Search String: Display: Description: Sort:

Results:

References: [ +from:4cx250b@miamioh.edu: 282 ]

Total 282 documents matching your query.

1. Re: [Amps] Question about separate power supply/RF section (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Sat, 19 Jan 2013 11:23:40 -0700
Vic, I'm a little puzzled by your proposed schematic. You didn't mention what tube you'll be using in your new amplifier, but I'm guessing you'll be using a grounded grid triode(s) design. The custom
/archives//html/Amps/2013-01/msg00112.html (9,993 bytes)

2. Re: [Amps] Question about separate power supply/RF section (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Sat, 19 Jan 2013 14:00:17 -0700
Hi Vic, Ahh, now I see what you're doing, though I still don't quite see how you're providing operating and cutoff bias to the control grid of the 4cx1000a. I'm guessing the "swamping resistor") is t
/archives//html/Amps/2013-01/msg00115.html (12,541 bytes)

3. Re: [Amps] Question about separate power supply/RF section (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Sat, 19 Jan 2013 14:47:03 -0700
No, the B- is only grounded at the RF deck, at the same spot that the cathodes are grounded. To steer the cathode current properly, it is important that the B- lead NOT be grounded at the power suppl
/archives//html/Amps/2013-01/msg00117.html (14,591 bytes)

4. Re: [Amps] 8877 won't load on 80M (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Sun, 27 Jan 2013 18:02:24 -0700
Sounds to me like there are two possibilities, One, your input network is miswired or not switching into the 80m position properly, and second is the same for your tank circuit. There isn't much else
/archives//html/Amps/2013-01/msg00163.html (7,976 bytes)

5. [Amps] Pi-L Switching Question (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Thu, 31 Jan 2013 12:24:19 -0700
I'm building a 160m/80m duoband amplifier with a Pi_L network and would appreciate comments on a issue pertaining to switching the L2 inductor (a toroid). On 160m I'll be using the full inductance (7
/archives//html/Amps/2013-02/msg00001.html (7,933 bytes)

6. Re: [Amps] SHV connectors... (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Wed, 13 Feb 2013 12:17:40 -0700
Felipe, I think those connectors (reverse-polarity SHV-BNC) are intended for RG6, which I believe may be a larger diameter than RG142 (but more flexible). I think RG6 Quad Shield is very high quality
/archives//html/Amps/2013-02/msg00103.html (9,551 bytes)

7. [Amps] Hammond Manufacturing to take over P.W. Dahl Transformer Line (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Thu, 14 Feb 2013 16:27:51 -0700
Jeff W8CQ called me and asked me to convey the following message to the reflector. I'm sure you'll agree that this is very good news! Jim W8ZR "As with the sadness that I announced that Harbach Elect
/archives//html/Amps/2013-02/msg00117.html (7,997 bytes)

8. Re: [Amps] Transformer choice (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Mon, 4 Mar 2013 05:55:20 -0700
Hi Ulf, To me the choice depends on how much you trust Company B. If Company B can be trusted to meet their quoted specifications (2000VA with 2.5% voltage drop at full load), then I'd go with them.
/archives//html/Amps/2013-03/msg00042.html (10,005 bytes)

9. Re: [Amps] Coupling a blower to an air system socket (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Sat, 16 Mar 2013 07:42:46 -0600
Very interesting concept, Ian. I'm wondering how the 25-30% downward flow past the filament pins is adjusted? Presumably one needs to size an outside vent on the underchassis to exhaust that air. Als
/archives//html/Amps/2013-03/msg00221.html (10,393 bytes)

10. [Amps] Blower Question (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Thu, 21 Mar 2013 20:23:44 -0600
Hi All, I've been rummaging through my box of fans and blowers, looking for a compact blower to power three GU74-B tetrodes. I've got a cute little EBM blower, marked G2E085-AA05-10, which I believe
/archives//html/Amps/2013-03/msg00285.html (7,258 bytes)

