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301. [Amps] worthwhile patents on RF amplifiers? (score: 1)
Author: jtml@losalamos.com
Date: Fri, 12 Feb 2016 17:13:04 -0700
I was looking through some recent solid state RF amplifier patents, and 2 stood out for comment here. You may be able to view these or at least the cover sheet and abstracts with online free patent v
/archives//html/Amps/2016-02/msg00043.html (9,012 bytes)

302. [Amps] Ceramic tube temp too low? (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Mon, 14 Mar 2016 22:08:28 -0600
Didn't see your call sign but assuming you are building this for licensed amateur service, here is one opinion. You cannot damage a ceramic metal tube with too cold liquid, within reason. Two things
/archives//html/Amps/2016-03/msg00032.html (8,143 bytes)

303. [Amps] new high power transistor announced (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Tue, 26 Apr 2016 22:07:33 -0600
NXP (Philips) combined Rf power products with Freescale Semiconductor (Motorola) a while back. Thankfully, product development has continued and NXP Semiconductors just announced a new LDMOS transist
/archives//html/Amps/2016-04/msg00049.html (8,038 bytes)

304. [Amps] Thinking out loud 3-500Z and the like gettering with > RF? (score: 1)
Author: jtml@losalamos.com
Date: Mon, 13 Jun 2016 14:21:26 -0600
This is a kind of crude way to heat the anode of an expensive triode. The receiving tube companies did use RF induction heating, but the high power transmitting/industrial tubes are bombarded using t
/archives//html/Amps/2016-06/msg00043.html (8,213 bytes)

305. [Amps] Thinking out loud 3-500Z and the like gettering (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 19 Jun 2016 17:47:19 -0600
A common process is using Induction Heating with graphite crucibles, From wikipedia... "Induction heating is often used to heat graphite crucibles (containing other materials) and is used extensively
/archives//html/Amps/2016-06/msg00075.html (9,147 bytes)

306. [Amps] LDMOS HEAT SPREADERS (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Fri, 26 Aug 2016 01:44:52 -0600
I wonder if a high power transistor could mount on a chill block sold for puck type very high power devices. For instance, http://catalog.chtechnology.com/viewitems/extruded-bonded-fin-heat-sinks/liq
/archives//html/Amps/2016-08/msg00070.html (8,877 bytes)

307. [Amps] SB220 QSK bias and RF relay mounting (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 18 Sep 2016 14:37:09 -0600
Its been a long time since I replaced the open frame power relay in mine and installed a vac relay for output and small RF relay for input switching. I removed the OEM relay and mounted it in that ge
/archives//html/Amps/2016-09/msg00101.html (8,822 bytes)

308. [Amps] SB220 QSK bias and RF relay mounting (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 24 Sep 2016 09:50:03 -0600
Warren If it works OK, then go with it as you have it. If the relays don't seem to pull in quickly, might consider getting the relay coils out of the immediate AC magnetic field of the chokes (60 Hz)
/archives//html/Amps/2016-09/msg00111.html (8,958 bytes)

309. [Amps] SB-220 question (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 16 Oct 2016 12:00:50 -0600
It appears that the 1000pF red ceramic capacitor was replaced with the flat maroon capacitor in yours. Someone left the 1000 pF stock capacitor in the chassis but disconnected it. Maybe it was suspec
/archives//html/Amps/2016-10/msg00067.html (10,256 bytes)

310. [Amps] RF voltage on VHF strip line (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Fri, 28 Oct 2016 18:43:53 -0600
strip line for 144 MHz. Some may prefer to think of it has two quarter wave lines with the tube between them. This is a "teflon sandwich" line where the upper brass plate is connected to the tube ano
/archives//html/Amps/2016-10/msg00141.html (10,689 bytes)

311. Re: [Amps] Machlett 3-500Z tubes (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 26 Nov 2016 10:01:52 -0700
Machlett was a long time producer of unique power tubes that was originally related to Raytheon I believe. They made a number of unique tubes such as magnetic focused triodes for megawatt modulators,
/archives//html/Amps/2016-11/msg00124.html (8,848 bytes)

312. [Amps] Amps] SB-220 update & gettering (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 26 Nov 2016 10:19:22 -0700
Good to hear you found the keying circuit issue and fixed that. Would hate for that relay to only partially close while a kW of RF is trying to come through the contacts. You don't need to see cherry
/archives//html/Amps/2016-11/msg00125.html (11,031 bytes)

313. [Amps] SB-220 update and gettering (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 26 Nov 2016 10:58:19 -0700
Rob I emailed you a very authoritative paper from RCA in AIEE in 1935, although very old, the designs have not changed much. The technology hasn't changed much since then. Most modern Tantalum or Mol
/archives//html/Amps/2016-11/msg00128.html (7,676 bytes)

314. Re: [Amps] SB-220 update and gettering (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 26 Nov 2016 16:37:39 -0700
Hello Rob, I believe that you misunderstand that I am only talking about graphite anode tubes. Sheet metal anodes with vertical fins, made with Tantalum, which is what Eimac and some knock-offs used,
/archives//html/Amps/2016-11/msg00135.html (11,147 bytes)

315. [Amps] SB-220 update and gettering (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 26 Nov 2016 19:41:14 -0700
This is a good way to run a lot of dissipation with low voltage swing in the tube. I have seen this done at one of the National Labs for large RF triodes, for same effect. The anode of the tube in th
/archives//html/Amps/2016-11/msg00138.html (8,999 bytes)

316. [Amps] SB-220 update and gettering (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 26 Nov 2016 23:25:14 -0700
It is my understanding that the 3-500Z has a filament heated getter that is always active when the tube is on. Also, if it has a special coated anode with gettering ability, then that is active. If t
/archives//html/Amps/2016-11/msg00142.html (9,338 bytes)

317. Re: [Amps] Amps] SB-220 update & gettering (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sat, 26 Nov 2016 10:53:05 -0700
Rob Attached is a very authoritative paper from RCAm in AIEE in 1935, although very old, the designs have not changed much. The technology hasn't changed much since then. Most modern Tantalum or Moly
/archives//html/Amps/2016-11/msg00150.html (8,794 bytes)

318. [Amps] Harris Diamon UHF (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 18 Dec 2016 11:23:47 -0700
If you have schematic of the module, you might be able to extrapolate and get a starting point for the L and C changes required to pull those down in frequency. You'll need the Harris print that list
/archives//html/Amps/2016-12/msg00417.html (8,552 bytes)

319. [Amps] Harris DX transmitters (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 18 Dec 2016 11:49:48 -0700
The Harris DX design, first released in the DX10 in the late 1980s, used inexpensive plastic switching FETs and was essentially a giant digital to analog converter. The audio is first converted into
/archives//html/Amps/2016-12/msg00419.html (9,676 bytes)

320. [Amps] Decline of homebrewing? (score: 1)
Author: John Lyles <jtml@losalamos.com>
Date: Sun, 8 Jan 2017 19:50:08 -0700
My first home computer was a Rockwell AIM-65 6502-based SBC, that I bought used, and built a separate 22 pin card cage with homemade power supply, wirewrapped 4K SRAM (2114), Real time clock, Serial
/archives//html/Amps/2017-01/msg00194.html (9,691 bytes)

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