That's 93kw at pep. All being able to meet spec for occupied bandwidth.
What a disenguous statement.
- Glenn W9IQ
Glen try picking up your dog eared Eimac high gloss catalog.
4x15 with class C....and plate modulated. 23.5 kw UN modulated CXR. 94 - 117.5 kw PEP output (100-125% modulation). Every AM station in NA runs 125% positive modulation, which is the NRSC limit.
At just 100% positive modulation, B+ will double. The plate current also doubles. Plate load Z stays the same.
In the case of his 4CX-20,000C amp, it's 16.97 kv loaded...at full power output. But he's running it in class AB1. It's not being plate modulated.
Total V on the anode is a helluva lot higher than the loaded B+ on any GG amp, or plate modulated class C tube. The derived RF voltage in the output tank circuit will back feed through the plate block cap assy..and superimpose itself onto the anode. On a GG triode amp, the total V is just under double the loaded B+ voltage. EG: A L4B will have 4.5 kv on it's anode, when driven. A good 3-500Z will hi pot test to 16 kv.
IMD on his 4x20 amp is rated at -32 dbc. and -50 dbc if pre-distortion is used.
However, I call BS on his claimed 100 kw pep output on SSB. He only has a 30 kva CCS xfmr. On SSB, maybe 60 kw pep input..and 40 kw pep out. (he rates it at 40 kw out on CW..and only 25 kw on RTTY).
Even W8JI manages to obtain stupid amounts of PO, from that 3 x 4CX-15,000 (11M) amp on his FB page.
It's never the people whom have run extreme qro that argue about power output. It's people that have built small amplifiers.
Remember the plywood box? 14kw on 40 meters with a ridiculously small xformer. Measures was using iirc a 68 lb one? SSB, unprocessed only. But you saw the difference on the receive end.
Now we are going to argue with what Eimac recommends for their tubes.
--Shane
WP2ASS / ex KD6VXI
You need to remember that you are presenting things here that are totally foreign to most. And even sitting here commenting, I don't play at this level but at least DO understand it. And as you have seen in other threads in here, if it's over the 1500 watt FCC mandated level of power output it gets poo pooed quick and some just loose their minds over it.
AM radio stations have been doing this crap since I don't know when. Hell in the 30's and 40's WLW went to 500KW daytime operation. And they stayed clean or the FCC would have shut them down. But even now there are 50KW AM stations running 125% modulation and stay in their lane so to speak. And there is no technical reason that a 100KW amp couldn't do that as well. Not to mention stations like Radio America and others that were VERY high powered. 1.5 MW stuff with BIG ERP's, Acre's or antenna's and the like and they too 'stayed in their lane'.
Are WE as hams suppose to be running these power levels, of course not. But there are some that do. A CB'er is NOT gonna bother to buy an amp that's built for running 3.5 to 30 so they can talk on CB channel 6. Most of them believe that all that extra tuning capacitance and inductance in the Pi network reduces their power. Which of course is nonsense, but they aren't looking to run clean for the most part, they just want to see the meter go farther to the right.
And I don't think many even understand the power requirements for these amplifiers. You mentioned the 3 tube 3CX15K box. The filament on those requires 6.3 volts at 160 amps. So three of them require 480 amps to heat up. Before the plate supply is even turned on. Running the math backwards, 6.3 volts at 480 amps is 3000 watts. So the filament power requirement at 3000 watts is 12.6 amps at 240. But that ADD's to the plate supply requirement which has to exceed the actual power output of the amp by some amount. And at 100KW at 240 volts, that's 416 amps of input current. The biggest residential power feed I ever saw was 400 amps on a HUGE all electric home. And the power bill to run something like this would be stupid. And NOT within the reach of someone that runs LMR400 instead of LDF4-50 heliax cable because they can't afford the hard line.
And in truth, these discussions of why it's not possible, can't be done, it's illegal bore the hell out of me. It's the same thing from the same people. That either don't understand it, are jealous of it or just see a need to condemn it on it's face. But by God, i bet every damn one of them would be swinging their beam if you were to announce that the 100KW amp is going to some uninhabited island that is in a grid square with no other people and it's getting activated. Because THEN it's fine, there is no FCC or regulatory body to say you can't run 100KW on the ham bands. And they will be the first ones to try to make contact with that expedition.
