Well Jeff, I both agree and disagree with your statements below. I agree with your statement about guys not measuring at all. But I strongly disagree with telling these same guys they can do "adequat
Jeff, Is using a sound card good enough? One of my elmers <sk> had a dedicated two channel audio generator for testing. Motorola published a white paper by Helge Granberg on IMD measurements: http://
The average ham has even less ability to accurately measure the 1 dB compression point on an amplifier than he has of accurately measuring IMD. Most don't have one accurate wattmeters much less two
Wrong again Joe. Joe, K1JT, has real insight into this area. He has programmed the DSP in the soundcard tone generator to produce a smooth phase transistion between one tone and the next. The result
If the average ham simply reduced the power of his ricebox to 75-80% of its ratings he would pick up a 3-6dB IMD improvement at least. Then he can use a decent amp instead of operating in GIGO mode.
Martin, There are 2 ways to look at this. If you look at it from a "is this the official lab-standard proper way" standpoint, it comes up a loser. I'm not suggesting it is. And If you look at it from
Rob, Yes of course the 1950 volts is way too low and I suggested to him that he should bump up that voltage and 520 mills for 100% duty cycle is too high. I think Tom W8JI changed the rating on the A
Amen to that last paragraph. A pair of 4-400's will run for many years in BCB 24/7 service at 1000-1200W out. Thats carrier power, the PEP is 4000-4800W. The 813 is my favorite for the most underate
The beauty of 1 dB compression power is that unlike two tone testing, absolute accuracy is not required to achieve proper operation of the amp. All that is required is some linear response indication
This only works if the amps is tuned for max carrier power and then the drive is reduced so that the PEP output power is 20-25% less than the carrier tune up power. Otherwise if the amp is tuned for
You start by reducing the internal low level drive control so that the panel control doesnt go beyond 80W for a 100W rig. You can fine tune by adjusting the bias a bit more towards Class A; just eno
I don't care what kind of transition Joe has programmed into the DSP. The rise time/wave shaping makes little difference with a class C amplifier because the sharp turn on/turn off characteristic an
Sure, if you end up reducing the drive by 3 dB because the user can't tell the difference between 1 dB compression in the amplifier and 1 dB of foldback in the drive due increased input SWR. You do
There is no turn on/turn off. That's what I'm trying to tell you. The smooth phase transition that occurs as the tones change from one to the other is exactly the same as slowly turning the knob on a
Jeff, No insult intended - It was a legit question based on what I had been exposed to so far. As a side note, I am looking for a service monitor. I also need some sort of two-tone source & if the so
That is carrier power only Joe. PEP is 4X the carrier on AM Carl KM1H _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listin
He was talking about a class-c amplifier and I fully agree with Joe, there will be no smooth transition at all 73 Peter There is no turn on/turn off. That's what I'm trying to tell you. The smooth ph
What are you talking about? How does measured power applied to the input jack have anything at all to do with what's going on in the exciter? I don't understand your point. 100 Watt carrier doesn't c
When I was gainfully employed I could often bring the latest and best of HP home for the weekend...got real spoiled. But I really do enjoy retirement! These days I have a 20 year old SA plus lab gra
NO! You have to know what the two values are in order to know what the ratio is, Even if you're using a two channel scope, it is necessary to measure the specific RF voltages. Then, IF you know the