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381. Re: [Amps] Class A for AM (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 15 Nov 2006 05:42:11 -0500
I was using the theoretical maximum. The practical maxmium could be any value less than that (and proably will be). I haven't designed that many class A amplifiers where efficiency was an issue, so
/archives//html/Amps/2006-11/msg00196.html (10,704 bytes)

382. Re: [Amps] Russian power L-coupler (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Fri, 17 Nov 2006 08:10:26 -0500
They are sometimes called variometers. They have terrible Q at minimum inductance, especially at higher frequencies. Of all the common methods, this is the least efficient way to vary inductance ove
/archives//html/Amps/2006-11/msg00215.html (6,955 bytes)

383. Re: [Amps] Russian power L-coupler (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Fri, 17 Nov 2006 13:10:07 -0500
The area that primarily causes Q reduction in a roller inductor at lower frequencies is the shunt capacitance from the inductor to the frame and the countering flux generated by end plates if metall
/archives//html/Amps/2006-11/msg00222.html (9,348 bytes)

384. Re: [Amps] Russian power L-coupler (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Fri, 17 Nov 2006 16:10:51 -0500
I don't think everyone has a grasp of how poor that design is for wide range inductances. Let's assume it takes 20 feet of #12 wire to have enough inductance to cover 160 meters. On ten meters the s
/archives//html/Amps/2006-11/msg00225.html (10,537 bytes)

385. Re: [Amps] 30L-1 Blows Fuse at 600ma (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Mon, 20 Nov 2006 05:36:52 -0500
Jerry, Your amplifier has either an open primary or a broken or open connection in the primary wiring path to one of the two primary windings on the transformer. This could be an open connection at
/archives//html/Amps/2006-11/msg00235.html (7,447 bytes)

386. Re: [Amps] FL2100B (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Wed, 22 Nov 2006 20:53:53 -0500
What is the problem exactly Carl? 73 Tom _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2006-11/msg00246.html (6,372 bytes)

387. Re: [Amps] Prmetheus (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Thu, 23 Nov 2006 17:55:34 -0500
2400 watts key down = 2400 watts carrier = 2400 watts CW = 2400 watts PEP 73 Tom _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mai
/archives//html/Amps/2006-11/msg00253.html (6,639 bytes)

388. Re: [Amps] SB-220 grid current (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sat, 25 Nov 2006 12:27:20 -0500
No. No plate voltage causes the grid meter to pin at low levels of drive. In a GG amp a negative grid meter swing is caused by a short from the cathode to chassis ground. That can be a shorted tube
/archives//html/Amps/2006-11/msg00264.html (7,004 bytes)

389. Re: [Amps] Prmetheus (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sat, 25 Nov 2006 12:12:43 -0500
On CW, key down is PEP. On CW, carrier=keydown=PEP On SSB voice, PEP and average power have no fixed relationship at all. In a solid state amp PEP SSB power it often is limited by linearity. SSB PEP
/archives//html/Amps/2006-11/msg00265.html (8,053 bytes)

390. Re: [Amps] Follow-up on Bouncy Meter (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sun, 3 Dec 2006 16:31:55 -0500
If a hairspring is broken the meter will stick (if it hangs up on something), not read at all (the current path is through the springs in conventional movements), or it will be far too sensitive (in
/archives//html/Amps/2006-12/msg00007.html (8,725 bytes)

391. Re: [Amps] Low Pass Filters (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Mon, 4 Dec 2006 06:02:34 -0500
The impedance of the filter is going to be 50 ohms. That alone will keep the voltage under tow. The current through the filter however will be substantial. If the actual power is 600 watts average an
/archives//html/Amps/2006-12/msg00009.html (8,265 bytes)

392. Re: [Amps] *** SPAM *** Re: Follow-up on Bouncy Meter (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Mon, 4 Dec 2006 13:49:28 -0500
A dozen different things occur when the hairsprings are bad, but they all have one common thread. The meter reading is way off because the spring is part of the calibration. It also has never, to my
/archives//html/Amps/2006-12/msg00016.html (8,348 bytes)

393. Re: [Amps] FW: Re: current ratings (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Tue, 5 Dec 2006 18:17:17 -0500
Not necessarily. It's often because RF capacitors are voltage limited. It's an E = I*X*1.414 problem. Either increasing capacitance (lowering reactance), increasing frequency, or increasing voltage
/archives//html/Amps/2006-12/msg00033.html (7,700 bytes)

394. Re: [Amps] Optoisolator for Keying Collins 30L-1 to Modern Rigs (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sat, 9 Dec 2006 06:12:43 -0500
The problem with a relay keying another relay is activation times are added. Whatever small relay's time you add in, it makes an already poor situation worse. Say you have 13mS on the large amplifie
/archives//html/Amps/2006-12/msg00046.html (8,036 bytes)

395. Re: [Amps] PiL Output Network Adjustment (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Fri, 15 Dec 2006 05:14:30 -0500
A few comments: Toroids in theory are self -shielding. This would mean all flux is confined to the iron core magnetic path, and any short would take the reactance of all other areas of the winding to
/archives//html/Amps/2006-12/msg00093.html (10,638 bytes)

396. Re: [Amps] 2 x 4-250A Amp (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Sun, 17 Dec 2006 18:13:15 -0500
The filament transformer is 10 volts with no center tap and the two five volt filaments are wired in series. The B- is thru a meter to a resistor across the filaments.The article with the amp suggest
/archives//html/Amps/2006-12/msg00120.html (9,102 bytes)

397. Re: [Amps] filament choke (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Mon, 18 Dec 2006 05:03:55 -0500
I've done that on very large amps. Depends on the core material selected. You have to look at flux density at PEAK cathode current and the number of bifilar turns. One thing about the open ended rod
/archives//html/Amps/2006-12/msg00130.html (8,964 bytes)

398. Re: [Amps] MLA2500 10 Meter Mod (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Mon, 18 Dec 2006 08:20:01 -0500
Bob, Dentron kind of built to fit the mood of the day and the availability of parts. Dentron did a combination of five things to prevent 10 meter operation: 1.) They moved the adjustable stop in the
/archives//html/Amps/2006-12/msg00134.html (8,196 bytes)

399. Re: [Amps] QST (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Mon, 18 Dec 2006 14:05:22 -0500
Also Motorola's board has some design issues, so it isn't just QST authors who could use improvement. The rest of the errors are what I would call small 73 Tom ______________________________________
/archives//html/Amps/2006-12/msg00147.html (8,657 bytes)

400. Re: [Amps] QST (score: 1)
Author: "Tom W8JI" <w8ji@w8ji.com>
Date: Tue, 19 Dec 2006 13:43:02 -0500
I don't think that article was all that bad. It had significantly fewer mistakes and more accurate technical advice than the "Nearly Perfect Amplifier" article. It would be nice if people would subm
/archives//html/Amps/2006-12/msg00174.html (7,544 bytes)

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