SB PROP @ ARL $ARLP050
ARLP050 Propagation de K7RA
ZCZC AP50
QST de W1AW
Propagation Forecast Bulletin 50 ARLP050
From Tad Cook, K7RA
Seattle, WA December 4, 2009
To all radio amateurs
SB PROP ARL ARLP050
ARLP050 Propagation de K7RA
Recent sunspot activity--which ended on November 22--pushed up the
moving average we've been tracking for several years. Because we
have all the data for November, we now have the most recent 3-month
average of daily sunspot numbers, which centers on October. For
2009, the 3 month moving average centered on January through October
was 2.19, 2.02, 1.49, 2.01, 4.23, 5.2, 4, 4, 4.64 and 7.1. The
latest value is the highest since April 2008, when it was 8.89.
The monthly averages of daily sunspot numbers are also rising,
although not as smoothly as the three month average. The monthly
averages for March through November 2009 are 0.77, 1.27, 3.97, 6.6,
5.07, 0.39, 6.6, 7 and 7.7. The November average is the highest
since March, 2008 when it was 15.87.
Current projections show a steady quiet planetary A index of 5 for
December 4, then 8 for December 5-6, and back to 5 through the end
of the month. Solar flux predictions show December 4-6 at 72, 73 on
December 7-10, then 75 on December 11-23. The predicted solar flux
value of 75 seems to correspond to the return of an active region
that we can see emerging from the dark spot on STEREO. An area that
looked promising a few days ago has moved over the horizon and not
produced any sunspots.
Geophysical Institute Prague predicts quiet to unsettled conditions
December 4, unsettled December 5, and quiet December 6-10.
The same 45 day forecast from NOAA and US Air Force referenced above
also predicted a planetary A index of 5 for December 3, but in fact
all indices that day were zero, according to
http://www.swpc.noaa.gov/ftpdir/indices/DGD.txt. The last time the
planetary A index was five or above was November 24-26. The
directory at http://www.swpc.noaa.gov/ftpmenu/forecasts/45DF.html
has links to the daily forecast for the past few weeks. By sampling
the forecasts, you can see that the forecasters seem to prefer a
planetary A index of 5 for their minimum value. Five is an indicator
of very stable and quiet conditions, but in fact conditions have
been even quieter.
Low geomagnetic activity should be good for the ARRL 160-Meter CW
Contest this weekend. And, perhaps we will see some sunspots return
for the ARRL 10-Meter Contest the following weekend.
Over the past few years we've received reports from Dave Greer, N4KZ
of Frankfort, Kentucky, usually about 6 meters. The last was in
Propagation Forecast Bulletin ARLP028 in July. How do I know? By
pointing a search engine at the propagation bulletin archive on the
ARRL web site.
Use any search engine, such as lycos.com, bing.com, altavista.com or
google.com, enter a call sign or a word or any string of characters,
then a space, followed by site:http://www.arrl.org/w1aw/prop/ and
hit Search. In this case, I entered N4KZ
site:http://www.arrl.org/w1aw/prop/ and found seven bulletins since
May 19, 2005 containing that call. This will be number eight.
This time N4KZ wrote about 40 meters:
"I've been operating 40 meters for a little more than 40 years now
and the band has impressed me with its daylight DX numerous times
during the past few years. The most recent examples occurred during
the recent CQWW CW DX contest. On Sunday, November 29 at 1931 UTC I
worked 4O3A in Montenegro on the low end of 40-meter CW. That was
2:31 p.m. EST, a good two-and-a-half hours before my local sunset.
That might not be a big deal for East Coast stations but I don't
often hear Europe here that early. But just a minute later, I tuned
lower and heard an A71 station in Qatar, in Zone 21, working a
pile-up of Europeans in the contest. I didn't hear a single European
on frequency but the A71 had a decent signal into my Central
Kentucky QTH. Two or three U.S. stations were calling the A71 but I
don't think any of them ever made it through the European wall."
