[ok, answer under since the other guys did] Based on a fairly limited sample, I've had one complete failure, (fairly expensive array with separate controller) and a number of instances where power fa
I would also be very interested in SPICE models for triodes and tetrodes used in larger amateur amplifiers. I'm no SPICE expert and have limited time, but would contribute in some way if I could. 73,
And then there's the question of who works on all that complexity, and supports it in the long term? Amateur amplifier suppliers come and go. I think it's fair to say *most* amateurs aren't qualified
The TenTec L-network design is interesting and has lower losses than most, but when I called them about it they wouldn't stand behind QRO AM/CW/digital operation on 160M even with a 50-ohm resistive
"(+24 kW of aural power)" - Sounds like my wife when she gets together with her sisters and the big black kettle... My SDR receivers have response pretty much down to DC, and their audio mixes to a s
These make it easy: http://www.ebay.com/itm/4-ea-800-Watt-Hybrid-200-ohm-Load-Resistor-500-mHz-/370454666736?pt=LH_DefaultDomain_0&hash=item5640d19df0#ht_734wt_1396 <http://www.ebay.com/itm/4-ea-800-
True, but at only half the dissipation. :-) 73, Jim N7CXI _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
I'm getting around to servicing the blower (again) in my very last complete Alpha PA77, and decided that since I'll have the side off I might as well add the toroid and caps to put it on 160m. Note i
That might be the right question. Starting at the supply end on the 77Dx: From the 15uH molded choke, there's .002uF to ground. At the junction of the 15uH and 90uH chokes, there's .005 total to grou
Jerry, Welcome to the "old Alphas owners group". If you think the 78 is heavy, try a 77. Yikes. ;-) Suggestions: (1) Put a reverse-biased rectifier diode between collector and emitter on that transis
And just so it's in the archives: The components for adding 160m to the original Alpha 77, PA-77, "D" and "S" models are are below. (apparently ETO built "D" and "S" models that did not have 160m, be
If I can find those T225-2's I bought from you I'll build and test one that way. Good idea. I need to order some of that tubing, though. Amidon? 73, Jim, N7CXI _______________________________________
Spot on, Jim. The 76A and the 78 suffer from both vibration and turbulence, with the effects compounded by resonances in the sheet metal cover. Better blower mounting and fuzz would help a lot, a sca
And put in acoustically-isolated HVAC systems to get rid of the heat, as well. No foolin' ... 73, Jim N7CXI _______________________________________________ Amps mailing list Amps@contesting.com http:
I'd hate to warp the cover MIG welding, but then I'm no welder at all - just guessing. Also - just read your last... Angle stock would be stronger, but we're trying to dampen resonance. my seat-of-th
And that's where we have to be careful. I work on dampening and otherwise normalizing enclosures and spaces for artsy designers, so if there's a measurable resonance in a waterfall decay display when
We can worry about the aerospace applications when the patents clear... :P 73, Jim N7CXI _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.
Good results. Assuming the blower is running in balance, freshening the rubber baby buggy bumpers it mounts on might help some more with the vibration. Turbulence is tougher. Apple has been working o
I need to make up some MHV cables for a 4KV 2A max DC supply, (both B+ and B-) and I made the mistake of looking up the voltage ratings for RG-58, RG-59 and LMR-240 cables, all commonly used with tho
Thanks to all for the suggestions. I'll see if I can find some stranded RG-59 to fit the MHV connectors and check the assemblies out on the BVT before I put them into service. 73, Jim N7CXI _________