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




"Joe" wrote in message thlink.net...
Thank you for the info. Today I connected the transmitter data pin to my
square wave generator with a 1Khz square wave (at 3V peak) and I could see
it on the receiver output pins, both the linear and digital pins on the
receiver output pretty much the same signal. The only thing I was confused
about is that, when I first switch the receiver on, the digital output is
quiet (it goes to 5volts at first and then drops to and stays at zero
volts). Once I transmit the square wave to it and turn the transmitter off,
the digital output is very noisy (low frequency, I think) and never settles
back to zero. The linear line comes up to about 2 volts on power up, shows a
pretty good square wave when the transmitter is on and then goes back to the
2 volt level when the transmitter is turned off and stays much quieter.

I can probly filter out the noise on the digital line, or capacitively
couple the linear line to get rid of the dc, but I still need to study this
more. The range was amazing! I measured about 60 feet (~20meters) and the
signal was still strong. This was with the receiver in a building and the
transmitter outside. I can still get more range out of it I am sure, so I
will be testing that also.

I have never worked with phase lock loops before, but I do have a few in my
cmos collection, along with the data sheets. Do you know of any links I can
visit to see some applications of the cd4046B PLL?

Thanks,
Joe
KB1KVI