()blivion
Active Member
Hi.
Looking to build my own unlicensed radio projects. Sadly, I suspect there is a chance this idea will go over like a fart in church, you radioaficionados don't seem to take kindly to those trying to do anything without a licence, whether there are legal and good intentions or otherwise. But I have to ask the question as I have been trying to get into the science for just about as long as I have been doing electronics, and I just can't seem to get anything concrete. Finally, I would rather learn from people who know about RF interference than blindly build some random schematic I found on google that may or may not be a pollution nightmare.
To that end...
Could someone share whatever simple, legal, moral, and overall worthwhile schematics/projects they have, (or know of) for doing full duplex ISM and/or Part 15 compliant RF coms between microcontrollers? Or possibly help me design something from the ground up?
What I'm mostly after in the RF section is...
1) Frugal construction, using cheap, common, discrete parts and techniques.
2) Design immunity from causing realistically problematic RF pollution.
3) Flexibil vectors for modulation, changing carriers, and what have you using the MCU.
Know that...
1) I am fully aware of the prebuilt cheap modules. I want to build it out of parts.
2) My power and range is of course very low. A few feet/meters, no more than ten.
3) I prefer using GP BJT's. No reason in particular other than that I have a bunch.
4) I have a more or less controlled environment, and a reasonable head on my shoulders.
5) I DO NOT have a lot of radio equipment, I'm a low budget hobbyist. (I of course have basic electronic equipment.)
6) I live in a rural area, I highly doubt there is strong chance of me causing significant RF interference unless I really tried.
Here is an example of something that is about what I am looking at for transmitting. https://www.swharden.com/blog/2011-08-06-ridiculously-simple-avr-mcu-am-radio-transmitter/ I wouldn't mind building something a little more complicated. Maybe some provisions for FM modulation. I tried to build this already and it didn't even have enough power to transmit a few inches. I wasn't sure if it was radiating more power on a band that was out of range of my receiver, so I was too afraid to up the power without knowing what exactly was happening.
I like the idea of a regenerative design for the receiver portion. The SNR of superhet is cool and all, but I think I like the absolute gain AND simplicity of the regen more. I just don't know how I should proceed if I also want a BJT built MCU interfaceable design.
Let me know if you have something good to share. Thanks.
Looking to build my own unlicensed radio projects. Sadly, I suspect there is a chance this idea will go over like a fart in church, you radioaficionados don't seem to take kindly to those trying to do anything without a licence, whether there are legal and good intentions or otherwise. But I have to ask the question as I have been trying to get into the science for just about as long as I have been doing electronics, and I just can't seem to get anything concrete. Finally, I would rather learn from people who know about RF interference than blindly build some random schematic I found on google that may or may not be a pollution nightmare.
To that end...
Could someone share whatever simple, legal, moral, and overall worthwhile schematics/projects they have, (or know of) for doing full duplex ISM and/or Part 15 compliant RF coms between microcontrollers? Or possibly help me design something from the ground up?
What I'm mostly after in the RF section is...
1) Frugal construction, using cheap, common, discrete parts and techniques.
2) Design immunity from causing realistically problematic RF pollution.
3) Flexibil vectors for modulation, changing carriers, and what have you using the MCU.
Know that...
1) I am fully aware of the prebuilt cheap modules. I want to build it out of parts.
2) My power and range is of course very low. A few feet/meters, no more than ten.
3) I prefer using GP BJT's. No reason in particular other than that I have a bunch.
4) I have a more or less controlled environment, and a reasonable head on my shoulders.
5) I DO NOT have a lot of radio equipment, I'm a low budget hobbyist. (I of course have basic electronic equipment.)
6) I live in a rural area, I highly doubt there is strong chance of me causing significant RF interference unless I really tried.
Here is an example of something that is about what I am looking at for transmitting. https://www.swharden.com/blog/2011-08-06-ridiculously-simple-avr-mcu-am-radio-transmitter/ I wouldn't mind building something a little more complicated. Maybe some provisions for FM modulation. I tried to build this already and it didn't even have enough power to transmit a few inches. I wasn't sure if it was radiating more power on a band that was out of range of my receiver, so I was too afraid to up the power without knowing what exactly was happening.
I like the idea of a regenerative design for the receiver portion. The SNR of superhet is cool and all, but I think I like the absolute gain AND simplicity of the regen more. I just don't know how I should proceed if I also want a BJT built MCU interfaceable design.
Let me know if you have something good to share. Thanks.