Isn't there built in disconnect at the end of an electrolytic capacitor that disconnects the guts when they blow up? I have seen shorted oil filled capacitors and boy do they make a mess when they pu
Roger, I have built my share of VHF, UHF and Microwave amplifiers through the years. In the process, I have learned a lot about how they work and will share a few "secrets" with you. The book you are
Hi David, I am working on a power supply project with a similar application. My project will be used with a twt and I would also like to keep the voltage from soaring during standby. I found that a r
Tom, you mentioned having a stiff 240vac line. How stiff? What does it measure when the amplifier is maxed out in the SSB position at the 1000w level? 73, Gerald K5GW In a message dated 2/12/2010 9:3
Tom, I am not familiar with the terms "v bias" and "r bias". Are saying the zener bias diodes have been replaced with resistors? 73, K5GW In a message dated 2/12/2010 9:40:18 A.M. Central Standard Ti
Tom, that makes sense and sounds like a must do modification. I can't contribute anything to this discussion so will humbly bow out. 73, Gerald K5GW In a message dated 2/12/2010 9:49:21 A.M. Central
Hi Jim, I will rephrase a bit. I used peak power in the efficiency numbers and should have used rms power. My bad. Assuming the plate current is 1A for both examples, low power would generate 2200w p
Oh, I left off one summary point: The tank efficiency does not increase with more B+. Due to the associated higher Q, the tank efficiency actually decreases. The tube efficiency does increase with mo
Hi Roger, I share your pain with 8877 prices these days. In fact, if any of my amplifiers using this tube looses a tube it will be rebuilt for one of the Russian tubes. If you want a low profile 2m a
Wow, that email must have gone long path; it was sent 02/12/10! 73, Gerald K5GW In a message dated 2/17/2010 10:49:29 A.M. Central Standard Time, TexasRF@aol.com writes: Hi Roger, I share your pain w
John, every dc power supply has some ripple. If the power supply has a nominal output of 2500vdc and the ripple voltage is 125 vpp then that would be 5% peak modulation or 3.5% rms. I think this is 2
Hi Alex, I didn't see anyone reply to your suggestion to add a one ohm resistor in the plate transformer primary so I will. This is a really bad idea from voltage regulation viewpoint. It would be th
Hi Alex, no, I didn't forget what inrush protection is; that is why I suggested the 25 ohm resistor and shorting relay. You are the one suggesting installing a one ohm resistor and leaving it in the
Hi Gary, I have tried using solid state relays in that application with poor reliability. The last attempt was a 70A unit that worked ok for a while but a flashover in the plate circuit took it out i
Jim, you might check W.W. Grainger for that. If they are still available they will be in their catalog and web site. 73, Gerald K5GW In a message dated 3/4/2010 3:05:56 P.M. Central Standard Time, n7
Hi Roger, that is exactly how I use it and it works wonderfully well! I am using a $20 adjustable Dayton timer set for 10 seconds. No runs, no hits, no errors! 73, Gerald K5GW In a message dated 3/4/
Say, I have always wondered about snake oil: Is it supposed to attract snakes?,repel snakes?, made from snakes? or what? Where do you buy it? What does it smell like?, taste like? (probably like chic
If you use a PNP transistor in the bias circuit, the collector can be bolted to the chassis for excellent heat sinking. Of coarse the rest of the circuit has to be designed for that configuration. I
Carel, dielectric losses in PTFE are many times lower than the dielectric material in ceramic capacitors. Your idea should work just fine electrically. Your challenge will be the mechanical design to