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Total 109 documents matching your query.

81. [Amps] Speaking of Palomar (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Wed Mar 12 18:14:37 2003; Motorola bank them might If the amp does not have a filter, you can be sure it has no bias and probably is not correctly impedance matched. A filter would make it a CW amp (but add clicks if it was; /archives//html/Amps/2003-03/msg00487.html (8,976 bytes)
82. [Amps] Relay derating with frequency? (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Wed Mar 12 18:27:39 2003; Bill, You really need to measure a relay for current AND cut one open. There amount of RF current and voltage varies a great deal from manufacturer to manufacturer, some are great and will actually; /archives//html/Amps/2003-03/msg00489.html (6,895 bytes)
83. [Amps] CB Amps (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Thu Mar 13 05:55:46 2003; the FCC ID number on all auctions........" CB amp, ebay mess that would have to deal with homebrew amps, old amps, non hams selling amps for an estate sale etc The biggest problem is Hams buy the jun; /archives//html/Amps/2003-03/msg00497.html (9,609 bytes)
84. [Amps] CB Amps (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Thu Mar 13 07:46:34 2003; One local ham picked up an 10-12 sweep tube amp from a Hamfest, four tubes driving eight or something similar. It had 80-10 meters on it. He actually uses the thing with a Kenwood transceiver on 20; /archives//html/Amps/2003-03/msg00500.html (9,286 bytes)
85. [Amps] Speaking of Palomar (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Thu Mar 13 13:49:53 2003; There is no such thing as a class AB1 bipolar amplifier. Bipolar transistors linear amplifiers, by electrical requirements, draw base current over at least half the input cycle. Sub 1 indicates no d; /archives//html/Amps/2003-03/msg00533.html (8,382 bytes)
86. [Amps] LK500ZB advice (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Thu Mar 13 14:06:30 2003; larger. of I'd be REALLY careful with an external power transformer!!! You not only have the leads to worry about, you have the power transformer case. Be absolutely positive the transformer case is; /archives//html/Amps/2003-03/msg00535.html (7,754 bytes)
87. [Amps] pi-net tanks (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Sat Mar 15 09:11:20 2003; Circulating currents are a function of loaded or operating Q as well as VAR power (or current or voltage if you like and impedances). Even relatively small tubes can overheat big wires when operatin; /archives//html/Amps/2003-03/msg00576.html (8,219 bytes)
88. [Amps] pi-net tanks (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Sat Mar 15 11:43:34 2003; VAR Operating Q varies with loading and tuning setting, and Q also varies with power level becuase the load on the device end of the tank changes. We may design Q to be a certain value in a certain; /archives//html/Amps/2003-03/msg00584.html (7,693 bytes)
89. [Amps] Accuracy of Ameritron forward power meter? (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Sun Mar 16 11:30:35 2003; between Directional couplers always require care to make flat, but the problem is almost never a "shield" between the current transformer secondary and primary. The largest problems are almost alway; /archives//html/Amps/2003-03/msg00600.html (7,638 bytes)
90. [Amps] Need a Capacitor- help (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Mon Mar 17 03:49:44 2003; which worked, but was about 10pf to high. Unfortunately, after soldering and unsoldering it a couple times I killed it. Mirage or other amplifier manufacturers have small multilayer caps that have v; /archives//html/Amps/2003-03/msg00617.html (7,991 bytes)
91. [Amps] Some Advice Needed (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Mon Mar 17 11:19:22 2003; someone that would machine this from Teflon. He did find a willing person but in order to get the Teflon in the correct size it would require a 1500 dollar min purchase from the Teflon supplier. This; /archives//html/Amps/2003-03/msg00633.html (6,841 bytes)
92. [Amps] Need a Capacitor- help (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Mon Mar 17 11:49:21 2003; Let's not forget how small chip caps are and how low the typical voltage ratings are. Standard chips are also physically very small and can't handle any heat or mechanical stress, they also have les; /archives//html/Amps/2003-03/msg00636.html (7,031 bytes)
93. [Amps] PSA2500 Power Supply (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Mon Mar 17 11:52:23 2003; standpoint, must, benefit: is and I'm missing something here Eric. What does the fact it is an open loop have to do with EMI??? 73 Tom; /archives//html/Amps/2003-03/msg00637.html (7,088 bytes)
94. [Amps] Silly idea? (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Mon Mar 17 20:01:52 2003; thermal Hi Kim, In all my conversations with engineers at Eimac, they always assured me any reduction in filament voltage below the specified range would "be lost in the noise" of other failures. My; /archives//html/Amps/2003-03/msg00652.html (9,259 bytes)
95. [Amps] 813 No parasitics (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Tue Mar 18 06:08:17 2003; As a general rule the most difficult to stabilize tubes are tubes with low upper frequency limits. The grid and anode leads inside such tubes are usually thin and long. 73 Tom; /archives//html/Amps/2003-03/msg00661.html (7,760 bytes)
96. [Amps] Silly idea? (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Tue Mar 18 06:16:29 2003; Inrush related failures are pretty rare Pete, especially if you do not oversize components in the filament. Buzz WA4GPM, a former senior engineer at Salt Lake, told me they strapped 3-500Z's filamen; /archives//html/Amps/2003-03/msg00662.html (8,504 bytes)
97. [Amps] 813 No parasitics (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Tue Mar 18 20:21:15 2003; They sure would. It is pretty simple to see that lower frequency energy from an arc or flashover caused by outgassing in the tube would make it through all the low-pass filters right up to the PA. V; /archives//html/Amps/2003-03/msg00689.html (7,952 bytes)
98. [Amps] 813 No parasitics (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Tue Mar 18 20:36:18 2003; You can still find them in old US military surplus gear, and in some old boat-anchor gear.; /archives//html/Amps/2003-03/msg00690.html (7,911 bytes)
99. [Amps] Re: Filament Current Limiting (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Tue Mar 18 20:40:23 2003; but The filament choke cancels all differential mode inductance, because of the bifilar winding. The inductance it does have is too low anyway to mean anything. Most of the current limiting is cause; /archives//html/Amps/2003-03/msg00691.html (7,109 bytes)
100. [Amps] Silly idea? (score: 131): Author: w8ji at contesting.com (Tom Rauch); Date: Tue Mar 18 20:56:17 2003; to Those amplifiers contain buck-boost windings on the primary and had carefully selected secondary winding placement and design plus a step-start circuit. You can measure the filament voltage right; /archives//html/Amps/2003-03/msg00692.html (8,880 bytes)

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