"Joe" wrote in message
hlink.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.


Hi, Joe -

I think the linear output is from the detector in the receiver while the
digital output is following an amplifier with AGC (automatic gain control).
If so, then you may find that the linear output will decrease in amplitude
with distance but the digital output will stay constant until the range is
so great that the signal drops into the noise. Using the decoder on the
digital output eliminates the noise you see when the transmitter is off.

Sounds like a fun project.

John

"The other John Smith" wrote in message
link.net...

"Joe" wrote in message
hlink.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.


Hi, Joe -

I think the linear output is from the detector in the receiver while the
digital output is following an amplifier with AGC (automatic gain
control).
If so, then you may find that the linear output will decrease in amplitude
with distance but the digital output will stay constant until the range is
so great that the signal drops into the noise. Using the decoder on the
digital output eliminates the noise you see when the transmitter is off.

Sounds like a fun project.

John

Hi John,

Yes, it is fun. Looks like I will be learning about PLLs too. By the decoder
do you mean the holtek? I was not going to use the encoder and decoder,
since this is not a really critical application. I was planning on
generating a square wave with a 555 at the transmitter data pin and then
when the receiver detects it, take a picture. Yes, I think you are right
about the linear pin, because I noticed the magnitude of the received signal
seemed to drop a little with distance, but the digital pin stayed strong the
whole distance when I moved the transmitter from it. The linear pin seems to
be much quieter tho.

I still haven't worked on this yet today, so off I go to work on it some
more and maybe I can get a working circuit soon.

Regards,
Joe
KB1KVI

----- Original Message -----
From: "Joe"
Newsgroups: rec.radio.amateur.homebrew
Sent: Friday, April 16, 2004 7:15 PM
Subject: questions about 433MHZ modules

Hi, Joe -

I think the linear output is from the detector in the receiver while the
digital output is following an amplifier with AGC (automatic gain
control).
If so, then you may find that the linear output will decrease in
amplitude
with distance but the digital output will stay constant until the range
is
so great that the signal drops into the noise. Using the decoder on the
digital output eliminates the noise you see when the transmitter is off.

Sounds like a fun project.

John

Hi John,

Yes, it is fun. Looks like I will be learning about PLLs too. By the
decoder
do you mean the holtek?


Yes, that's what I meant.


I was not going to use the encoder and decoder,
since this is not a really critical application. I was planning on
generating a square wave with a 555 at the transmitter data pin and then
when the receiver detects it, take a picture. Yes, I think you are right
about the linear pin, because I noticed the magnitude of the received
signal
seemed to drop a little with distance, but the digital pin stayed strong
the
whole distance when I moved the transmitter from it. The linear pin seems
to
be much quieter tho.


Yes, it would be because of the lower gain. If you need the AGC associated
with the digital output, you might be able to use a phase detector IC on
that output to detect your 555's frequency. Maybe the phase detector output
would be quiet with no incoming carrier. On the other hand, you may not need
any more than what you've already tested. If you're happy with the distance
you get using the detector output, don't worry about it.


I still haven't worked on this yet today, so off I go to work on it some
more and maybe I can get a working circuit soon.


Good luck with it and let us know how it works when you're done.

John

"John" wrote in message
...
----- Original Message -----
From: "Joe"
Newsgroups: rec.radio.amateur.homebrew
Sent: Friday, April 16, 2004 7:15 PM
Subject: questions about 433MHZ modules

Hi, Joe -

I think the linear output is from the detector in the receiver while
the
digital output is following an amplifier with AGC (automatic gain
control).
If so, then you may find that the linear output will decrease in
amplitude
with distance but the digital output will stay constant until the
range
is
so great that the signal drops into the noise. Using the decoder on
the
digital output eliminates the noise you see when the transmitter is
off.

Sounds like a fun project.

John

Hi John,

Yes, it is fun. Looks like I will be learning about PLLs too. By the
decoder
do you mean the holtek?


Yes, that's what I meant.


I was not going to use the encoder and decoder,
since this is not a really critical application. I was planning on
generating a square wave with a 555 at the transmitter data pin and then
when the receiver detects it, take a picture. Yes, I think you are right
about the linear pin, because I noticed the magnitude of the received
signal
seemed to drop a little with distance, but the digital pin stayed strong
the
whole distance when I moved the transmitter from it. The linear pin
seems
to
be much quieter tho.


