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: Jamin Lynch on January 19, 2020, 01:11:12 pm

Title: IEM Antenna Question
Post by: Jamin Lynch on January 19, 2020, 01:11:12 pm
Is there a way to affectively use 5 Senn G4 IEM systems with 1 AC41 antenna combiner with 1 paddle?

I'm trying to avoid buying another AC41

Thanks
Title: Re: IEM Antenna Question
Post by: Keith Broughton on January 19, 2020, 02:55:19 pm
Is there a way to affectively use 5 Senn G4 IEM systems with 1 AC41 antenna combiner with 1 paddle?

I'm trying to avoid buying another AC41

Thanks
I would think that a good quality passive combiner could be used to take the output of the AC41 and the output of the single transmitter and send to 1 antenna.
Title: Re: IEM Antenna Question
Post by: Henry Cohen on January 19, 2020, 05:03:37 pm
I would think that a good quality passive combiner could be used to take the output of the AC41 and the output of the single transmitter and send to 1 antenna.

Yes, but with caveats: The splitter/combiner needs to have the highest port to port isolation possible at the frequency range of interest, 25dB minimum, and be capable of handling the input power levels at hand. Most splitter/combiner power ratings are as a splitter, with the power rating that presented to the input, or S, port. Unless input power levels as a combiner are explicitly given, the rule of thumb for determining that power level is 20% of the S port input power level divided by the number of opposing ports.

Either of these Mini-Circuits 2-way units are good for this application.
ZAPD-900-5W-N (https://www.minicircuits.com/WebStore/dashboard.html?model=ZAPD-900-5W-N%2B)
ZA2CS-600-10W (https://www.minicircuits.com/WebStore/dashboard.html?model=ZA2CS-600-10W)
Title: Re: IEM Antenna Question
Post by: Erik Jerde on January 19, 2020, 11:59:40 pm
Is there a way to affectively use 5 Senn G4 IEM systems with 1 AC41 antenna combiner with 1 paddle?

I'm trying to avoid buying another AC41

Thanks

Iíve used a Shure passive split/combine for this quite successfully.  I donít remember the part number off hand but they were sold in pairs and Shure had an application example showing this exact usage.
Title: Re: IEM Antenna Question
Post by: Keith Broughton on January 20, 2020, 06:15:12 am
Yes, but with caveats: The splitter/combiner needs to have the highest port to port isolation possible at the frequency range of interest, 25dB minimum, and be capable of handling the input power levels at hand. Most splitter/combiner power ratings are as a splitter, with the power rating that presented to the input, or S, port. Unless input power levels as a combiner are explicitly given, the rule of thumb for determining that power level is 20% of the S port input power level divided by the number of opposing ports.

Either of these Mini-Circuits 2-way units are good for this application.
ZAPD-900-5W-N (https://www.minicircuits.com/WebStore/dashboard.html?model=ZAPD-900-5W-N%2B)
ZA2CS-600-10W (https://www.minicircuits.com/WebStore/dashboard.html?model=ZA2CS-600-10W)
Thanks for the clarification, Henry.
Both those devices are quite reasonably priced compared to buying another active combiner.
Title: Re: IEM Antenna Question
Post by: Jamin Lynch on January 20, 2020, 11:32:33 am
Yes, but with caveats: The splitter/combiner needs to have the highest port to port isolation possible at the frequency range of interest, 25dB minimum, and be capable of handling the input power levels at hand. Most splitter/combiner power ratings are as a splitter, with the power rating that presented to the input, or S, port. Unless input power levels as a combiner are explicitly given, the rule of thumb for determining that power level is 20% of the S port input power level divided by the number of opposing ports.

Either of these Mini-Circuits 2-way units are good for this application.
ZAPD-900-5W-N (https://www.minicircuits.com/WebStore/dashboard.html?model=ZAPD-900-5W-N%2B)
ZA2CS-600-10W (https://www.minicircuits.com/WebStore/dashboard.html?model=ZA2CS-600-10W)

Great info.

I thought about a splitter but was concerned about signal loss through the splitter and if it would pass power.

Thanks
Title: Re: IEM Antenna Question
Post by: Keith Broughton on January 21, 2020, 05:36:17 am
Great info.

I thought about a splitter but was concerned about signal loss through the splitter and if it would pass power.

Thanks
Any passive device will introduce some loss but this should be fine for your application.
What do you mean by "pass power"?
Title: Re: IEM Antenna Question
Post by: Jamin Lynch on January 21, 2020, 03:20:29 pm
Any passive device will introduce some loss but this should be fine for your application.
What do you mean by "pass power"?

