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Registered Member #29
Joined: Fri Feb 03 2006, 09:00AM
Location: Hasselt, Belgium
Posts: 500
Avi, You may want to build a power amplifier using a microwave tube and a coaxial cavity. Check out the availability of so-called "lighthouse" tubes on eBay. An old 2C39 will give you about 50W of power (with proper cooling). The ARRL books have good discussion on this.
If you can find a klystron or travelling wave tube amplifier , you will be in great shape!
You will need to study things like resonators and coupling a bit... You will also likely need driver amplifiers and a signal source (a PLL synthesizer or bench RF signal generator). Of course, this will depend on your application. You will need to study a bit, but don't be put off. Skin effect is not a big problem if copper or silvered cavities are used.
Do your homework and you will be rewarded......with a good job as an RF engineer!!! :)
Registered Member #682
Joined: Sat May 05 2007, 04:16PM
Location: Israel
Posts: 10
WaveRider wrote ...
Avi, You may want to build a power amplifier using a microwave tube and a coaxial cavity. Check out the availability of so-called "lighthouse" tubes on eBay. An old 2C39 will give you about 50W of power (with proper cooling). The ARRL books have good discussion on this.
If you can find a klystron or travelling wave tube amplifier , you will be in great shape!
You will need to study things like resonators and coupling a bit... You will also likely need driver amplifiers and a signal source (a PLL synthesizer or bench RF signal generator). Of course, this will depend on your application. You will need to study a bit, but don't be put off. Skin effect is not a big problem if copper or silvered cavities are used.
Do your homework and you will be rewarded......with a good job as an RF engineer!!! :)
Hey man Thanks for the cheer up! you see I only lerned a bout skin effect last simmester... it was only a footnote.. I hope it will be ok... Avi
Registered Member #543
Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992
Avi, sad to say, it will not be "OK."
Waverider has commented without first reading your Japanese paper on eddy current induction heating, and, what is more, reccomended that you spend your money on obsolete equipment - valves {US: tubes} which no one now would think of using except for a few very specialised applications.
There are dozens of papers on eddy current formation and skin depth at varying frequency on the web, and you'd be best off going back to square one with them.
Registered Member #682
Joined: Sat May 05 2007, 04:16PM
Location: Israel
Posts: 10
You guys made me think again ! (thanks) all I am trying to do is to have the Eddi's current create me a strong changing in time (as fast as possible) magnetic field Instead of putting sin AC current on the coils I'll put a strong 1 sickle of Square wave (like trigger but with high voltage) only so I could do a measurement in the time it takes to the Square wave signal to grow from 0 to what ever voltage I'll apply Any thought on that?
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
I don't know what your ultimate aim is, but since you are not trying to generate an intense static field I guess the best (simplest) approach is to use the techniques used in a "coin shrinker"
The usual problems in generating an intense field are core saturation - so don't use a ferromagnetic core - use an air-core current density - so use a pulsed current - use a high voltage pulse-capacitor.
There are many "coin shrinker" projects here in the 4hv forums, and many more via google.
Registered Member #29
Joined: Fri Feb 03 2006, 09:00AM
Location: Hasselt, Belgium
Posts: 500
Harry is right.. The link to your paper was not working for me, so I could not read it...
TWTs, valves and klystrons still play a big role on high power operations... (I toured a UHF TV station a short while ago and witnessed a brand new 250kW 670MHz water cooled klystron amplifier in operation...Wow!! 50dB of gain in one package! what a rush! :)
Back to your application...after trying your link again (it worked), 1GHz is not what you need.. Sorry for leading you in the wrong direction by not having all the info... What your paper describes is a "flux concentrator" for pulsed situations...much like some researchers propose for advanced coilguns.. Certainly not 1GHz stuff.... I'll shut up now.... :(
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Need help to generate a 1GHz signal
