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questions about 433MHZ modules
Hello to the group,
I just found this forum and hopefully, I can learn some more about homebrewing stuff. I have been a hobbyist in electronics for a little over a year now and recently received my element 2 tech license. Last year I built an infrared transmitter and receiver pair to trigger my camera remotely (about a 50 foot range). Since then, I have wanted to do the same thing with RF. I have a tek465b oscilloscope and a dmm, and have built some of my own test equipment (square wave signal generator, power supply, battery tester) and lots of timer circuits with 555's and cd 4060s. Recently I have been experimenting with audio and ultrasound with opamps. All of my projects are battery operated. I recently bought the Velleman RX 433 and TX 433 modules to try and remotely control my camera. Each module has a 'data' pin, the receiver also has a linear pin, which I am not sure how to use yet. I have been reading the data sheets and app note on the velleman site and it shows something called a HT12E being used to generate the data on the TX module and a HT12D to use these modules for remote control. I googled for the HT12E and it says it is a LSI encoder and you need the HT12D as the matching decoder (on the receiver). Not being familiar with all the terminology yet, I am wondering why I couldn't just generate a square wave to the data pin of the TX module, and, then, at the receiver, use a divide down counter to make sure enough pulses arrived, and then trigger my relay. Does anyone know if this will work? or would it just be easier (and maybe more reliable) to use the HT encoder and decoder? I am asking because I am not familiar with the type of waveform or pulse shape that the Holtek generates, and, I am not sure if I just want to try pushing a 555 type square wave thru my TX unit and maybe end up letting the smoke out. Any suggestions or ideas are appreciated. TIA, Joe KB1KVI |
Hi Joe,
IMHO the linear output of the RX is for testing purposes, you should let it unused. The encoder/decoder pair is used as a key-and-lock, for better reliability and security. Your solution using a pulse generator at the TX side might do for a camera remote control - it can be less safe than, say, a car alarm. A bandpass filter or a PLL checking the frequency of the pulses on the receiver output should work even better than a counter only. The TX unit has limits for input voltage and frequency. If you do not exceed them, no damage should take place. BR from Ivan "Joe" wrote in message hlink.net... Hello to the group, I just found this forum and hopefully, I can learn some more about homebrewing stuff. I have been a hobbyist in electronics for a little over a year now and recently received my element 2 tech license. Last year I built an infrared transmitter and receiver pair to trigger my camera remotely (about a 50 foot range). Since then, I have wanted to do the same thing with RF. I have a tek465b oscilloscope and a dmm, and have built some of my own test equipment (square wave signal generator, power supply, battery tester) and lots of timer circuits with 555's and cd 4060s. Recently I have been experimenting with audio and ultrasound with opamps. All of my projects are battery operated. I recently bought the Velleman RX 433 and TX 433 modules to try and remotely control my camera. Each module has a 'data' pin, the receiver also has a linear pin, which I am not sure how to use yet. I have been reading the data sheets and app note on the velleman site and it shows something called a HT12E being used to generate the data on the TX module and a HT12D to use these modules for remote control. I googled for the HT12E and it says it is a LSI encoder and you need the HT12D as the matching decoder (on the receiver). Not being familiar with all the terminology yet, I am wondering why I couldn't just generate a square wave to the data pin of the TX module, and, then, at the receiver, use a divide down counter to make sure enough pulses arrived, and then trigger my relay. Does anyone know if this will work? or would it just be easier (and maybe more reliable) to use the HT encoder and decoder? I am asking because I am not familiar with the type of waveform or pulse shape that the Holtek generates, and, I am not sure if I just want to try pushing a 555 type square wave thru my TX unit and maybe end up letting the smoke out. Any suggestions or ideas are appreciated. TIA, Joe KB1KVI |
Hi Joe,
