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41. Re: [Amps] Transfer capacitance, was GI-46B Question (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Fri, 15 Oct 2004 23:53:08 -0400
Art... Let's put this back on the reflector...it's getting interesting. All the data sheet from the gda.pl site list values like input C 10 pF output C .05 pF Transfer C 5 pF But the data sheets at n
/archives//html/Amps/2004-10/msg00222.html (13,129 bytes)

42. Re: [Amps] why does input SWR change when HV applied? (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sun, 17 Oct 2004 13:14:29 -0400
Neil, The cathode match works into both the input capacitance and the resistive component of the cathode. The resistive component comes from the fact that the cathode circuit carries both the plate a
/archives//html/Amps/2004-10/msg00243.html (8,910 bytes)

43. [Amps] High Temp silcone rubber sheet,was chimney material suggestion GI35b (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sat, 23 Oct 2004 09:40:57 -0400
This question reminds me. Who supplies the red high temp (silicone?) rubber sheet used in chimneys on some of the commercial amps? jeff, wa1hco Manuel R. Alonso / KC4MNE wrote: Hello Could PVC pipe b
/archives//html/Amps/2004-10/msg00375.html (7,679 bytes)

44. Re: [Amps] Zero Crossing circuit (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Wed, 17 Nov 2004 20:03:55 -0500
Ed... I've used zero voltage switched solid state relays twice in 2KW amplifiers, one at 432 and one at 144 MHz. The 432 amp included the normal step start circuit, but once I noticed that the zero v
/archives//html/Amps/2004-11/msg00256.html (10,141 bytes)

45. Re: RE : [Amps] Zero Crossing circuit (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Thu, 18 Nov 2004 19:07:29 -0500
Jos... Why you you need a snubber circuit related to a zero voltage switch. they switch on and off at zero volts...no snubber required. jeff, wa1hco hermans wrote: I still have a few hundreds of low
/archives//html/Amps/2004-11/msg00280.html (9,767 bytes)

46. Re: [Amps] Re: Step-start calculation (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sat, 20 Nov 2004 12:04:32 -0500
PSU designer (http://www.duncanamps.com/psud2/download.html) can do this calculation and I've got it running here. The model needs some values for various parameters. Here's some results for some sam
/archives//html/Amps/2004-11/msg00331.html (9,639 bytes)

47. Re: [Amps] Re: Step-start calculation (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sat, 20 Nov 2004 13:38:04 -0500
Rich... Thanks for the numbers, its educational. The program assumes mains resistance of zero. Since you know the value, it adds to primary winding resistance. Results at 240V in, 2.2M RL, parallel 2
/archives//html/Amps/2004-11/msg00336.html (10,351 bytes)

48. Re: [Amps] Re: Step-start calculation (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sat, 20 Nov 2004 16:11:11 -0500
Ok...re-running for full wave doubler Vout = 9010V with bleeders Vout = 7615 to 7395V at 4K load (220V ripple) Ipk turnon = 58 Amps Still a nice power supply Joe Subich, K4IK wrote: Thanks for the nu
/archives//html/Amps/2004-11/msg00339.html (8,601 bytes)

49. Re: [Amps] Re: Step-start calculation (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sun, 21 Nov 2004 14:10:17 -0500
Dennis... A transformer has inductance when open circuit, but when something's connected to its secondary, that impedance get transferred to the primary by the square of the turns ratio. So, when the
/archives//html/Amps/2004-11/msg00350.html (9,534 bytes)

50. Re: [Amps] Re: Step-start calculation (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sun, 21 Nov 2004 18:31:06 -0500
Will... Wow...that's a scary paper. But, I just don't understand it. ...And the calculations don't make sense. For example, the paper insists that zero voltage switching will cause horrible problems
/archives//html/Amps/2004-11/msg00358.html (13,489 bytes)

