Topband: Re: [160m] Spot Light Effects...

[Ford Peterson]

Tom wrote:

> I agree with you Ford. It would be very interesting to log
> signal level changes over certain paths, even if local.
> That would be information that has value to the entire
> community, even if we don't know or can't prove why it
> happens.

Then let's do it!  If a few talented folks step forward and contribute some computer prowess, we could make this an interesting and scientifically significant breakthrough in understanding the physics of this wild and whacky world of Topband...

> It seems to me the duct theory falls totally apart when
> applied to a signal from NY to my QTH in GA. The extremely
> low power beacon signal on 80 had exactly the
> characteristics DX signals from 10,000 miles often do.

Likewise, some of the locals here in MN are becoming active on Topband and are VERY active VHF/UHF contesters.  I have heard them make comments about their bewilderment as to the connection of E propagation on VHF to topband spotlight propagation.  Again, they have no proof--neither do I.  Only gut speculations after sitting and twiddling the knobs for dozens of hours on end on busy Topband weekends.
 
> We don't need to have accurate absolute levels, but we need
> to have accurate level change data. The major problem is
> accurately recording relative level changes over a long
> period of time.

I agree completely.  I have software that reads the dials on my IC746 and reproduces the S Meter on the screen in quite excellent fashion.  So the data can be extracted from the AGC loop in these radios.  Don't ask me how.  My manuals look like gobbly-gook but do describe how to do the software query.  I'm thinking of a QSY to a beacon, query the meter 10 times in 5 seconds, average the results, and post it to a file.  Then QSY to the next beacon, and continue the process for the entire evening.  12 beacons, 10 (or more) queries per 5 seconds, gives 120 data points per minute.  Times 100 stations, is 12000 data points, times 60 minutes, times 12 hours, is only 8M points summarized down to 864K points.  Record grid square (integer), frequency and result (integer) could be as few as 4 bytes of data -- a data file of 3.5MB per night.  That's nothing in terms of cumulative data complexity.  The complexity comes in the proper coordination of it all--and getting people to participate in the project.

> There also might be use for modest to high power beacons
> tucked out of the way of high traffic volume areas on 160.
> Perhaps that would eliminate the need for so many CQ's that
> largely go unanswered. Either that or we should consider
> calling frequencies. The spotty nature of propagation on 160
> often means stations in one area that on any particular day
> are unreadable waste a good bit of time and energy trying to
> stir up activity. A series of modest power beacons with
> reasonable antennas scattered around the world, especially
> in combination with a calling frequency, would (at least in
> my mind) be a real asset.

I guess in my mind's eye, I've been pondering a series of simple experiments involving a few evenings of various propagation conditions.  It sounds like you are pondering a more-or-less permanent system.  Finding dedicated people, with the right compliment of equipment, in the right locations, all-the-time, would be virtually impossible and quite problematic for the community to digest.  Nobody wants to 'give up' a single kHz of topband to beacons or any other 'noise source.'  But most could part with the bandwidth for a couple of evenings for a good cause.  I'm thinking that a series of initial experiments involving a few weekday evenings may prove quite interesting.  At least that's my view.

If there are parties interested in figuring out the technical aspects of such a project, contact me off-reflector.  Maybe I'll put together a team that can investigate and then report progress on these reflectors.  I would likely choose to start a reflector with only the "team" as members, to facilitate communications and limit 'opinions' on these matters to a minimum.  Human horsepower needed involves knowledge of topband, radios, software, and raw-brute-strength.  This could be very interesting indeed...

73

Ford-N0FP
ford at cmgate.com