Search String: Display: Description: Sort:

Results:

References: [ +from:garyschafer@comcast.net: 654 ]

Total 654 documents matching your query.

381. Re: [Amps] High SWR (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Fri, 24 Apr 2009 13:20:30 -0400
The only thing that high swr on a yagi should tell you is that the feed line does not match the driven element impedance perfectly. 73 Gary K4FMX _______________________________________________ Amps
/archives//html/Amps/2009-04/msg00322.html (12,396 bytes)

382. Re: [Amps] filament transformers (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Sat, 16 May 2009 10:55:23 -0400
It is quite easy to wind some transformers. I did a couple of filament transformers for a 4CX1000 some years ago. I used an old tv transformer where the primary winding was on the bottom, next to the
/archives//html/Amps/2009-05/msg00088.html (8,193 bytes)

383. [Amps] 3 1/8 inch line to N adaptor wanted (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Fri, 12 Jun 2009 17:55:03 -0500
I am looking for an adaptor to go from a 3 1/8 inch flange connector to an N connector or LC or?? I have a large bird dummy load with a 3 1/8 inch flange connector on it and need to go to something s
/archives//html/Amps/2009-06/msg00062.html (6,685 bytes)

384. Re: [Amps] Grounded Grid (Screen) 4CX250B power gain (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Tue, 21 Jul 2009 21:40:46 -0500
Bill Orr specifically says in his notes that the "supper cathode driven mode" is NOT recommended for the 4CX250 family of tubes. 73 Gary K4FMX _______________________________________________ Amps mai
/archives//html/Amps/2009-07/msg00260.html (11,487 bytes)

385. Re: [Amps] Grounded grid 8122's (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Tue, 21 Jul 2009 21:55:21 -0500
Well, no they are not the same. There is a difference in what we all call "grounded grid" and "cathode driven". With a tetrode in grounded grid mode you are driving the grid and the screen. In order
/archives//html/Amps/2009-07/msg00262.html (9,240 bytes)

386. Re: [Amps] Grounded Grid (Screen) 4CX250B power gain (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Tue, 21 Jul 2009 22:01:37 -0500
Definitions: The Collins 30S1 is called a "cathode driven" amplifier not a "grounded grid" amplifier. Even though the grid and screen are at RF ground the DC grid and screen voltages are not at groun
/archives//html/Amps/2009-07/msg00263.html (14,220 bytes)

387. Re: [Amps] Grounded Grid (Screen) 4CX250B power gain (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Tue, 21 Jul 2009 22:04:35 -0500
Not when using a tetrode. 73 Gary K4FMX _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2009-07/msg00264.html (9,438 bytes)

388. Re: [Amps] Grounded Grid (Screen) 4CX250B power gain (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Tue, 21 Jul 2009 22:09:01 -0500
The 4CX250 actually can be run in AB2 as it can stand a couple of watts of grid dissipation. There are AB2 specs for that tube. The 4CX1000 is only rated for AB1 operation. Zero grid current, howeve
/archives//html/Amps/2009-07/msg00265.html (10,461 bytes)

389. Re: [Amps] cathode driven/grounded grid magic revealed. (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Tue, 21 Jul 2009 22:18:31 -0500
It is well known that a grounded grid amplifier places a varying load on its driver stage. It is recommended that the driver stage be heavily swamped to avoid such load variations. A driver stage dri
/archives//html/Amps/2009-07/msg00266.html (10,387 bytes)

390. Re: [Amps] Grounded grid 8122's (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Wed, 22 Jul 2009 22:03:34 -0500
How would you propose to run a tetrode in class AB1 with the grid and screen directly grounded? 73 Gary K4FMX _______________________________________________ Amps mailing list Amps@contesting.com ht
/archives//html/Amps/2009-07/msg00297.html (9,461 bytes)

391. Re: [Amps] Old Transmitter designs (was cathode driven/groundedgrid magic revealed.) (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Wed, 22 Jul 2009 22:04:59 -0500
You disagree with Bill Orr? 73 Gary K4FMX _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2009-07/msg00298.html (9,163 bytes)

392. Re: [Amps] Old Transmitter designs (was cathode driven/groundedgridmagic revealed.) (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Wed, 22 Jul 2009 22:47:17 -0500
You misunderstand Bill. We are not talking about a tuned circuit at the input of the grounded grid amp. We are talking about what effects the varying load has on the driver. If the driving source ha
/archives//html/Amps/2009-07/msg00300.html (9,520 bytes)

393. Re: [Amps] grounding grids (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Wed, 29 Jul 2009 22:51:58 -0500
How much does it vary from band to band? The idea is the higher in frequency you go the lower the impedance is due to the capacitor. At lower frequencies the capacitor has higher impedance but the im
/archives//html/Amps/2009-07/msg00385.html (21,090 bytes)

394. Re: [Amps] grounding grids (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Wed, 29 Jul 2009 22:55:37 -0500
The main problem with the 572B is the long internal grid leads of the tube. 73 Gary K4FMX The SB-200 is even _______________________________________________ Amps mailing list Amps@contesting.com http
/archives//html/Amps/2009-07/msg00386.html (7,959 bytes)

395. Re: [Amps] grounding grids (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Wed, 29 Jul 2009 23:03:51 -0500
Rich Measures claims that the grid bypass capacitors used in the SB 220 are series resonant at or near the parasitic frequency of the tubes and actually provide a lower impedance to ground than a pie
/archives//html/Amps/2009-07/msg00387.html (14,856 bytes)

396. Re: [Amps] grounding grids (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Wed, 29 Jul 2009 23:09:16 -0500
How then would you account for the reduced IM products of a tube operated in GG verses the same tube operated in a standard grid driven configuration? 73 Gary K4FMX _________________________________
/archives//html/Amps/2009-07/msg00388.html (10,296 bytes)

397. Re: [Amps] grounding grids (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Fri, 31 Jul 2009 20:54:29 -0500
Joe, What makes you think that the impedance between the grid and common changes by a factor of 10:1 between 3.5 and 29.7 MHz? 73 Gary K4FMX _______________________________________________ Amps maili
/archives//html/Amps/2009-07/msg00458.html (14,764 bytes)

398. Re: [Amps] Subject: grounding grids (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Sun, 2 Aug 2009 21:00:47 -0500
No red herring here. Joe made the statement that "the impedance between grid and common changes by a factor of 10:1 between 3.5 and 29.7 MHz". I am asking why he thought that, because we are talking
/archives//html/Amps/2009-08/msg00036.html (9,281 bytes)

399. Re: [Amps] Alpha 374A ? (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Sun, 2 Aug 2009 22:17:30 -0500
How about if my antenna has 10db less gain than a dipole? :>) 73 Gary K4FMX _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/l
/archives//html/Amps/2009-08/msg00041.html (8,423 bytes)

400. Re: [Amps] plate bypass capacitor (score: 1)
Author: "Gary Schafer" <garyschafer@comcast.net>
Date: Sat, 8 Aug 2009 22:59:20 -0500
Choke values are not so different at RF than those measured at typical audio frequencies. What happens on 160 meters and even 80 meters with a choke that is "too small" for the frequency involved is
/archives//html/Amps/2009-08/msg00137.html (10,948 bytes)

Current List: 381 - 400
Page: [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20]
This search system is powered by Namazu