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Total 20 documents matching your query.

1. [AMPS] HF-2500 (score: 1): Author: falk@investusa.net (Kenneth C. Falk, CCIM); Date: Sun, 2 Jul 2000 08:54:16 -0400; Anyone have a used HF-2500 for sale. My budget is up to US$1,100. Ken Falk AB4JB Lexington, VA -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: amps@contesting.com Administrative reques; /archives//html/Amps/2000-07/msg00009.html (6,406 bytes)
2. [AMPS] HF-2500 (score: 1): Author: on4ma@village.uunet.be (Marc Wullaert); Date: Sun, 2 Jul 2000 18:01:23 +0200; thats a third of the selling price ...if you find one at your budget ,check the tubes. -- FAQ on WWW: http://www.contesting.com/FAQ/amps Submissions: amps@contesting.com Administrative requests: amps; /archives//html/Amps/2000-07/msg00010.html (6,846 bytes)
3. [Amps] hf-2500 (score: 1): Author: "K1TTT" <K1TTT@ARRL.NET>; Date: Thu, 13 Dec 2012 17:26:09 +0000; I have an older Commander HF-2500 that needs a new transformer. Anyone have a source for good ones?? Or does anyone want an RF deck and doorstop? _______________________________________________ Amps; /archives//html/Amps/2012-12/msg00076.html (6,809 bytes)
4. Re: [Amps] hf-2500 (score: 1): Author: "K1TTT" <K1TTT@ARRL.NET>; Date: Sat, 15 Dec 2012 13:32:51 +0000; Thanks for all the suggestions, for what the deck is worth I think I'll keep it and try the rewinding path. For anyone needing to work on these amps, here are a few links to my repair and modificatio; /archives//html/Amps/2012-12/msg00087.html (9,560 bytes)
5. Re: [Amps] hf-2500 (score: 1): Author: Bill Turner <dezrat1242@yahoo.com>; Date: Mon, 17 Dec 2012 19:27:46 -0800; REPLY: The HF-2500 should not be used on 40 meter full power RTTY, or any lower frequency either. I melted the toroid twice on mine on 40 meters during a RTTY contest. It does not use a toroid on 20-; /archives//html/Amps/2012-12/msg00098.html (7,487 bytes)
6. Re: [Amps] hf-2500 (score: 1): Author: "K1TTT" <K1TTT@ARRL.NET>; Date: Wed, 19 Dec 2012 17:15:03 +0000; Agreed, that is why I have modified one to do only 40-10m... removing the 80m and 160m coils from the toroid removes the shorted turns problem and makes it run very nicely doing rtty on 40m. also the; /archives//html/Amps/2012-12/msg00106.html (8,894 bytes)
7. Re: [Amps] hf-2500 (score: 1): Author: Bill Turner <dezrat1242@yahoo.com>; Date: Wed, 19 Dec 2012 12:26:03 -0800; REPLY: As David found out, shorted turns on a toroid or any iron core coil are a no-no unless you do some very careful design and testing, which Command obviously did not do. Shorted turns on an air; /archives//html/Amps/2012-12/msg00114.html (7,767 bytes)
8. Re: [Amps] hf-2500 (score: 1): Author: "Jim W7RY" <w7ry@centurytel.net>; Date: Wed, 19 Dec 2012 17:16:33 -0800; Bill We already had this discussion on here about a year ago. But I 'm going to repeat it. Alpha, Ameritron, Jerry K8RA, myself W7RY, and many others all use toroids with shorted turns on our "L" coi; /archives//html/Amps/2012-12/msg00125.html (9,327 bytes)
9. Re: [Amps] hf-2500 (score: 1): Author: "Jeff Blaine" <keepwalking188@yahoo.com>; Date: Sat, 22 Dec 2012 09:45:08 -0600; They don't work very well in that implementation (the hf-2500). A guy across town had the exact same failure scenario as David did. Not quite a "china syndrome" but a melt-down none the less. I think; /archives//html/Amps/2012-12/msg00133.html (10,418 bytes)
10. Re: [Amps] hf-2500 (score: 1): Author: Larry Benko <xxw0qe@comcast.net>; Date: Sat, 22 Dec 2012 09:25:27 -0700; I used to think that shorted turns on powdered iron toroids was bad until I did some tests. My tests were not exhaustive but winding some the inductance to ~1/2 of the inductance with the turns not s; /archives//html/Amps/2012-12/msg00134.html (10,808 bytes)
