Hi, I'm looking at the spec sheet for the 3-500Z at http://www.scottbecker.net/tube/sheets/088/3/3-500Z.pdf At the top of the second pages, it gives numbers for various parameters at different levels
ORIGINAL MESSAGE: REPLY: Spec sheets don't know anything about load or no load. If it says for example, 3000 volts at 500 mA, that's what it means. 73, Bill W6WRT ____________________________________
Thanks for the reply, but I don't think I follow. Guess I had interpreted the spec sheet as meaning that, if you configure the tube in class B grounded grid and apply HV of 2000v, you should expect t
Does anyone have any further thoughts or comments on this? Is it OK to put the amp into WSJT service at 400 watts? 73, Bill NZ5N _______________________________________________ Amps mailing list Amps
Bill, Any tube run within its specified limits is OK, however with ham radio the limiting factor is cooling. You have to take into account that tube specs are listed for CCS operation. This assumes t
Thanks, Lou. There is little info available about this homebrew amp so I'm just trying to be safe. Have not yet tried it in WSJT mode but tube appears normal in color during my testing so far. The
Bill, considering you can run up to 3500 volts on the 3-500, the 1950v you have is low. When you raise the plate voltage you lower the amount of plate current and grid current you need for a given ou
you say you are getting 400 w. with 520 ma Ip. I think that's 120 ma over the max Ip for a single 3-500 so you're possibly in trouble right there. you say you increase drive and get no more suds whic
Rob, You have to remember that the tube ratings are for CCS not SSB or CW service. CCS service is 100% duty cycle, SSB is 30% duty cycle and CW is about 45% duty cycle. It is not the higher plate cur
At 2700V @ 400 ma it doesnt matter if its CCS or not, thats all the tube will do safely in SSB service especially in an AL-80 series with marginal cooling. Anything over 700W or so is pushing its lon
Regarding the 400 ma rating, I've often wondered why it matters as long as the plate dissipation is not exceeded. The only thing I can think of is the possibility that the filament emissive ability c
Bill, WSJT is a linear mode (multiple tone frequency shift keying) - it does not tolerate clipping/compression well. Since the 3-500 is specified for for 400 mA MAXIMUM you are running it well into c
At 2700V @ 400 ma it doesnt matter if its CCS or not Carl, how do you account for a pulse rating on a tube? For a 3cpx1500a7 tube the plate current is 50AMPS and the Anode V is 10KV and the output po
Try sticking to the 3-500Z and the service in the discussion Lou. You might also want to look at the 3-500Z Eimac specs at the Absolute Maximum Ip rating for Class B linear service. And at some point
Carl, If you don't mind, I want to jump on the soapbox here and mention something. In discussions with hams on transmitted spectral purity, I keep hearing "I don't have a SA" and "SA is an expensive
Hi Lou, I saw ur setup at Dayton but I didn't have time to stop and say hello. Sorry about that but I'll make a point to do so next year. A few points: I don't know what Rauch did or didn't do--for o
Sorry Joe, but that is wrong. WSJT is *ONE TONE AT A TIME*. It can and does not only tolerate Class C amplifiers, but thrives on it! I run my 2x4CX250B's class C at 1100 watts output on 2 meter EME J
Wrong answer for amplifier testing. While you can approximate proper "two-tone" testing with a sound card tone source when evaluating a transceiver, a LOT more is required for accurate and technicall
Larry, You are 100% right if an absolute accurate measurement is needed. But if you simply want to know if you are in the 20's or the 30's, then the method I describe is fully adequate to the task. I
WSJT may be one tone at a time but that still does not eliminate the need for reasonable linearity unless one wants to generate "clicks" every time the tone shifts. With class C any attack/decay is