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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: Gian Luca Cavalliini on May 05, 2018, 02:40:43 am

Title: Antenna switch
Post by: Gian Luca Cavalliini on May 05, 2018, 02:40:43 am
Is there any reliable antenna switch on the market? I'd like to have a couple in my RF utility case...
Thanx in advance!
GLuca
Title: Re: Antenna switch
Post by: Henry Cohen on May 05, 2018, 04:20:41 am
Is there any reliable antenna switch on the market? I'd like to have a couple in my RF utility case...

What exactly do you mean by “antenna” switch? Do you mean an RF switch?
Mechanical, electro-mechanical or solid state?
SPST, SPDT, 2PST, 2PDT, etc.?

Title: Re: Antenna switch
Post by: Lee Douglas on May 05, 2018, 12:00:28 pm
Total wireless amateur here, with a hopefully not too dumb question:  What wireless transmitting or receiving situation would warrant the need to switch antenna input/outputs, beyond the diversity switching built into the system(s)?
Title: Re: Antenna switch
Post by: Lyle Williams on May 05, 2018, 04:35:25 pm
Switches could be handy for A/B testing to determine if a zillion dollar paddle/combiner farm really was better than the 1/4 wave whips (in a particular application).

I agree it is not something I would normally want for my wireless mics.

Make sure that whatever you get is rated for the frequencies and impedance in use.

If you need to switch multiple cables simultaneously, then coax relays can work well.  I like latching relays, which change state with power applied but then don't require power.  I use these to select from a bank of bandpass filters in a non-radio-mic application.

The fastest switching is done with diodes.  I have a couple of units in my junk box and wondered if I could build something to detect preamp overload and switch in attenuation, or switch away to a different antenna, or, or, or some other daydream.  They are still in my junk box.  :-)
Title: Re: Antenna switch
Post by: Henry Cohen on May 05, 2018, 07:34:50 pm
What wireless transmitting or receiving situation would warrant the need to switch antenna input/outputs, beyond the diversity switching built into the system(s)?

Whenever there might be secondary coverage areas only needed for a specific segment, but not the whole show. A red carpet outside before the show itself; Green room confidence; a back corner for a special entrance, etc. Turning off these areas when not needed means less chance of interference or rgeceive system saturation, and for TX, turning off uneeded areas can mitigate phasing issues or RF power loss (switching vs splitting). Actually done rather often on large scale shows with a distributed antenna system.
Title: Re: Antenna switch
Post by: Gian Luca Cavalliini on May 05, 2018, 09:42:48 pm
Whenever there might be secondary coverage areas only needed for a specific segment, but not the whole show. A red carpet outside before the show itself; Green room confidence; a back corner for a special entrance, etc. Turning off these areas when not needed means less chance of interference or rgeceive system saturation, and for TX, turning off uneeded areas can mitigate phasing issues or RF power loss (switching vs splitting). Actually done rather often on large scale shows with a distributed antenna system.

Yes, this is main application for me. For example, in Italy we have a lot of ancient beautiful theatre with dressing rooms far from stage where is impossible to have good RF coverage; but I also think sometimes could be useful for IEM in big arena shows. And, why not, also for some better testing...  ;)
Title: Re: Antenna switch
Post by: Gian Luca Cavalliini on May 05, 2018, 10:02:04 pm
Sorry Henry, forgot to answer your question... I was thinking about SPDT electromechanical. But I don't know if simpler mechanical could perform well enough for this kind of application, advices are welcome  :)
Title: Re: Antenna switch
Post by: Pete Erskine on May 05, 2018, 10:15:27 pm
Is there any reliable antenna switch on the market? I'd like to have a couple in my RF utility case...
Thanx in advance!
GLuca

Wisycom system 288 is the professional antenna switch.

https://wisycom.com/products/product/mat288/
Title: Re: Antenna switch
Post by: Jason Glass on May 06, 2018, 03:09:27 am
Sorry Henry, forgot to answer your question... I was thinking about SPDT electromechanical. But I don't know if simpler mechanical could perform well enough for this kind of application, advices are welcome  :)

Mechanical works extremely well and is cost effective.

RLC Electronics SM-2-B.

http://www.rlcelectronics.com/products/9-switches/44-standard_coaxial_spdt,_50_.html?_75_ohm,_sr-2_series=

Sent from my Nexus 5 using Tapatalk
Title: Re: Antenna switch
Post by: Diogo Nunes Pereira on May 06, 2018, 03:15:55 am
Would this do the trick?

http://www.mfjenterprises.com/Product.php?productid=MFJ-2702N

:D

Title: Re: Antenna switch
Post by: Lyle Williams on May 06, 2018, 03:51:46 am
Would this do the trick?

http://www.mfjenterprises.com/Product.php?productid=MFJ-2702N

:D

Yes. 
Title: Re: Antenna switch
Post by: Lee Douglas on May 07, 2018, 09:02:59 pm
Whenever there might be secondary coverage areas only needed for a specific segment, but not the whole show...

Thanks for the answers, everybody, and sorry for the thread high-jack.  Obviously I was thinking too small!  Love learning new things.