NJDTechnologies

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OFF AIR but hope to be back by 1115z Saturday morning if I don't oversleep

Continued improvements for domestic openings; Trans-Pacific openings were slow to develop and were limited to path between VK and JA; W5EST presents ‘VIEWPOINT: HOW WILL 630M RF PATHS BEHAVE IN THE 8/21/17 SOLAR ECLIPSE?’

– Posted in: 630 Meter Daily Reports, 630 Meters

The details for May 22, 2016 can be viewed here.

IMPORTANT REMINDER: Neither 630-meters nor 2200-meters are open to amateurs in the US yet.  Please continue to be patient and let the FCC finish their processes.  Click here to view the proposed “considerate operators” frequency usage guide for 630-meters under Part-97 rules that was developed with the input of active band users.

Reports suggest that noise was down significantly overnight compared to several recent sessions.  This morning the most active lightning containing storms were located along the gulf coast although NOAA indicates that there are large regions of rain across North America, potentially contributing to elevated precipitation static.  Domestic openings appear relatively normal for this time of year while long-haul paths have generally taken a step back early in the session except for successful reports between VK and KH6.  I expect this path to improve as the morning progresses.

11-hour North American lightning summary

 

Geomagnetic conditions continue at quiet to elevated-quiet levels as the general trend is one of improvement, at least “on paper”.  The Bz continues to point to the South this morning but has been highly variable over the course of the session and solar wind velocities are beginning to trend downward into the 450 km/s range with a few excursions to near 530 km/s.  DST values are significantly more variable than the previous session but like other values, are generally trending close to the centerline.

 

 

 

Al, K2BLA / WI2XBV, reported a 100% improvement for the session, decoding two WSPR stations.  Al indicates that noise was less than yesterday but still moderately high.

Ken, K5DNL / WG2XXM, indicates that he reported WD2XSH/15  and he received reports from 31 unique stations including WH2XCR, ZF1EJ and five Canadian stations.

Neil, W0YSE/7 / WG2XSV, reported that he decoded three WSPR stations with WG2XXM as his best DX and he received reports for thirteen unique stations including WE2XPQ and WH2XCR.

Larry, W7IUV / WH2XGP, provided reports for four WSPR stations and he received reports from 26 unique stations.  As W7IUV, Larry provided reports for four WSPR stations.

WH2XGP session WSPR activity (courtesy NI7J)

 

Phil, VE3CIQ, reported that he decoded three WSPR stations including  WH2XGP who was his best DX.  Phil was decoded by sixteen unique stations, all of which were within 1,000 km of his station.

Ernie, KC4SIT / WI2XQU, reported that propagation was weak and noise was high in spite of no local storms.  Ernie indicates that he heard no stations last night but I am gathering that local ground wave stations are hearing him.

Dave, N4DB, reported a better session as he decoded eight WSPR stations including the recently elusive WH2XGP at a distance of 3489 km.

Mike, WA3TTS, reported “…Good condx overnight, XGP audible,,, I started the eveing off with the SE EWE antenna from 0000 to 0200, then SW EWE antenna 0200 to 0800, then NW EWE antenna 0800 to SR… 9 stations decoded on 630m band”:

“I ran split IF 2 receivers for 630m/2200m. WH2XND 92 decodes and WH2XZO 2 decodes on 2200m band. I think it was Doug’s first attempt to TX on 2200m:”

Trans-Pacific reports (excluding KL7 and KH6) can be viewed here.

Hideo, JH3XCU, provided this link detailing VK -> total JA DX and VK -> JA peak S/N for the session.

Roger, VK4YB, reported, “RN was low again, but station was QRT for most of the evening owing to operator error. By the time I got back on air it was sunrise in Calif. If there was any TP, I missed it.”  Roger received reports from JA1NQI/2 and  JA3TVF and shared two-way reports with WH2XCR.

John, VK2XGJ, provided early reports for WH2XCR following a receiver change.  John explains:

“Local sunset was 0700 z, I don’t know if it is the change of radio or not.  Generally I use the Kenwood R 5000, tonight the Icom R8500 just to be different.”

Regional and continental WSPR breakdowns follow:

North American 24-hour WSPR activity

 

European 24-hour WSPR activity

 

Central / Asiatic Russian 24-hour WSPR activity

 

Japanese 24-hour WSPR activity

 

Oceanic 24-hour WSPR activity

 

Eden, ZF1EJ, provided reports for one WSPR station and he was reported by seven unique stations.

ZF1EJ 24-hour WSPR activity

 

Laurence, KL7L / WE2XPQ, concentrated reports along the western coast of North America with an emphasis on the Northwest.  He provided reports for four WSPR stations and received reports from three unique stations.  He shared two-way reports with WH2XCR and those reports are included in Merv’s report detail below.

WE2XPQ 24-hour WSPR activity

 

Merv, K9FD/KH6 / WH2XCR, provided reports for VK3HP and VK5FQ and he shared two-way reports with WE2XPQ and VK4YB.  He received reports from VK2XGJ not long after local sunset in Australia.  Most of Merv’s mainland reports were concentrated along the western portions of North America in addition to reports of WG2XXM.  Merv was off air prior to sunrise and may be experiencing more power utility problems.  DX report details can be viewed here.

