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Total 139 documents matching your query.

41. Topband: Chokes-Ferrite vs. air (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Tue, 19 Jun 2001 13:30:59 +0200
W9UCW: In my opinion and experience this ratio in a coax choke is by far not enough. 73, Mauri I4JMY -- FAQ on WWW: http://www.contesting.com/FAQ/topband Submissions: topband@contesting.com Administr
/archives//html/Topband/2001-06/msg00049.html (6,868 bytes)

42. Topband: Antenna Interaction Question (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Fri, 29 Jun 2001 20:30:15 +0200
K9AY: reduce My other solution to such a problem when using a small RX loop have been to include also the TX antenna into the receiving system. (see Cq-magazine Feb. 2000) This could be good for thos
/archives//html/Topband/2001-06/msg00071.html (7,510 bytes)

43. Topband: 160 Antenna's Modeled (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Thu, 19 Apr 2001 19:35:49 +0200
Inherent antenna efficiency takes in account for losses in the antenna itself and in the nearby area but an efficiency of this kind doesn't insure for optimal pattern if the distant ground, that one
/archives//html/Topband/2001-04/msg00046.html (9,091 bytes)

44. Topband: low angle, high angle (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Mon, 23 Apr 2001 15:56:06 +0200
K9LA: Other than the Radio Luxemburg old tales, can you explain what should it happen, and why, with propagation of radio waves around electrons gyro frquency ? 73, Mauri I4JMY -- FAQ on WWW: http://
/archives//html/Topband/2001-04/msg00068.html (6,873 bytes)

45. Topband: Tee Antenna (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Wed, 25 Apr 2001 19:21:09 +0200
ex-KV4FZ: The reason why Broadcast AM radio antennas are on flat terrain instead on hilltops is because elevating a vertically polarized antenna from ground the low angle radiation is decreased and m
/archives//html/Topband/2001-04/msg00077.html (7,821 bytes)

46. Topband: Re: (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Sat, 3 Mar 2001 12:14:00 +0100
Any test is interesting but practically speaking the problem of vertical wire at beverage ends is totally neglectable and doesn't deserve efforts and time waste. Care about proper termination relativ
/archives//html/Topband/2001-03/msg00035.html (7,016 bytes)

47. Topband: 160m international contest scoring (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Mon, 5 Mar 2001 09:47:26 +0100
If a contest starts at 22:00z friday and finishes at 16:00z sunday, between January and March there is a world area where two sunsets and two sunrises occur without the need that a full 48 hours pass
/archives//html/Topband/2001-03/msg00041.html (8,514 bytes)

48. Topband: Rx Loop and Tower Radiating Noise? (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Thu, 22 Mar 2001 22:43:51 +0100
When you point to a tower that's only 40'apart of the loop, actually you couple the loop to the tower (both are infact vertically polarized and only 0.075WL spaced). Because of that, not necessarily
/archives//html/Topband/2001-03/msg00116.html (7,494 bytes)

49. Topband: superdirectivity (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Sun, 25 Mar 2001 13:37:26 +0200
The assumption that S/N is determined by directivity is correct, anyway this is a theorical perspective assuming perfect and noiseless receivers. In the real life this concept works if the band noise
/archives//html/Topband/2001-03/msg00132.html (8,183 bytes)

50. Topband: WPX (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Mon, 26 Mar 2001 19:51:08 +0200
If WPX would count mults by band or at least add countries to pfx mults, the band would be surely much more active than generally is during this contest. Any all band entry, MM apart, can infact skip
/archives//html/Topband/2001-03/msg00141.html (7,388 bytes)

51. Topband: modeling question (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Mon, 26 Mar 2001 23:30:28 +0200
Tom's warning is expecially important for parasitic elements. The voltages between the boom and an insulated yagi element can be elevate or the currents involved when grounding it to the boom can be
/archives//html/Topband/2001-03/msg00143.html (7,863 bytes)

52. Topband: modeling question (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Tue, 27 Mar 2001 23:08:39 +0200
W7IUV: Hi Larry, in this case I was not pointing out about the coax placement because of safety reasons. The cables, running from the base of a shunt fed tower to a yagi antenna, or to a rotator, are
/archives//html/Topband/2001-03/msg00149.html (8,178 bytes)

53. Topband: modeling question (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Thu, 29 Mar 2001 10:27:01 +0200
Hi Ricky, in the specific case, a choke balun used with a yagi hasn't enough inductive reactance to isolate the dipole from the line and its presence is almost ininfluent. The coax is infact at a clo
/archives//html/Topband/2001-03/msg00152.html (8,281 bytes)

54. Topband: Yagi on RF excited towers (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Sat, 31 Mar 2001 19:48:35 +0200
If the grounding is performed with bolts and metal fixtures and removing isolation, something may vary because the equivalent diameter of the element is slightly changed. If you leave the existing fi
/archives//html/Topband/2001-03/msg00163.html (7,220 bytes)

55. Topband: SSB Contest, CW Subband (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Sat, 24 Feb 2001 15:57:42 +0100
What sort of band plan can exist in a band that's not yet homogeneus in allowed space and use, and with different rights, and full with non amateur services, all around the world with peculiar differ
/archives//html/Topband/2001-02/msg00084.html (8,735 bytes)

56. Topband: SSB on CW segment (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Sun, 25 Feb 2001 16:03:04 +0100
A consistent number of European countries reserves for amateurs much more space than a small 10 KHz band, 100 or even 200 KHz are not uncommon. The own country situation doesn't necessary reflect a W
/archives//html/Topband/2001-02/msg00089.html (8,448 bytes)

57. Topband: Fw: CQWW 160m Contest (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Wed, 28 Feb 2001 13:44:39 +0100
Hy Wally, I don't think Your idea can be supported as is. Decreasing the difference with points between intercontinental and continental QSOs in a band that has an elite of operators (few ones but go
/archives//html/Topband/2001-02/msg00105.html (8,304 bytes)

58. Topband: Fw: CQWW 160m Contest (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Wed, 28 Feb 2001 20:16:52 +0100
if "bad like An EI is favoured but North America is far enough to be a sunset/sunrise matter not an overnight traffic. After all the EI doesn't have the chances to work all the eastern Europe and as
/archives//html/Topband/2001-02/msg00112.html (11,176 bytes)

59. Topband: Question abt gain in bi- vs uni-directional Beverage (score: 1)
Author: i4jmy@iol.it (Maurizio Panicara)
Date: Sat, 6 Jan 2001 10:53:49 +0100
Very "short beverages" apparently work if one neglects to consider what happens in the vertical plane. A 250-300 (about half wave) feet wire parallel to ground and without termination approach a very
/archives//html/Topband/2001-01/msg00050.html (8,901 bytes)

60. Topband: Re: Minimum discernible signal ? (score: 1)
Author: i4jmy@iol.it (i4jmy@iol.it)
Date: Mon, 15 Jan 2001 13:20:44 +0100
W8JI: S56A: excessive. Hi Mario (S56A), unluckily we can't agree just that 20db of extra attenuation is optimal. Average receiver sensitivity is probably unnecessary and S/N remains good even attenua
/archives//html/Topband/2001-01/msg00156.html (9,070 bytes)


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