What kind of Transistors are suitable in a TV Transmitter RF amplifier circuit

Status
Not open for further replies.

Thread Starter

Maz2858

Joined Jan 27, 2021
25
Hi, i want to make an analog TV Transmitter (with audio) in VHF or UHF band, and i'm asking If RF mosfet RD06HVF1 can work as the final stage amp and what transistors i can use for the preamp/buffers
Thx
 

Yaakov

Joined Jan 27, 2019
3,492
The UHF TV band runs for 475-890 MHz. A Part 15 device, which yours would be, is restricted to very specific emissions, both by type and power, in that band. In fact, as you can see by the attached chart, there is only 806-890 MHz at exceedingly low power available. The power level is actually the same as what is allowed for spurious emissions which gives you an idea how little field strength you are allowed. Note, this is the actually transmitted signal, not the power dissipation at the final transistor, the power input to it, or the power input to the antenna. It is a measure of the actual radiated power from the antenna.

You would be operating under Part 15 authority for "Home-Build Transmitters Not for Sale" and would have to follow the rules for that. That includes not causing interference to licensed services and complying with the technical standards in Part 15.

The relevant sections of the FCC's OET Bulletin 63 are attached, and you can find the entire document here, and you should read it carefully.

I suspect the frequency and power limits will not be compatible with your idea.


1629035828925.png


1629035514501.png
 

Thread Starter

Maz2858

Joined Jan 27, 2021
25
I dont live in usa but thx
I know it isnt compatible but i will broadcast for a short amount of time on an unused channel and probably with a dummy load
 
Last edited:

Papabravo

Joined Feb 24, 2006
16,792
I dont live in usa but thx
I know it isnt compatible but i will broadcast for a short amount of time on an unused channel and probably with a dummy load
At least in the USA we can advise you as to the law and the potential risks. If you live in an authoritarian country you may be subject to arbitrary and indefinite sanctions regardless of what have actually done or not done. I advise to think carefully about what you are doing.
 

Yaakov

Joined Jan 27, 2019
3,492
Maybe if you could explain why you are trying to build this we could help more. As it is, there doesn't seem to be any legitimate purpose for it, and it has the potential to cause harmful interference to other services, not just UHF TV.

Generally, people aren't willing to help with things that appear to run afoul of regulatory agencies, wherever they are located.
 

Thread Starter

Maz2858

Joined Jan 27, 2021
25
Maybe if you could explain why you are trying to build this we could help more. As it is, there doesn't seem to be any legitimate purpose for it, and it has the potential to cause harmful interference to other services, not just UHF TV.

Generally, people aren't willing to help with things that appear to run afoul of regulatory agencies, wherever they are located.
The only powerful transmitters that I made are fm transmitters, so I want to make a powerful tv transmitter because the rf part is more challenging to make
 

Yaakov

Joined Jan 27, 2019
3,492
I am not trying to lecture you so please don't take it that way. The right way to do things like this is to get an amateur radio license and then you will have legal authorization and allocated spectrum. You will also be able to use relatively high power, and make radio contacts with other amateurs with the equipment you build.
 

Thread Starter

Maz2858

Joined Jan 27, 2021
25
Where i live i can't get a radio license since I'm too young, and the only type of amateur tv broadcasting allowed in my country is sstv
i know that there are potential risks, but i need help for my project, so if nobody wants to help me here, i will make another thread somewhere else
thanks a lot for your advises
 

Yaakov

Joined Jan 27, 2019
3,492
Remember that when you make a transmitter, if it is built incorrectly, you can interfere with things that might relate to health and safety, or cause great inconvenience to your neighbors.

I can't help you with this because I think it is a bad idea and wouldn't do it myself.

I hope everything works out well.
 

Thread Starter

Maz2858

Joined Jan 27, 2021
25
Remember that when you make a transmitter, if it is built incorrectly, you can interfere with things that might relate to health and safety, or cause great inconvenience to your neighbors.

I can't help you with this because I think it is a bad idea and wouldn't do it myself.

I hope everything works out well.
thanks for your help, i'll remember
 
Status
Not open for further replies.
Top