Three Passive Splitter Hacks for Antenna Distribution

antenna splitter for IEMs

Here are three simple and low-cost wireless audio antenna distribution configurations using the RF Venue 2x1SPLIT passive splitter/combiner—a versatile accessory we’ve used for years to build affordable wireless racks in conjunction with our antenna combiners and distributors.

Homebrew 8 Channel IEM combiner

This setup effectively creates an eight channel combiner for much, much less than a standalone active 8 channel transmitter combiner.

Route both outputs of two four channel IEM transmitter combiners through a single passive 2X1SPLIT, and finally into a helical antenna.

Were we building this kit out for a customer, it would look like this:

Passive intermodulation could potentially be introduced under less than ideal circumstances with this setup, just as it can occur at other physical connections throughout the RF chain.

But, if frequencies are properly coordinated, and the splitter in use has good isolation between ports, harmful harmonics are not likely to occur.

Never use an active combiner in place of the passive 2X1SPLIT, and never directly connect two or more IEM transmitters directly to a passive splitter/combiner like the 2X1SPLIT.

There are some engineers who prefer to use two or more four channel combiners with dedicated antennas, as a measure of redundancy. That’s fine, but remember to space active antennas a good distance apart to avoid near-field interactions that may result from antenna farming.

Diversity Fin DAS

Here’s a request we get all the time: “we want the same wireless microphone to function across two or more rooms.”

We use two Diversity Fins and two 2X1SPLITs to accommodate those requests.

In effect we create a simplified DAS, or distributed antenna system. In a DAS, talent freely wanders through a series of coverage “zones” without fear of losing reception. Signal sent to the same receiver(s) or different receivers depending on the engineer’s design.

Distributed systems can get complicated. That’s why we leave the bulk of the expertise in this area to Professional Wireless, who specialize in DAS.

Spectrum analyzer "wiretap"

If you have a spectrum analyzer, you can “tap” your antenna feed or, even better, one of the outputs on an antenna distributor, using the 2X1SPLIT.

Simply place the splitter in-between one branch of one output of a distributor. Feed one of the splitter’s outputs to the analyzer, and return the other output to the receiver.

The goal is visualize RF from the perspective of the receivers. The nearer the tap is to the final destination of the signal, the better the data the analyzer can retrieve for you, since it is seeing what the system is seeing.

This setup is great for taking a peek at RF activity from the system’s perspective, and for troubleshooting RF where an ambient scan has not revealed anything, but it is generally not recommended for routine operation.

The splitter adds one additional point of failure to the signal chain, and poaches a few dB of amplitude, changing the receiver’s interpretation of the two diversity signals.

If you want to do a wiretap during actual performances it’s much better to tap from an unused output on a distro, or on the cascade output of the final distro in a daisy-chain.

Want better wireless? Download our eBook on three essential concepts for correctly deploying and maintaining interference-free wireless audio systems.

Get ebook