"But I've heard Europe even earlier in the day on 40 meters. A
couple years ago, a PA station from the Netherlands was a S5 on SSB
into Kentucky at high noon in the dead of Winter. I never heard
anything like that on 40 meters during high sunspot years."
"I've also been quite pleased at my ability to work DX from my
100-watt 40-meter SSB mobile station since the broadcast stations
signed off between 7.1 and 7.2 MHz. I have worked numerous
Europeans, Russians, three VK stations, and some Africans from my
car. I'm just running an IC-706MKIIG and a Workman helical whip
antenna."
Thanks, Dave!
Bob Elek, W3HKK of Johnstown, Ohio also commented on 40 meters this
week, but first had a lot to say about stealth antennas and
experiences with wire antennas on the low bands.
Bob was a serious DXer and contester from 1976 to 1995, but then
moved to a home with deed restrictions. He write, "He "began
experimenting with stealth antennas hidden in a small wooded area
behind my last home, adjacent to a golf course. I spent years trying
assorted home made loops, verticals, bob-tail curtains and inverted
Ls (all mired deep in the trees to keep them hidden from prying
eyes) that would fit in my situation using nothing more than
existing trees for support. I also gravitated to the WARC bands and
160-80-40m.
A few observations:
1. Upper corner, direct fed bobtail curtains only a few feet off the
ground work very well. I worked worldwide (India, Afghanistan,
Kazakhstan, JA, JT etc) on 12 and 17m with them, and highly
recommend them to anyone who has two properly spaced supports to
hang them from.
2. While the trees clearly muted performance, delta loops, and
quarter wave inverted Ls (however crudely erected) are also fine
performers on 40-80-160m. I was fortunate to have one 80 foot oak
tree which served as the support for many of my experimental, less
than ideal antennas.
3. I began putting up home made ground planes for 30 and 20m, from
cheap fiberglass telescoping fishing poles taped to a short length
of PVC piping, with 14 wire serving as the radiator (taped of
course) and radials/guy wires. These performed well despite being
surrounded by trees.
This past Summer, I moved to 3 rural acres in central Ohio. Due to
the almost complete absence of trees on my property, I decided to go
with home made ground planes for 20, 30, and 40m, plus a single feed
two band inverted L for 80 and 160 supported by a 15 foot (!) tree
in the back yard. Yes, a mere 15 feet high inverted L, at the apex!
I run 100 watts, mostly on CW, but some SSB as well.
The new QTH differs from the last one in that it is on open rolling
hills with cornfields to the east, is sloping slightly downhill for
1000'+ to the east, north and west, and slightly uphill to the
south. My antennas are lined up E-W about 50 feet apart, with 4-16
radials, both on ground and 3-4 feet above ground. SWR runs 2 to
4:1, with direct fed 52 ohm coax (cobbled together from left over
scraps that are 20-40 years old. My antenna analyzer (MFJ-259) shows
losses are acceptable for the appropriate frequencies. Those where
it was excessive, I threw out).
Point #1: On 160 meters, even a single coax direct fed pair of 15
foot vertical inverted Ls, with the remainder of their quarter
wavelength sloping down to 7 feet above ground at the ends, perform
pretty well. 150 ft of cobbled coax (soldered at the joints, then
taped) matched through a tuner in the shack allow me to work all
over the US and as far as the west coast on the 3905 Net on 1.892
MHz on a regular basis. In the November CW DX Test I worked 3
Caribbean and 2 South American stations, in limited operating. This
with 100 watts and the 15 foot vertical portion on my inverted L,
plus 8 ground laid radials, four for each band. On 80 meters I've
done less operating, but one would expect similar if not slightly
better performance there. I have worked all over the US, plus a
couple of Europeans, North Africans, and Caribbean/Latin American
stations on SSB around 3.798 MHz.
By comparison, at my last QTH, with the top of the vertical portion
of my 160 meter L at 80 feet, and 4 radials, I worked into Europe,
Africa and the Caribbean/South America about 100 times with 100
watts, with the antenna buried in trees. In one 160 meter SSB
contest I made 553 contacts with it in one weekend. Not bad for an
antenna in the woods with a handful of radials.
