Mon 13th Aug 2012, 07:51
Build FM Transmitter Output Amplifier
I know this is not a circuit design forum, but would anyone here know how to build a good yet simple FM transmitter output signal amplifier from scratch? (That is, buying components and soldering them in necessary arrangement, not mining for ore, etc.) I want to build an amplifier for a simple smartphone automobile transmitter.
In terms of how I would go about doing this, this video essentially shows how I would open up the device and solder leads to it. However, instead of soldering an antenna, I would solder a coaxial lead to the homebrew amplifier, and the amplifier would output to a carefully crafted antenna. Is there a good resource which would instruct me on how to do this?
Also, just for learning's sake, how powerful would I be able to make such a transmitter without the signal becoming distorted? (I don't intend to break any laws, I'm just trying to figure out how FM signal amplifiers work.)
Thanks for any help!
Tue 14th Aug 2012, 02:38
You're looking for a "linear amplifier", they are quite simple devices in essence.
Regardless of the mode (FM, AM, CW, SSB etc) a linear is a linear. It multiplies the input by a factor.
What you want to build is probably illegal, but as far as Amateur Radio Linear Amplifiers go, you might be able to find one for 4m that would work.
Tue 14th Aug 2012, 02:57
Last edited by amanisdude; Tue 14th Aug 2012 at 03:10.
Reason: added another quesiton
Tue 14th Aug 2012, 14:51
70MHz = 4m, sorry was thinking in old money again...
Valves (tubes) require several Voltages for operation, ergo, more complicated power supply - OK if you have them in the junk box, but go for solid state if building from scratch.
Google around you can find loads of circuit diagrams - http://www.seekic.com/uploadfile/ic-...4273524769.jpg
There are also loads of transistors available, to suit your power requrements...
Tags for this Thread