I created one on a Trinity once when someone left one in the studio for a few weeks, sounded the same more or less as the J Edgar patch on the Alpha 2 we had once. Used a Pulse/Square wave with LFO'd PWM and an envelope on the pitch, fastish attack slower release, sustain at maximum.

Came out like the hoover 2 patch in the link IQ kindly gave. Imagine you could get link 1 by changing the pitch envelope. You may need extra oscillators or chorus (as above) to make it fat enough for you.

Not sure if there's anyway of getting the Juno 106 to modulate the pitch with the filter envelope so it may depend on what Juno you have...