It doesn't need to pass power to power the transmitter unit? I guess I'm not sure how it is to be connected
Title: Re: IEM Antenna Question
Post by: Jason Glass on January 21, 2020, 04:37:57 pm
Any passive device will introduce some loss but this should be fine for your application.
What do you mean by "pass power"?

Physics dictates that any 2-way passive combiner attenuates output power by -3 dB plus insertion loss.  This comes out to about -3.5 dB for good quality 2-way combiners.  It also means that they reduce your output power by more than 50%.  If you're working large areas or trying to function in a high RF noise environment, the reduction in system reliability is huge.

It doesn't need to pass power to power the transmitter unit? I guess I'm not sure how it is to be connected

Power the transmitters from what?  The antenna isn't a battery.   ;)  You'll power 4 of your 5 TX with the AC41 coax inputs and must power the 5th with an AC adapter.
Title: Re: IEM Antenna Question
Post by: Jamin Lynch on January 21, 2020, 04:47:46 pm
Physics dictates that any 2-way passive combiner attenuates output power by -3 dB plus insertion loss.  This comes out to about -3.5 dB for good quality 2-way combiners.  It also means that they reduce your output power by more than 50%.  If you're working large areas or trying to function in a high RF noise environment, the reduction in system reliability is huge.

Power the transmitters from what?  The antenna isn't a battery.  You're powering 4 of your 5 TX with the AC41 and must power the 5th with an AC adapter.

I wasn't sure if the AC41 could somehow power the 5th transmitter through the splitter since the AC41 is able to power the other 4. I guess not then.

Thanks
Title: Re: IEM Antenna Question
Post by: Jason Glass on January 21, 2020, 04:55:40 pm
I wasn't sure if the AC41 could somehow power the 5th transmitter through the splitter since the AC41 is able to power the other 4. I guess not then.

Thanks

Aah, understood.  That would exceed the total power draw specs for the AC41 DC supply, and combiners typically only output DC on their RF input ports.  Generally, RX antenna splitters do the opposite.
Title: Re: IEM Antenna Question
Post by: brian maddox on January 21, 2020, 05:07:31 pm
Physics dictates that any 2-way passive combiner attenuates output power by -3 dB plus insertion loss.  This comes out to about -3.5 dB for good quality 2-way combiners.  It also means that they reduce your output power by more than 50%.  If you're working large areas or trying to function in a high RF noise environment, the reduction in system reliability is huge.
...

This was what i was thinking, especially with the Sennies since they are 30mW transmitters IIRC.
Title: Re: IEM Antenna Question
Post by: Jason Glass on January 21, 2020, 05:44:03 pm
This was what i was thinking, especially with the Sennies since they are 30mW transmitters IIRC.

Morsel of info: Senny gifted the world by upping G4's output options to 10/30/50 mW.

Their engineering philosophy seems to embrace lower TX power paired with more sensitive RX than the competition's.  It appears that they achieve comparable function by having very good RX tracking filtering.  Lower TX power inherently allows their cheapest combiners to have looser isolation and amplification specs while still generating tolerably low IMD products.  Their fine "German engineering" certainly lives up to its reputation and results in a large $ to performance ratio.
Title: Re: IEM Antenna Question
Post by: brian maddox on January 21, 2020, 08:07:17 pm
Morsel of info: Senny gifted the world by upping G4's output options to 10/30/50 mW.

Their engineering philosophy seems to embrace lower TX power paired with more sensitive RX than the competition's.  It appears that they achieve comparable function by having very good RX tracking filtering.  Lower TX power inherently allows their cheapest combiners to have looser isolation and amplification specs while still generating tolerably low IMD products.  Their fine "German engineering" certainly lives up to its reputation and results in a large $ to performance ratio.

Two Morsels in One.  Thanks!
Title: Re: IEM Antenna Question
Post by: Don Boomer on January 22, 2020, 01:20:59 pm
Lower TX power inherently allows their cheapest combiners to have looser isolation and amplification specs while still generating tolerably low IMD products.

The lowest power that gives you satisfactory performance is the way to go (both IEMs and wireless mics). And if you switch to a helical antenna you are likely picking up 10dB from the antenna.
Title: Re: IEM Antenna Question
Post by: Keith Broughton on January 22, 2020, 03:58:06 pm
The lowest power that gives you satisfactory performance is the way to go (both IEMs and wireless mics). And if you switch to a helical antenna you are likely picking up 10dB from the antenna.
A bit of info most users don't understand.
More is not always better in RF world!