Sunday, August 16, 2009

Radio propagation newsletter

Another quiet week on the cun. Last week on earth we neglected to mention the Perseids meteor shower, which peaked this week on August 12-13. A nice statistical display from the International Meteor Organization is at .

A look at on August 13 showed possible heightened geomagnetic activity returning around August 18-19, with a planetary A index of 20 and 12, respectively.

Geophysical Institute Prague expects quiet conditions August 14, unsettled August 15, quiet August 16-17, unsettled August 18, quiet to unsettled for August 19 and quiet on August 20 The predicted planetary A index from the Space Weather Prediction Center for those same dates is 5, 5, 5, 5, 20, 12 and 8. Check the link in the previous paragraph to see if the forecast changes and is updated.

The autumnal equinox is less than 40 days from now, to occur on September 22 at 2118z. Even if there are no sunspots, we should see a shift and seasonal improvement compared to summer. Comparing the first day of fall to mid-July, 20 meter conditions from New England to the Czech Republic shows an end to openings during the evening on the USA end, and daytime openings shifting to earlier hours. The July 20 meter opening from 1930-0200z shifts to 1330-2200z in September. 17 meters shows very little chance of propagation over the same path in summer, but in fall opens 1330z to 1900z.

A similar shift occurs on the West Coast. From California to Japan, in summer the 20 meter opening is in local nighttime at the W6 end, strongest 0630-1030z. In the fall it happens earlier, 2200-0330z. On 17 meters over the same path, signals are much stronger in the fall, with openings around 2200-0230z.

Jim Spears, N1NK of Tiverton, Rhode Island, wrote to comment on the current sporadic-E season, which he noted should be winding down. Jim says he hasn't seen much sporadic-e activity, and checked six meters most days, but June was very good for him into Europe. Jim wrote, ''With a 5 element Yagi at 40 feet and THP 1.5Kfx amp I improved my distance record to the east by working 4X4DK, DK1MAX, and OE5D as new ones. A number of other new ones in EU (mostly southern) and Caribbean along with 8R1TO and PV8ADI in South America were also worked leaving me with a current total of 73 worked and 67 confirmed, all via Es. I also failed to work any west coast US stations, something that has been a regular occurrence the past few years''.

Jim noted that July was extremely wet and stormy in New England, and doesn't know if this is coincidental, but he saw little six meter propagation to anywhere. ''It seemed that the propagation was completely skipping over or bypassing us. There were very few moments when I would hear any signal on the band at all''.

In an email Jim received from Mick, W1JJ, also in Rhode Island, but with a better antenna system, the 6 meter E season was about average for Mick, who has been active on 6 meters for 50 years. He worked 3 new countries, bringing his 6 meter total to 186. Mick says openings were slow in May, much better in June, but he had only a couple of good openings to Europe. In July he worked 4X4, SV, SV9, SV5, OD, TZ and TA. To the west, he had a couple of good openings to W6 and one to KH6. He sent along an audio file of JA7QVI on six meters, who was quite loud, and the only JA he worked in the past couple of years. Mick worked him at 2258z on July 8. In the Six Meters Marathon he totaled 94 countries from the first week in May through August 3.

Pat Dyer, WA5IYX of San Antonio, Texas wrote about digital television vs. the old analog system and its usefulness as an indicator of VHF propagation. ''Some have had much more luck than myself at decoding DTV via Es, but here are two samples of my best,. (1187 mi) and (950 mi)''.

''A vivid example of what was available on low-VHF TV for Es from here vs. now on DTV is shown on these maps A prime problem in getting
DTV Es decoded stems from the system's intolerance for co-channel signals (unless one is dominant by 15 db). Many a time the 54.310 MHz DTV pilots can be heard on my FT-847 as a mixture of signals with a 4-Hz beat rate (note how many US DTV Ch 2 stations are to my NW-N, and can come in simultaneously). Ch 5, with the most US DTV stations of any low- VHF channel, has been occupied by ''local'' KCWX-DT-5 (23kw ERP at c. 50 mi) since Jul 1. Rapid QSB and multipath (ghosting common on Es) also contribute to complicating any decodes. Also, unlike with NTSC, the entire 6-MHz wide channel of data needs to be in well for ATSC to work - if the Es MUF is ''sharp'' you're doomed, where with NTSC video without audio was not

Ken Miller, K6CTW of Rancho Cucamonga, California also wrote this week. ''Although this is now over 2 weeks old, I did want to let you know that I was able to work the VK9NI DXpedition on 40 CW while commuting to work here in Southern California. Since I'm only running about 60 watts I found it amazing that I was able to ''make the trip''. They must have had some super ops and a great antenna on 40 but never the less, conditions do seem to be holding in the early morning here to the Western pacific. I hear all sorts of DX on when I'm driving in, and it really makes the commute bearable''.

So nice to hear of good results from a modest setup. Since a standard mobile antenna would only be about one-sixteenth wavelength on 40 meters, running 100 watts into a much more efficient half-wave dipole from home should surely net a contact with Norfolk Island.

Ken along with Chip Margelli, K7JA, were the heroes who demonstrated morse code speed and efficiency by beating a champion text messager (or is that messenger?) in a contest on the Tonight Show in 2005. Many have seen it, but you can watch it again at . In light of financial travails of the past couple of years, pay special attention to the comments by the wife that Jay Leno interviews at the start of the segment.

July 31 Propagation Bulletin ARLP031 mentioned Kai Siwiak, KE4PT and his Secret Ham Message, linked from the page at . Kai wasn't expecting the puzzle's mention in the bulletin, and reported an overwhelming response from readers who solved the problem.

Now that two weeks have passed, we can mention a clue to folks who didn't quite get it, like the author of this bulletin. Yes, you can use standard techniques for solving simple ciphers, such as counting the occurrence of each character, ranking them, then solving by examining the frequency of occurrence for each letter of the English language. This assumes it is in English, which it is, but there is an easier way for CW operators to solve this. Contemplate the page visually, then think of Morse. Don't quite see it? Look again.

CW operators' ears perk up when morse code appears in motion picture soundtracks, and various online forums and websites over the years have listed films containing telegraphy. One is, a Thai website from Jeerasak Pitiwatsakul, E20TCM, which reproduces data from the now defunct Morse Goes to the Movies site.

Early Thursday morning I ran across another film with morse, but this time only in the soundtrack, seemingly unrelated to the action on the screen. I checked out a DVD from the public library, the mid-eighties movie Runaway Train and I might have missed the Morse, except I was wearing headphones.

Forty minutes into the movie, there is a scene in a railway control room that was supposed to look hi-tech at the time. Perhaps it was an attempt to lend a sort of authenticity for the audience, but the audio contains various bleeps and blurps under the dialog, as the characters stare into old monochrome CRT monitors in horror. I nearly fell off the couch between minute 40:10 and 40:15 when I heard, ''DE K7VVV''. K7VVV happens to be my callsign before K7RA, and now held by a ham in California. However, at the time the movie was produced my call was KT7H, so I claim no connection. Perhaps others will hear DE KZVVV instead, but as my mind attempts to construct patterns from many sensory inputs, it tends to fall back on familiar patterns.

If you would like to make a comment or have a tip for our readers, email the author at
(ARLP33 via Dave Raycroft/ODXA)