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BOOTY MONSTER
Guest
Note the disclaimer on his page regarding US sales. There is a reason for that. A few of them actually. IMHO WM amps are basically not much more than a Dave Made in hams clothing.
DX Hound, I underestimated you and you have earned my respect for whatever it's worth to you. I do have to polity disagree on two minor points. The efficiency rating would not have to be high in order to obtain 250 watts output. You could actually decrease the efficiency all the way down to 50%. At that point you have 250 watts going into the load and 250 watts as collector dissipation. At 50% efficiency you could be running in the linear mode too.
The duty cycle at 250 watts would also not be limited to short duration pulse either. As W8JI commented, the duty cycle is related to the heat dissipation and the heatsinks ability to remove it. So long as you don't exceed the transistors dissipation and the heatsink is adequate, 100% duty cycle is possible at 250 watts.
Bravo! Bravo! Let the discussion continue.
I know that I have learned from this lively discussion and different viewpoints.
Like the beer commercial always said 'it doesn't get any better than this"
I know that I have learned from this lively discussion and different viewpoints.
Like the beer commercial always said 'it doesn't get any better than this"
But yet they continue to come up with better beer, oh wait the next beer is always better.
Good thread anyhoot.
And No One Got Banned!
Lol, This Forum has come a Long way from what it was during the old EZ Board Days.
Thanks to everyone that sticks around and shares Info through the sometimes heated topics ....
73 to All
Jeff
B
BOOTY MONSTER
Guest
i think i got banned over at wwpdx . LMFAO !!! it wont recognize my name and password over there anymore .
no biggie though , that place has become %80 watergate post over there .
first time ive been banned just for trying to make a post and have some discussion about it
it is what it is
no biggie though , that place has become %80 watergate post over there .
first time ive been banned just for trying to make a post and have some discussion about it
it is what it is
This is what I still dont get, 50 ohm nominal load, 18v with 250 watts is 13.89 amps. take 50% efficincy and that drops to 125 watts output.
to overcome this, would you not have to increase drive and thus double current. ??? That means you would be at 27amps per device and now reached the 250 watt dissipation limit. I just cant see this device sustaining at 27 amps.
P.S. I want to see the spec on that output filter assy in the WM1200, wonder if they would sell just it? and what its rated for? That would be perfect for my DX3200 10-160 project
to overcome this, would you not have to increase drive and thus double current. ??? That means you would be at 27amps per device and now reached the 250 watt dissipation limit. I just cant see this device sustaining at 27 amps.
P.S. I want to see the spec on that output filter assy in the WM1200, wonder if they would sell just it? and what its rated for? That would be perfect for my DX3200 10-160 project
B
BOOTY MONSTER
Guest
There you go Booty, I titled you as Banned so you can feel at home, let me know if you want it changed back
B
BOOTY MONSTER
Guest
These are good questions. 18 volts with 250 watts is 13.89 amps but you've calculated for a total input power of 250 watts. The maximum theoretical output would be when the collector dissipation itself has reached 250 watts. The input power required to do that will depend on the amplifiers efficiency. You also make a valid point I overlooked. At 18 volts it will not be possible to reach the maximum collector dissipation before you exceed the maximum current. However, with class C you don't need to come close to the maximum dissipation to make 250 watts output.
I have to admit I have learned some things from this tread also
I thought the 2SC2879 was rated at 20 amps maximum collector current for the last 20 years. It's actually rated at 25 amps. Which explains why the 20 amps fuses in my protection circuit worked best at preventing transistor failure. It takes a few extra amps before that fuse is going to heat up and melt. Back then I didn't even have an amp meter that could read higher then 10 amps DC.
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B
BOOTY MONSTER
Guest
thanks to this forum and its admins/mods for allowing this ....... enthusiastic ..... sharing of comments to take place without freaking out or banning anyone