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References: [ +subject:/^(?:^\s*(re|sv|fwd|fw)[\[\]\d]*[:>-]+\s*)*\[Amps\]\s+SB\-220\s+Bias\s+Question\s*$/: 49 ]

Total 49 documents matching your query.

21. Re: [Amps] SB-220 bias question (score: 1)
Author: "Joe Subich, W4TV" <lists@subich.com>
Date: Sat, 29 Aug 2009 20:48:51 -0400
The higher circulating currents will very likely cause the pi-network coil or bandswitch to fail. But then the failure will probably be blamed on a parasitic rather than misuse. ____________________
/archives//html/Amps/2009-08/msg00619.html (10,083 bytes)

22. Re: [Amps] SB-220 bias question (score: 1)
Author: "Joe Subich, W4TV" <lists@subich.com>
Date: Sat, 29 Aug 2009 20:48:51 -0400
Not that it matters but you want Ep and Ip to go to 70% each in order to reach half power (.7x.7= .5). By keeping them in the same ratio, the plate load impedance remains the same. If Ep and Ip sent
/archives//html/Amps/2009-08/msg00620.html (15,283 bytes)

23. Re: [Amps] SB-220 bias question (score: 1)
Author: Gudguyham@aol.com
Date: Sat, 29 Aug 2009 20:52:53 EDT
But then the failure will probably be blamed on a parasitic rather than misuse. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailm
/archives//html/Amps/2009-08/msg00621.html (7,894 bytes)

24. Re: [Amps] SB-220 bias question (score: 1)
Author: Gudguyham@aol.com
Date: Sat, 29 Aug 2009 20:56:36 EDT
Reducing the power output without changing the plate voltage will result in a miss-tuned condition. If the pi-network is tuned for full output and the drive reduced (power adjusted). If the output is
/archives//html/Amps/2009-08/msg00622.html (8,823 bytes)

25. Re: [Amps] SB-220 bias question (score: 1)
Author: "Carl" <km1h@jeremy.mv.com>
Date: Sat, 29 Aug 2009 21:19:24 -0400
Excuse the brain fart! That was the same voltages that the NCL-2000 used back in 1963. However holding a SB-220 to a KW input still requires that the drive be reduced or the amp improperly loaded. Id
/archives//html/Amps/2009-08/msg00623.html (16,389 bytes)

26. Re: [Amps] SB-220 bias question (score: 1)
Author: "Bill, W6WRT" <dezrat1242@yahoo.com>
Date: Sat, 29 Aug 2009 18:23:28 -0700
ORIGINAL MESSAGE: REPLY: I think you are mistaken about the circulating currents going up. If that really was happening, the voltages across each of the pi-network elements would also go up. Since th
/archives//html/Amps/2009-08/msg00624.html (9,573 bytes)

27. Re: [Amps] SB-220 bias question (score: 1)
Author: "jerome schatten" <romers@shaw.ca>
Date: Sat, 29 Aug 2009 18:33:29 -0700
And by extension, consider an amplifier tuned with a steady tone for maximum power out when the i/p side of the pi network matches the tube plate Z and the output of the pi matches the load Z. If the
/archives//html/Amps/2009-08/msg00625.html (8,811 bytes)

28. Re: [Amps] SB-220 bias question (score: 1)
Author: "Joe Subich, W4TV" <lists@subich.com>
Date: Sat, 29 Aug 2009 21:30:02 -0400
No, I'm saying they are all designed to operate at 1500 Watts output. If one reduces power without reducing the plate voltage appropriately, the plate load impedance will change. Unless the "L" in t
/archives//html/Amps/2009-08/msg00626.html (10,020 bytes)

29. Re: [Amps] SB-220 bias question (score: 1)
Author: "Joe Subich, W4TV" <lists@subich.com>
Date: Sun, 30 Aug 2009 00:17:43 -0400
No ... with SSB the plate load impedance is dynamic as opposed to static (a single value) with CW or RTTY. For SSB or any other amplitude modulated emission, the calculation of plate load impedance
/archives//html/Amps/2009-08/msg00627.html (10,154 bytes)

