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References: [ +from:alexeban@gmail.com: 257 ]

Total 257 documents matching your query.

241. Re: [Amps] Permeability tuned tuning coils, with taps? (score: 1)
Author: "Saandy" <alexeban@gmail.com>
Date: Wed, 15 Jan 2014 11:23:12 +0200
As far as known, it has never been done before, simply because nobody really needed it: it was more of a solution waiting for a problem. Winding coils on a core was done to reduce size, and concoctin
/archives//html/Amps/2014-01/msg00061.html (7,966 bytes)

242. Re: [Amps] Permeability tuned tuning coils, with taps? (score: 1)
Author: "Saandy" <alexeban@gmail.com>
Date: Thu, 16 Jan 2014 11:50:16 +0200
Somewhere in the seventies, in the ARRL handbook, there appeared a 6 meter amplifier tuned variometer style with a one turn shorted coil, rotating in the stationary tank coil. It wasn't very wideband
/archives//html/Amps/2014-01/msg00071.html (11,141 bytes)

243. Re: [Amps] Permeability tuned tuning coils, with taps? (score: 1)
Author: "Saandy" <alexeban@gmail.com>
Date: Sat, 18 Jan 2014 22:22:36 +0200
Actually it is permeability tuning in reverse: inserting the slug decreases inductance, but the net result is the same- moving the core changes the inductance. The physical mechanism is different: in
/archives//html/Amps/2014-01/msg00142.html (10,908 bytes)

244. Re: [Amps] MOVs (score: 1)
Author: "Saandy" <alexeban@gmail.com>
Date: Fri, 24 Jan 2014 19:49:28 +0200
Guys , think! Nothing gets conducted to a point not connected anywhere! A MOV is intended to a supposedly safe limit a voltage differential between 2 points. Protection between the line and something
/archives//html/Amps/2014-01/msg00243.html (9,299 bytes)

245. Re: [Amps] transistor mounting question (score: 1)
Author: "Saandy" <alexeban@gmail.com>
Date: Sat, 8 Feb 2014 07:06:41 +0200
If at all possible, it's better not to tamper with the transistor's cases. I've seen cases of chips cracking inside from machining stresses. Would be easier and safer to rework the heatsink. This is
/archives//html/Amps/2014-02/msg00056.html (7,951 bytes)

246. Re: [Amps] 3-500Zs inverted (score: 1)
Author: "Saandy" <alexeban@gmail.com>
Date: Fri, 4 Apr 2014 06:13:59 +0300
Guys don't talk stupid: if he asks he doesn't know. He's afraid to make a mistake (expensive!). Don't confuse him more! Let's stick to helping him. We're hams, remember? Alex 4Z5KS Yes. I can confirm
/archives//html/Amps/2014-04/msg00039.html (12,030 bytes)

247. Re: [Amps] strip line design (score: 1)
Author: "Saandy" <alexeban@gmail.com>
Date: Fri, 23 May 2014 10:58:43 +0300
Absolutely!!!! When connecting ANYTHING o a strip line you have 2 possibilities: 1) connect to a point half a wavelength away from the tube and reflect whatever impedance happens to be there to the t
/archives//html/Amps/2014-05/msg00123.html (7,745 bytes)

248. Re: [Amps] Understanding S Parameters (score: 1)
Author: Saandy Eban <alexeban@gmail.com>
Date: Wed, 17 Jun 2015 11:32:30 +0300
Quite so. However, at low frequencies the input impedance of a fet is about 1 to 5 nF in parallel with a quite high resistance. You might say a pure reactance, more or less. On the other hand, termin
/archives//html/Amps/2015-06/msg00041.html (11,159 bytes)

249. Re: [Amps] Re-imagining the 30S-1 (score: 1)
Author: Saandy Eban <alexeban@gmail.com>
Date: Sun, 12 Jul 2015 15:59:37 +0300
It all depends on what your intent is: do you want to restore it or do you want to operate it? If the first, you must rebuild it the way Collins did it, otherwise it won't be a restoration. Ic it's t
/archives//html/Amps/2015-07/msg00035.html (8,487 bytes)

250. Re: [Amps] Ham sells fine grit thing to clean contacts (score: 1)
Author: Saandy <alexeban@gmail.com>
Date: Mon, 17 Aug 2015 08:40:36 +0300
Guys,please bear in mind that silver oxide is a good conductor, so ther's no need to touch it if if isn't burned or pitted. It's going to live much longer if you leave it alone! Alex 4Z5KS Sent from
/archives//html/Amps/2015-08/msg00055.html (9,279 bytes)

251. Re: [Amps] Regulated filament current (score: 1)
Author: Saandy <alexeban@gmail.com>
Date: Sun, 06 Sep 2015 08:21:48 +0300
...definitely! 12.6Vdc is just an indication that the correct amunt of current is flowing there. Don't forget : what woks is P=I^2 and this  defines the temperature. Even the Volt is in essence deriv
/archives//html/Amps/2015-09/msg00018.html (10,798 bytes)

252. Re: [Amps] NTC thermistors as soft start (score: 1)
Author: "Saandy" <alexeban@gmail.com>
Date: Tue, 2 Feb 2016 18:02:47 +0200
The problem with NTC resistors in a HV power supply is not regulation: when they're hot their resistance is low and have no effect. The problem is recovery time. I the power supply is working and you
/archives//html/Amps/2016-02/msg00014.html (11,931 bytes)

253. Re: [Amps] Bird slugs component values ? (score: 1)
Author: "Saandy" <alexeban@gmail.com>
Date: Sat, 12 Mar 2016 21:52:37 +0200
....on the repeater builder's site there is a nice paper on slugs. If you look at the low VHF ones, they look more or less like HF slugs . I'm going to try to open up a 100W HF slug. If I can do I'll
/archives//html/Amps/2016-03/msg00019.html (9,549 bytes)

254. [Amps] : LDMOS HEAT SPREADERS (score: 1)
Author: alexeban <alexeban@gmail.com>
Date: Sun, 28 Aug 2016 16:03:42 +0300
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. It's flat on top so it could take a flat package and still a
/archives//html/Amps/2016-08/msg00072.html (9,420 bytes)

255. [Amps] : LDMOS HEAT SPREADERS (score: 1)
Author: alexeban <alexeban@gmail.com>
Date: Sun, 28 Aug 2016 16:12:22 +0300
Guys,bon.'t try applying cooling lliquid against the flange: it is not dsigned to withstand corrosion of any kind! What you can do is glue the device on the heatsink using silverr loaded epoxy from E
/archives//html/Amps/2016-08/msg00073.html (9,318 bytes)

256. Re: [Amps] 3 Phase XFMR (score: 1)
Author: alexeban <alexeban@gmail.com>
Date: Thu, 03 Nov 2016 09:10:39 +0200
Same thing happened to me, but with an offline converter (28V,  1500W, 3 phase, 110 V per phase ). The darned thing works beautifully in feeding four 300W  rms SSA's.  basically no reason whi it shou
/archives//html/Amps/2016-11/msg00022.html (8,514 bytes)

257. Re: [Amps] SS amps and auto-tune. Is it even necessary? (score: 1)
Author: alexeban <alexeban@gmail.com>
Date: Sun, 11 Dec 2016 13:33:47 +0200
I think the ARF15XX line has 300 V devices.at the kW level involved, the output impedance is disgustingly close to 50 ohms. Actually when designing for high VWSR operation, you have to take into cons
/archives//html/Amps/2016-12/msg00367.html (28,967 bytes)

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