Search String: Display: Description: Sort:

Results:

References: [ +from:manfred@ludens.cl: 419 ]

Total 419 documents matching your query.

261. Re: [Amps] Alpha 76 question (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Tue, 24 Nov 2015 00:41:41 +0000
Ted, I don't know anything specific about that Alpha, but I have seen this kind of arcing at regular intervals when there is a simple power supply that has no bleeder and no load on it. There are ver
/archives//html/Amps/2015-11/msg00148.html (7,365 bytes)

262. Re: [Amps] More on "baby ur radio" (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Mon, 21 Dec 2015 20:36:43 +0000
Bill, and all, So, absent migration, do transistors "wear out"? That's a rather philosophical question. One might argue that over the years there will be corrosion, radiation damage, who knows what e
/archives//html/Amps/2015-12/msg00044.html (10,969 bytes)

263. Re: [Amps] Amplifier description? (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Tue, 19 Jan 2016 13:41:38 +0000
Hi Petter, Could someone with English as their first language please describe what this amplifier really does? I have some trouble getting all the technical details right. http://www.ebay.com/itm/25W
/archives//html/Amps/2016-01/msg00044.html (8,567 bytes)

264. Re: [Amps] transformer distortion question (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Mon, 14 Mar 2016 19:09:16 +0000
Hi Drax, Probably you will want to use fewer turns in the secondary, since the next stage will likely have a lower input impedance. You are driving your IRF510 into saturation. Note that saturation o
/archives//html/Amps/2016-03/msg00031.html (9,267 bytes)

265. Re: [Amps] SCR to adjust 240v to 200v (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Wed, 17 Aug 2016 00:36:44 +0000
Jim, So, I was just asking if anyone on Amps had tried using an SCR to control a large choke-input power supply ? I haven't done it myself, but I have worked with equipment from the 1970s that worked
/archives//html/Amps/2016-08/msg00039.html (10,861 bytes)

266. Re: [Amps] Ldmos heat spreaders (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 19 Aug 2016 15:51:38 +0000
Ian, Steve, and all, I've only found up to 6mm think would this be okay ? It's less than optimal, but better than having no spreader. Here is a useful online calculator for heat spreaders: http://www
/archives//html/Amps/2016-08/msg00042.html (13,133 bytes)

267. Re: [Amps] SCR to adjust 240v to 200v (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 20 Aug 2016 22:35:31 +0000
Paul, and all, The gates of SCR's need to be pulse fired for reliable phase control. Commercial units have pulse train burst applied to the gates through a pulse transformer. The phase angle of the b
/archives//html/Amps/2016-08/msg00050.html (10,305 bytes)

268. Re: [Amps] LDMOS HEAT SPREADERS (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sun, 28 Aug 2016 18:02:34 +0000
John, 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-sin
/archives//html/Amps/2016-08/msg00074.html (12,259 bytes)

269. Re: [Amps] LDMOS HEAT SPREADERS (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Wed, 31 Aug 2016 14:49:56 +0000
Alex, I don't know about that, but you have liquid cooled heatsinks for high power processors capable of taking care of a few hundreds of watts. In the PC overclocking scene, a lot of snake oil is be
/archives//html/Amps/2016-08/msg00079.html (13,466 bytes)

270. Re: [Amps] Buzzing transformer (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 30 Sep 2016 18:59:36 +0000
Hi, some general rules about buzzing transformers: - Tighten it up. Torque all the bolts, and don't forget to tighten up the center leg too. That's best done by driving insulating wedges of suitable
/archives//html/Amps/2016-10/msg00009.html (11,507 bytes)

271. Re: [Amps] one question test for hams (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 14 Oct 2016 14:26:36 +0000
Charly, Answer True or false....... "All failures of ham radios are caused, ultimately, by excessive heat." False, of course. There are lots of failures caused by corrosion, impact, vibration, chemic
/archives//html/Amps/2016-10/msg00049.html (8,073 bytes)

272. Re: [Amps] Ampleon BLF189XR 1900W LDMOS transistor (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Thu, 20 Oct 2016 14:55:03 +0000
Kevin, Jim, and all, W6PQL tested the NXP BLF188XR, the device he uses in his 1KW amps, and came up with 1100W before hitting 1dB compression and it's a 1400W "peak" device. Is there a web page or so
/archives//html/Amps/2016-10/msg00100.html (21,044 bytes)

273. Re: [Amps] Ampleon BLF189XR 1900W LDMOS transistor (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 29 Oct 2016 17:13:19 +0000
Kevin, Jim, and all, Yes, I had a look at his site. His BLF188XR HF amplifier has a 1:9 imepdance ratio at the output, and a 50V supply, so it can only produce about 750-800W without touching saturat
/archives//html/Amps/2016-10/msg00146.html (21,166 bytes)

274. Re: [Amps] LDMOS and VSWR (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Mon, 31 Oct 2016 20:33:26 +0000
Jim, The videos on YouTube were all running CW at various frequencies. No pulse modes. Unfortunately you are mistaken there. Jeff is right. They were pulsing the amplifier in that video. If you look
/archives//html/Amps/2016-11/msg00003.html (8,992 bytes)

275. Re: [Amps] "Conventional" current flow (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 04 Nov 2016 13:50:01 +0000
Hi all, there is one thing that still needs to be said in this thread, regarding the real flow of current. Unless somebody already said it and I missed it, of course... It's that while in most physic
/archives//html/Amps/2016-11/msg00028.html (10,325 bytes)

276. Re: [Amps] 3D Printed ABS Plastic for Chimneys? (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 25 Nov 2016 23:50:17 +0000
Hi Dieter, Maybe you could consider 3D-printing a mold, to make your chimney from plain common silicone caulk squeezed into that mold? I don't know whether silicone caulk adheres to ABS or the other
/archives//html/Amps/2016-11/msg00116.html (8,801 bytes)

277. Re: [Amps] "Conventional" current flow (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Sat, 03 Dec 2016 15:18:14 +0000
I can't like that model of the electrons moving slowly but the charges moving fast. When it comes to simplistic models, I much prefer the one I saw in the instruction manual of a didactic toy, when I
/archives//html/Amps/2016-12/msg00029.html (11,348 bytes)

278. Re: [Amps] SS amps and auto-tune. Is it even necessary? (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Fri, 09 Dec 2016 16:25:32 +0000
Roger, Tom, and all, I can't help giving my 5 cents (or whatever) on this... With first generation SS amps, auto tune was almost a necessity, BUT with the new amps? It totally depends. If you only op
/archives//html/Amps/2016-12/msg00219.html (31,063 bytes)

279. Re: [Amps] MOSFET amp filtering - was: auto-tune (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Mon, 12 Dec 2016 15:44:15 +0000
Several good points were brought up. Some comments: Indeed a diplexer filter looks very much like a dummy load to the amplifier, aiding stability, while a normal lowpass filter looks highly reactive
/archives//html/Amps/2016-12/msg00301.html (23,908 bytes)

280. Re: [Amps] MOSFET amp filtering - was: auto-tune (score: 1)
Author: Manfred Mornhinweg <manfred@ludens.cl>
Date: Mon, 12 Dec 2016 16:49:31 +0000
Steve, If the topic is filtering and maintaining a good match - then why can we not transform up to the input impedance of an inexpensive multiband matching system? The problem is imperfect transform
/archives//html/Amps/2016-12/msg00305.html (11,542 bytes)

Current List: 261 - 280
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