"OK1SIP" wrote in message
om...
Hi Joe,
the receiver is probably a superregen type. Superregens are very noisy
with no carrier on their input. Superhet modules reduce the noise
problems, but they are more expensive and complicated.
I worked enough with 4046, but I have no link at hand. It comprises a
VCO and two phase comparators - you use only one of them. What I
remember:
1/ Set the tuning range of the VCO as necessary - not too wide, not
too narrow. Two resistors and a capacitor affect both the the central
frequency and the sweep. Check the tuning range with the loop open and
a variable control voltage applied.
2/ I always used the phase comparator No.2. The comparator No.1 (a XOR
gate in fact) usually did not give me satisfying results.
3/ The filter between the phase comparator output and the VCO control
input is essential for the dynamics of the PLL. Do not underestimate
its design.
IMHO for your purpose you should set the central frequency to the
frequency of the 555 at the transmitting side and a very narrow sweep.
If the proper signal is received, the PLL locks, which is indicated on
one of the 4046 pins. This is your "activated" signal. Otherwise the
VCO runs freely and the loop stays unlocked.

Ivan OK1SIP




Hello Ivan,

I was just going to use a bandpass filter, but I will probly play around
with the PLL, since I have never used them before. Thanks for the tips.

Joe
KB1KVI