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ARRL Propagation Bulletin ARLP004 (2015)

ARLP004 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 4  ARLP004
From Tad Cook, K7RA
Seattle, WA  January 23, 2015
To all radio amateurs 

ARLP004 Propagation de K7RA

Average daily sunspot numbers for January 15-21 dropped 50.7 points
relative to the previous seven days, to 61.9. Average daily solar
flux declined from 151.3 to 126.2. For the past ten days sunspot
numbers have remained below 100. This benchmark has no special
significance, but the last time there were this many consecutive
days with double-digit sunspot numbers was October 5-20, 2014.

Geomagnetic numbers indicated more stable conditions, with average
daily planetary A index declining from 9.6 to 6.4, and average daily
mid-latitude A index dropping from 8 to 4.7.

The latest prediction from USAF/NOAA has solar flux at 130 and 135
on January 23-24, 130 on January 25-26, 135, 140 and 145 on January
27-29, 135 on January 30 through February 1, 130 on February 2-3,
125 on February 4-6, 130 on February 7-9, 125 on February 10-11 and
120 on February 12-13. Solar flux reaches a low of 115 on February
18, and peaks again at 135 on February 26-28.

Predicted planetary A index is 15 on January 23-24, 18 on January
25-26, 8 on January 27-28, 12 on January 29-30, 15 on January 31
through February 1, then 12, 15, 12 and 5 on February 2-5, 10 on
February 6-7, 8 on February 8-9, 5 on February 10-12, then 8, 5 and
12 on February 13-15, 10 on February 16-18, and 8 on February 19-20.

F.K. Janda, OK1HH predicts geomagnetic activity will be active to
disturbed on January 23, quiet on January 24, mostly quiet January
25, active to disturbed January 26-28, quiet January 29, active to
disturbed January 30, mostly quiet January 31, disturbed February
1-2, quiet to unsettled January 3, quiet to active January 4, active
to disturbed February 5, quiet to active February 6-8, mostly quiet
February 9-13, quiet to active February 14, and quiet to unsettled
February 15-17.

Randy Crews, W7TJ of Spokane, Washington posted these observations:

"Thanks for the link and update from NASA in your last bulletin. A
couple things I wanted to add to amplify on the trend and outline a
unique historical perspective.

"Cycle 24's peak is past and will fall into the ranks of the lower
Sunspot Cycles 10, 12, 13, 14, and 16. NASA's article pointed out
Cycle 24 being the smallest since Cycle 14 in 1906. It will probably
mirror Cycle 12 or 13 finishing with a smoothed sunspot number in
the high 70s low 80s plus or minus. A few additional points make
this cycle unique in addition to the second peak being higher than
the first: In past strong sunspot cycles (21, 22, and 23) we have
had what I would call the 'top 3' being 3 outstanding years of high
solar activity (the year prior to the peak, the year of the peak,
and the year after where Solar flux values have averaged between 150
and 225).

"Tying this observation to Cycle 23 (a lower but normal cycle in
2000, 2001, and 2002) during these peak years propagation on 10, 12,
and 15 meters was outstanding almost ALL the time. Cycle 24 has
bestowed just a little over one year of this type of propagation -
late 2013 to present. Graphically seen from the Solar activity
report from this Web link:


"Things become more interesting with the fact Cycle 24 will
obviously finish with a smoothed sunspot number of less than 100.

"This is the first time this has occurred since Cycle 16 finished in
1933 (over 80 years ago!).

"Link with the corresponding data:


"Graphically, Cycle 24 will fit into the BIG picture as follows,
accurately done by K9LA:


"Connecting the dots from the graphs, historically there have been
decades of high and low solar activity spanning several sunspot
cycles. As one source has pointed out, got most of our radio amateur
lifetimes we have experienced some of the highest solar activity
periods in history, 1950 to 2009. The Graph from NASA of the current
trend pretty well sums up the overall direction:



"Cycle 24 will be a low cycle very likely to be followed by several
other low or even lower cycles - supported by the current and
historical data.  Make the most of the current band conditions and
upcoming DXpeditions - it certainly looks as if we are heading
toward a 'Propagation Winter.'"

Thanks, Randy.

I do not know if we are headed toward a "propagation winter" and
quiet Sun or not, although plenty of experts much smarter than me
might think so. I like to remember when some of the best minds made
a case for the upcoming Cycle 24 to be the biggest ever, and of
course it did not turn out that way.

I hope to be around for the next cycle, might even see the one after
that, but I doubt I will see three cycles out. When I started as a
Novice it was Cycle 20, right after the big one, and it sure seemed

We heard from Rich Zwirko, K1HTV of Amissville, Virginia. He wrote:

"Other than a few Es openings, 6 meters has been pretty quiet the
past few weeks. I think that we have seen the last of any 50 MHz E-W
F2 skip for this solar cycle and possibly future cycles. Magic
Banders will have to rely on summer multi-hop E-skip and SSSP
chordal openings for the next long haul 6 Meter DX contacts."

He also mentioned that his son, Andy, K1RA of Warrenton, Virginia is
operating a RaspberryPi as a multi-band HF WSPR beacon running only
10 milliwatts. (RaspberryPi is a tiny and inexpensive computer that
is popular as a microcontroller. See )

This not only changes bands automatically according to a timing
cycle, but the microprocessor actually generates the RF and connects
directly to the antenna feedline, via some simple filtering. The
signal is output as a square wave, but the harmonics are easy to
filter out and at 10 mw are simple to control. The beacon callsign
is KW4VA and the grid locator is FM18cr.

