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1. Topband: A few words (score: 1): Author: Robert Brown <bobnm7m@cnw.com>; Date: Sat, 8 Jan 2005 08:47:51 -0800 (PST); Friends in Radio Land In treating low-band propagation, I am proposing we pay attention to the state of the neutral atmosphere, in which the ionosphere is embedded. I suggest we use the control point; /archives//html/Topband/2005-01/msg00129.html (8,211 bytes)
2. Re: Topband: Topband Propagation (score: 1): Author: Robert Brown <bobnm7m@cnw.com>; Date: Fri, 7 Jan 2005 23:19:22 -0800 (PST); could this provide an indicator of what is going on? It seems to me, if refraction is occurring along certain paths, (read: skewing, spotlighting, peaks, nulls) then the atmospheric data at altitude; /archives//html/Topband/2005-01/msg00113.html (8,291 bytes)
3. Re: Topband: Topband Propagation (score: 1): Author: Robert Brown <bobnm7m@cnw.com>; Date: Fri, 7 Jan 2005 19:09:03 -0800 (PST); Ford, What I am proposing amounts to using the control point method, of HF propagation, to find the variables which most influence MF propagation. But the data is local, small-scale, from above 30 km; /archives//html/Topband/2005-01/msg00108.html (8,564 bytes)
4. Topband: Topband Propagation (score: 1): Author: Robert Brown <bobnm7m@cnw.com>; Date: Fri, 7 Jan 2005 15:07:37 -0800 (PST); Friends in Radio Land, As I watch the postings on the Reflector, I see a growing interest in Topband propagation but the interest seems misguided, toward setting up many beacons instead of looking di; /archives//html/Topband/2005-01/msg00105.html (8,014 bytes)
5. Topband: Spotlight Effect (score: 1): Author: Robert Brown <bobnm7m@cnw.com>; Date: Mon, 3 Jan 2005 14:53:57 -0800 (PST); Friends in Radio Land, Those interested in the "spotlight effect" would do well to read the work on dawn enhancements by Nick, VE7DXR, and Bob, VE3OSZ, in the November '99 and January 2002 issues, re; /archives//html/Topband/2005-01/msg00040.html (6,701 bytes)
6. Topband: QSB (score: 1): Author: Robert Brown <bobnm7m@cnw.com>; Date: Wed, 13 Oct 2004 11:03:11 -0700 (PDT); Friends in Radi Land The recent postings about long-period (2-3 minute) QSB were interesting in that there seemed to be no magnetic/auroral activity at the time. This suggested an origin associated w; /archives//html/Topband/2004-10/msg00062.html (7,263 bytes)
7. Re: Topband: Topband Propagation - Moon Effects ! (score: 1): Author: Robert Brown <bobnm7m@cnw.com>; Date: Thu, 7 Oct 2004 11:43:37 -0700 (PDT); Friends in Radio Land, I do not doubt there are lunar tidal effects on the ionosphere, but like geomagnetic effects, they must be small in magnitude. The L-component of magnetic variations is found b; /archives//html/Topband/2004-10/msg00036.html (8,524 bytes)
8. Topband: 3B9C Contacts (score: 1): Author: Robert Brown <bobnm7m@cnw.com>; Date: Sat, 27 Mar 2004 14:59:16 -0800 (PST); Friends in Radio Land, The antipodal enhancement of 3B9C's signals in NA is not likely as there are "large geographic variations in ionospheric structure" (Davies, 1989). More to the point is magneto; /archives//html/Topband/2004-03/msg00296.html (7,122 bytes)
9. Re: Topband: mag-field still sick ! (score: 1): Author: Robert Brown <bobnm7m@cnw.com>; Date: Tue, 30 Sep 2003 05:39:30 -0700 (PDT); Wolf, Thanks for the posting; it's good to hear from you again. During times of high geomagnetic activity, the solar wind can distort the high-latitude lines of force and carry E- and F-region electr; /archives//html/Topband/2003-09/msg00146.html (7,343 bytes)
10. Topband: A few words (score: 1): Author: Robert Brown <bobnm7m@cnw.com> (Robert Brown); Date: Sat, 18 Jan 2003 15:33:48 -0800 (PST); Hello Earl, My remarks were focused on refraction, a more gradual change in propagation direction. Scatter and reflection are other means that can alter propagagtion direction and give larger effects; /archives//html/Topband/2003-01/msg00141.html (8,163 bytes)
