Propagation de K7RA




Propagation Forecast Bulletin 51  ARLP051

From Tad Cook, K7RA

Seattle, WA  December 16, 2016

To all radio amateurs


Average daily solar indices over the past week were lower than the previous seven days, with average daily sunspot number declining from 40.9 to 13, and average daily solar flux dropping 10 points from 82.2 to 72.2.

Geomagnetic indicators were higher, with average daily planetary A index rising from 4.9 to 13.3, and mid-latitude A index from 3.4 to 9.

Predicted solar flux is 72 on December 16-20, 75 on December 21-22, 88 on December 23-27, 86 on December 28-29, 88 on December 30 through January 1, 86 on January 2-3, 84 and 82 on January 4-5, 80 on January 6-7, 73 on January 8-9, 75 on January 10-14, 82 on January 15-16, 86 on January 17-18, 88 on January 19-23, 86 on January 24-25 and 88 on January 26-28.

Predicted planetary A index is 5 on December 16, 8 on December 17-18, 15 on December 19-20, then 25, 28, 12, 10 and 8 on December 21-25, 5 on December 26 through January 1, then 8, 10, 20 and 22 on January 2-5, 16 on January 6-7, 8 on January 8, 5 on January 9-12, 8 on January 13-14, then 12, 16, 22 and 30 on January 15-18 then 12, 10 and 8 on January 19-21, and 5 on January 22-28.

From Petr Kolman, OK1MGW, “the geomagnetic activity forecast for the period December 16 to January 11, 2017:

“Geomagnetic field will be:

  • Quiet on December 16, 30-31, January 10-11
  • Mostly quiet on December 17, 26-29, January 8-9
  • Quiet to unsettled on December 18-19, 23-25, January 1-3
  • Quiet to active on December 20, January 6-7
  • Active to disturbed on December 21-22, January 4-5

“Amplifications of the solar wind from coronal holes are expected on December 17-23, January 2-7.”

Evan Rolek, K9SQG of Beavercreek, Ohio wrote: “For me, poor propagation is something that is LOVED! Why? It is easier to make A-B antenna comparisons and to identify which antenna works the best, then I’ll be ready when propagation improves. (Not for me since it will be 5-10 years when it gets better, and I’ve already submitted my application to the Silent Key Club.)”

In conversation with Lee Gordy, W4KUT, I asked him about 10 and 15 meters at the peak of Cycle 19.

“Just after the peak of SS Cycle 19, my only antenna was a 40 meter dipole (up abt 30 or 40 feet), fed with 75 ohm coax…my xmt VFO was pretty much stuck on the low end of 40 CW.

“I had a Viking Ranger II, which had a Pi Network output. It could load up bed springs. So, I could trick the 40 mtr ant into radiating just about ANY frequency, but with way less than the advertised output power.

“One summer afternoon there was a knock on the door. It was my ham buddy, K4AIP (Roger, aka Rozy), out of breath, he’d just bicycled over from across town…(Not everybody in those days had telephones).  ‘Hey man, I just worked Nigeria on 15! Fire up your rig. I bet he’s still there.’

“We went into the shack and tuned up my 40 mtr ant on 15 AM phone (this was before the proliferation of SSB). And yep, there was the Nigerian at 20 over S9…WOW!

“Because of the mismatch, I probably had less than 5 watts ERP. I gave the guy a call…HE CAME BACK to me!  WOW! “From Atlanta to Nigeria and back, on less than 5 watts. I’ve still got that QSL card – 5N2FEL.

“Cycle 19…it’ll probably never be that good again – Lee, W4KUT”

Regarding propagation during last weekend’s ARRL 10 Meter Contest, Jon Jones, N0JK of Lawrence, Kansas wrote:

“Sporadic-E popped up on both 6 and 10 meters Saturday Dec. 10. The Es allowed contestants in the ARRL 10 meter contest to fill their logs.

“10 was wide open to W4, W5 and west to AZ, CO and NM from Kansas 1645z to 1800z. My first contact was VP5CW at 1645z via double hop Es. Worked several stations in Colorado which is a fairly short distance.

“I went out fixed mobile later and found strong Es on 10 meters from 1930-2200z to W1, W2 and W3. MUF at this time seem lower, probably just above 30 MHz Worked VHFers W3EP and K1RO. Only F-layer DX I worked was PX2B at 2052z.”

Sam, K5SW EM25 Oklahoma wrote me about 6 meter Es Dec. 10:

“The minor E season of Dec/Jan had 50 MHz open today, Dec. 10th. From 1700z-1800z I worked FM05, FM17, and FM16 stations. I heard beacons from that area. Maybe we will have some E-skip during the Jan VHF contest, too.”

Jon wrote this on Sunday:

“The 10M Contest was a bust Sunday.  Only Q I had was with W2GDJ NY at 1904z. “Ran 5 W to mobile whip both days.”

Also got this report from Bil Paul:

“Of course the 10m contest was happening this weekend. I wasn’t at all sure 10m would be open. But I went up to check it out.

“DX-wise, I found South America coming in: Peru, Chile, and Argentina. I was able to contact CE2DK in Chile and a Mexican station with 10w SSB and a vertical dipole.

“I heard an American East Coast station coming in with a peculiar flutter for a short time. “Bil Paul KD6JUI Dixon, CA”

Gary, K7GS of Spokane, Washington wrote regarding the 10 meter contest:

“Conditions in the inland Pacific Northwest were poor at best. Good TEP openings to SA on Saturday along with some east coast and southeast propagation. On Sunday no east coast or Midwest propagation but we did experience some TEP to central SA plus one or two W6s via short skip. Let’s hope it will not be much worse in the coming few years.”

A couple of interesting links from Brian Calvert, KG7MU, regarding out of phase solar magnetic fields:

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 December 8 through 14 were 14, 12, 0, 13, 13, 14, and 25, with a mean of 13. 10.7 cm flux was 74.8, 72.9, 72.2, 71.4, 70.8, 71.2, and 72.4, with a mean of 72.2. Estimated planetary A indices were 23, 25, 16, 15, 6, 4, and 4, with a mean of 13.3. Estimated mid-latitude A indices were 14, 18, 11, 11, 5, 2, and 2, with a mean of 9.


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