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121. Re: [Amps] Best source for Gigavac GH-1 ? (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sun, 10 Nov 2013 09:37:23 -0700
Jim, Generally vacuum relays designed for hot switching have copper based contacts while the others are tungsten based. My tests with the RF1D were due to the fact that I scavenged it from a piece of
/archives//html/Amps/2013-11/msg00216.html (11,155 bytes)

122. [Amps] All the recent UHF connector discussion (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Wed, 13 Nov 2013 15:45:10 -0700
I had made some UHF connector measurements recently and this discussion encouraged me to publish them. If interested see http://www.w0qe.com/Technical_Topics/uhf_connector_compensation.html 73, Larry
/archives//html/Amps/2013-11/msg00294.html (7,243 bytes)

123. Re: [Amps] All the recent UHF connector discussion (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Wed, 13 Nov 2013 17:48:26 -0700
Dave, I am also not aware of any UHF calibration standards. I used the HP cal kit which is an offset (both open and short) cal kit with the open also having a fringing capacitance. The VNA removes th
/archives//html/Amps/2013-11/msg00300.html (10,459 bytes)

124. Re: [Amps] Discrepencies in Pi-net calculators (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Tue, 19 Nov 2013 22:31:50 -0700
Steve, According to my calculations all 3 networks match 50 ohms to 135 ohms @ 28.03MHz. However Group 1 has a Q of 1.9, Group 2 has Q of 4.7, and Group 3 has Q of 2.7 according to my understanding o
/archives//html/Amps/2013-11/msg00388.html (8,408 bytes)

125. Re: [Amps] Discrepencies in Pi-net calculators (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Wed, 20 Nov 2013 18:53:41 -0700
Steve, Look at the quality of the groups. The group 3 solution shows up on several university web sites including 2 text books I have. Therefore I wouldn't just base my decision on the quantity in ea
/archives//html/Amps/2013-11/msg00400.html (10,375 bytes)

126. Re: [Amps] PARALLEL CAPS IN OUTPUT (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Wed, 04 Dec 2013 12:10:28 -0700
Not true Peter, Unmatched (assuming 50 ohm output Z in 50 ohm circuit) the max possible voltage is (1+p) times the 1:1 SWR voltage. The reflection coefficient p = (SWR-1)/(SWR+1). In a matched circui
/archives//html/Amps/2013-12/msg00030.html (10,881 bytes)

127. Re: [Amps] PARALLEL CAPS IN OUTPUT (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Wed, 04 Dec 2013 13:14:12 -0700
Gerald, You are correct except you are unable to generate a 1,000,000:1 SWR. A line loss of .001dB will produce a return loss of never less than .002dB which is a reflection coefficient of .999769 wh
/archives//html/Amps/2013-12/msg00035.html (12,861 bytes)

128. Re: [Amps] PARALLEL CAPS IN OUTPUT (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Wed, 04 Dec 2013 13:43:19 -0700
Peter, This not a question about who got what right but what is really correct. _Please follow this example:_ 1.) Start with a 1W signal generator with a 50 ohm output will generate 7.07Vrms into a 5
/archives//html/Amps/2013-12/msg00036.html (14,925 bytes)

129. Re: [Amps] PARALLEL CAPS IN OUTPUT (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Wed, 04 Dec 2013 16:30:01 -0700
Peter, I'm not sure where this is going. The original statement was about the output capacitor voltage maximums. Obviously other things in the matching network can arc over first but that is a differ
/archives//html/Amps/2013-12/msg00040.html (19,367 bytes)

130. Re: [Amps] PARALLEL CAPS IN OUTPUT (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Wed, 04 Dec 2013 18:37:43 -0700
Multiple reflections in the data world are very easy to see with a TDR. They do exist and the only thing to keep them from going on forever is the reflection coefficient at both ends and the loss in
/archives//html/Amps/2013-12/msg00044.html (11,855 bytes)

131. Re: [Amps] PARALLEL CAPS IN OUTPUT (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Wed, 04 Dec 2013 20:00:49 -0700
Peter, In your argument the output is not matched to the new open circuit and as such can not produce the voltage I calculated as being the maximum possible. You are correct in this case. However if
/archives//html/Amps/2013-12/msg00046.html (12,657 bytes)

132. Re: [Amps] Solid State Relays Again (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Mon, 10 Feb 2014 22:27:36 -0700
Unfortunately you don't get the choice of when to switch off the SSR usually. Triacs and SCRs only switch off when the current falls below some minimum hold current. There are ways to force a turnoff
/archives//html/Amps/2014-02/msg00091.html (11,265 bytes)

133. Re: [Amps] 8877 input Z (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Fri, 28 Mar 2014 12:48:23 -0600
If the load is 50 ohms (using 50 just for example purposes) in parallel with 42pF a series inductance matches well enough that a given inductance will be good for more than 1 band. However if you add
/archives//html/Amps/2014-03/msg00179.html (9,211 bytes)

134. Re: [Amps] Alpha 9500 goes weird when grounding the Key In line (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sat, 24 May 2014 08:19:50 -0600
Which of the possible 19 faults does the amp show? If you don't remember the fault, press the RCL button followed by the FLT button and the last fault will show in the display. 73, Larry, W0QE After
/archives//html/Amps/2014-05/msg00126.html (7,731 bytes)

135. Re: [Amps] RG6 Power Handling (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Thu, 19 Jun 2014 10:32:25 -0600
RG-142 (50 ohm) Same size as RG-58 and rated at 30MHz 1:1 SWR of 3.1KW average power Larry, W0QE what 50 coax cable would be recommended for the internal wiring of a compact 160-10m legal limit ampli
/archives//html/Amps/2014-06/msg00056.html (8,427 bytes)

136. Re: [Amps] RG6 Power Handling (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Thu, 19 Jun 2014 11:53:09 -0600
Hmmmmm! Re-reading the original post I made an assumption that may or may not be correct. I assumed the coax was to be used at the output side where it would be subject to the full amplifier power. I
/archives//html/Amps/2014-06/msg00058.html (10,734 bytes)

137. Re: [Amps] 50V FET output transformer (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Thu, 24 Jul 2014 08:21:43 -0600
Dan, I have built approximately 50 RF transformers in the past several years. There are 2 types of loss in these circuits: dissipative loss (think heat) and mismatch loss (think uncontrolled leakage
/archives//html/Amps/2014-07/msg00104.html (9,258 bytes)

138. Re: [Amps] Question about 4CX800 amplifiers (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sun, 17 May 2015 21:16:10 -0600
Morel, I would not call a series LC circuit a "rejection" in this case. 20pF in series with 150nH has a resonant frequency of 91.9MHz. In this application I am nearly certain they are for impedance m
/archives//html/Amps/2015-05/msg00121.html (8,020 bytes)

139. Re: [Amps] L-C-L vs C-L-C (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Thu, 09 Jul 2015 22:30:44 -0600
Ron, There are 2 types of both networks (lowpass and highpass). *C-L-C Pi* is a lowpass with the ability to ground one side of the capacitors *L-C-L Pi* is a highpass with both sides of the capacitor
/archives//html/Amps/2015-07/msg00026.html (8,548 bytes)

140. Re: [Amps] HV transformer and Variac (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Thu, 23 Jul 2015 15:43:02 -0600
Gerald and others, To add to the auto-transformer (variac) discussion I did a quick simulation in LTSpice to make sure my memory was correct before making a fool out of myself. :-) There are 2 curren
/archives//html/Amps/2015-07/msg00109.html (11,097 bytes)


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