sexta-feira, 24 de fevereiro de 2017

ARLP008 Propagation de K7RA

ARLP008 Propagation de K7RA

At 0124 UTC on February 22 Australian Space Weather Services issued
a geomagnetic disturbance warning for February 22-24:

"The effect of a high speed solar wind stream from a recurrent
coronal hole is expected to raise geomagnetic activity to active
levels from 22 to 24 February with the possibility of minor storm
periods on 23 and 24 February.

"Increased geomagnetic activity expected due to coronal hole high
speed wind stream from 23-24 February 2017.

"Geomagnetic Activity Forecast
23 Feb:  Unsettled to Active, isolated Minor Storm periods possible
24 Feb:  Unsettled to Active" on February 22 issued a Solar Wind Advisory: "Earth
is about to enter a stream of solar wind flowing from a hole in the
Sun's atmosphere. NOAA forecasters estimate a 60% chance of polar
geomagnetic storms on February 23rd as the solar wind speed quickens
to 550 km/s or more. Arctic sky watchers should be alert for auroras
on Thursday and Friday nights. See updates and sightings at"

Over the past week, February 16-22, average daily sunspot number
compared to the previous seven days increased from 17.6 to 19.1,
while average solar flux increased from 75.1 to 78.5.

Geomagnetic indicators were slightly higher, with average planetary
A index increasing from 4.7 to 11.3, and average mid-latitude A
index changing from 2.9 to 9.

Predicted solar flux (on February 22) is 84 on February 23-24, 83 on
February 25, 82 on February 26 through March 1, 78 on March 2, 73 on
March 3-4, 72 on March 5-7, 73 and 74 on March 8-9, 75 on March
10-14, then 74, 75, 77 and 79 on March 15-18, 82 on March 19-24,
then 80, 78 and 76 on March 25-27, 75 on March 28-29, 73 on March
30-31, and 72 on April 1-3.

Predicted planetary A index is 18 and 12 on February 23-24, 8 on
February 25-26, then 16, 24 and 20 on February 27 through March 1,
15 on March 2-5, 8 on March 6, 5 on March 7-14, then 10, 20, 15, 10
and 12 on March 15-19, 10 on March 20-21, then 12, 15, 20 and 18 on
March 22-25, then 8, 30, 25 and 20 on March 26-29.

Geomagnetic predictions are included as usual this week from F.K.
Janda, OK1HH, but first is a shorter term forecast from Thomas Bayer
of the Department of Geomagnetism at the Budkov Observatory:

"Geomagnetic activity forecast for the period February 24-March 2, 2017

"Quiet: episodically Feb 25-26
Unsettled: Feb 25-Mar 2
Active: Feb 24-25, 28, Mar 1
Minor storm:  possible Feb 24, 28
Major storm: 0
Severe storm: 0

"Geomagnetic activity summary: 'We expect unsettled conditions
during the next week. Tomorrow, Friday, February 24, we expect an
active episode, unlikely minor storm event. The other active episode
is probable at February 28-March 1. The activity is probable at
active/minor storm again.

"'The other days, we expect at most unsettled conditions. During the
coming weekend, the activity can briefly decrease to quiet level,
then, we expect at most unsettled conditions till the active episode
mentioned above."'

"Tomas Bayer
RWC Prague
Institute of Geophysics of the ASCR, Prague
Department of Geomagnetism
Budkov observatory (BDV)"

"Geomagnetic activity forecast for the period February 24-March 22,

"Geomagnetic field will be:
Quiet on March 7-8, 11-12, 15
Mostly quiet on February 25-26, March 6, 14
Quiet to unsettled February 24, March 9-10, 13, (21-22)
Quiet to active on February 27, March 3-5, 16, 19-20
Active to disturbed on February 28, March 1-2, 17-18

"Amplifications of the solar wind from coronal holes are expected on
February 27-28, March 3-5, (6-8)

"Remark: Parenthesis means lower probability of activity enhancement
and/or lower reliability of prediction.

