433 MHz receiver and transmitter sharing one antenna
hi!
i’m about to design a little raspberry hat including 433 mhz sender and receiver. is there any disadvantage when both share one antenna (both antenna pins are wired to the same antenna)? in my opinion it should have the same effect as if they were directly next to each other. am i wrong?
@quotschmacher your answer is probably on google,
https://www.google.com/search?q=433mhz+share+antenna+with+receiver+site:electronics.stackexchange.com&client=ms-android-samsung&prmd=sivn&sa=X&ved=2ahUKEwjM0-qVuvbbAhWJfFAKHR3cBWsQrQIoBDAAegQIBRAK&biw=360&bih=560#fsc=_XuI0W9vRGYyZkwWZh7noBQ7:630
It is a great idea but hard to acomplish i think.
Come to think about it, does a sender/receiver combined PCB even excist?
@Gleno0h this link really helped.
And i think shields like this already exist, but my main goal is a ir receiver. But then there is a lot of unused space on the shield so 433 MHz stuff is just my addition and i like to develop such things.
I don`t think that this is a good idea because if the sender is using the antenna the full power goes too the receiver.
This will destroy the receiver.
@v1per said in 433 MHz receiver and transmitter sharing one antenna:
I don`t think that this is a good idea because if the sender is using the antenna the full power goes too the receiver.
This will destroy the receiver.
that’s exactly what i found out with the search result @Gleno0h gave me. but what is more interesting: connecting both is exactly what pilight https://www.pilight.org/shop/#pcbkits is doing.
On the picture you can’t see exactly how the tracks on the board run.
But is there an antenna on it? If then determined 2 separate conductor tracks as antenna.
@v1per said in 433 MHz receiver and transmitter sharing one antenna:
On the picture you can’t see exactly how the tracks on the board run.
that’s true. but if you visit the soldering instructions it is possible to see it.
in the first image: the pinheader, left pin is antenna from the receiver, fifth is the antenna und 7th is the antenna pin from the sender
You’re right… thats strange.
i think it’s possible because both - rx and tx - are powered with 5v. but if you give more power to the sender (12v battery) this would be a bad design. and this is the point i missed - different voltages.
@quotschmacher i actually cant find any shield which does both.
@Gleno0h maybe we talk about different things… i want to design a hat / shield for the rpi where i can simply connect a single sender and a single receiver. so no combined module. but as they are both directly next to each other, the receiver always receives anything the sender is sending. so my thought was: if it get’s every signal, why can’t they share an antenna? and the answer seems to be: because of voltage and current.
@quotschmacher somehow my previous post was posted, which i cancelled. Strange.
Conclusion: to share the antenna in the given scenario you would need a switching module to switch the antenna between rx and tx (half duplex mode). Explanation is given in the threads
"It always takes longer than you expect, even when you take into account Hofstadter's Law.", Hofstadter's Law
