I'm curious. How do I figure out how much current I can squeeze through a tube. Lets use the 4cx250FG for example. 4cx250FG It's heater draws 14 watts. The max plate voltage is 2KV and it's rated as
Look at the constant current curves for the highest screen potential allowed. Find the zero grid volts line. When the emissive limit is reached the curves begin to turn upward. My guess for the 4cx2
The most I've ever known of is running them in real cut off class C with about 400mA of anode current key down. The user had a source of really good ones that took 3kV in cutoff and 2.7kV key down. O
My experience has been that only 1/3 or so of the 4CX250B's that I have found at hamfest have really tested good. I don't know about the FG's. However, the real bargains are the 4X150A/7034. They sel
To: <amps@contesting.com> good idea, Steve. Paralleling tubes is a lot easier than most builders think. As RL decreases, more Tune-C is naturally needed to maintain a Q of c. 10. cheers - Rich..., 8
Author: gdaught6@leland.Stanford.EDU (George T. Daughters)
Date: Wed, 20 Sep 2000 09:41:13 -0700
< snip > Many moons ago, an engineer at Eimac in San Carlos told me "if you supply enough air to keep their temperature within spec, the 4x150a's are good for 250 watts dissipation." 73, George T. Da
As I understand it, too much air is indicated when the tubes blow out of the sockets. cheers, George. - Rich..., 805.386.3734, www.vcnet.com/measures. end -- FAQ on WWW: http://www.contesting.com/FA
Yes, but at the same time, your also adding Cg. Which is usually minute with one tube but begins to add up with several. Mike(y) W3SLK -- Original Message -- From: measures <2@vc.net> To: Steve Thomp
As I understand it, too much air is indicated when the tubes blow out of the sockets. Rich, this is solved by mounting the tube and socket upside down so that the tube is blown into the socket. This
--Original Message-- From: Mike Sawyer <kc4slk@csrlink.net> To: measures <2@vc.net>; Steve Thompson <rfamps@ic24.net>; AMPS <amps@contesting.com> To: <amps@contesting.com> Date: 20 September 2000 21:
I used to have a 4cx250 socket with a hold-in device. cheers, Colin - Rich..., 805.386.3734, www.vcnet.com/measures. end -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: amps@contestin
To: <amps@contesting.com> Even with only two tubes, ignoring Cg on 15m and 10m is not good engineering practice because it typically results in too much SWR for an exciter to deal with . The solutio
_________________________________________________________________ The preferred blower motor is a Ford 460 ci V8. Anything less is asking for trouble. 73, Bill W7TI -- FAQ on WWW: http://www.contesti
Too much air is when your blower sucks in the neighbor's cat who is just passing by on the sidewalk 100 feet away, causing you to have to stop contesting and clean it out of the fins and off the ceil