? "I'm trying to think but nuthin' happens". . .Curly ? Sparking contacts don't create transients? ? we are not talking about the bias contacts. We are talking hotswitching the RF input contacts whe
? Would you expect a change in input potential to cause a change in anode current? Rich... R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures -- FAQ on WWW: http://www.contesting.com/ampfaq.
....... ? Rich knows that all power grid tubes have finite emissive capabilities. He also knows that when over-driven, a TL-922 can not produce much more than 1800w-pep due the emissive limit of a 3
? Impossible? see page 33 in the Oct., 1990 *QST*. I observed no "poor wiring" in this TL-922. Rich... R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures -- FAQ on WWW: http://www.contesting
Hi Peter, If the tune C is equal to the tube output C, then the That's true. In that case the voltage across the tank tuning cap would be just as as high as obtainable at HF, if the tube operated jus
That still doesn't mean that the resistors are at room temperature. Fast moving air at 100° C still spells an ambient temperature of 100° C. And the resistor's dissipation ratings are corres
Oh, sure. But my question is not wether or not it happens. But as Tom pointed out, the filter action of the input pi-network will limit the response of the spark pulse. Plus how large an amplitude i
Jon ? agreed. The question is how much? Sparks contain wideband energy. The pi tuned input is a low-pass filter with a Q of as low as 0.75 in a stock 922. . ? The 3-500Zs are already in conduction wh
? name a tube whose anode cooler exit air is c. 100 degrees C. In the 922, cool air gets sucked past the suppressors. ? I was not there. - later Rich... R. L. Measures, 805-386-3734, AG6K, www.vcnet
Sure glad to hear that, Don. You had me a little nervous there for a minute. 73, Jerry W5KP -- FAQ on WWW: http://www.contesting.com/ampfaq.html Submissions: amps@contesting.com Administrative reques
Rich, you are avoiding answering the issue directly. The question was: Does the spark that is created by hotswitching the input relay have enough amplitude to create a sufficient signal at the input
100 C was an example. It doesn't matter if it is 50 C or 30 C or 2000 C. I wan't using it as literal. The fact is that supressor resistors operate at elevated temperatures ABOVE 25 C. Their dissipat
Hi Jon, If an amplifier is unstable, in other words if feedback exceeds loss and the phase is correct, it will oscillate no matter what the perturbance is. Even shot noise from the normal process of
I said I needed to quit this, and here I am. The trend is gain goes UP as drive is reduced. That's why were don't have to hit our oscillators with hammers to start them, and why amplifiers gain compr
Could have been an HF oscillation for all I know as I didn't have a freq counter at the time to measure them. I guess I could have used my MFJ-259 but didn't think about that until now! Needless to
Author: Dick Green" <dick.green@valley.net (Dick Green)
Date: Mon, 7 Jun 1999 23:10:20 -0400
when I tell the story of how I thermally burned them up in my amp on 10M. Just to throw in an empirical observation, I burned up the stock suppressors on my "new" LK550 while tuning up on 10M at full
More fundamental current goes through the resistors as the frequency goes up, because of the increasing reactance of the shunt inductor. I suspect that because most parasitic suppressors are 'designe
I've seen amps unstable at HF stabilized by that technique. The SB- 220 has an RF choke in parallel with silver mica caps. The RF choke has multiple periodic resonances where it goes from inductive
Hi Peter, Worse yet, virtually all carbon and metal resistors are wound with a spiral. They are inductive. Not only does that decrease the effectiveness of the suppressor, the spiral can couple magne
Another method which is very effective at reducing the current in the resistor is to use a one or two turn link in the plate circuit, coupled to a parallel resonant tuned circuit tuned to the parasit