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1. [Amps] Eimac vs Svetlana (score: 1): Author: helge.skram@med.ge.com (Skram, Helge (MED)); Date: Thu, 19 Dec 2002 14:39:50 +0100; Hello I confronted Eimac with the information below, concerning quality of Eimac vs Svetlana. In a previous posting there were more statements about Eimac that were strange. I am interested in this,; /archives//html/Amps/2002-12/msg00222.html (13,850 bytes)
2. [Amps] Need 25/35 mfd @ 5/6000 vdc oil filled cap (score: 1): Author: helge.skram@med.ge.com (Skram, Helge (MED)); Date: Wed, 6 Nov 2002 13:55:33 +0100; Try out http://www.torontosurplus.com/ There you will find: General Electric Geconol Capacitor - 28F2032 / S215B35339-0100 23?F, 5200 VDC The dimensions are: 10 1/6" H x 4 9/16" W x 2 7/8" D 228 in s; /archives//html/Amps/2002-11/msg00052.html (8,385 bytes)
3. [Amps] Re: [Amps] various parasitic sources... chassis, tubes, etc... (score: 1): Author: helge.skram@med.ge.com (Skram, Helge (MED)); Date: Wed, 6 Nov 2002 17:57:39 +0100; YES, YES, YES, this agrees with what I have seen in my amplifier projects. Reverse feedback must be kept below forward gain at any frequency. The grids (including g2) must be grounded effectiviely a; /archives//html/Amps/2002-11/msg00060.html (8,680 bytes)
4. [Amps] Hot Switching (score: 1): Author: helge.skram@med.ge.com (Skram, Helge (MED)); Date: Fri, 15 Nov 2002 16:09:29 +0100; Re hot switching of RF-relays, I think it is a real problem, confirmed by own measurements. Modern tranceiver put our RF too fast for most relays. It may help but is not cured by switching RF relays; /archives//html/Amps/2002-11/msg00252.html (7,927 bytes)
5. [Amps] Thomson YL1050 Cavity Neutralization 432 Mhz (score: 1): Author: helge.skram@med.ge.com (Skram, Helge (MED)); Date: Wed, 30 Oct 2002 12:35:40 +0100; Hello It is a surprise that a grounded G2 and G1(via caps) can oscillate. My experience is with a 432MHz PA with YL1111 (eq.RS1064C) according to Dubus and DB6NT. G2 is physically grounded and G1 is; /archives//html/Amps/2002-10/msg00313.html (9,399 bytes)
6. RE: [Amps] PS Theory ? (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Thu, 28 Aug 2003 15:39:55 +0200; The peak current will depend on capacitors and resistances. Peak current can be very high. What is important ia average current. PSU seems simple, but if you have specific requirements for loaded vol; /archives//html/Amps/2003-08/msg00061.html (10,983 bytes)
7. RE: [Amps] PS Theory ? (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Tue, 2 Sep 2003 15:32:55 +0200; Agree, this works fine. Mains voltage drop may be significant for multi kilowatt psu's. I have used the same method to determine the transformer resistance to use in the PSU Designer. Load down the t; /archives//html/Amps/2003-09/msg00017.html (9,015 bytes)
8. RE: [Amps] buck-boost (b-b) (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Fri, 5 Sep 2003 16:05:50 +0200; I used an external adjusting buck boost transformer for a project. My problem was that the HV transformer would give too much voltage. This is easy to correct by lowering the mains voltage input. I t; /archives//html/Amps/2003-09/msg00048.html (9,196 bytes)
9. RE: [Amps] Ameritron AL-1500 (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Mon, 8 Sep 2003 15:35:09 +0200; In short I agree. It is not a good idea to put in a extra tube in any comercial amp. You would probably need so many parts, that it would be a better idea to homebrew a new amp. I have a nice one tub; /archives//html/Amps/2003-09/msg00077.html (12,386 bytes)
10. RE: [BULK] - [Amps] NCL 2000? (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Tue, 30 Sep 2003 15:30:59 +0200; My advice is: Don't convert from 8122 to 4CX250b. I am aware that many get 1kw out of these, but the signal is not linear. The anode voltage will be far beyond the max spec for the 4cx250b. In the lo; /archives//html/Amps/2003-10/msg00000.html (9,336 bytes)
