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21. Re: [Amps] Asynchronous coax matching transformer (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sat, 01 Aug 2009 19:34:55 -0600
Roger, You are confusing insertion loss with return loss. A return loss of 20dB is the same as an SWR of 1.22:1 which is also equal to a reflection coefficient of 0.1. Insertion loss is a combination
/archives//html/Amps/2009-08/msg00015.html (20,937 bytes)

22. Re: [Amps] Asynchronous coax matching transformer (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sat, 01 Aug 2009 18:59:45 -0600
Carl, I asked myself what a mated PL-259/SO-239 connector "really" looked like RF wise many times after hearing all kinds of horror stories. Finally after procuring a couple network analyzers and the
/archives//html/Amps/2009-08/msg00061.html (18,917 bytes)

23. Re: [Amps] SB-220 bias question (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sun, 30 Aug 2009 10:24:35 -0600
Might I make a simple suggestion. Analog Devices gives away a free program called LTSpice (http://www.linear.com/designtools/software/ltspice.jsp) which is a great tool for understanding how circuits
/archives//html/Amps/2009-08/msg00637.html (10,259 bytes)

24. Re: [Amps] SB-220 bias question (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sun, 30 Aug 2009 11:47:33 -0600
WHOOPS, not Analog Devices but Linear Technology. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
/archives//html/Amps/2009-08/msg00641.html (11,143 bytes)

25. Re: [Amps] AL 1500 P.O. Meter Function (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sun, 04 Oct 2009 23:11:45 -0600
Joe, You are correct about trying to measure power based on voltage but in your example an SWR of 2:1 is the same as a reflection coefficient (Rho) of 0.333 meaning that the voltage on the line will
/archives//html/Amps/2009-10/msg00079.html (8,651 bytes)

26. Re: [Amps] Checking Plate Choke resonance (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Tue, 13 Oct 2009 19:37:27 -0600
Let me add a little insight here. I believe everyone agrees that a series resonance would be disastrous for a plate choke. However for a parallel resonance there are 2 distinct cases. Case #1: Just b
/archives//html/Amps/2009-10/msg00207.html (11,479 bytes)

27. Re: [Amps] Checking Plate Choke resonance (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Tue, 13 Oct 2009 21:45:05 -0600
Bill, I have no intention of waging a war of words. Argue as you wish but let's build a circuit and analyze it. I just did a simulation in LTSpice of a tube (voltage controlled current source) in par
/archives//html/Amps/2009-10/msg00212.html (10,728 bytes)

28. Re: [Amps] Checking Plate Choke resonance (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Tue, 13 Oct 2009 23:03:47 -0600
Bill, I would not call this circuit "very lightly loaded" with an effective 1000 ohms across the circuit. The impedance of 100uH @ 9MHz (which was used in my example) is +j5655. I would be glad to bu
/archives//html/Amps/2009-10/msg00215.html (10,559 bytes)

29. Re: [Amps] FW: Decent HF directional coupler for RF power meas. (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Mon, 07 Dec 2009 21:05:18 -0700
Phil, Since the TDS-2XXX scopes are not 50 ohm input, don't ignore the capacitance in the probe. See the appendix in the manual on page 153. The capacitance will be less at the 10X probe setting but
/archives//html/Amps/2009-12/msg00220.html (10,365 bytes)

30. Re: [Amps] OM power power supply design (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Wed, 09 Dec 2009 16:05:20 -0700
Alek, Two power supplies, each with their own diodes and capacitors do NOT change anything regarding voltage breakdown in the 2 transformers when the outputs ar put in series. Think of the circuit li
/archives//html/Amps/2009-12/msg00252.html (9,670 bytes)

31. Re: [Amps] Need #9 Allen wrench MUCHO (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Mon, 11 Jan 2010 13:26:48 -0700
McMaster Carr www.mcmaster.com item number 7289A35 <javascript:TargetLink('TR9531','tr','PT95311','7289A35');> or 6958A34 <javascript:TargetLink('TR9556','tr','PT95561','6958A34');> and many other 9m
/archives//html/Amps/2010-01/msg00075.html (9,101 bytes)

32. Re: [Amps] Plate Choke Resonances (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sat, 30 Jan 2010 22:27:47 -0700
I just ran a simulation with a tube with a 3000 ohm impedance and 3000V peak AC on the plate connected to a 100uH plate choke at 10MHz. The AC current in the choke was about 440mA peak. Then placing
/archives//html/Amps/2010-01/msg00557.html (9,859 bytes)

33. Re: [Amps] Plate Choke Resonances (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sun, 31 Jan 2010 00:11:50 -0700
Come on Bill. No weasel words like "Tesla Effect". That doesn't prove anything at all. Just describe a schematic showing what you are claiming with values and I will be glad to simulate it. I certain
/archives//html/Amps/2010-01/msg00560.html (9,913 bytes)

34. Re: [Amps] Plate Choke Resonances (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sun, 31 Jan 2010 09:33:56 -0700
Let's talk about facts and not experiences or memories! 1.) Every reasonably complex electronic product designed is simulated beforehand 2.) Simulation software is extremely accurate if the actual ci
/archives//html/Amps/2010-01/msg00576.html (11,163 bytes)

35. Re: [Amps] Advice: harmonics from Alpha 91B on 160 (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sun, 31 Jan 2010 09:44:10 -0700
FCC Part 97.307(d) "For transmitters installed after January 1, 2003, the mean power of any spurious emission from a station transmitter or external RF amplifier transmitting on a frequency below 30
/archives//html/Amps/2010-01/msg00578.html (11,192 bytes)

36. Re: [Amps] QRO Questions (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Sat, 06 Feb 2010 09:38:57 -0700
You are referring to RG-142 which can carry over 3KW on 10m. It is teflon and lower loss than RG-58 but it does NOT have less loss than RG-214. It gets its power handling capability by being able to
/archives//html/Amps/2010-02/msg00145.html (7,875 bytes)

37. Re: [Amps] QSK-5 insertion loss... (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Fri, 12 Feb 2010 12:58:38 -0700
Paul, There are two kinds of loss: dissipative and non-dissipative. A 1 dB dissipative loss at 1500W is 308W which would clearly blow up the QSK-5 in a second or two. However crummy wiring in an encl
/archives//html/Amps/2010-02/msg00360.html (8,952 bytes)

38. Re: [Amps] Mangian (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Mon, 01 Mar 2010 08:44:15 -0700
Guys, The stuff is Manganin wire and it's claim to fame is that it has nearly perfect zero temperature coefficient which is good for meters etc. See http://en.wikipedia.org/wiki/Manganin and the stuf
/archives//html/Amps/2010-03/msg00006.html (6,899 bytes)

39. Re: [Amps] WD-40 is not.... (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Mon, 01 Mar 2010 10:27:35 -0700
WD-40 is not recommended for long term contact with the skin. If you actually want the facts rather than just guess what is in WD-40 the MSDS is available at http://www.wd40.com/files/pdf/msds-wd4947
/archives//html/Amps/2010-03/msg00013.html (13,500 bytes)

40. Re: [Amps] Are exciter RF delays to prevent hot keying cataloged anywhere? (score: 1)
Author: Larry Benko <xxw0qe@comcast.net>
Date: Wed, 17 Mar 2010 21:50:14 -0600
Take a look at http://www.w0qe.com/amplifier_timing.html where I measured several radios. Not a huge sample but may be of interest to you. You need to look at both relay closure and release since som
/archives//html/Amps/2010-03/msg00359.html (8,047 bytes)

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