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References: [ +subject:/^(?:^\s*(re|sv|fwd|fw)[\[\]\d]*[:>-]+\s*)*\[Amps\]\s+Drake\s+L4B\s+to\s+6\s+Meters\s+Help\s*$/: 33 ]

Total 33 documents matching your query.

21. [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: "Michelle" <michelle_melt@windstream.net>
Date: Mon, 12 Dec 2016 19:25:32 -0500
When an amp is converted for mono band usage, you can forget about what the original MFG'ers rating on the amp was. since he kept referring to CW<<<< Michelle ________________________________________
/archives//html/Amps/2016-12/msg00331.html (8,605 bytes)

22. [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: "Michelle" <michelle_melt@windstream.net>
Date: Mon, 12 Dec 2016 19:53:00 -0500
If hams have been running Drake L4 and L4B amps since the early 70's or perhaps before with the L4 at zero bias, why all of a sudden you want to idle the thing down just because it is for 6 meters? T
/archives//html/Amps/2016-12/msg00332.html (9,744 bytes)

23. Re: [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: Paul Baldock <paul@paulbaldock.com>
Date: Mon, 12 Dec 2016 19:51:03 -0800
Michelle Did you say that you are running the 2 tubes a zero bias and have about 100mA idle current. I think it should be more like 200mA in the SSB position. This would suggest that either your high
/archives//html/Amps/2016-12/msg00340.html (9,332 bytes)

24. [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: "Michelle" <michelle_melt@windstream.net>
Date: Mon, 12 Dec 2016 23:59:24 -0500
Michelle Did you say that you are running the 2 tubes a zero bias and have about 100mA idle current. I think it should be more like 200mA in the SSB position. This would suggest that either your high
/archives//html/Amps/2016-12/msg00341.html (9,638 bytes)

25. Re: [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: gudguyham--- via Amps <amps@contesting.com>
Date: Tue, 13 Dec 2016 02:21:56 -0500
Self cut off bias has NOTHING to do with operating bias! Operating bias is set by Zener diodes or a string of diodes in the CT return of the filament transformer. The more string diodes or the higher
/archives//html/Amps/2016-12/msg00343.html (11,375 bytes)

26. Re: [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: gudguyham--- via Amps <amps@contesting.com>
Date: Tue, 13 Dec 2016 02:22:55 -0500
That's what I've been saying all along. Sent from AOL Mobile Mail Michelle Did you say that you are running the 2 tubes a zero bias and have about 100mA idle current. I think it should be more like 2
/archives//html/Amps/2016-12/msg00344.html (10,521 bytes)

27. Re: [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: gudguyham--- via Amps <amps@contesting.com>
Date: Tue, 13 Dec 2016 02:32:24 -0500
Like I said, self bias is for cut off bias not operating bias. Cut off bias is one thing and operating bias is another. The self cut of bias mod doesn't change operating bias. It only does because so
/archives//html/Amps/2016-12/msg00346.html (11,452 bytes)

28. Re: [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: gudguyham--- via Amps <amps@contesting.com>
Date: Tue, 13 Dec 2016 02:34:26 -0500
Obviously not done right or poor workmanship or tubes. Output quite low. Sent from AOL Mobile Mail Mike, I saw this on Eham.com for sale.SB 220 converted to 6 meters only as per QST April 08 minus va
/archives//html/Amps/2016-12/msg00347.html (10,578 bytes)

29. Re: [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: Joe <nss@mwt.net>
Date: Tue, 13 Dec 2016 07:46:22 -0600
This Thread is interesting, I have not dig into this old beast of a SB-220 yet to remember how or what the circuit is composed of. But back in the 80's This SB-220 had a mod added that made it run a
/archives//html/Amps/2016-12/msg00348.html (12,038 bytes)

30. Re: [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: "Jim Thomson" <jim.thom@telus.net>
Date: Tue, 13 Dec 2016 09:19:11 -0800
Too much operating bias drastically lowers the idle current and you need more drive power to make more suds. The Drake L4B when properly converted to 6 meters should easily do 1300 watts pep on SSB w
/archives//html/Amps/2016-12/msg00352.html (10,283 bytes)

31. [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: "Michelle" <michelle_melt@windstream.net>
Date: Tue, 13 Dec 2016 21:54:05 -0500
Ok, Here's where I am at: Removed zener from the self cut off bias mod, Idle current now 200 ma. Plate voltage 2300 under load (SSB mode) Plate current .810 (was 650) Grid 230 (was 220) Drive 100 wat
/archives//html/Amps/2016-12/msg00356.html (8,941 bytes)

32. Re: [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: Paul Baldock <paul@paulbaldock.com>
Date: Thu, 15 Dec 2016 07:38:00 -0800
Here's the results from my modified SB220 Plate voltage 2500V under load (SSB mode) Plate current .75A Grid 230mA Drive 75 watts Output 1100 watts (key down, not pep) Voltage and current readings are
/archives//html/Amps/2016-12/msg00374.html (9,406 bytes)

33. [Amps] Drake L4B to 6 Meters Help (score: 1)
Author: "Michelle" <michelle_melt@windstream.net>
Date: Thu, 15 Dec 2016 12:43:28 -0500
Here's the results from my modified SB220 Plate voltage 2500V under load (SSB mode) Plate current .75A Grid 230mA Drive 75 watts Output 1100 watts (key down, not pep) Voltage and current readings ar
/archives//html/Amps/2016-12/msg00378.html (9,104 bytes)

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