Episode 628 I try a couple receivers. Good bad and different. A look at the board and schematic lead to some interesting findings. Be a Patron: / imsaiguy
Your first module is a superregenerative receiver, the second is a superheterodyne receiver. The IC in the superregen unit is used as a Schmitt trigger to provide noise immunity.
We bought a bunch of these from a local distributor, the description said something along the lines of "Outputs digital noise when no carrier is being received" - We were able to get it to work at low datarates and checksum, but the microcontroller was awake 24/7 trying to pick out signal from the noise....
I one without a crystal. Seems to work. Mines a little different. There's a through hole resistor on the top. It's marked on the silkscreen underneath so not a bodge.
the bad receiver needs 470uF on power supply, 2u2 between data output and ground and R15 needs 1MOhm resistor in pair so total resistance will be around 680kOhm
Had the same probvlem with noisy output. Run the module from 9V and it cleaned up. This is due to the comparator thresholds being non-optimally set. With good antennas up to 100m range.
For a few months I had terrible qrm on our uk 70cm contest night. Every few minutes I'd get a rapid ticking noise which slowly increased in frequency. Out of the blue a neighbour asked if I'd change the battery in her domestic heating oil tank level indicator. On investigation I found battery was ok and on monitoring the signal from the little 433MHz transmitter I heard the dreaded ticks. The senser was caked with white dust and the circuit board had a few corroded joints. After a good clean and made good a few solder joints it was back working and to my great relief I later had a tick free contest. It's not often that qrm is so easily fixed. 73
@M0KOV I suspect that you are within range of the PAVE PAWS radar transmitter at RAF Fylingdales, UK. The Pave PAWS (Precision Acquisition Vehicle Entry Phased Array Warning System) radar transmits 600 kW pulses hopping on every 1 MHz throughout the 420-450 MHz frequency band. In search mode the pulse bandwidth measures about 300 kHz centered around each MHz mark with a peak signal strength of -90 dBm (S9+3dB) to me. In tracking mode the pulse bandwidth can increase to 30 MHz. The pulses duration is milliseconds, too fast to register on many S meters. You may hear the pulses as random ticking or clicking sounds and can see them as a jumping baseline on a panadapter. I have posted some videos of PAVE PAWS signals I receive here from Beale AFB on my KP4MD TH-cam channel.
@@kp4md Thank you for the interesting reply. Nobody in our contest group heard any similar signals to the ones that I was receiving, that included a station situated 3 miles away and another station near Thirsk which is between me and Fylingdales. This noise was at s8 and was identical to the small 433 tx, it splattered over the band and rose 300Hz presumably as it warmed up. Shall certainly check out PAWS and ask if any of our group members has heard it. 73 Steve
Sir please help me, I made a 4 channel transmitter and receiver circuit using 433Mhz rf module with HT12E and HT12D ic. But when I provided both the reciver and transmitter circuit same voltage 5v then communication didn't work that is data was not received. But when I powered the transmitter circuit with low voltage than receiver circuit around 2.5 v then communication between the two worked and data is successfully received that is led on the receiver side turned on. Why is this happening?
Those modules suck. You can send digital stuff at really low speed, but the amount of filtering and error correction you need to add is ridiculous. And you still have less than 50% chances of receiving it properly.
Nrf24l01 are soooooo much better, especially once you know their quirks. Not to mention that you actually have channels and some error handling/acking.
A marked amount of radio-related projects for an Ex-Ham person? : ) Why am I convinced there's a "Macho-Grande" story in here somewhere, like when a Ham transceiver fell off the table onto a beloved pet?
Don't worry, lots of non radio stuff will be coming in a couple days. Got tricked into RF stuff with the TinySA. No drastic radio stories. Just normal high voltage shocks and loud capacitors blowing up. No animals were harmed.
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Your first module is a superregenerative receiver, the second is a superheterodyne receiver.
The IC in the superregen unit is used as a Schmitt trigger to provide noise immunity.
