ARRL Propagation Bulletin


Welcome to the “ARRL Propagation Bulletin” update from Big Island ARRL News.

Views expressed in this Amateur/Ham Radio news summary are those of the reporters and correspondents.

Content supplied by HQ ARRL, 225 Main Street, Newington, CT, 06111, W1AW, and Tad Cook (K7RA).

Accessed on 06 April 2019, 1955 UTC, Post 925.

Source (via email):

http://www.arrl.org/w1aw-bulletins-archive/ARLP014/2019

Please click link or scroll down to read the complete bulletin.

SB PROP @ ARL $ARLP014
ARLP014 Propagation de K7RA

ZCZC AP14
QST de W1AW  
Propagation Forecast Bulletin 14  ARLP014
From Tad Cook, K7RA
Seattle, WA  April 5, 2019
To all radio amateurs 

SB PROP ARL ARLP014
ARLP014 Propagation de K7RA

Sunspots have been coming and going, and now this week they
returned.

No sunspots were seen from January 31 through March 4, then from
March 13 to 17, and again March 25 to 30.  They returned on Sunday,
March 31 but only lasted four days, through Wednesday, April 3.
Sunspot numbers over that period were 14, 17, 18 and 17.

Average daily sunspot numbers declined from 16 in last week's report
to 9.4 this week. Average daily solar flux declined from 75.2 to
69.5. Average daily planetary A index rose from 3.7 to 8.4, while
average middle latitude A index went from 3.9 to 7.3.

Predicted solar flux is 70 on April 5 to 11, 69 on April 12 and 13,
70 on April 14 to 22, then 69, 68, 69 and 69 on April 23 to 26, 70
on April 27 through May 7, 69 on May 8 to 10, and 70 on May 11 to
19.

Predicted planetary A index is 12, 10, 12 and 8 on April 5 to 8, 5
on April 9 to 11, then 15 and 8 on April 12 and 13, 5 on April 14 to
23, then 10, 8, 5, 8, 10 and 8 on April 24 to 29, 10 on April 30
through May 1, 8 on May 2 and 3, 10 on May 4, 5 on May 5 to 8, then
15 and 8 on May 9 and 10, and 5 on May 11 to 19.

In last week's bulletin ARLP013 we presented a message from Dr.
Tamitha Skov, WX6SWW in which she complained about overhyped space
weather stories in the mainstream press. I think we may have seen
another example this week from a British tabloid:

https://bit.ly/2I95JkS

This was published on Wednesday when the planetary A index was
slightly unsettled at 12, on Thursday it was 8, and predicted values
of 12, 10, 12 and 8 follow on April 5 to 8 and 5 on April 9 and 10.
This is not expected to cause blow outs of "electrical transformers
and power stations," as mentioned in the article, nor "leave people
vulnerable to cancer".

The story was picked up by another UK publication:

https://bit.ly/2YQ0yMI

Note they quote Spaceweather.com predicting only "a minor stream of
solar wind."

The Washington Post also addressed this issue:

https://wapo.st/2CHJKxS

F. K. Janda, OK1HH sends us his geomagnetic activity forecast for
the period April 5 til May 1, 2019.

"Geomagnetic field will be: 
Quiet on April 9, 14, 17 to 19, 
Quiet to unsettled on April 5 to 8, 16, 20, 26, 
Quiet to active on April (15, 21 to 23,) 24, 27 to 29, May 1 
Unsettled to active on April (10 -) 11, 13, 25, 30 
Active to disturbed April (12) 

Solar wind will intensify on on April (6,) 12 and 13, 15 and 16, (19
to 22,) 23 and 24, (25 to 30, May 1)

Parenthesis means lower probability of activity enhancement."

Mike Schaeffer, KA3JAW in Easton, Pennsylvania wrote on Thursday
night:

"Spring season high frequency band Es is slowly emerging out of its
dormant state. On Friday, April 5, 0100 UTC (Thursday, April 4, 9:00
PM EDT local) I was monitoring the 11 meter Citizen Band (27 MHz)
and noticed a swooshing, light fading condition on channel (28),
which is normally inactive. All of a sudden like a flick of a light
switch Es emerged from the states of GA, AL and LA. The average
distance from Easton, PA was about 1,000 miles. Activity lasted for
a brief time of about ten minutes. This occurred one hour,
thirty-two minutes after local sunset (7:28 PM). 10.7cm flux = 70."

Thanks to John Pieszcynski, W2FV of Trout Lake, Washington for his
tip on problems with satellite debris during solar minimum, from Dr.
Tony Phillips of Spaceweather.com:

https://bit.ly/2CZyxsD

At 2345 UTC on Monday, April 1 Steve Sacco, NN4X in Florida sent
this query about something I otherwise heard nothing about:

"Is there some kind of solar event going on?  I don't see anything
of note at SolarHam.com.  

Several folks across the U.S. are hearing an extremely broad-band
noise in the 30M area. I'm not able to peak it from any heading with
my 2L Yagi."

The latest from Dr. Skov:

https://youtu.be/_dRoznalAg4

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 at
http://arrl.org/propagation-of-rf-signals. For an explanation of
numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere.

An archive of past propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation. More good
information and tutorials on propagation are at http://k9la.us/.

Monthly propagation charts between four USA regions and twelve
overseas locations are at http://arrl.org/propagation.

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins.

Sunspot numbers for March 28 through April 3, 2019 were 0, 0, 0, 14,
17, 18, and 17, with a mean of 9.4. 10.7 cm flux was 68.4, 68.8,
69.4, 69.5, 69.3, 70.8, and 70.6, with a mean of 69.5. Estimated
planetary A indices were 11, 7, 4, 11, 8, 6, and 12, with a mean of
8.4. Middle latitude A index was 10, 6, 3, 9, 6, 5, and 12, with a
mean of 7.3.
NNNN
/EX