(Operated by Jensen Technical Services, Lemont, IL)

HOVERCRAFT INTERCOM SYSTEM

After much research and experimenting I assembled an intercom system complete with Active Noise Canceling Headphones and a CD player for my Hovercraft, and it works!  The headphones are David Clark H10-56 helicopter headphones.  I tried other models but they didn’t offer enough hearing protection for long trips.  The H10-56 headphones come stock with a coiled cord, this cord was heavy and pulled slightly.  The fine people at David Clark replaced the coiled cord with a straight one for me at no charge.

These headphones seal around the ear with a comfortable gel ring.  Attention must be paid to the style of eyewear used.  Since the gel is somewhat firm, glasses with large arms may prevent the headset from properly sealing thus reducing the noise protection.  You may need to experiment with different types of eyewear.

The intercom system I use is a PS Engineering, Aerocom ST.  (This model has been replaced by the newer Aerocom III with automatic digital squelch level control.)  This stereo intercom was modified with a special notch filter to reduce unwanted ambient noise.  It is equip with separate volume and squelch controls for pilot and passenger.  This unit should be mounted where it is safe from water spray but allows for squelch adjustments.  At casual cruising speeds the squelch will need to be adjusted lower than when cruising at full throttle.  A small price to pay for being able to communicate in an open cockpit hovercraft!

Unlike less expensive intercom systems which continuously allow background noise into the headset or use a "push to talk" button to communicate, the squelch circuitry in the Aerocom ST blocks out all background noise and automatically enables conversations to be heard.

The Aerocom ST has an external jack, into which I plug a portable CD player in for background music.  When my passenger or I speak, the music is muted.  This unit also provides signal inputs & outputs for 2-way communications via an external radio.

The main key to making this whole system work was the least costly component.  Mic Muffs, Oregon Aero’s Model 90015 leather microphone covers.  These Mic Muffs replace the stock windscreen on the David Clark microphones. These little babies really work!