Wireless Help - feeding one set of antennas through four splitters

[sdauditorium]

We just purchased two Sennheiser directional antennas (2003 version-passive) and have four passive splitters feeding our mic units.

Two of the splitters we have are the G3 series version with the following RF ports:
Ant RF In A
Ant RF In B
RF Out A
RF In A/B: DC Out

The other two splitters are of the G2 version with the following RF ports:
In A
In B
Out A

I've read the Sennheiser manual and pretty sure I have it correct, but what's the proper cable routing that should be used to link the four splitters together to make sure that they're all receiving both antenna feeds?

 

[mbenonis]

How many systems are you looking to feed?

 

[sdauditorium]

We have 17 systems. Until I purchase a 5th splitter, one system will be using the stock 1/4" stock whip antennas for the time being.

 

[mbenonis]

Hmm, I can't seem to find the splitter manuals on Sennheiser's site. Are you sure that they don't have an Antenna B loop-through? Also, what are the model numbers for the splitters?

 

[sdauditorium]

They are Sennheiser A2003-UHF.

Here's a product link: Full Compass, Sennheiser A2003-UHF

 

[mbenonis]

Do you by chance know the splitter model numbers too?

 

[sdauditorium]

Do you by chance know the splitter model numbers too?

The G3 version is Sennheiser ASA1/NT. The G2 version is ASP 2.

 

[mbenonis]

So looking at the way these things are supposed to work, I'm not sure how you'd get sixteen dual outputs without an additional splitter. The problem is that the splitters only have a 'thru' port for the A input, and not the B input. In an eight-channel system, you put one antenna into each unit's A input, and connect the thru to the other unit's B input.

So, in your case, you need to either get a pair of two-way splitters and drive two separate eight-channel systems, or get a fifth dual-four-way splitter and drive each of your existing units with that.

That help at all?

BTW, the ASA1 unit is an active splitter and not a passive one. Just FYI.

 

[sdauditorium]

So looking at the way these things are supposed to work, I'm not sure how you'd get sixteen dual outputs without an additional splitter. The problem is that the splitters only have a 'thru' port for the A input, and not the B input. In an eight-channel system, you put one antenna into each unit's A input, and connect the thru to the other unit's B input.

So, in your case, you need to either get a pair of two-way splitters and drive two separate eight-channel systems, or get a fifth dual-four-way splitter and drive each of your existing units with that.

That help at all?

BTW, the ASA1 unit is an active splitter and not a passive one. Just FYI.

Would I still be able to use 1 set of paddles, or would I have to purchase another set? Also, if I got a pair of two-way splitters, what would you recommend or spec?

 

[FMEng]

Would I still be able to use 1 set of paddles, or would I have to purchase another set? Also, if I got a pair of two-way splitters, what would you recommend or spec?

A pair of two-way splitters is all you need to make this work. Almost any 50 ohm, passive splitter with a frequency range that includes 400-700 Mhz will work fine. The two-way, Lectrosonics ZSC24 is one such product and it is significantly less overpriced than the ones sold by most of the pro audio companies. A passive splitter of any kind should not cost more than around $100, unless there are really unique requirements.

Interestingly, Lectrosonics and AKG both re-badge passive splitters from Mini Circuits, and mark up the price. Buying directly from Mini Circuits would be about half the cost. Their model number is ZSC-2-4 (sound familiar?). They make top notch stuff.
Mini-Circuits Home

If you go with a pair of four-way ZFSC-4-1, you will have enough ports to avoid looping through anything and you can plug in two more receivers, too. The small penalty is an extra -3 dB of loss per receiver.

 

[sdauditorium]

A pair of two-way splitters is all you need to make this work. Almost any 50 ohm, passive splitter with a frequency range that includes 400-700 Mhz will work fine. The two-way, Lectrosonics ZSC24 is one such product and it is significantly less overpriced than the ones sold by most of the pro audio companies. A passive splitter of any kind should not cost more than around $100, unless there are really unique requirements.

Interestingly, Lectrosonics and AKG both re-badge passive splitters from Mini Circuits, and mark up the price. Buying directly from Mini Circuits would be about half the cost. Their model number is ZSC-2-4 (sound familiar?). They make top notch stuff.
Mini-Circuits Home

If you go with a pair of four-way ZFSC-4-1, you will have enough ports to avoid looping through anything and you can plug in two more receivers, too. The small penalty is an extra -3 dB of loss per receiver.

I checked out the Mini-Circuits site with the product number, but I could only find 4-way active powered splitters but no passive. I think that'll be the route I'll go if those are the correct models.

 

[mbenonis]

I second getting the Mini-Circuits splitters. The best you're going to get for the price. Here's what FMEng was referring to with the four-way splitter (you'll need two):

http://www.minicircuits.com/pdfs/ZFSC-4-1+.pdf

BTW, this does the same EXACT thing that the passive (ASP2) Sennheiser unit does, minus power distribution. Maybe I oughta start recommending this in my FAQ over the Mfr. antenna distros.

 

[mbenonis]

BTW, you might find this interesting reading if you haven't read it already:

Do Multicouplers (Antenna Distros) Prevent Intermod? « Mike Benonis

 

[avare]

I second getting the Mini-Circuits splitters.[/url]

BTW, this does the same EXACT thing that the passive (ASP2) Sennheiser unit does, minus power distribution. Maybe I oughta start recommending this in my FAQ over the Mfr. antenna distros.

I hope the quoting was not too cryptic. Mini-Circuits also sells bias tees. All that is then needed is a low voltage power supply and you have the complete equivalent circuit.

I recall an ex employee of Sennheiser's writing about the early days of wireless and one the (then big three) newtworks wanted an antenna splitter/distributor. The box cost the network thousands of dollars, and contained Mini-Circuits splitters.

Andre

 

[mbenonis]

I hope the quoting was not too cryptic. Mini-Circuits also sells bias tees. All that is then needed is a low voltage power supply and you have the complete equivalent circuit.

I recall an ex employee of Sennheiser's writing about the early days of wireless and one the (then big three) newtworks wanted an antenna splitter/distributor. The box cost the network thousands of dollars, and contained Mini-Circuits splitters.

Andre

Somehow, this doesn't surprise me in the least. The only thing more obscenely priced than antenna distro units is wireless mics antennas. $300+ for a LPDA printed on FR4? C'mon, I could have that fabbed for $30.

 

[sdauditorium]

I ended up picking up two of the Mini Circuits splitters like mentioned as well as 8 BNC cables, so I should be all set to go. Thanks again.

 

[mbenonis]

I ended up picking up two of the Mini Circuits splitters like mentioned as well as 8 BNC cables, so I should be all set to go. Thanks again.

What kind of coax cable/how long? Little jumpers?

 

[sdauditorium]

What kind of coax cable/how long? Little jumpers?

6' jumpers...50 ohm/RG58

 

[mbenonis]

6' jumpers...50 ohm/RG58

6' should be OK, but I wouldn't recommend anything longer at these frequencies. 6' of RG-58 loses about 16.9 dB at 100', so for 6' that comes out to about 1 dB.

In layman's terms, that's 80% efficient (20% of the received signal strength is thrown away as heat in each cable run).

 

[sdauditorium]

6' should be OK, but I wouldn't recommend anything longer at these frequencies. 6' of RG-58 loses about 16.9 dB at 100', so for 6' that comes out to about 1 dB.

In layman's terms, that's 80% efficient (20% of the received signal strength is thrown away as heat in each cable run).

Would it be advantageous to switch to 3' jumpers instead? I should be able to reach all of the splitters, but I'd have to check.