11. RE: [Amps] Power meter calibration (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Mon, 6 Oct 2003 15:27:24 +0200; Ignoring diode non-linearity and other spurious imperfections, the output of a directional coupler is a constant fraction of the forward voltage from the transmitter. The scale of the meter shall be; /archives//html/Amps/2003-10/msg00050.html (8,400 bytes)
12. RE: [Amps] Future availability of 3cx1200a7 and 3cx1500a7 (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Fri, 24 Oct 2003 10:37:31 +0200; ...none of which addresses the question asked! He's **buying** an amp, not building. He wants to know about the likely continued **availability** of the 3CX1200A7, 8877, and 4CX800A, not alternatives; /archives//html/Amps/2003-10/msg00223.html (12,898 bytes)
13. RE: [Amps] Water cooling heat exchanger approaches (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Tue, 28 Oct 2003 10:18:12 +0100; Hi I have a 23cm 2x 7289 amp from VE1ALQ using water cooling. Yes I came into the same situation, where do you get a "small transmission oil cooler". Couldn't find any, but then came to think that th; /archives//html/Amps/2003-10/msg00264.html (8,614 bytes)
14. RE: [Amps] Water cooling heat exchanger approaches (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Wed, 29 Oct 2003 15:52:47 +0100; The water is in direct contact with the 7289's. The original air cooler radiator has been removed and replaced by water cooler jacket. This screwed directly onto the anode. There is a input and a out; /archives//html/Amps/2003-10/msg00282.html (12,373 bytes)
15. RE: [Amps] About single 4CX250b output power (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Tue, 4 Nov 2003 16:52:47 +0100; Ian, I guess you know this already, so it's for information. "only -19dB and quite irresponsible by implying that level of IMD is fit to be put on the air". I may agree, but it depends. You can not o; /archives//html/Amps/2003-11/msg00040.html (10,323 bytes)
16. RE: [Amps] Benefits of 3-phase power? (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Fri, 21 Nov 2003 15:49:55 +0100; The mains frequency choice must also have something to do with wavelength. The wavelength for 1000Hz is 300km. An open quarter wavelength line at 75km, would be a short at the supplier side. The wave; /archives//html/Amps/2003-11/msg00310.html (10,929 bytes)
17. RE: [Amps] Toroid Plate Transformers (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Fri, 5 Dec 2003 14:26:52 +0100; Hi In my experience, torodial transformers should be the choice for new designs. I have built several amps and until my last project used EI core transformers. These have been custom made here in Nor; /archives//html/Amps/2003-12/msg00061.html (8,694 bytes)
18. RE: [Amps] bird 43 slug (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Mon, 2 Feb 2004 13:41:56 +0100; Hello I purchased new from RF Parts one of the Bird 500w 400-1000MHz, that I intended to use on 1296MHz measuring power from a 2x7289 cavity amp. I have 3 Bird 43 meters in use. I stopped using the B; /archives//html/Amps/2004-02/msg00009.html (8,520 bytes)
19. RE: [Amps] WTB : RCA 8122 (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Wed, 31 Mar 2004 13:33:54 +0200; Hi, You can buy 8122 from Burle http://www.burle.com/, that is the tube division of the formerly RCA company. The 8122 is not so cheap, it comes at $415 each for European customers. The 8122 is a nic; /archives//html/Amps/2004-03/msg00361.html (8,772 bytes)
20. RE: [Amps] Glass Power Tube rebuilders (score: 1): Author: "Skram, Helge (MED)" <helge.skram@med.ge.com>; Date: Mon, 7 Jun 2004 13:31:12 +0200; The problem that I have experienced with rebuilders is that they haven't been able to get the glass in sizes that used to be common, i.e., a blank in the size of a 3-1000Z diameter, from Germany (Sho; /archives//html/Amps/2004-06/msg00043.html (9,675 bytes)

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