiet day; it'll teach you a lot. If you can't google up the PDF, I can send you a link.

Appreciate the suggestion. The full story is that our venue is being replaced, to include some new (great?) equipment. So we're just trying to duct tape our way to the finish line in our current facility.

 

[Jay Ashworth]

Appreciate the suggestion. The full story is that our venue is being replaced, to include some new (great?) equipment. So we're just trying to duct tape our way to the finish line in our current facility.

Gotcha. Best of luck...

 

[themuzicman]

Essentially you're looking for another E88. The only other thing sold really is the A3 which could work with proper band-planning as the 3 range is 650-668 but you'd be limited to 653-663 to stay legal (G range Cellular band ends at 652 and the Guard band is 652-653). Additionally, you need to limit beltpack transmit of the 3 range to 20mW. There is some language in the manual on how to set these limitations, though it doesn't cover how you limit beltpack transmit strength.

As for that Reverb.com unit you posted - I'd be VERY wary of that particular listing. It's Clair/Soundworx rental stock which means it's been road abused hard. At least 3 of the BP antennas need to be replaced ($30 each). I also dislike the transmitter modification done to those units to have channel A and B on separate antennas. That's a minor gripe but does make sense in some circumstances.