How does a heart rate monitor pickup my heart beat and transmits?

I would like to know in details how a Polar or Mia Heart Rate Monitor
(HRM) pickup my heart beat and how it transmit the signal.

1) I want to know why does the HRM need moisture?

2) Why the paralleled grooves are important on the transmitter side of
the HRM?
There are two, one on each side of the transmitter?

3) What is the wave length of the HRM?

4) Is the length of the plastic "wings" are important for the
transmitter or the pickup of the heart beat?

Does the antenna use a Yagi or coplanar antenna for the transmitter
and for the reception?

5) Has every knows the heart is submerged in a saline fluid where only
Ultra Short wave length can reach the heart due this saline solution.
How does the HRM picks up the heart beat?
Is it by induction?
Is it by conduction?
Is it by using OPamps?
etc

6) How does the electronic circuit works on the transmitter and
receiver side?

7) I've checked the length of the strap and I was able to verify that a
regular cleaning improve the transmission and low down the interference
level? why?

8) How is the transmitter ?receiver encrypted? Is it the ASK code? or
other ?

9) Is there a HRM which can download directly its data to a laptop
through the infrared port?
Guy (gnh888)

You're not asking much then, are you ;-)