I’ve been experimenting with my RF Explorer RF scanner and Touchstone Pro scanning software on the kitchen table to get a handle on what does what. Today I had a meeting at a church I previously designed the sound system for and out of my own curiosity too my RF scanning rig. The church’s RF gear consists of (5) Sennheiser EW100 beltpack transmitters / receivers with the stock antennas. When the gear was installed about 5 years ago, I used the receivers onboard scan function to select frequencies. Recently I was told that there has been some sort of noise / static. Having asked the logical questions to narrow the hunt down, it appears that the issues happen when some or all of the people wearing transmitters go to the far end of the building to greet the congregation. That part of the building is a separate structure with mostly stone between the receivers. There are some stained glass windows. After setting up my RF scanner rig and beginning to scan, I noticed that (2) of the frequencies in use were very near some peaks shown in Touchstone Pro. This is exactly why having a RF scanner & software is necessary. When the Sennheiser unit performs it’s scan it last about 2 minutes. There is no information given about what it finds during the scan, at what level any interfering signals are. It just says, “X frequencies clear…” Knowing what I know now, scanning for 2 minutes is a poor indication of what might happen 2 minutes or 2 hours or 2 days later. In my view the most important function a RF scanner rig can play is to collect an RF history at a certain location. A 2 minute scan could easily miss all sorts of things.

So I retuned (2) of the (5) units and then sync-ed the transmitters to the receivers. Then I tested both mics and then took one for a long walk while my friend watched the RF level indicator on the Sennheiser receiver. He said that the level did drop a bit when I went to the other part of the building but not completely out.

Touchstone Pro can export CSV files in various formats to be imported into Intermodulation coordination software like IAS, Shure’s WWB & . I saved my results in two different formats and packed up.