Yes, it would be because of the lower gain. If you need the AGC associated
with the digital output, you might be able to use a phase detector IC on
that output to detect your 555's frequency. Maybe the phase detector
output
would be quiet with no incoming carrier. On the other hand, you may not
need
any more than what you've already tested. If you're happy with the
distance
you get using the detector output, don't worry about it.


I still haven't worked on this yet today, so off I go to work on it some
more and maybe I can get a working circuit soon.


Good luck with it and let us know how it works when you're done.

John


Hi John,

See my question about surface mount antennas posted above (LOL). Maybe I
should just leave the PLL out of the circuit and see if I can use just the
receiver. The digital pin of the receiver seems to be noisy only when the
transmitter it within a few feet of it, once I move it away, the noise goes
away. Thanks.

Joe
KB1KVI

"Joe" wrote in message
k.net...

Hi John,

See my question about surface mount antennas posted above (LOL). Maybe I
should just leave the PLL out of the circuit and see if I can use just the
receiver. The digital pin of the receiver seems to be noisy only when the
transmitter it within a few feet of it, once I move it away, the noise
goes
away. Thanks.

Joe
KB1KVI

I think everybody would be better off if I stayed out of the discussion on
surface mount antennas.

Yes, I agree about trying it as it is. If you're happy with the performance
as it is, no reason to change at this time. You could make the effort later
if your requirements change.

John

"Joe" wrote in message
k.net...

Hi John,

See my question about surface mount antennas posted above (LOL). Maybe I
should just leave the PLL out of the circuit and see if I can use just the
receiver. The digital pin of the receiver seems to be noisy only when the
transmitter it within a few feet of it, once I move it away, the noise
goes
away. Thanks.

Joe
KB1KVI

I think everybody would be better off if I stayed out of the discussion on
surface mount antennas.

Yes, I agree about trying it as it is. If you're happy with the performance
as it is, no reason to change at this time. You could make the effort later
if your requirements change.

John

"John" wrote in message
...
----- Original Message -----
From: "Joe"
Newsgroups: rec.radio.amateur.homebrew
Sent: Friday, April 16, 2004 7:15 PM
Subject: questions about 433MHZ modules

Hi, Joe -

I think the linear output is from the detector in the receiver while
the
digital output is following an amplifier with AGC (automatic gain
control).
If so, then you may find that the linear output will decrease in
amplitude
with distance but the digital output will stay constant until the
range
is
so great that the signal drops into the noise. Using the decoder on
the
digital output eliminates the noise you see when the transmitter is
off.

Sounds like a fun project.

John

Hi John,

Yes, it is fun. Looks like I will be learning about PLLs too. By the
decoder
do you mean the holtek?


Yes, that's what I meant.


I was not going to use the encoder and decoder,
since this is not a really critical application. I was planning on
generating a square wave with a 555 at the transmitter data pin and then
when the receiver detects it, take a picture. Yes, I think you are right
about the linear pin, because I noticed the magnitude of the received
signal
seemed to drop a little with distance, but the digital pin stayed strong
the
whole distance when I moved the transmitter from it. The linear pin
seems
to
be much quieter tho.


Yes, it would be because of the lower gain. If you need the AGC associated
with the digital output, you might be able to use a phase detector IC on
that output to detect your 555's frequency. Maybe the phase detector
output
would be quiet with no incoming carrier. On the other hand, you may not
need
any more than what you've already tested. If you're happy with the
distance
you get using the detector output, don't worry about it.


I still haven't worked on this yet today, so off I go to work on it some
more and maybe I can get a working circuit soon.


Good luck with it and let us know how it works when you're done.

John


Hi John,

See my question about surface mount antennas posted above (LOL). Maybe I
should just leave the PLL out of the circuit and see if I can use just the
receiver. The digital pin of the receiver seems to be noisy only when the
transmitter it within a few feet of it, once I move it away, the noise goes
away. Thanks.