Andy wrote:

"I've been running a Raspberry Pi and the JamesP6000 WSPRryPi code
under my club call KW4VA recently, which you can read about at the
following URL for info, links and DX spot maps:


"In short the RPi CPU can natively generate about 10 milliwatts of
RF from 0-250 MHz off one of its GPIO pins. The WSPR code is based
off some earlier code developed in the UK to allow generation of FM
signal at 100 MHz:


"I'm running one of the IO pins to external wire antennas.  I was
stuck at about 7500 km for a few years until this past week when I
was spotted by ZS6AF on 17m at 13322 km, then in the last two days
by ZL1RS on 20m at 13811 km and finally VK2DDI on 30m at 15729 km.
Here are the spots from the WSPR propagation database:

"Timestamp       MHz        SNR Reporter RGrid  km

2015-01-19 08:22 10.140240  -27 VK2DDI  QF55hf  15729 
2015-01-15 10:18 14.097116  -24 ZL1RS   RF64vs  13811 
2015-01-08 21:14 18.106032  -22 ZS6AF   KG54mk  13322

"I've been playing with very low power WSPR for a while now.  In the
past I'd been using a PIC controller by AA0ZZ and a 0-60 MHz DDS
board by N2APB that also put out about 10 mw and was using a 30m
dipole in the attic at 30'. Then I was stuck on one band at a time,
usually 10m.  I'm sure the outside dipoles and wires at 45' help a
bit. With the use of the RPi though I've have been able to
automatically band hop. I think this too has helped to increase my
DX spots by other WSPR stations. I run 80, 40, 30, 20m every 2 mins
at night and 20, 17, 15, 12 10m every 2 mins during the day."

This weekend are the ARRL January VHF Contest (see
and and the CQ World Wide 160 meter
CW Contest (

For the 160 meter CW contest we would like to see very quiet
geomagnetic conditions. OK1HH predicts disturbed conditions on
Friday, then quiet on Saturday and mostly quiet Sunday. Quiet is a
good outlook, although I don't know what the effect of Friday's
conditions might be on the rest of the weekend if they are

NOAA/USAF predicts an A index of 15 on Friday and Saturday and 18 on
Sunday. This is neither quiet nor disturbed, but I would
characterize it as unsettled conditions.

Let's hope for dead quiet geomagnetic conditions over the entire
weekend. Have fun!

Following up on last week's link to an article about the National
Radio Quiet Zone and the people who flock there, N7SO sent another

We also heard from a ham who used to work there, Rob Welsh, N3RW,
who wrote:

"I was previously employed at NRAO Green Bank (see on a Milky Way mapping project. Given that
NRAO GB is in the National Radio Quiet Zone, I was given permission
to put my QRP rig on the air on 17 meters using the HF Bruce array
at the observatory entrance. Few stations I worked believed that I
was running just 5 W. With about 100 feet of RG-58 between the dorm
and the antenna, I bet I was radiating more like 3 W at best."

Info on a Bruce Arrays:

Rob also wrote in a subsequent email:

"The Bruce Array at the entrance to the Green Bank site is a rebuild
of the antenna used by physicist Karl Jansky who in the 1930s
studied radio noise for the Bell System's HF radio circuits.

"Jansky eliminated all noise sources except one which occurred 4
minutes earlier each day. In conversations with others, he was told
that the stars rise 4 minutes earlier than solar time.

"Jansky may have been the first to discover galactic radio noise as
he was recording the radio noise emitted by the Milky Way.

"One of my tasks while employed at GB was to perform a VSWR vs.
frequency plot of the Bruce Array. The center frequency, as I
remember, was about 20 MHz, so with a QRP antenna tuner I was able
to find a match for the 17 meter band.

"Radio astronomers consider the HF bands as 'low frequency' for
astronomical observations. There has been an increase in HF
observations at HF with the purpose of identifying galactic sources
at lower energy levels.

"Also at the entrance to the site is a rebuild of Grote Reber's
(W9GFZ, SK) 30 foot parabolic antenna. Reber read Jansky's published
work and went about measuring galactic radio noise at VHF.

"See my article in the December 2009 issue of QST titled 'How the
Ionosphere Was Discovered.'

"The callsign, W9GFZ, has been issued to NRAO and used at both the
Green Bank site and at the Very Large Array in New Mexico. I've
observed at both sites.

"You may see the antenna systems at GB by using:
and on the left side of the main page, surf to 'telescopes.'  My QSL
card has the 45 foot antenna on the front. That is the system I used
to map a quadrant of our galaxy at wavelengths of 3.5 and 2.1 cm.
Big antennas sure are interesting!"

If you would like to make a comment or have a tip for our readers,
email the author at,

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at For an explanation of the
numbers used in this bulletin, see An archive of past
propagation bulletins is at More good
information and tutorials on propagation are at

Monthly propagation charts between four USA regions and twelve
overseas locations are at

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bulletins are at

Sunspot numbers for January 15 through 21 were 62, 75, 49, 78, 62,
57, and 50, with a mean of 61.9. 10.7 cm flux was 131.4, 124.7,
121.9, 125.8, 130, 125.6, and 123.9, with a mean of 126.2. Estimated
planetary A indices were 6, 7, 7, 5, 5, 4, and 11, with a mean of
6.4. Estimated mid-latitude A indices were 5, 6, 5, 3, 2, 5, and 7,
with a mean of 4.7.