30. Re: [Amps] SB-220 bias question (score: 1)
Author: "Bill, W6WRT" <dezrat1242@yahoo.com>
Date: Sun, 30 Aug 2009 00:09:45 -0700
ORIGINAL MESSAGE: REPLY: I get the feeling we're talking about two different things here. Just to be clear, the pi-network, properly tuned, "looks" like a pure resistance at a certain value to the tu
/archives//html/Amps/2009-08/msg00628.html (9,667 bytes)

31. Re: [Amps] SB-220 bias question (score: 1)
Author: "Bill, W6WRT" <dezrat1242@yahoo.com>
Date: Sun, 30 Aug 2009 05:24:36 -0700
That part is correct, however only the efficiency suffers. No harm is done.. That part is incorrect. The voltages and currents do not increase when power is reduced. They decrease. 73, Bill W6WRT ___
/archives//html/Amps/2009-08/msg00629.html (9,133 bytes)

32. Re: [Amps] SB-220 bias question (score: 1)
Author: "Carl" <km1h@jeremy.mv.com>
Date: Sun, 30 Aug 2009 08:44:13 -0400
Note that I used the basic Class C Rp calculation to show the points I am trying to make. Its simpler than selecting whatever offset is in vogue this week for calculations of a linear stage. Carl KM1
/archives//html/Amps/2009-08/msg00630.html (8,113 bytes)

33. Re: [Amps] SB-220 bias question (score: 1)
Author: "Joe Subich, W4TV" <lists@subich.com>
Date: Sun, 30 Aug 2009 10:12:31 -0400
Again, you did not read what I wrote ... If you change the network by changing the plate load impedance as you do when you run 1000 watts in the high voltage position the VALUES of the capacitors mu
/archives//html/Amps/2009-08/msg00633.html (11,575 bytes)

34. Re: [Amps] SB-220 bias question (score: 1)
Author: "DF3KV" <df3kv@t-online.de>
Date: Sun, 30 Aug 2009 16:46:50 +0200
Changing the Q at constant power level changes the currents in the pi-net, not the voltages 73 Peter ORIGINAL MESSAGE: REPLY: I think you are mistaken about the circulating currents going up. If that
/archives//html/Amps/2009-08/msg00634.html (9,923 bytes)

35. Re: [Amps] SB-220 bias question (score: 1)
Author: "Bill, W6WRT" <dezrat1242@yahoo.com>
Date: Sun, 30 Aug 2009 08:15:43 -0700
ORIGINAL MESSAGE: REPLY: There is your fundamental error. Simply by reducing the drive (without retuning), you DO NOT change the impedance the network presents to the tube. The impedance is the same
/archives//html/Amps/2009-08/msg00636.html (9,104 bytes)

36. Re: [Amps] SB-220 bias question (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sun, 30 Aug 2009 10:24:35 -0600
Might I make a simple suggestion. Analog Devices gives away a free program called LTSpice (http://www.linear.com/designtools/software/ltspice.jsp) which is a great tool for understanding how circuits
/archives//html/Amps/2009-08/msg00637.html (10,259 bytes)

37. Re: [Amps] SB-220 bias question (score: 1)
Author: Gudguyham@aol.com
Date: Sun, 30 Aug 2009 13:33:03 EDT
To insist that circulating current INCREASES when drive is reduced is utter nonsense. Period. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contes
/archives//html/Amps/2009-08/msg00640.html (8,079 bytes)

38. Re: [Amps] SB-220 bias question (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sun, 30 Aug 2009 11:47:33 -0600
WHOOPS, not Analog Devices but Linear Technology. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2009-08/msg00641.html (11,143 bytes)

39. Re: [Amps] SB-220 bias question (score: 1)
Author: "DF3KV" <df3kv@t-online.de>
Date: Sun, 30 Aug 2009 21:22:26 +0200
Circulating current is not increasing because drive is reduced, but because Q is increased (L remains the same) by tuning for lower output at higher voltage. 73 Peter ORIGINAL MESSAGE: REPLY: There i
/archives//html/Amps/2009-08/msg00642.html (9,568 bytes)

40. Re: [Amps] SB-220 bias question (score: 1)
Author: "Bill, W6WRT" <dezrat1242@yahoo.com>
Date: Sun, 30 Aug 2009 18:44:06 -0700
ORIGINAL MESSAGE: REPLY: That was not the original question. You are talking about RETUNING after lowering power, and if you do that then I agree - Q will be increased. The original question asked if
/archives//html/Amps/2009-08/msg00644.html (9,183 bytes)

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