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References: [ +from:john.kaufmann@verizon.net: 56 ]

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41. Re: Topband: How to determine impedance (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Fri, 26 Jan 2018 12:34:22 -0500
Here's another method that's based on the engineering textbook transmission line equation and use of an impedance analyzer to make an impedance measurement. You can look up the transmission line equa
/archives//html/Topband/2018-01/msg00266.html (11,333 bytes)

42. Re: Topband: elevated radials (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Sun, 21 Oct 2018 18:22:38 -0400
We just went through the exercise of tuning up the elevated radials on the KC1XX 160m vertical array in advance of the upcoming CQWW DX Contests. The first thing is to make each of the radials look a
/archives//html/Topband/2018-10/msg00175.html (9,261 bytes)

43. Re: Topband: elevated radials (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Mon, 22 Oct 2018 11:47:55 -0400
When you are using just a single vertical, some pattern skew is probably acceptable. However, at KC1XX we are using several verticals in an array and nonideal radiation from the individual verticals
/archives//html/Topband/2018-10/msg00182.html (11,882 bytes)

44. Re: Topband: Working LP from VK6 to the USA - season approaches (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Thu, 1 Nov 2018 10:47:39 -0400
I was one of the lucky ones to work VK6VZ on LP last November 7. I got him at 2128Z with signals peaking from the east. It was exactly at my sunset. I was followed by two other W1 stations before the
/archives//html/Topband/2018-11/msg00002.html (10,686 bytes)

45. Re: Topband: Which compromise receiving antenna (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Tue, 6 Nov 2018 20:40:41 -0500
I designed the YCCC preamp so I can answer the question about the AD8055 op amp. As used in the YCCC preamp, the linearity is actually very good. We use a YCCC receiving array at KC1XX in a multi-ope
/archives//html/Topband/2018-11/msg00029.html (11,146 bytes)

46. Re: Topband: YCCC op amp preamp... (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Tue, 13 Nov 2018 18:00:08 -0500
You can find a schematic on p.54 of the user's manual which can be download from the DXE Web site: https://static.dxengineering.com/global/images/instructions/dxe-yccc-switch. pdf. 73, John W1FV Is t
/archives//html/Topband/2018-11/msg00080.html (7,823 bytes)

47. Topband: Vertical vs. horizontal antennas at KC1XX (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Mon, 26 Nov 2018 11:27:21 -0500
I would like to add some additional observations to the ongoing discussion about horizontal vs. vertical antennas on 160. At the KC1XX contest station where I operate the low bands (160 and 80), we j
/archives//html/Topband/2018-11/msg00260.html (11,468 bytes)

48. Re: Topband: Vertical antennas aren't always best for DX (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Mon, 26 Nov 2018 20:53:27 -0500
The statement that the half of a horizontal dipole's radiation is vertically polarized is misleading and needs qualification. There is a vertically polarized component off the ends of the dipole but
/archives//html/Topband/2018-11/msg00271.html (9,664 bytes)

49. Re: Topband: Vertical antennas aren't always best for DX (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Tue, 27 Nov 2018 08:16:05 -0500
In considering the *total power* radiated by any antenna, you need to look at the 3-dimensional antenna pattern, not a 2-dimensional slice. The total radiated power is the 3-dimensional integration o
/archives//html/Topband/2018-11/msg00275.html (12,926 bytes)

50. Re: Topband: Vertical antennas aren't always best for DX (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Tue, 27 Nov 2018 09:35:52 -0500
JC, You said: " Every dipole or inverted V irradiate 50% of the power horizontal polarized broadside with the wire and 50% of the power vertical polarized along the wire." You cited EZNEC as evidence
/archives//html/Topband/2018-11/msg00278.html (16,222 bytes)

51. Re: Topband: Detuning TX ant + QSK (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Wed, 28 Nov 2018 08:18:41 -0500
Jim, I use Gigavac GH-1 vacuum relays for detuning my TX antennas when receiving. The contact closure/release time is 6 msec. You have to dial in enough QSK delay in your radio so that you don't hot-
/archives//html/Topband/2018-11/msg00293.html (7,858 bytes)

52. Re: Topband: Detuning TX ant + QSK (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Wed, 28 Nov 2018 17:34:42 -0500
The user's manual I wrote for the YCCC low-band receiving array contains a section on detuning antennas that are near the receiving array. You can download the manual at: https://static.dxengineering
/archives//html/Topband/2018-11/msg00310.html (10,141 bytes)

53. Re: Topband: capacity needed for Deturning tower (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Sat, 22 Dec 2018 07:11:59 -0500
On 160 I've used a vertical wire of 20 feet with a 1000 pF variable capacitor to detune a tower at its base. You can scale that to 80. 73, John W1FV Hi again, This may not be possible to answer with
/archives//html/Topband/2018-12/msg00218.html (8,186 bytes)

54. Re: Topband: Rx splinter (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Sat, 2 Feb 2019 11:56:27 -0500
The BCC splitter design suggested by PC2A is based on the "magic tee" splitter. An excellent tutorial on magic tee splitters can be found on W8JI's Web site: https://www.w8ji.com/combiner_and_splitte
/archives//html/Topband/2019-02/msg00028.html (9,314 bytes)

55. Re: Topband: Rx splinter (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Sat, 2 Feb 2019 14:48:52 -0500
It just realized that the number of turns I specified (in my post below) to use on the Fair-Rite binocular core will be a tight fit inside the core. The number should be scaled down as follows: 5 tur
/archives//html/Topband/2019-02/msg00031.html (9,575 bytes)

56. Re: Topband: 4sq vs SAL 30 Mkii in a forest (score: 1)
Author: "John Kaufmann" <john.kaufmann@verizon.net>
Date: Mon, 18 Feb 2019 19:01:25 -0500
I have an 8-circle array in the woods. The tallest trees in my area are about 60-70 feet, so your trees might be larger and denser than mine. However, my system works very well, judging by the fact t
/archives//html/Topband/2019-02/msg00186.html (9,501 bytes)


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