11. Topband: A few words (score: 1): Author: bobnm7m@cnw.com (Robert Brown); Date: Sat, 18 Jan 2003 11:12:35 -0800 (PST); Friends in Radio Land - Given the recent interest in skewing, a few words of explanation would seem in order. In simple terms, skewing is just a case of horizontal refraction and results from a wave; /archives//html/Topband/2003-01/msg00137.html (8,922 bytes)
12. Topband: Last word? (score: 1): Author: bobnm7m@cnw.com (Robert Brown); Date: Fri, 17 Jan 2003 06:13:50 -0800 (PST); Friends in Radio Land - While Tom, KN4LF, says that the simplest way to look at skewing or refraction is by means of a "principle of least absorption" , I still maintain that principle does not exist; /archives//html/Topband/2003-01/msg00106.html (7,883 bytes)
13. Topband: FYI (score: 1): Author: bobnm7m@cnw.com (Robert Brown); Date: Thu, 16 Jan 2003 09:38:04 -0800 (PST); Friends in Radio Land In a recent posting Tom, KN4LF, said "medium frequency path skewing is that the transmitted RF signal will "always" seek to propagate along the path with least absorption, which; /archives//html/Topband/2003-01/msg00090.html (7,955 bytes)
14. Topband: Good conditions on 160? (score: 1): Author: bobnm7m@cnw.com (Robert Brown); Date: Thu, 19 Dec 2002 14:16:31 -0800 (PST); Friends in Radio Land, How about night at the winter solostice during Solar Minimum? "Soon, maybe not tomorrow but soon!" 73, Bob, NM7M; /archives//html/Topband/2002-12/msg00241.html (6,290 bytes)
15. Topband: Re: 160 Propagation and weather (score: 1): Author: bobnm7m@cnw.com (Robert Brown); Date: Fri, 1 Nov 2002 06:29:29 -0800 (PST); Friends in Radio Land - With regard to low-band propagation and weather being related, it is fairly obvious from some basic facts: 1) The ionosphere floats or is suspended in the atmosphere, with ele; /archives//html/Topband/2002-11/msg00006.html (7,506 bytes)
16. Topband: Re: Large TSTM Areas (score: 1): Author: bobnm7m@cnw.com (Robert Brown); Date: Tue, 29 Oct 2002 09:04:45 -0800 (PST); Friends in Radio Land - Lightning discharges in the D-region, "sprites" as observesd by the University of Minnesota, could give rise to momentary bursts of Xrays and electrons but the ionization woul; /archives//html/Topband/2002-10/msg00154.html (6,737 bytes)
17. Topband: The Moon (score: 1): Author: bobnm7m@cnw.com (Robert Brown); Date: Mon, 21 Oct 2002 08:55:17 -0700 (PDT); Friends in Radio Land - The discussion of the "full moon effect" has now reached "tidal proportions", with a question from Bob, G3REP, as to whether the moon could influence the earth's magnetic fiel; /archives//html/Topband/2002-10/msg00108.html (6,954 bytes)
18. Topband: Full Moon, Oct 21-Questions (score: 1): Author: bobnm7m@cnw.com (Robert Brown); Date: Fri, 18 Oct 2002 06:14:32 -0700 (PDT); Don, Energetic, UV photons, are required for photo-ionization of the atmospheric constituents that go to make up the ionosphere. The table below gives the energies and UV thresholds: N2 < 1270 A > 9.; /archives//html/Topband/2002-10/msg00068.html (7,489 bytes)
19. Topband: Reciprocity (score: 1): Author: bobnm7m@cnw.com (Robert Brown); Date: Sat, 28 Sep 2002 11:05:28 -0700 (PDT); Friends in Radio Land - Recently, the reflector carried some remarks about reciprocal propagation. Unfortunately, they did not convey the idea that low-band propagation is magneto-ionic in nature, i.; /archives//html/Topband/2002-09/msg00205.html (7,645 bytes)
20. Topband: Displacement current (score: 1): Author: bobnm7m@cnw.com (Robert Brown); Date: Thu, 5 Sep 2002 07:45:42 -0700 (PDT); Joe, Thanks for the note. I used to teach E&M at UC Berkeley and our order of Maxwell's Equations in teaching was as follows: Div D = rho, Coulomb's Law Div B = 0, no magnetic poles Curl H = j + dD/d; /archives//html/Topband/2002-09/msg00042.html (7,006 bytes)

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