WH2XCR 24-hour WSPR activity

 

Jim, W5EST, presents, “VIEWPOINT: HOW WILL 630M RF PATHS BEHAVE IN THE 8/21/17 SOLAR ECLIPSE?”:

“Some scientific teams have been preparing for years for this August’s “Great American Solar Eclipse.”   Fortunately for MF/LF amateurs and experimenters, we can simply keep our existing TX and/or RX equipment running all morning in the Pacific Northwest, or from about noon to mid-afternoon in middle North America and East Coast.  You may even have some antenna and equipment improvements in mind for your station by then.

For the general public, and much of the scientific community, the visible Sun will be the main center of interest as the Moon hurtles along in its orbit some quarter million miles from us and casts its shadow of the moving Moon itself onto the North American continent.  Down here, that shadow will move  3-4 times the speed of a passenger jet from Oregon to South Carolina.

As radio people, we in our own homes have a special privilege – to experience the eclipsed MF/LF/HF ionosphere as that shadow scans the radio reflecting regions high above us. And WSPR can even gather numerical information to boot.  Only August’s real solar eclipse will tell us for sure what it will do on the 630m mystery band.

I want to occasionally blog any background information that might help us interpret the results of whatever solar eclipse operations MF/LF operators muster in August.  Earlier this month,* this blog offered some description of the upcoming eclipse, some history of amateur receptions in earlier solar eclipses, and some favorable 630m eclipse signal levels.

Now let’s introduce one more resource –radio path simulation – in preparation for these eclipse radio efforts.  What is radio path simulation and what can it do for us?

Radio path simulation can provide a path-specific graph of expected relative SNR behavior during that 90 minute eclipse. Given a path from your transmitter TX station to a particular receiving RX station, simulation can provide a relative SNR curve over the duration of the eclipse from partial to total to partial, or just varyingly partial. Even if you are receiving RX-only, simulation can provide a relative SNR curve for a given path to your RX from a particular TX station over the time of the eclipse.

For 630m radio path eclipse simulation purposes, I’ve prepared an extensive set of calculations based on my assumptions about the ionosphere, combined with publicly-available astronomical calculations of the solar eclipse track timewise geographically across the continent.**

The WSPR database compilation of your 630m WSPR receptions during the solar eclipse, or the decodes your TX station yields at distant RX stations, can also be graphed for comparison with the graph from radio path simulation for this eclipse. The extent that the comparisons diverge can suggest, as they probably will, that my assumptions about the ionosphere need to be corrected or improved and in what way.

If you want to contribute better wisdom, please e-mail mrsocion@aol.com ASAP.  I hope to blog simulated eclipse SNR curves for various paths near, along, or across the eclipse track and you may see your station call letters accidentally selected even if you may not be available for eclipse day.

Here’s a list of as many of my assumptions as possible:

  1. 630m 1-hop and 2-hop will essentially follow a great circle during the eclipse.
  2. Some propagation skew may occur about when the oval of totality crosses the RF path.  Within +/-6 minutes of the center of totality intersecting the path, some SNR wiggle may occur when the RF path grazes an edge of the oval of totality. The simulation will not try to graph or model such wiggles. Their timing will be left for analysis from the WSPR database .
  3. Ionospheric winds, if any, will not significantly disturb ionization changes due instead to the shadowing effect of the solar eclipse on the D-region and E-region.
  4. The E-region will present a 630m RF-reflecting contour that’s the same height above the earth everywhere on the continent, except perhaps in and around the oval of totality where an upward hollowing may occur.
  5. The D-region will present a 630m RF-reflecting contour that’s the same height above the earth everywhere on the continent, except perhaps in the oval of totality.
  6. The simulation will assume 80km high reflecting contour in daytime E-region and a 40km high daytime D-region. These daytime-lowered altitudes are lower than at night, and their values can be adjusted if need be.
  7. D-region absorption to 630m RF generally declines or increases as the percentage of the Sun’s disc remaining unobscured by the Moon’s shadow declines or increases during the eclipse.
  8. However, D-region 630m RF absorption responds to the Sun percentage like an RC circuit responds to a varying voltage source. Then take 10log10 to convert to dB.  I assume the time constant is 30 minutes, adjustable.  This means that the RF absorption may continue to decline somewhat before increasing after totality passes a particular geographic place. In other words, the RF signal peak on a path may be delayed a few minutes after totality crosses the 630m RF path line.
  9. D-region daytime 630m RF absorption is assumed 15dB per RF-ray crossing. On 1-hop, 15dB ascent and 15 dB descent loss sum to 30dB daytime RF absorption compared to night. On 2-hop, two hops each with 15dB ascent and 15 dB descent loss sum to 60dB daytime RF absorption compared to night.
  10. The solar eclipse will present respective different Sun percentages to each RF-ray crossing of the D-region depending on the geographic locations above which each RF-ray crossing occurs.  Simulation will keep track of absorption at each D-region RF ray crossing and add them up, minute by minute.  1-hop presents two D-region crossings for eclipse enhancement, while 2-hop presents four D-region crossings for eclipse enhancement.  Simulation will help tell whether reception of 2-hop is likely or unlikely.
  11. D-region daytime 630m RF absorption is directly proportional to solar ionizing flux (Sun percentages x sine of Sun elevation angle).  During the eclipse, the sun elevation angle will be assumed steady while Sun percentage will decline and increase rather dramatically.

TU & GL!

Endnotes:
*1: This blog May 4, 5, 8, 9, 10.
**2: https://eclipse.gsfc.nasa.gov/SEpath/SEpath2001/SE2017Aug21Tpath.html (scroll 20% for Table, col. 3 Central Line.

Additions, corrections, clarifications, etc? Send me a message on the Contact page or directly to KB5NJD gmail dot (com)!