51. Re: [Amps] Re: Step-start calculation (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sun, 21 Nov 2004 20:07:01 -0500
Will...Indeed that's what it says. But what's all this stuff about magnetizing current in transformers?? Someone needs to explain that effect. The paper seems to say that a transformer with nothing c
/archives//html/Amps/2004-11/msg00363.html (11,699 bytes)

52. Re: [Amps] How to drive 6M 8877 with DownEast 50-28 ... IPA? (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Wed, 01 Dec 2004 21:52:02 -0500
Tom... IMD in almost all linear amplifiers follows the 3:1 rule...for a 1 dB increase in power output, the _absolute_ IMD levels increase by 3 dB. This rule is so reliable that it forms the basis of
/archives//html/Amps/2004-12/msg00019.html (11,329 bytes)

53. Re: [Amps] How to drive 6M 8877 with DownEast 50-28 ... IPA? (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sat, 04 Dec 2004 08:15:49 -0500
I didn't see this on the list, so here it is again. Tom: did you get the original? ...or did my email mess up? jeff, wa1hco jeff millar wrote: Tom... IMD in almost all linear amplifiers follows the 3
/archives//html/Amps/2004-12/msg00068.html (12,121 bytes)

54. Re: [Amps] Cell Phone power amps (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sun, 05 Dec 2004 14:48:57 -0500
And the answer is... ...it depends. * The 860 to 896 MHz band amps will operate just fine at 903...matching networks run very wide. * Feed forward type amplifiers will require removing a filter and s
/archives//html/Amps/2004-12/msg00086.html (7,472 bytes)

55. Re: [Amps] Unknown tube amp (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sun, 12 Dec 2004 11:35:35 -0500
833s don't twist and both plate and grid lie on top. I'd say 810's but they have 4 pins on the base Maybe browse through and old handbook looking for a base diagram that looks right and then scan the
/archives//html/Amps/2004-12/msg00181.html (7,848 bytes)

56. Re: [Amps] Unknown tube amp (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sun, 12 Dec 2004 17:12:57 -0500
Excellent pics...here the 250TH spec. Looks right http://www.dscc.dla.mil/Downloads/MilSpec/Docs/MIL-PRF-1/prf1ss878.pdf Chris Howard wrote: Here are the pictures! www.yipyap.com/radio_stuff/PA-1.jpg
/archives//html/Amps/2004-12/msg00198.html (9,748 bytes)

57. Re: [Amps] Re: unknown tube amp (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sun, 12 Dec 2004 20:26:05 -0500
Not a bad idea...but the 250TH has a small diameter grid connection and the 810 (if I recall correctly) has a larger one. The picture isn't too clear, but the grid terminal looks like small diameter
/archives//html/Amps/2004-12/msg00202.html (6,861 bytes)

58. Re: [Amps] 8122 x 12 (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Tue, 28 Dec 2004 23:55:53 -0500
That design is called a "transmission line amplifier". The tube output capacitance makes it very difficult to create a matched wide bandwidth amplifier. But, a transmission line can consist of a seri
/archives//html/Amps/2004-12/msg00372.html (8,121 bytes)

59. Re: [Amps] 8171 (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Thu, 27 Jan 2005 09:58:00 -0500
Barrie... Here's some design ideas, based on a smith chart analysis using the gsmc-1.1 program, assuming 25 pF output capacitance and 3K plate load impedance (with strays). I can run the numbers for
/archives//html/Amps/2005-01/msg00534.html (8,580 bytes)

60. Re: [Amps] GS35B Plate connection suggestions wanted (score: 1)
Author: jeff millar <wa1hco@adelphia.net>
Date: Sat, 05 Feb 2005 12:03:13 -0500
The one time I did it...used a stainless hose clamp around the base of the copper fins and pinched a wire under it. jeff, wa1hco Tomm Aldridge wrote: There are quite a few sites out there showing GS3
/archives//html/Amps/2005-02/msg00152.html (8,030 bytes)

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