11. Re: [Amps] hf-2500 (score: 1): Author: Bill Turner <dezrat1242@yahoo.com>; Date: Sat, 22 Dec 2012 11:24:53 -0800; REPLY: Read my post again. I said they are a no-no UNLESS you do some careful design and testing, which Command apparently did not do. Alpha did, and their design works fine. 73, Bill W6WRT _________; /archives//html/Amps/2012-12/msg00138.html (8,148 bytes)
12. Re: [Amps] hf-2500 (score: 1): Author: Bill Turner <dezrat1242@yahoo.com>; Date: Sat, 22 Dec 2012 21:18:07 -0800; REPLY: Don't forget they are usually wrapped with tape which is also a good heat insulator. Designers, if you insist on toroids in a standard pi network you only need three: 40, 80 and 160 meters. Sp; /archives//html/Amps/2012-12/msg00142.html (8,398 bytes)
13. Re: [Amps] hf-2500 (score: 1): Author: "Carl" <km1h@jeremy.mv.com>; Date: Sun, 23 Dec 2012 10:17:53 -0500; I have a 2500 on the bench right now and there is no sign of overheating. The owner uses it strictly on 75 SSB which might explain it but the amp easily puts out 2200W +. Perhaps different gauge wire; /archives//html/Amps/2012-12/msg00157.html (13,042 bytes)
14. Re: [Amps] hf-2500 (score: 1): Author: "Gary Schafer" <garyschafer@comcast.net>; Date: Sun, 23 Dec 2012 11:22:21 -0500; I have an old TMC amplifier with a pair of 3-500 tubes. It originally had a toroid tank that had turns shorted for the higher bands. The core was quite large. The tank covered 160 - 15 meters. Effici; /archives//html/Amps/2012-12/msg00163.html (13,275 bytes)
15. Re: [Amps] hf-2500 (score: 1): Author: Larry Benko <xxw0qe@comcast.net>; Date: Sun, 23 Dec 2012 11:08:29 -0700; Gary, Nothing is black and white! Just because someone says something there is always more to the story. Air (u=1) definitely has considerable flux leakage. Obviously as the permeability goes up so d; /archives//html/Amps/2012-12/msg00164.html (9,310 bytes)
16. Re: [Amps] hf-2500 (score: 1): Author: "Gary Schafer" <garyschafer@comcast.net>; Date: Sun, 23 Dec 2012 13:22:21 -0500; Hi Larry, My problem was that of low efficiency and getting rid of the shorted turns made quiet a difference. If I remember right the power out went up around 300 watts on 20 meters. We had a discuss; /archives//html/Amps/2012-12/msg00165.html (10,206 bytes)
17. Re: [Amps] hf-2500 (score: 1): Author: "Carl" <km1h@jeremy.mv.com>; Date: Mon, 24 Dec 2012 21:17:56 -0500; There is a big difference between a multiband toroid up thru 10M and another for just 80/160 as we have been discussing. From a packaging constraint a properly sized toroid is an acceptable compromis; /archives//html/Amps/2012-12/msg00171.html (11,206 bytes)
18. Re: [Amps] hf-2500 (score: 1): Author: "K1TTT" <K1TTT@ARRL.NET>; Date: Tue, 25 Dec 2012 12:45:56 +0000; In the HF-2500 the ONLY failures I have had were on 40m and 80m contest RTTY. On these amps half or three quarters of the turns are shorted on the toroid on 80m and 40m respectively. To make it worse; /archives//html/Amps/2012-12/msg00176.html (15,536 bytes)
19. Re: [Amps] hf-2500 (score: 1): Author: "Carl" <km1h@jeremy.mv.com>; Date: Wed, 26 Dec 2012 16:35:01 -0500; Thanks for that info Dave, I'll keep it in mind for when a fried critter arrives. Carl KM1H In the HF-2500 the ONLY failures I have had were on 40m and 80m contest RTTY. On these amps half or three q; /archives//html/Amps/2012-12/msg00186.html (16,641 bytes)
20. Re: [Amps] hf-2500 (score: 1): Author: Bill Turner <dezrat1242@yahoo.com>; Date: Thu, 27 Dec 2012 20:07:35 -0800; REPLY: W8JI is correct. Another way of explaining it is that on a toroid, every turn is tightly coupled to every other turn. On an air core coil, especially a long one, the tightest coupling is betwe; /archives//html/Amps/2012-12/msg00190.html (8,730 bytes)

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