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Total 586 documents matching your query.

1. Re: [Amps] Parasitics can kill (score: 1)
Author: "k7fm" <k7fm@teleport.com>
Date: Wed, 30 Sep 2009 07:16:44 -0700
"Hey, thats an excellent application for an otherwise useless item, a hot knife for cutting foam." And, the old Heath electronic switch, which was used to switch inputs to the single channel scopes,
/archives//html/Amps/2009-09/msg00370.html (7,948 bytes)

2. Re: [Amps] FW: 3-500Z heater voltage reduction (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Tue, 15 Sep 2009 13:37:35 -0700 (GMT-07:00)
I like to put a resistor in the primary of a filament transformer, because it is easier to find a standard value. However, that is not possible if the transformer also contains other secondaries. But
/archives//html/Amps/2009-09/msg00209.html (7,328 bytes)

3. Re: [Amps] Query about capacitor value (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Tue, 15 Sep 2009 10:19:15 -0700 (GMT-07:00)
Modulators are used to heat cool, damp basements. The red glow of the plates are also used for therapy. It is called "modulating therapy", which is a wonderful self-therapy for introverts, and the mo
/archives//html/Amps/2009-09/msg00200.html (8,731 bytes)

4. Re: [Amps] parasitic oscillation techniques (score: 1)
Author: "k7fm" <k7fm@teleport.com>
Date: Mon, 24 Aug 2009 20:48:15 -0700
Rich Measures name has come up, as well as purported comments from Eimac about his advice. The date of Rich's first article on parasitics was April 1986, in Ham Radio. Notably, it said nothing about
/archives//html/Amps/2009-08/msg00485.html (11,062 bytes)

5. Re: [Amps] plate bypass capacitor (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Mon, 10 Aug 2009 11:19:57 -0700 (GMT-07:00)
"that would require a choke with a reactance of 22,000 ohms, or about 2000 uH. I have never seen a design with that much inductance for the plate RF choke, or anywhere close to it.." I'll bet you hav
/archives//html/Amps/2009-08/msg00240.html (8,530 bytes)

6. Re: [Amps] Manganin RF choke? (score: 1)
Author: "k7fm" <k7fm@teleport.com>
Date: Sun, 9 Aug 2009 07:46:33 -0700
What I was particularly interested in was the construction of the plate rf choke. It is 100 uh and made of #28 manganin wire. The article has a brief description on the use of this material. "The out
/archives//html/Amps/2009-08/msg00145.html (8,043 bytes)

7. Re: [Amps] grounding grids (score: 1)
Author: "k7fm" <k7fm@teleport.com>
Date: Wed, 29 Jul 2009 19:24:14 -0700
The Heath SB-220 used an rf choke to ground the grid, bypassed by 3 x 200 pf capacitors. Interestingly, the Drake L4 amplifier used an rf choke to ground the grid, bypassed by 3 x 200 pf capacitors.
/archives//html/Amps/2009-07/msg00381.html (9,093 bytes)

8. Re: [Amps] HT-33A (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Fri, 24 Jul 2009 20:08:47 -0700 (GMT-07:00)
I think the comment was directed at condition. A higher price for those that look pretty. Same thing with cars. A driver is much less than a looker. Also, as I recall, the HT-33 uses a nice oil fille
/archives//html/Amps/2009-07/msg00332.html (7,454 bytes)

9. Re: [Amps] Grounded Grid (Screen) 4CX250B power gain (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Tue, 21 Jul 2009 13:37:00 -0400 (EDT)
"Tokyo High Power marketed a cathode driven 2 X 4X150/4CX250 amp that had IMD on par with grid driven. The price was high for the power and didnt sell well in the US. The few I worked on were well bu
/archives//html/Amps/2009-07/msg00239.html (8,875 bytes)

10. Re: [Amps] Grounded Grid(Screen) 4CX250B power gain (score: 1)
Author: "k7fm" <k7fm@teleport.com>
Date: Tue, 21 Jul 2009 06:15:46 -0700
"I have never understood why people did this. If you want a triode, get a triode. I guess if you have a tetrode lying around taking up space but you really want a triode it makes sense, sort of, but
/archives//html/Amps/2009-07/msg00235.html (11,220 bytes)

