QST de W1AW  
Propagation Forecast Bulletin 38  ARLP038
>From Tad Cook, K7RA
Seattle, WA  September 29, 2017
To all radio amateurs 

SB PROP ARL ARLP038
ARLP038 Propagation de K7RA

Over the past week we saw solar indices decline. Lower activity
persists, and the uptick in solar activity on September 2 to 10,
when sunspot numbers were 71, 96, 122, 122, 79, 94, 89, 49 and 38
and solar flux was 100, 120, 140, 121, 133, 129, 117, 107 and 100
will probably not be seen again til the upside after solar minimum,
perhaps in 2021 or 2022.

But perhaps we will be surprised again.

Average daily sunspot numbers declined over the past few weeks from
87.3 to 45 and 13.6, and average daily solar flux from 114.1, to
97.6 and 72.6.

Average daily planetary A index was 18, 27.3 and 21.1 while average
mid-latitude A index (measured in Virginia, at a magnetometer on
Wallops Island was 16.7, 18.3 and 17.1.)

Predicted solar flux is 70, and 85 on September 22 and 23, 90 on
September 24 to 28, 105 on September 29, 115 on September 30 through
October 6, then 110, 85, 76, 75, 74, and 73 on October 7 to 12, 72
on October 13 and 14, 75 on October 15 to 19, 95 on October 20, 110
on October 21 to 25, and 115 on October 26 through November 2, then
110, 85 and 76 on November 3 to 5.

Predicted planetary A index is 5, 8, 12, 16, 8, 25 and 35 on
September 22 to 28, then 20, 18, 15, 12, and 8 on September 29 to
October 3, 5 on October 4 to 10, 25 on October 11 to 13, then 20,
15, 12 and 10 on October 14 to 17, 5 on October 18 and 19, then 8,
18, 12, and 8 on October 20 to 23, 20 on October 24 to 26, then 18,
15, 12 and 8 on October 27 to 30, and 5 October 31 through November
5.

Geomagnetic activity forecast for the period September 22 thru
October 18, 2017 from F.K. Janda, OK1HH of the Czech Propagation
Interest Group.

'Geomagnetic field will be:

Quiet on September 22, 24
Mostly quiet on September 23, 26, October 18
Quiet to unsettled September 25, October 5 and 6
Quiet to active on September 27, 30, October 1 to 4, 7 and 8, 10 and
11, 14 to 17
Active to disturbed on September 28 and 29, October 9, 12 and 13

Amplifications of the solar wind from coronal holes are expected on
September 27 to 29, October (1,) 2 to 5, (8, 11 and 12,) 13 to 15,
(16 and 17)

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

Brad Miskimen, N5LUL of Amarillo, Texas wrote:

'VHF conditions were amazing this morning (19 Sep 17) at 1400 UTC. I
was listening on our local 146.94 repeater frequency and heard other
repeater id's coming around. N0UGO in North Platte, NE and WB5BRY in
Lubbock, TX both loud and clear. Found the correct PL tone to access
UGO had had a nice QSO with KR1STO for about 10 minutes.'

Thanks to D. Moore for sending this piece about the biggest solar
flares in a decade, earlier this month:

bit.ly/2w9SFCM

Don't forget to hit 'continue' at the bottom to read the rest of the
story.

Dick Bingham, W7WKR of Stehekin, Washington wrote:

'Well, it won't be long now until I begin signing w7wkr on
630-meters instead of wd2xsh/26.

I registered yesterday at the UTC's website

https://utc.org/plc-database-amateur-notification-process/

so will begin using my own call by mid-October.

PLEASE register your call/location at the website listed above so we
can keep the few KHz allotted to us free of PLC signals as time goes
on.

73 Dick/w7wkr and wd2xsh/26 at CN98pi'

Chuck Zabriskie, KE5HPY, in Houston, Texas wrote recently: 

'Thought one could add WSPR to the propagation aids discussed in
your recent report. With the high flux report, I put my homebrew 10m
WSPR rx on-line and happily recorded TI, CE, ZL and multiple VK
calls for the first time in a long while. Of course those were
regular events a couple of years ago but now are rare enough to me
get excited to look at the logs.'

I seem to be out of synch with Dr. Tamitha Skov, as she has been
issuing new spaceweather videos shortly after I post a new
propagation bulletin, so all I can report is the latest from the
previous week:

https://www.youtube.com/watch?v=gIhABAXtV4Y

Try searching for her videos to find later issued reports.

For more information concerning radio propagation, see the ARRL
Technical Information Service at
arrl.org/propagation-of-rf-signals.  For an explanation of
numbers used in this bulletin, see
arrl.org/the-sun-the-earth-the-ionosphere.

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

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

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

Sunspot numbers for September 14 to 20, 2017 were 11, 13, 13, 13,
12, 11, and 22, with a mean of 13.6. 10.7 cm flux was 74.2, 72.8,
72.1, 72.2, 72.2, 70.6, and 73.9, with a mean of 72.6. Estimated
planetary A indices were 25, 36, 30, 17, 22, 8, and 10, with a mean
of 21.1.  Estimated mid-latitude A indices were 19, 30, 23, 13, 21,
6, and 8, with a mean of 17.1.