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Total 67 documents matching your query.

21. [Amps] Why hasn't solid state replaced tubes? (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Thu Mar 6 01:41:05 2003
It does give equal weighting to splatter that only occurs on transient peaks of the modulating waveform. But transient IMD could for example include splatter that occurs on almost every word, which m
/archives//html/Amps/2003-03/msg00230.html (12,054 bytes)

22. [Amps] re: Arcos & Unknown 2m 2x4cx250b designs (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Fri Mar 7 04:15:08 2003
I've tried to find out about as many 4CX250 VHF amp designs as possible... but this is a new one. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://w
/archives//html/Amps/2003-03/msg00288.html (8,096 bytes)

23. [Amps] Why hasn't solid state replaced tubes? (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Fri Mar 7 06:55:28 2003
Yes, noise testing is a possible test method... but if our objective is to measure spectrum occupancy with voice signals, there is absolutely no point in simulating a voice signal when we can use a *
/archives//html/Amps/2003-03/msg00293.html (10,394 bytes)

24. [Amps] Why hasn't solid state replaced tubes? (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Fri Mar 7 13:09:00 2003
Forgive me, but you're still missing the point: measuring low-order IMD simply doesn't tell us everything we need to know - not even approximately. On the air, there is a vital difference between the
/archives//html/Amps/2003-03/msg00306.html (11,261 bytes)

25. [Amps] Alpha 86 (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Fri Mar 7 13:25:52 2003
I just finishing repairs and upgrades to an SB-1000, including having replaced that burned-out 160m switch wafer with an AL-80 spare from Ameritron. There was no sign of that particular amp ever havi
/archives//html/Amps/2003-03/msg00309.html (9,063 bytes)

26. [Amps] Why hasn't solid state replaced tubes? (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Sat Mar 8 06:37:39 2003
I have. The key point that you are still missing is that your logic does not work in reverse! If a signal is not "clean" on the opposite sideband, you cannot predict whether it will be causing signif
/archives//html/Amps/2003-03/msg00322.html (12,664 bytes)

27. [Amps] 4CX1600B vs. GU84B (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Sat Mar 8 08:53:08 2003
Some of these cross-references are vague to the point of being misleading (for example, some people call the GS35b a "Russian 8877", which it certainly isn't). www.nd2x.net is the best source for dat
/archives//html/Amps/2003-03/msg00331.html (8,037 bytes)

28. [Amps] AL-80B questions (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Sun Mar 9 13:41:41 2003
High-gain amplifiers for the VHF bands are perfectly stable too, if they use tubes with short, well-grounded grid (or cathode) connections. The key feature is the total length and inductance of that
/archives//html/Amps/2003-03/msg00381.html (9,249 bytes)

29. [Amps] AL-80B questions (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Sun Mar 9 18:20:11 2003
Not true. VHF/UHF amps all have multiple resonances, both above and below the operating frequency. You can't avoid resonances, but you *can* prevent oscillation, by making sure that feedback at all r
/archives//html/Amps/2003-03/msg00399.html (10,591 bytes)

30. [Amps] Mailing list for parasitic osciallations. (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Thu Mar 13 11:20:54 2003
So it was. We all believed that Wes's measurements on the suppressors would answer all the questions. But during the debate that followed, we found out that it isn't as simple as we'd believed. There
/archives//html/Amps/2003-03/msg00522.html (11,042 bytes)

31. [Amps] Silly idea? (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Tue Mar 18 09:18:35 2003
That kind of personal attack, on the honesty of someone who is not even a member of this list, is something that I deeply despise. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Edito
/archives//html/Amps/2003-03/msg00667.html (9,023 bytes)

32. [Amps] Glitch resistor? (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Thu Mar 20 15:26:55 2003
Go for it, if the price is right and you have the space. 50 ohms is on the high side of what you really need to protect the tube against a glitch (current surge) but that means it will be even more e
/archives//html/Amps/2003-03/msg00746.html (7,445 bytes)

33. [Amps] Hard-drive Dive (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Sun Mar 23 07:52:37 2003
K7FM had written: Let's be careful with the facts here. Looking at the schematic of the 30S-1, there is no conventional R/L parasitic suppressor. There is an "L101" between the anode connector and th
/archives//html/Amps/2003-03/msg00786.html (10,175 bytes)

34. [Amps] Hard-drive Dive (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Sun Mar 23 10:00:33 2003
No nichrome there, then... In effect, this taps C1 of the pi tank part-way along the inductor, so that Cmin doesn't add so much to the total input capacitance. On the other hand, it makes the design
/archives//html/Amps/2003-03/msg00789.html (10,044 bytes)

35. [Amps] Re: COLLINS Engineering (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Sun Mar 23 12:42:25 2003
Cue Peter Chadwick... (if he's not travelling again) -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/g3sek
/archives//html/Amps/2003-03/msg00793.html (8,401 bytes)

36. [Amps] HT power supplies? (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Mon Mar 24 14:49:34 2003
Since this circuit relies on being critically close to resonance, but absolutely never hitting resonance, it would be very unsuitable for use with a generator whose speed can vary (just a thought, si
/archives//html/Amps/2003-03/msg00815.html (7,930 bytes)

37. [Amps] Parasites (parasitics) (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Thu Mar 27 16:42:15 2003
Yawn... here we go again... Feedback C is significant, but is only one of the factors that determine VHF stability. The factor that is usually more important is the length and inductance from grid to
/archives//html/Amps/2003-03/msg00889.html (9,379 bytes)

38. [Amps] candles (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Thu Mar 27 16:50:40 2003
"Candles"? Cricket stumps, old chap. -- 73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB) Editor, 'The VHF/UHF DX Book' http://www.ifwtech.co.uk/g3sek
/archives//html/Amps/2003-03/msg00890.html (6,716 bytes)

39. [Amps] Parasites (parasitics) (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Fri Mar 28 03:29:58 2003
How do you arrive at those inductance figures? What do believe they show, and why? How many 887s from VHF amps have you looked at? Again, what do you believe that shows, and why? If an 8877 can be ma
/archives//html/Amps/2003-03/msg00902.html (9,139 bytes)

40. [Amps] Filament Inrush Control (score: 170)
Author: G3SEK at ifwtech.co.uk (Ian White, G3SEK)
Date: Fri Mar 28 09:04:09 2003
The delay isn't really a key parameter. The big current surge is over within a 3-4 mains cycles. After that, the current slowly ramps down, so you can short out the series resistor as soon as you li
/archives//html/Amps/2003-03/msg00905.html (11,197 bytes)


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