11. Re: [Amps] Grounded Grid(Screen) 4CX250B power gain (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Mon, 20 Jul 2009 13:03:07 -0700 (GMT-07:00)
"Anyone have a comment about the theory behind connecting the grid through a resistor to the cathode in a "grounded grid" amp" We know that in a 4CX250 that the control grid will fail if much power i
/archives//html/Amps/2009-07/msg00227.html (10,783 bytes)

12. Re: [Amps] TEKTRONIX 454A FS (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Sat, 27 Jun 2009 15:13:25 -0700 (GMT-07:00)
And, unlike the 5 year old scopes, you can repair them - with parts you can still find. The 454A is my favorite scope. 73, Colin K7FM _______________________________________________ Amps mailing list
/archives//html/Amps/2009-06/msg00129.html (6,848 bytes)

13. Re: [Amps] HV switch-mode power supply (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Sat, 23 May 2009 22:11:43 -0700 (GMT-07:00)
The solar generation system for homeowners still is not very efficient when it comes to installation. In my case, I installed a new roof, then covered much of it with solar panels. That is a waste of
/archives//html/Amps/2009-05/msg00180.html (8,841 bytes)

14. Re: [Amps] HV switch-mode power supply (score: 1)
Author: "k7fm" <k7fm@teleport.com>
Date: Sat, 23 May 2009 08:55:21 -0700
I just figured my power is costing me 2 cents per kwh. I installed a 2.5 kw solar panel. Cost $20,000. Credits and rebates dropped it down to $14,000. The home is in a sun belt and I figure over 25 y
/archives//html/Amps/2009-05/msg00167.html (9,346 bytes)

15. Re: [Amps] SB 220 with 3 400 tubes (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Mon, 27 Apr 2009 12:53:51 -0700 (GMT-07:00)
It has been noted that the 3-400 has a lower plate dissipation than the 3-500. However, it is not quite that simple. The dissipation is controlled by the air blowing by, and both the power supply and
/archives//html/Amps/2009-04/msg00388.html (7,949 bytes)

16. Re: [Amps] Dentron mla-2500 meters (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Mon, 16 Mar 2009 15:15:24 -0700 (GMT-07:00)
Whew! I looked at the subject and thought this was an amp mod to go on 2500 meters. I was real curious and started to calculate where 2500 meters ended up. I was also real curious what kind of antenn
/archives//html/Amps/2009-03/msg00450.html (7,459 bytes)

17. Re: [Amps] Step-start; improved circuit. (score: 1)
Author: "k7fm" <k7fm@teleport.com>
Date: Sat, 7 Mar 2009 07:02:54 -0800
As a member of the KIRSS fan club (Keep it really simple stupid), I have never had a problem with the contacts on a simple step-start circuit. All you need is a cycle or two delay and if the delay is
/archives//html/Amps/2009-03/msg00230.html (8,160 bytes)

18. Re: [Amps] Minimum Value of RF Plate Chokes (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Fri, 27 Feb 2009 07:43:45 -0800 (GMT-08:00)
"...don't do that! You'll never know what combination will hit resonance in what band without a network analyzer, especially in a multiband amplifier until it's too late!" The fact that a network ana
/archives//html/Amps/2009-02/msg00696.html (8,652 bytes)

19. Re: [Amps] Minimum Value of RF Plate Chokes (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Thu, 26 Feb 2009 12:47:22 -0800 (GMT-08:00)
"I think that a switchable choke arrangement is a FAR better option to consider, rather than building a separate, dedicated low-band amplifier...although if I could ever get my paws on a good 833A, o
/archives//html/Amps/2009-02/msg00689.html (8,427 bytes)

20. Re: [Amps] equipment faceplates-stencil etc (score: 1)
Author: Colin Lamb <k7fm@teleport.com>
Date: Thu, 19 Feb 2009 10:01:34 -0800 (GMT-08:00)
Use Dymo labels. It will assure that no one will steal it. You do not even need to lock the door on your hamshack. 73, Colin K7FM _______________________________________________ Amps mailing list Amp
/archives//html/Amps/2009-02/msg00570.html (7,382 bytes)

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