Totally plausible as I have noticed when I tune a FM receiver
to my dipper's carrier, I can deviate the carrier with my voice
if I get close to the case of the dipper. Found that out the other
day when I turned up the volume on my HT and got a squeal
from the dipper!

Now when I'm searching for the carrier and my scanner stops
on a signal, I tap the dipper's case with a coin and not only do
I hear it quite clearly on the scanner but it sounds like a mic
in a coffee can. Helps to differentiate between birdies and my
target carrier.

Love it!

Ken KG0WX