11. Re: [Amps] Blower Question (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Sat, 23 Mar 2013 08:21:56 -0600
Hi Bryan, Tnx for your helpful comments. The various data sheets for the GU74B/4CX800A are not entirely consistent, but the numbers are in the ballpark to those you mentioned. With a three-tube ampli
/archives//html/Amps/2013-03/msg00300.html (10,770 bytes)

12. [Amps] Alpha 8410 Circuit Errors (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Mon, 25 Mar 2013 12:24:14 -0600
I think there may be a couple of errors in the on-line schematics of the Alpha 8410, and I wonder if somebody with an 8410 could check the schematics in their manual for me to see if the diagrams are
/archives//html/Amps/2013-03/msg00328.html (8,030 bytes)

13. Re: [Amps] 425 amp (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Wed, 3 Apr 2013 20:07:47 -0600
Sounds like there's no HV on the tubes. If the HV meter reads okay, then it might be an open plate choke. Jim W8ZR Sent from my iPhone _______________________________________________ Amps mailing lis
/archives//html/Amps/2013-04/msg00014.html (7,611 bytes)

14. Re: [Amps] vacuum relay (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Sun, 7 Apr 2013 12:04:21 -0600
I think the Gigavac K60C has been replaced by the more modern G60C. If it has the same specs (roughly) as the G60C, it is not suitable for QSK. The G60C relay is designed for switching DC or 60HZ loa
/archives//html/Amps/2013-04/msg00027.html (7,529 bytes)

15. Re: [Amps] Look at this Custom 10kW Amp (score: 1)
Author: MU 4CX250B <4cx250b@miamioh.edu>
Date: Thu, 11 Apr 2013 11:36:49 -0600
I respectfully suggest we stop this thread and return to the technical discussion of RF amplifiers. Jim W8ZR Sent from my iPhone _______________________________________________ Amps mailing list Amps
/archives//html/Amps/2013-04/msg00073.html (9,809 bytes)

16. Re: [Amps] Plate choke explodes (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Sat, 13 Apr 2013 15:28:13 -0600
A couple of thoughts, Drax. First, re the Z-50, as Carl notes, it has a self-resonant frequency of about 70 MHz, with a note on the Ohmite data sheet saying that stray capacitance and external circui
/archives//html/Amps/2013-04/msg00106.html (10,652 bytes)

17. Re: [Amps] Millen HV connectors - cable? (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Tue, 16 Apr 2013 21:04:37 -0600
I strongly recommend against using Millen HV connectors for homebrew construction. Although used in many commercial designs several decades ago, no manufacturer would today consider using Millen HV c
/archives//html/Amps/2013-04/msg00137.html (9,842 bytes)

18. Re: [Amps] Millen HV connectors - cable? (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Tue, 16 Apr 2013 21:51:17 -0600
Yep, that's what I meant! Jim REPLY: Don't you mean makes before and breaks AFTER the center conductor? Bill, W6WRT _______________________________________________ Amps mailing list Amps@contesting.c
/archives//html/Amps/2013-04/msg00141.html (8,459 bytes)

19. Re: [Amps] HV resistor source (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Tue, 16 Apr 2013 22:03:57 -0600
That's going to be quite a resistor, inasmuch as 4KV across a 30 ohm resistor amounts to a half million watts of dissipation! A 4KV pulse 50uS wide, once per second, would dissipate 25W. 73, Jim W8ZR
/archives//html/Amps/2013-04/msg00144.html (7,872 bytes)

20. Re: [Amps] How to test an 8877 tube (score: 1)
Author: "Jim Garland" <4cx250b@miamioh.edu>
Date: Fri, 19 Apr 2013 14:28:15 -0600
There's no way to see if the tube breaks down with HV applied, other than by putting HV on it. If your only source of HV is your amplifier, then you can put a light bulb in series with the anode cap,
/archives//html/Amps/2013-04/msg00181.html (8,617 bytes)


This search system is powered by Namazu