"F.K. Janda, OK1HH Czech Propagation Interested Group OK1HH
compiling weekly forecasts since 1978 e-mail: ."

Jon Jones, N0JK (Editor of The World Above 50 MHz, the QST monthly
VHF column since 2011) sent some notes on last weekend's ARRL
International CW DX Contest. (The Phone contest weekend will be on
March 4-5, 2017).

"Feb 19 5:47 PM:

"To Tad, The 10 meter band was like 'day' and 'night' between
Saturday and Sunday of the ARRL DX CW contest.

"I operated fixed mobile single band on 10 with a full size 1/4 wave
whip both days. Saturday was nice sunny warm weather, but almost a
dead band. I found PJ2T and PJ4X, both weak with QSB, and worked. I
called XR2K for over an hour with luck. Did he mean NO Luck? - Ed.
That was it. Is this how 10 meters will be at solar minimum?"

(Often in the past, N0JK used a shortened CB antenna, commonly used
during the CB craze in the 1970s, on the back of his car for 10
meters while parked in his driveway in Lawrence, Kansas, so a full
quarter wave at 8 feet, 3 inches is quite an improvement).

"10 meters was so much better Sunday. It was a flashback to how 10
was in the 2016 ARRL DX CW when the solar flux was around 100. I set
up, turned on the radio and 100 watt PY2NY was blasting in on 28.034

"CE, CX and PY were strong for hours. Caribbean and Central American
contest stations were up and down the band. Not bad for a solar flux
of just 77.

"Worked PJ7AAA at 1856z who was running just a 'K3 and Buddipole.'
XR2K in the log with one call at 1940z. Picked up the KH6LC multi-op
at 1955z for Hawaii on what sounded like side-scatter. They were
about 559, but hearing well. KH6LC said in their 3830 post, 'We
watched 10 meters all weekend which paid off Sunday morning when it
opened for us at 1715z.'

"KH6LC made 488 North American contacts on 10.

"10 meters folded for me around 2200z. I dropped down to 15 and gave
a very loud KH6LC (op Fred K6IJ) a contact and then A31MM. Fred,
K6IJ made 1690 contest contacts from KH6LC on 15 meters. The solar
flux was the same, 77 on both Saturday and Sunday. Why was 10 so
much better on Sunday?"

(Note: Solar flux was rising at 74.4, 76.6, 78.1 and 80.1 on Friday
through Monday).

"Feb 19 7:11 PM

"Addition - TI8/AA8HH observed, 'Tough going on Saturday on 10
meters but Sunday was better.'

"Feb. 22 E51DWC and VP6EU Pitcairn worked many in North America on
10 meters.

"Feb. 23 I heard VP6EU with a good signal on 10 meter SSB with a
large pileup. I could not get through so.

"Dropped down to 12 Meters, and VP6EU was on 24.895 MHz CW in the
clear CQing, and in the log with one call at 2139z. Also worked TX5T
Australs on 24.897 MHz. Solar flux of 83, K of 3.

"VP6EU tried 6 Meters Feb. 22 at 2005z, but I am unaware of any
contacts. A G-1 geomagnetic storm may occur Feb 23/24, if the
geomagnetic field gets active.

"73 -- Jon N0JK"

According to the ARRL DX Bulletin, the CQ World Wide 160-Meter SSB
Contest is this weekend. Check for

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
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  Instructions
for starting or ending email distribution of ARRL bulletins are at

Sunspot numbers for February 16 through 22, 2017 were 23, 14, 13,
23, 25, 19, and 17, with a mean of 19.1. 10.7 cm flux was 74, 74.6,
76.6, 78.1, 80.7, 82.5, and 83.2, with a mean of 78.5. Estimated
planetary A indices were 9, 20, 16, 10, 10, 4, and 10, with a mean
of 11.3. Estimated mid-latitude A indices were 7, 16, 11, 9, 8, 4,
and 8, with a mean of 9.
Propagation Forecast Bulletin 8  ARLP008
From Tad Cook, K7RA
Seattle, WA  February 24, 2017
To all radio amateurs

Nenhum comentário:

Postar um comentário