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ARRL Propagation Bulletin ARLP025 (2021)

ARLP025 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 25  ARLP025
From Tad Cook, K7RA
Seattle, WA  June 18, 2021
To all radio amateurs 

ARLP025 Propagation de K7RA

Solar activity was lower this week, with average daily sunspot
number declining from 34.9 last week to 13.9 this week. This average
was affected by the one day with no sunspots, Saturday, June 12

Average daily solar flux dropped from 77.7 to 75.2. The Penticton
observatory in British Columbia (the source for 10.7 cm solar flux)
did not report a noon reading on Wednesday, June 16, so we averaged
the morning (76.9 at 1700 UTC) and afternoon readings (77.1 at 2300
UTC) to come up with 77 as a reasonable approximation.

Normally the local noon reading (2000 UTC) is the official number
for the day. You can get the three daily readings direct from the
Dominion Astrophysical Observatory at, .

On Thursday the noon flux reading was 85, higher than its been since
May 26, when it was 88.

Predicted solar flux for the near term is 75 on June 18-20, 80 on
June 21-25, 77 on June 26-28, 78 on June 29 through July 7, 79 on
July 8-10, 77 on July 11-13, 76 on July 14-16, 78 on July 17, 80 on
July 18-20, then 78 on July 21, and 77 on July 22-25.

Predicted planetary A index is 12 on June 18, 5 on June 19-25, 7 on
June 26, 5 on June 27 through July 4, then 15, 10 and 8 on July 5-7,
5 on July 8, then 8 on July 9-11, then 10, 12, 20 and 12 on July
12-15, and 5 on July 16-22, then 7 on July 23.

I am very excited about this forecast for the current solar cycle
25, in which we are now seeing only the early stages:

Forbes Magazine is reporting this:

"Geomagnetic activity forecast for the period June 18-July 15, 2021.
"Geomagnetic field will be:
quiet on: June 20, 24, 27-28, July 1, 10, 15
quiet to unsettled on: June 18-19, July 11, 14
quiet to active on: June 21, 23, 25-26, 29-30, July 2, 6-9
unsettled to active: (June 22, July 3-5, 12-13)
active to disturbed: - nothing!
"Solar wind will intensify on: June (18-19,) 21, (22-24, 29,) 30,
July (2,) 3, 5, 10-11.
- Parenthesis means lower probability of activity enhancement.
"F.K. Janda, OK1HH (from Czech Propagation Interested Group
compiling this geomagnetic activity weekly forecast since January

"Hi Tad,

"On June 4th-5th there was a very good 10M sporadic-E opening to
Europe which started well before I started at 2200 UTC. Ian, MM0TFU
was first in the log on 10 SSB with 58 reports both ways. Andy,
LZ2HM was next on CW with a good signal; no other EU stations within
1000 KM were worked. Most all of my QSOs were with the UK and
Ireland; I worked all 4 major UK DXCC countries. EI6JK and EI3EIB
were both loud after 2400 UTC, last QSO was 0022 UTC with a total of
about 20 EU QSOs. Signal levels were very good from most stations.

"On June 11th 10M was open on Es to somewhere most of the day. At
1900 UTC stations from FL and the Gulf Coast were loud including K4D
on Dog Island, IOTA NA-085, in the Big Bend area of the Gulf. Around
2000 UTC, I worked MO, NE, and MI. Then at 2200 UTC three very loud
VE3 stations from North Central Ontario. AC2CZ/VE2 in Montreal, PQ
running 12W to a dipole was next. Starting 2347 UTC I worked KS, MI,
MN, and IL before 2 double hop Es contacts after 2400 UTC with N7WWH
near the coast of north OR and KM6YSS in Canyon County, ID. At 0027
UTC, XE1XR in central Mexico was S9+ and easily worked followed by
Luis, XE2B at 0036 UTC. All contacts were on SSB.

"The ARRL June VHF contest was the 12th into the early hours of the
14th which found some sporadic-E most of the time. On 6M SSB and CW,
I made 130 QSOs with my poor performing Yagi. The Es started around
2230 UTC with stations in TN and TX and northern FL. Sunday morning
the 13th, Es started with W0WP in IA Grid EN42 and spread to other
W0s followed by an intense opening to the S and SW with my closest
contact being Ed, K3DNE in EM94 SC. Many GA stations were very loud
as were many in FL and some in TX and OK. I also caught Nova Scotia
and Newfoundland. At 1546 UTC, I found EA8BPX in the Canary Islands,
grid IL18, and was able to get through. In the afternoon many local
stations on FT8 were working EU stations mostly in Spain, France,
and Portugal. I worked F4ARU in France at 1834 UTC on SSB. Late
around 0100 UTC, the band was still open well to EM19 (NQ0P as loud
as a nearby local), EM49, and EM18.

"Today, the 17th there was an opening to Spain on 10M at 1950 UTC to
EA7HZ and EA3AR. My noise level was very high. MM0TFU was reporting
hearing beacons near my QTH and farther up the East Coast at
2200-2300 UTC. At 0012 UTC on the 18th, I worked VP9KD in Bermuda
who was S9+ for a new band slot on 10M SSB. 

"73, Jeff N8II."

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

For more information concerning shortwave radio propagation, see and the ARRL Technical Information
Service 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

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

Sunspot numbers for June 10 through 16, 2021 were 29, 13, 0, 22, 11,
11, and 11, with a mean of 13.9. 10.7 cm flux was 73.3, 77.3, 77.6,
68.9, 76.8, 75.5, and 77, with a mean of 75.2. Estimated planetary A
indices were 5, 10, 10, 7, 4, 17, and 14, with a mean of 9.6. Middle
latitude A index was 5, 11, 8, 7, 7, 15, and 15, with a mean of 9.7.


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