60W Linear Amplifier

[audioguru2]

Nice new project. http://www.electronics-lab.com/projects/rf/027/index.html
Sorry, but I am not a ham radio operator and are just curious. Others will be curious too.
What frequency or band does this amplifier operate at?
Are its output power and harmonics legal?

 

[ante1]

Audioguru,

I

 

[audioguru2]

Hi Ante,
I just assumed that this RF amp was rated at "Peak or Maximum" power, like car audio amps, to make the power number twice what is actually true. So with a 42W input from its power supply its actual output is 30W which is reasonable (a little more than 71% efficiency).
Its Mosfet is not biased much so it is operating in class-C, and since it doesn't have much output filtering its harmonics must be considerable. It will probably cause TV interference for many km.
That's why I asked if its harmonics are legal. Maybe they don't have "RF cops" in the author's country. :-[

I am going to guess that its frequency is about 144MHz and on the 2m band. ???

A guy on the web is building the world's highest-power audio amp with paralleled transmitter tubes. It uses KW just fot their heaters. He is blowing 500A mains breakers for his entire office building! I think that he uses many km of welded railroad tracks for a dummy load. ;D

 

[ante1]

Audioguru,

You are correct about the over rated power but 30W (71%eff) output requires no heat what so ever. The text does not reveal anything about the input power required for full output power. I

 

[audioguru2]

Hi Ante,
Where is the project's author? We are just guessing here.

I think that you are correct. I thought that the project is for VHF because its tuning coil has only 2 turns (I was thinking about those FM transmitter toy projects).
But now I realise that the tuning coil has a core and its tuning cap is whopping big. So its frequency is quite low and its poor output filtering will probably cause interference to just about eveything.

When I was only 16 years old (see, I can still remember that long ago), the RF cops "got" me for using a fan that had a badly-sparking motor (lotsa O2). They said that many people had radio and TV interference because of it. This project might be the same.