Point #2: And my main point. With my new 40 meter quarter wave
ground plane with 8 radials, in the open, 100 feet from the house,
direct fed by 52 ohm coax, my SWR is below 1.5:1, and I work nearly
all that I hear, even DX, even on SSB.
And in recent weeks I have heard KL7, VK6, ZLs, KH6s, ZSs, 9L5, CE,
CN2, EA9, HC8, OH0, P33, TX3A (Chesterfield Is), TFs, 6 JAs, and a
myriad of the more common countries, all on 40 meters, and I worked
them all. In addition, I heard several Chinese, Indonesian, and KH2
stations, multiple times, for long periods of time, and as late as
10 AM!
Point #3: What is going on with 40 meter propagation? While the
short skip is less frequent, about half the US is coming through
during the daytime with 59+ signals. And at night time, tuning
around 7.125-7.2 MHz SSB, the world is at our finger tips. With the
increasing wealth of Third World countries, kilowatts and 3-4
element Yagis are everywhere now, and these guys come through like
gang-busters, most any night. Look especially around their sunset
and sunrise times. Or look between 5-10 AM local time to Asia and
the Pacific. VK6s, JAs, China, Hong Kong, Malaysia, are there, often
in our portion of the phone band. A few recent examples: Last week
around 6 PM I heard a guy in NYC working JAs, who were then working
the Caribbean. Then a couple of ZSs broke in to say they were
copying Japan, the US, and the Caribbean all 59+. Amazing!
Another example, around 9 PM I heard a KL7 calling CQ through S-9
QRM, and I worked him arm chair copy both ways. I have heard VK6s
(the antipodal point on the globe from central Ohio) coming through
on 40 SSB both in the morning hours and in the late afternoon
routinely during the past month. As I recall, November conditions
were usually well down from September and October, but not this
year.
Point #4: I have often tuned 7.125-7.200 MHz and heard nothing, just
noise. Of course, the shortwave broadcast stations have vacated this
spectrum, but with the long skip we have large segments of unused
frequencies, in the evening hours. As I continue tuning the silent
frequencies, all of a sudden I will hear a 5-7 to 5-9+ station from
Brazil, Argentina or Europe call CQ, and I usually work them on my
first call.
So there is plenty of DX out there to be had. And vertical/ground
plane antennas that are far short of the optimum 120 radials, will
get you through far better than most dipoles or inverted Vs. So grab
a fishing pole, a rebar, some duct tape and 14 wire and go see for
yourself! Go get your share of the DX. They're listening for you!"
Whew! Thanks, Bob. Believe it or not, that was edited down for
brevity. To read more of Bob's writing, check out his narrative on
his trip to Brazil in the July-August 2005 issue of the NODXA Rag at
http://www.papays.com/rag0805.pdf.
If you would like to make a comment or have a tip for our readers,
email the author at, k7ra@arrl.net.
For more information concerning radio propagation, see the ARRL
Technical Information Service web page at,
http://www.arrl.org/tis/info/propagation.html. For a detailed
explanation of the numbers used in this bulletin, see
http://www.arrl.org/tis/info/k9la-prop.html. An archive of past
propagation bulletins is at http://www.arrl.org/w1aw/prop/.
Monthly propagation charts between four USA regions and twelve
overseas locations are at http://www.arrl.org/qst/propcharts/.
Instructions for starting or ending email distribution of this
bulletin are at http://www.arrl.org/w1aw.html#email.
Sunspot numbers for November 26 through December 2 were 0, 0, 0, 0,
0, 0, and 0 with a mean of 0. 10.7 cm flux was 74.7, 73.7, 72.9,
72.1, 72.4, 72.2, and 71.4 with a mean of 72.8. Estimated planetary
A indices were 6, 2, 3, 1, 2, 0 and 1 with a mean of 2.1. Estimated
mid-latitude A indices were 3, 0, 2, 1, 1, 0 and 0 with a mean of 1.
NNNN
/EX
