Building a 400mw FM Transmitter

In this video I'm building a 400mw FM transmitter, that supposed to have a range of up to 4km.
But the signal is very unclean and I wouldn't recommend to put an antenna on it.
The whole plan and builde instruction is from this webside: pira.cz/entx1.htm
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My Twitter: Sc...

[@jonhoyles714]

Great video and content, I have a little transmitter similar to this design and have been wanting to improve its performance so this is a great find for me very interesting

[@technicmasters7936]

The transmitters output is probably clean, but you have your SDR too close to it, try to have it like 10-20M from the transmitter and it would be clean, Because 1. if a signal source is too close to a SDR, it creates a lot of other freq, that dont actually exist, and 2. If you are like 2M away from the transmitter, there is leak from the circuit before the filter, but since there is no antenna before the filter, the signal travels about 5M, so try it about 20M away from it with the SDR...

[@thesciencefurry]

I can try that, but I'm pretty sure I had harmonics at some distance aswell.

[@TheXoriso]

I think the same, the SDR receiver has a overload due to the proximity to the transmitter. I think that exists best transistors for these purpose, for example, BF199, 2N4427, etc BFR91 and BFR96TS were transistors for ultralineal class-A amplifiers using in TV transmitters, tuner mixers and receivers pre-amplifiers.

[@NitrobenzeneNO3]

@@TheXoriso What are you even talking about?

[@slender1357]

Do you think i can use bfr90's ?