We bought a bunch of these from a local distributor, the description said something along the lines of "Outputs digital noise when no carrier is being received" - We were able to get it to work at low datarates and checksum, but the microcontroller was awake 24/7 trying to pick out signal from the noise....
First thanks for your video .the second transister is super regenartive detector.
The first op pam is schmitte triger.
I one without a crystal. Seems to work.
Mines a little different. There's a through hole resistor on the top. It's marked on the silkscreen underneath so not a bodge.
the bad receiver needs 470uF on power supply, 2u2 between data output and ground and R15 needs 1MOhm resistor in pair so total resistance will be around 680kOhm
Had the same probvlem with noisy output. Run the module from 9V and it cleaned up. This is due to the comparator thresholds being non-optimally set. With good antennas up to 100m range.
For a few months I had terrible qrm on our uk 70cm contest night. Every few minutes I'd get a rapid ticking noise which slowly increased in frequency. Out of the blue a neighbour asked if I'd change the battery in her domestic heating oil tank level indicator. On investigation I found battery was ok and on monitoring the signal from the little 433MHz transmitter I heard the dreaded ticks. The senser was caked with white dust and the circuit board had a few corroded joints. After a good clean and made good a few solder joints it was back working and to my great relief I later had a tick free contest.
It's not often that qrm is so easily fixed.
73
@M0KOV I suspect that you are within range of the PAVE PAWS radar transmitter at RAF Fylingdales, UK. The Pave PAWS (Precision Acquisition Vehicle Entry Phased Array Warning System) radar transmits 600 kW pulses hopping on every 1 MHz throughout the 420-450 MHz frequency band. In search mode the pulse bandwidth measures about 300 kHz centered around each MHz mark with a peak signal strength of -90 dBm (S9+3dB) to me. In tracking mode the pulse bandwidth can increase to 30 MHz. The pulses duration is milliseconds, too fast to register on many S meters. You may hear the pulses as random ticking or clicking sounds and can see them as a jumping baseline on a panadapter. I have posted some videos of PAVE PAWS signals I receive here from Beale AFB on my KP4MD TH-cam channel.
@@kp4md Thank you for the interesting reply. Nobody in our contest group heard any similar signals to the ones that I was receiving, that included a station situated 3 miles away and another station near Thirsk which is between me and Fylingdales. This noise was at s8 and was identical to the small 433 tx, it splattered over the band and rose 300Hz presumably as it warmed up.
Shall certainly check out PAWS and ask if any of our group members has heard it.
73 Steve
Sir please help me,
I made a 4 channel transmitter and receiver circuit using 433Mhz rf module with HT12E and HT12D ic. But when I provided both the reciver and transmitter circuit same voltage 5v then communication didn't work that is data was not received. But when I powered the transmitter circuit with low voltage than receiver circuit around 2.5 v then communication between the two worked and data is successfully received that is led on the receiver side turned on. Why is this happening?
Those modules suck. You can send digital stuff at really low speed, but the amount of filtering and error correction you need to add is ridiculous. And you still have less than 50% chances of receiving it properly.
Just need to add a MMIC Lean-yer to the xmtr for better s/n.
I have exactly this one , and bouncing like this it is normal. For receiving correct data you have to send data a copule of times or use CRC
@Peter Mortensen Thanks, edited. My first language is not English.
I wonder if that was a bad batch
Anyhow, that was VERY helpful
Many thx
Nrf24l01 are soooooo much better, especially once you know their quirks. Not to mention that you actually have channels and some error handling/acking.
A marked amount of radio-related projects for an Ex-Ham person? : )
Why am I convinced there's a "Macho-Grande" story in here somewhere, like when a Ham transceiver fell off the table onto a beloved pet?
Don't worry, lots of non radio stuff will be coming in a couple days. Got tricked into RF stuff with the TinySA. No drastic radio stories. Just normal high voltage shocks and loud capacitors blowing up. No animals were harmed.
👍👍👍
Your voice sounds exactly like John Cusack
Not really.
Dont use those modules from the same power supply, if you do so then this will never work.
Hmmmmmm?