Large CRT TV reuse.

[Cowthief]

Hello.

I have read what hams have to say about this.
I have seen the CB fraternity make it work.
Now, for the facts.
On the QRZ site, pictures were posted, as detailed.
Someone wanted to know what the voltage on the red lead was, around 50 volts at 10 amps was my reply.
So, somebody comes up with this 100% efficient.
The picture clearly shows 3 wires, a red, a black and a white.
There is +50 volts on the red and black wires, but -50 volts on the white and black wires.
The thing is around 50% efficient, and this is very easy to prove, just look at the pictures.
But, this is has no bearing on anything.
At the very start of this thread there were references to CB vs ham.
Again, the CB fraternity can make this work, and have been doing this for years, think of this as the modern TV sweep tube, like what you might find in an FT-101.
With that said, although I do not agree with operating CB at almost 1000 watts, somehow the CB types are able to do it, with used TV parts.

[kr0ne]

PICS OR IT DIDN'T HAPPEN...

[Cowthief]

Hello.

Look at what all the newer "Export" 10 meter radios are using for finals, power MOSFETs.
Yes, not RF transistors, but power transistors.
What is in the Mitsubishi large CRT sets is the equal to the HUF75343, a power MOSFET.
This is a VERY common transistor in older motor controllers as well.
As is the norm, the transistors are not soldered in place but spot brazed to thick copper plated brass wires, than the whole thing gets filled with epoxy.
A machined heat sink that has a cavity accepts this.
This is why there is no way to get to the transistors short of destroying them.
The other boards are the components board, directly behind the heat sink, and the rest of the HV and driver section, left behind as it is mounted on the CRT itself with a bracket, perhaps welded?
This is a very common means of high power construction.
Than the whole thing gets sonic welded to the back cover.
http://en.wikipedia.org/wiki/Ultrasonic_welding
Remember that I am only now beginning to understand how this stuff works.
In fact, I am one of the first to tell you, I did NOT come up with the idea of taking old Mitsubishi TV sets and building amplifiers.
The only contribution I have made is to modulate the transistors for AM, for a clean signal.
Again, this is not my idea, I just improved it.
This is not a ham amp, from about 3 to 24 MHz it does not work, and all the hams will tell you that, and why they call it a CB amp.
The basic idea has been around as long as TV sets have been using MOSFETs.
I see nothing wrong with a 10 and 12 meter only amp anymore than a 2 meter only amp.
Enjoy.

[kr0ne]

Pics or this thread needs locking!

[Mattylad]

please........ (lock it)

[Cowthief]

Hello.

I find this amusing.
Lock it? why?
The ones who have tried, have discovered that this really is the case.
Power MOSFETs really can do 24.5 to 32 MHz.
That is all that is in the Mitsubishi TV, a set of HUF75343 transistors.
Look up the part number, it says nothing about RF.
They are cheap.
Now look up the response time, 30 Microseconds, that is 33 MHz!
Anyhow, the facts have been presented.
Only hams have issues with it, it works just fine on 11 meters!
It will NOT work from 3 to 24 MHz!
Again, the transistors are cheap, very cheap, try it yourself.

[StormShadow]

Where the pics at?

[Cowthief]

Hello.

Yes, this is not the cycle time of 1.2 nanoseconds but the turn on time.
http://www.slac.stanford.edu/cgi-wrap/g ... -13410.pdf
Even then, 450 MHz, 33000 watts!
Remember that this is ONE transistor.
How about this for your CB radio?
http://www.semikron.com/products/produc ... 03737.html
21750 watts at 33 MHz.
Think ofcom would be upset?
At 12 volts DC, you could do a healthy 10000 watts, if you could provide the power!
To hell with the average CB amplifier, this thing would need the heat sink like the frame of a car.
Only a hybrid could power it.
And, what would you use for an antenna!
Talk about stirring the pot, things like this should do it!
You would need a massive insulator for you antenna.
But, nobody is going to build a CB transmitter that powerful.

[Cowthief]

Hello.

Yes, this is not the cycle time of 1.2 nanoseconds but the turn on time.
http://www.slac.stanford.edu/cgi-wrap/g ... -13410.pdf
Even then, 450 MHz, 33000 watts!
Remember that this is ONE transistor.
How about this for your CB radio?
http://www.semikron.com/products/produc ... 03737.html
21750 watts at 33 MHz.
Think ofcom would be upset?
At 12 volts DC, you could do a healthy 10000 watts, if you could provide the power!
To hell with the average CB amplifier, this thing would need the heat sink like the frame of a car.
Only a hybrid could power it.
And, what would you use for an antenna!
Talk about stirring the pot, things like this should do it!
You would need a massive insulator for you antenna.
But, nobody is going to build a CB transmitter that powerful.

[StormShadow]

33000 watts you'd fry your brain

[ChrisCSL]

33000 watts you'd fry your brain

So perhaps he did succeed

[wa10]

cowpat, once again you are clueless what some base stations can throw down, even this mobile would cut the lips clean off your prius,
http://www.youtube.com/watch?v=rBsQy0TbPr0

[Admiral]

He can't defend himself now, so maybe time for this nonsense to die a death?

[LeakyFeeder]

He can't defend himself now, so maybe time for this nonsense to die a death?

Couldnt agree more... Its run its course