HFU HF Underground
Technical Topics => The RF Workbench => Topic started by: digitalmod on February 12, 2018, 1857 UTC
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;D The engineers showed this design way back in 2005, no longer front line.
They also instead of toroids (labor intensive) they designed PC board coaxial matching. They also ran the pallet at full bore 1 kw at FM band frequencies switch between the two worst load scenarios that BLOW and explode systems. That is NO load (open) and short circuit. The damn thing kept pumping.
Drive for 1 kw out was 5 watts, they warned on could blow the system by OVER DRIVE !!
Technology way better than I ever thought!
http://www.pcs-electronics.com/1000w-planar-pallet-blf188xr-p-2355.html
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Buy something from broadcast concepts. Their stuff at least works, and its made here.
http://broadcastconcepts.com/MRF1K50h.html (http://broadcastconcepts.com/MRF1K50h.html)
Who wants FM anyway? I ran high power pirates for years on FM and the reward certainly wasn't worth the risk, and that was ten years ago. No one searches the FM band looking for something to listen to, not like the 80's anyway.
+-RH
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http://www.s8.voscast.com:9748
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The point here, I think, is the amp is broadband and will produce Kw plus 1.7-Fm bands. Just Driver protection and of course clean the bands with harmonic LPF. The class C mod is said 80 percent efficient at VHF. I would expect same HF.
If it could do kw peak, then surely it will do 300 watts fully modulated AM.
Now here is another FET miracle amp with 5 watts it pushes 1.7 kw.
The demo person shows power on Bird watt meter Vs a Chinese watt meter. Well, they seem right on.
So Class E Be fine if you are a high power licensed station, because the electric utility bills are quite a bit less with 50Kw output.
But , again the technology is there for trade offs and choices.
BTW I have several BCE Bricks.. one does 300 watts and it runs stone cold, drives with 1 watt.
I assume it has to be class E design, but its not a new amplifier, had it in closet for ten years.
Go here: https://www.youtube.com/watch?v=5nYH-bdt_iw
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Yes, but who wants to do AM at 100 Mhz? I don't get the point of you posting all this amp pallet stuff. I can read NXP's LDMOS portfolio just as well as the next guy.
WHY DON'T YOU JUST BUILD SOMETHING FOR CHRIST'S SAKE.
+-RH
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Yep, I'm fed up with the idle waffle
I will ignore future posts.
Str.
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???
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Oh dear the house of cranky old men. :P
That said, keep the ego in place mates. I posted for information only, since coming into the area I think construction is really my first love. However, being outside RF for at least 12 years, I am shazammed by material sciences and what its brought forth.
Recall fifty years ago a 600 watts AM transmitter would fill a garage.
Peace Bros ;D
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Oh dear the house of cranky old men. :P
That said, keep the ego in place mates. I posted for information only, since coming into the area I think construction is really my first love. However, being outside RF for at least 12 years, I am shazammed by material sciences and what its brought forth.
Recall fifty years ago a 600 watts AM transmitter would fill a garage.
Peace Bros ;D
Ain't that the truth. A friend who lives by himself on a farm will take anything you want to give him. In the early part of this century someone gave him a disassembled old water cooled MW 5kW transmitter. I want to say it was a post war Collins, but it's been nearly 20 years ago? That thing nearly filled the old tobacco barn it was stashed in. He never got it running and sold it a few years later. Who knows where it's at now?
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Well, Pigmeat, here is the logic. Do you want the freedom to switch between SSB or AM? Well, yes. That could mean a class AB/C switch or just a big heat sink to take the calories. Class E and D are indeed interesting to a newbie engineer type who wants to play on the bench. Yes, advances are HEAT less . The Baseband for any mode on shortwave unless we are talking a digital mode and if that be the case a BIG BAD linear amp will be needed.
If you are an equal lover of broadcast and engineering, after some thought and not wanting to REINVENT the wheel. I would choose a BIG BAD high gain FET (low drive) broadband amp. The exciter would be a DDS low power am or SSB exciter, 10 watts, or less with a pad to adjust drive.
BIG OLD BAD 100 volt or so DC powersupply. And you are set. There are predesigned FET amps with heat sinks in the KW range unfinished except for enclosure, harmonic filter and what ever else you want to throw inside the case.
An easy 250 watts HIgh FI am transmitter is born. Its NOT rocket science. Let the hard part be done by somebody else and not you because you will spend months just reinventing the donkey cart. :-X