- 101. Re: [Amps] Design VS parasitic (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Tue, 25 Aug 2009 10:38:42 +0300
- At Tadiran we tried once to add a diplexer with a 50 MHz crossover frequency and with a load connected to the high pass section. We got all kinds of interesting results, except the wanted one! Drop i
- /archives//html/Amps/2009-08/msg00487.html (10,784 bytes)
- 102. Re: [Amps] Design VS parasitic (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Tue, 25 Aug 2009 11:56:39 +0300
- There is one.... A thing which doesn't show up here is the transit time parameter: the time it takes from electrons to travel from the cathode grid area to the anode. It's a few nanoseconds for commo
- /archives//html/Amps/2009-08/msg00488.html (11,912 bytes)
- 103. Re: [Amps] parasitic oscillation techniques (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Tue, 25 Aug 2009 14:04:46 +0300
- ...probably whatever happened with the other companies who wanted young blood in their veins: moved under the heading that the Brits so succinctly call: the bloody companies. Instead of putting a "ta
- /archives//html/Amps/2009-08/msg00490.html (12,439 bytes)
- 104. Re: [Amps] RF parts and parasitics!! (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Thu, 27 Aug 2009 13:32:00 +0300
- Well, well, what do you know? Maybe we stirred up some guys who can provide more insight on the matter! Alex 4Z5KS I was just checking prices on new 3-500ZG tubes at the RF parts web site. Interestin
- /archives//html/Amps/2009-08/msg00538.html (9,545 bytes)
- 105. Re: [Amps] Tube gain vs frequency (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Thu, 27 Aug 2009 15:42:33 +0300
- The first question requires the longest answer: The foremost frequency wise limiting factor is the transit time: the time it takes for the electrons to travel from the cathode to the anode ( a few na
- /archives//html/Amps/2009-08/msg00539.html (10,185 bytes)
- 106. Re: [Amps] RF parts and parasitics!! (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Thu, 27 Aug 2009 15:42:33 +0300
- It does make a big difference! By convention' all impedances are measured from the electrode to ground The grid impedance is actually very high and mostly capacitive, as long as you don't draw grid c
- /archives//html/Amps/2009-08/msg00540.html (10,444 bytes)
- 107. Re: [Amps] RF parts and parasitics!! (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Thu, 27 Aug 2009 15:42:33 +0300
- Gentlemen: Please keep in mind that, by definition, a choke has a reactance at least 10 times of the other relevant impedances in a circuit. If it comes close to them in magnitude it is no longer a c
- /archives//html/Amps/2009-08/msg00541.html (15,031 bytes)
- 108. Re: [Amps] Loaded output circuits (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Tue, 1 Sep 2009 09:15:44 +0300
- What are you guys talking about? Most of us use the amplifiers on SSB: that has a peak to average of about 1 to 5. not only that, the peaks are reached about 5% of the time so for the most time we ar
- /archives//html/Amps/2009-08/msg00667.html (9,227 bytes)
- 109. Re: [Amps] Carbon Resistor Substitution (score: 1)
- Author: "alexeban" <alexeban@gmail.com>
- Date: Thu, 3 Sep 2009 17:51:05 +0300
- You have to be careful! The film resistors are formed by cutting a spiral groove in the metal film to lengthen the path and obtain higher resistance. It looks something akin to a wire wound resistor
- /archives//html/Amps/2009-09/msg00021.html (8,147 bytes)
- 110. Re: [Amps] LK-500 Metering (score: 1)
- Author: "alexeban" <alexeban@gmail.com>
- Date: Thu, 3 Sep 2009 17:51:05 +0300
- ...perhaps it might be worth considering the addition of a pair of diodes connected in antiparallel across meter. We used to do this in the past and it was cheap insurance for the meter! If the volta
- /archives//html/Amps/2009-09/msg00022.html (9,034 bytes)