Joe
KB1KVI

----- Original Message -----
From: "Joe"
Newsgroups: rec.radio.amateur.homebrew
Sent: Friday, April 16, 2004 7:15 PM
Subject: questions about 433MHZ modules

Hi, Joe -

I think the linear output is from the detector in the receiver while the
digital output is following an amplifier with AGC (automatic gain
control).
If so, then you may find that the linear output will decrease in
amplitude
with distance but the digital output will stay constant until the range
is
so great that the signal drops into the noise. Using the decoder on the
digital output eliminates the noise you see when the transmitter is off.

Sounds like a fun project.

John

Hi John,

Yes, it is fun. Looks like I will be learning about PLLs too. By the
decoder
do you mean the holtek?


Yes, that's what I meant.


I was not going to use the encoder and decoder,
since this is not a really critical application. I was planning on
generating a square wave with a 555 at the transmitter data pin and then
when the receiver detects it, take a picture. Yes, I think you are right
about the linear pin, because I noticed the magnitude of the received
signal
seemed to drop a little with distance, but the digital pin stayed strong
the
whole distance when I moved the transmitter from it. The linear pin seems
to
be much quieter tho.


Yes, it would be because of the lower gain. If you need the AGC associated
with the digital output, you might be able to use a phase detector IC on
that output to detect your 555's frequency. Maybe the phase detector output
would be quiet with no incoming carrier. On the other hand, you may not need
any more than what you've already tested. If you're happy with the distance
you get using the detector output, don't worry about it.


I still haven't worked on this yet today, so off I go to work on it some
more and maybe I can get a working circuit soon.


Good luck with it and let us know how it works when you're done.

John

I am working with RX433 and TX433 modules to create a remote camera
control. I previously received some excellent advice on this forum about
using a phase locked loop in the receiver section to detect the signal from
the transmitter and eliminate most of the noise.

I breadboarded both the receiver and transmitter and gave it a trial run. I
am still a little shaky on the PLL, it seems there's maybe a little black
magic involved with the design there, but overall the system works. It locks
at the proper frequency, but now I don't seem to have as much range as
before the PLL. As a 'range booster', I used a piece of 24ga wire about 30cm
long on the receiver and about 15cm (almost quarter wave) on the
transmitter. both 'antennas' were vertical to the breadboards. That helped
to extend the range about another 15 feet or so.

I saw a surface mount antenna advertised in the mouser catalog and I was
wondering if anyone has had any experience with these. It is made by Yageo,
part number is 4311-121-20043, but there does not seem to be a data sheet on
it at the mouser site or at the Yageo site. My concern is that the receiver
and transmitter boards will be in the horizontal plane, and I am wondering
if a straight up telescoping antenna would output a larger range radiation
pattern. If I mount a surface mount antenna to the boards, maybe the pattern
will all be radiating upwards? Does anyone know? Also, can someone steer me
to a good tutorial or site that discusses radiation patterns of different
types of antennas?


TIA,
Joe
KB1KVI

The surface mount antenna is likely to be a patch, or microstrip,
antenna. When mounted on a horizontal surface, They radiate or receive
most strongly straight up, although they do reasonably well at lower
angles and have some response at the horizon. Among other applications,
they're commonly used as GPS antennas, for receiving signals from
satellites. But a vertical antenna would almost certainly do much better
in your application.

I don't know of a site or tutorial that gives the kind of basic
information you're looking for, but you might find what you need at
http://www.cebik.com. Be cautious at other sites, since there's a huge
amount of misunderstanding and misinformation about antennas out there,
and the ability to make a fancy and professional looking web site has
nothing to do with whether the author really understands the subject
matter. If you're interested in a little more depth from a reliable
source, the _ARRL Antenna Book_ is a good investment.

Roy Lewallen, W7EL

Joe wrote:
. . .
I saw a surface mount antenna advertised in the mouser catalog and I was
wondering if anyone has had any experience with these. It is made by Yageo,
part number is 4311-121-20043, but there does not seem to be a data sheet on
it at the mouser site or at the Yageo site. My concern is that the receiver
and transmitter boards will be in the horizontal plane, and I am wondering
if a straight up telescoping antenna would output a larger range radiation
pattern. If I mount a surface mount antenna to the boards, maybe the pattern
will all be radiating upwards? Does anyone know? Also, can someone steer me
to a good tutorial or site that discusses radiation patterns of different
types of antennas?


TIA,
Joe
KB1KVI