RF Distribution Project (need some advice! )

Thread Starter

Simon Bellemare

Joined Nov 22, 2018
8
Hi guys!!
I'm trying to design a RF distribution for my wireless receivers.

I'm a sound recordist working in TV, so I have to deal with wireless microphones daily.
Basically the setup I would like to have is 2 dipole antennae connected to my 2 wireless receivers. I'm pretty good with a soldering iron and confident about SMD.

First open question ; Any advice for this setup? Does and don't ?

2nd question ; I've made a graph for every parts that would suits my needs, for example 20 different model of baluns/filters/power divider from mini-circuit that would work with my project. Some have lower insertion loss, but higher input return loss, Xphase unbalance, Xamplitude unbalanced, how do I tell which element is the most critical and that I need to watch for for this particular application?

I've made a schema to give you an idea of what I'm trying to do.



Thank you so much guys you are awesome! I'm new to this as you can see..

 
Last edited:

BR-549

Joined Sep 22, 2013
4,938
What are you transmitting? Just audio? Set com audio or broadcast audio? Mono or stereo?

How far? Space available for antenna? Moving or stationary units?

What is budget?
 

Thread Starter

Simon Bellemare

Joined Nov 22, 2018
8
Thank you for your reply!
It's actually receivers (as RX stands for). So it is for use with UHF microphone wireless receivers. Mono. Moving units (sound bag), space available ; dipole for this RF range is about 12" long so not a problem to mount on a bag. Budget is not a problem.
Thank you!
 

BR-549

Joined Sep 22, 2013
4,938
I can't seem to get a handle on what you want to do. Please state what you have.....then state what you want.

A receiver is all you need? All TX (that means transmitter) specs please.

Are you familiar with RF electronics.....or just audio?

I have no studio experience and don't know the lingo.

I shall retire and let someone familiar help you.
 

Thread Starter

Simon Bellemare

Joined Nov 22, 2018
8
Hi! Thank you for your support. I will try to break it down.

I already have my receivers in my sound bags with my recorders.
A sound bag looks like this ;

https://www.facebook.com/soundbagda...737483369589/1295203753889624/?type=3&theater
You can see 2 receivers (lectrosonics SRB) mounted. The receivers have on each 2x 1/4 wave whip SMA antenna.

The TX are little pack worn by actors. They have usually 50 to 250mW output power.

Antenna splitters already exist, but they are big and have to many outputs for my needs, like this one ;
https://www.raycom.co.uk/product/psc-rf-multi-sma-signal-splitter/
You connect the 2x RX's antennae with SMA connectors to the device (you see antenna A and B). After you have the main 2x BNC on which you connect the main antenna that will feed the whole rig.
So, what I'm trying to achieve, is based on the same principle. But instead of having a single box (which contain 2x 8channel antenna splitter for each BNC input), I would like to have a 2 output splitter, that lead directly to a dipole, in 2 separate boxes for the 2 main antenna.
Does this makes sens?
I just want to make a simplified version of a device that exist, but I'm concerned about what parts I need to use!
Thank you!
 

Tesla23

Joined May 10, 2009
495
Hi! Thank you for your support. I will try to break it down.

I already have my receivers in my sound bags with my recorders.
A sound bag looks like this ;

https://www.facebook.com/soundbagda...737483369589/1295203753889624/?type=3&theater
You can see 2 receivers (lectrosonics SRB) mounted. The receivers have on each 2x 1/4 wave whip SMA antenna.

The TX are little pack worn by actors. They have usually 50 to 250mW output power.

Antenna splitters already exist, but they are big and have to many outputs for my needs, like this one ;
https://www.raycom.co.uk/product/psc-rf-multi-sma-signal-splitter/
You connect the 2x RX's antennae with SMA connectors to the device (you see antenna A and B). After you have the main 2x BNC on which you connect the main antenna that will feed the whole rig.
So, what I'm trying to achieve, is based on the same principle. But instead of having a single box (which contain 2x 8channel antenna splitter for each BNC input), I would like to have a 2 output splitter, that lead directly to a dipole, in 2 separate boxes for the 2 main antenna.
Does this makes sens?
I just want to make a simplified version of a device that exist, but I'm concerned about what parts I need to use!
Thank you!
If you have your two antennas working with one receiver then all you really need is a couple of splitters
e.g. https://www.minicircuits.com/WebStore/dashboard.html?model=ZFSC-2-4+
and split each signal between the two receivers. This will cost you around 3.5dB in signal, so you will have slightly less range, but if you aren't marginal on range at the moment, you are probably OK. You don't really need the filters unless you already need them with one receiver.

If range is an issue, then you should amplify the signal before you split it, and before you amplify it you should filter it, but let's hope you don't need to do that.
 

Thread Starter

Simon Bellemare

Joined Nov 22, 2018
8
Thank you for your reply.
That part is interesting, although I am looking for a SMD so I can wire it directly to sma's output, and connect it to a dipole directly via a balun instead of a BNC connector.
That 3.5dB shouldn't be a huge factor.
Any cues about the parts I should use? Mini-circuits makes 20+ combiners that suits my needs, I don't know what I should look at into the specs. Most important is low input return loss? Isolation? Phase unbalance? Amplitude unbalance?

https://www.minicircuits.com/pdfs/ADP-2-9+.pdf
https://www.minicircuits.com/pdfs/JPS-2-1W.pdf
https://www.minicircuits.com/pdfs/ADP-2-1W+.pdf
https://www.minicircuits.com/pdfs/JPS-2-900.pdf
https://www.minicircuits.com/pdfs/ADP-2-4+.pdf

And then I've got the same amount of choices between baluns!
 
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