IMHO the linear output of the RX is for testing purposes, you should let it unused. The encoder/decoder pair is used as a key-and-lock, for better reliability and security. Your solution using a pulse generator at the TX side might do for a camera remote control - it can be less safe than, say, a car alarm. A bandpass filter or a PLL checking the frequency of the pulses on the receiver output should work even better than a counter only. The TX unit has limits for input voltage and frequency. If you do not exceed them, no damage should take place. BR from Ivan "Joe" wrote in message hlink.net... Hello to the group, I just found this forum and hopefully, I can learn some more about homebrewing stuff. I have been a hobbyist in electronics for a little over a year now and recently received my element 2 tech license. Last year I built an infrared transmitter and receiver pair to trigger my camera remotely (about a 50 foot range). Since then, I have wanted to do the same thing with RF. I have a tek465b oscilloscope and a dmm, and have built some of my own test equipment (square wave signal generator, power supply, battery tester) and lots of timer circuits with 555's and cd 4060s. Recently I have been experimenting with audio and ultrasound with opamps. All of my projects are battery operated. I recently bought the Velleman RX 433 and TX 433 modules to try and remotely control my camera. Each module has a 'data' pin, the receiver also has a linear pin, which I am not sure how to use yet. I have been reading the data sheets and app note on the velleman site and it shows something called a HT12E being used to generate the data on the TX module and a HT12D to use these modules for remote control. I googled for the HT12E and it says it is a LSI encoder and you need the HT12D as the matching decoder (on the receiver). Not being familiar with all the terminology yet, I am wondering why I couldn't just generate a square wave to the data pin of the TX module, and, then, at the receiver, use a divide down counter to make sure enough pulses arrived, and then trigger my relay. Does anyone know if this will work? or would it just be easier (and maybe more reliable) to use the HT encoder and decoder? I am asking because I am not familiar with the type of waveform or pulse shape that the Holtek generates, and, I am not sure if I just want to try pushing a 555 type square wave thru my TX unit and maybe end up letting the smoke out. Any suggestions or ideas are appreciated. TIA, Joe KB1KVI |
"OK1SIP" wrote in message om... Hi Joe, IMHO the linear output of the RX is for testing purposes, you should let it unused. The encoder/decoder pair is used as a key-and-lock, for better reliability and security. Your solution using a pulse generator at the TX side might do for a camera remote control - it can be less safe than, say, a car alarm. A bandpass filter or a PLL checking the frequency of the pulses on the receiver output should work even better than a counter only. The TX unit has limits for input voltage and frequency. If you do not exceed them, no damage should take place. BR from Ivan Hi BR, 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 |
"OK1SIP" wrote in message om... Hi Joe, IMHO the linear output of the RX is for testing purposes, you should let it unused. The encoder/decoder pair is used as a key-and-lock, for better reliability and security. Your solution using a pulse generator at the TX side might do for a camera remote control - it can be less safe than, say, a car alarm. A bandpass filter or a PLL checking the frequency of the pulses on the receiver output should work even better than a counter only. The TX unit has limits for input voltage and frequency. If you do not exceed them, no damage should take place. BR from Ivan Hi BR, 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 |
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 |
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 |
"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 |
"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 |
"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 |
"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 |
"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 |
"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 |
----- 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 |
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 |
"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 |
"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 |
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 |
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 |
"Roy Lewallen" wrote in message ... 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 Hi Roy, Thanks, I was reading my Radio Amateur Handbook to try and get some ideas and from the graphic figures they have in there, it did look like a vertical antenna would be better. I wanted to get another opinion though. Also, thanks for the link, I have added it to my favorites. There's a lot of stuff there to read so I can visit the site and learn more as I have time. Regards, Joe KB1KVI |
"Roy Lewallen" wrote in message ... 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 Hi Roy, Thanks, I was reading my Radio Amateur Handbook to try and get some ideas and from the graphic figures they have in there, it did look like a vertical antenna would be better. I wanted to get another opinion though. Also, thanks for the link, I have added it to my favorites. There's a lot of stuff there to read so I can visit the site and learn more as I have time. Regards, 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 |
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