- 111. Re: [Amps] Carbon Resistor Substitution (score: 1)
- Author: "alexeban" <alexeban@gmail.com>
- Date: Fri, 4 Sep 2009 07:34:39 +0300
- I would like to add one more: Florida RF laboratories. They make power resistors for high frequency uses, including two terminal types. They're really intended for use on a heatsink, but at reduced p
- /archives//html/Amps/2009-09/msg00035.html (9,663 bytes)
- 112. Re: [Amps] 4-1000A neutralization (score: 1)
- Author: "alexeban" <alexeban@gmail.com>
- Date: Sat, 5 Sep 2009 15:09:15 +0300
- The suppressor seems too small to me! I would expect to see about 2 to 4 turns of that copper strap, about 1 inch in diameter. As for the oscillation frequency, an educated guess would be 80-90 MHz,
- /archives//html/Amps/2009-09/msg00045.html (12,596 bytes)
- 113. Re: [Amps] The H&K 304H (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Sun, 6 Sep 2009 09:30:18 +0300
- A question: does the H&K incorporate an input tank circuit. If not adding one will improve the gain. Grounded grid tubes are known to have comparatively low gain, so that every improvement in matchin
- /archives//html/Amps/2009-09/msg00055.html (8,907 bytes)
- 114. Re: [Amps] FW: 3-500z Silly question (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Sun, 6 Sep 2009 10:03:38 +0300
- DC operation of a directly heated tube is problematic, to say the least. The DC component of the heater voltage combines with the bias voltage to produce a varying voltage along the filament, causing
- /archives//html/Amps/2009-09/msg00056.html (11,243 bytes)
- 115. Re: [Amps] Pair of SB-220s (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Sun, 6 Sep 2009 10:21:03 +0300
- Can be done! The best way is to use 3dB/90° hybrids since they tend to discourage oscillation and improve matching. They are also quite forgiving of imbalances in the amplifiers? input and output imp
- /archives//html/Amps/2009-09/msg00057.html (7,758 bytes)
- 116. Re: [Amps] 3CX800 and blower (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Tue, 8 Sep 2009 10:01:23 +0300
- I can concure with that. If Eimac says it's not recommended it means NO Alex 3Z5KS a According to the data sheet for this tube and from talking to the folks at CPI (Eimac) directly, forced air coolin
- /archives//html/Amps/2009-09/msg00084.html (9,587 bytes)
- 117. Re: [Amps] TL922 Power Plugs (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Wed, 4 Nov 2009 09:44:30 +0200
- To be precise, the danger is in NOT connecting the earth and the neutral together. The connection is crucial to the operation of the ground fault interrupter if fitted. Voltage drop differentials on
- /archives//html/Amps/2009-11/msg00037.html (9,845 bytes)
- 118. Re: [Amps] TL922 Power Plugs (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Wed, 4 Nov 2009 09:53:15 +0200
- The danger lies in the fact that the ground fault interrupter gets bypassed if you strap the ground and neutral wires at the appliance. The fault (leakage) current has to have a separate path to grou
- /archives//html/Amps/2009-11/msg00039.html (10,390 bytes)
- 119. Re: [Amps] TL922 Power Plugs (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Wed, 4 Nov 2009 09:55:45 +0200
- This is not detrimental if, that is, you have a ground fault interrupter AFTER the point where the wires are strapped together. Otherwise it won't activate and save your skin! Alex 4Z5KS If they are
- /archives//html/Amps/2009-11/msg00040.html (11,018 bytes)
- 120. Re: [Amps] TL922 Power Plugs (score: 1)
- Author: "Alex Eban" <alexeban@gmail.com>
- Date: Wed, 4 Nov 2009 11:34:52 +0200
- Oh, boy! If you had over 100V dropping on the wires, you used headphones wire! Just out of curiosity: the pole pig provides twice 120VAC on 2 separate pairs of wires that connect in series, or some 3
- /archives//html/Amps/2009-11/msg00042.html (14,556 bytes)
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