need to add a diode to the ground on the audible s-meter,
so that the op amp's ground is at -0.5v potential to the vco ic's ground.
that will lower the floor a bit, providing more range, since the op amp can't seem to output a voltage much below 0.3v

I also need to figure out how to get that IC's frequency REALLY far
down.  like down to 20hz or lower.

using an op amp to power the speaker may help the vco ic also,
it wasn't really meant to drive a speaker

idea for hide is to place a low powered transmitter hooked to a beam to blast the other side of a barrier (creek?) with a decent signal

could use an a/b coax relay too for multiple antennas