Those of us who work with heavy RF counts know the game using bread pans to alleviate RF Intermodulation when setting multiple transmitters side by side on a surface. In short – for those who don’t know – When you set multiple RF microphones together (and all switched on) in close proximity they will generate intermodulation artifacts that deem potentially usable frequencies unusable. I came up with this case to satisfy a need for an A2 Kit (containing things such as nexcare tape, batteries, markers, label tape, etc – really anything you would expect to find at an A2 station short of headphones). The case would travel without microphones (which live in the rack with the receiver of course) and contain all of the above necessities.
The felt microphone slots are lined with a few layers of Aluminum foil which act as the aforementioned bread pans, interrupting potential intermodulation for a cleaner spectrum, while giving the A2 a nice neat roll-away-proof mic rack for his work station.
The case uses DJ case style “lift-off hinges” which allows the two trays to be separated into two separate mic suppositories for those tight-fit A2 positions they’re always shoving us into.
Now for a test!
I hooked up a Shure UHF-R 8 channel rack (G1 frequency Band) with all 8 handhelds to test the effectiveness of the box. Using a TTi PSA2702 spectrum analyzer I compared the modulation effects of having multiple microphones on side by side both inside and outside of the aluminum lined slots.
Once I have my frequencies coordinated and all of my microphones and receivers programmed, I begin with a scan of the G1 frequency spectrum (470MHz-530MHz) to see what it looks like clean (left). I then proceeded to test multiple transmitters both inside and outside of the case. The following slideshow shows the result!
The Case works like a charm! And provides a clean workspace for the A2 in addition to the RF benefits! Huzzah!