NJDTechnologies

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Current Operating Frequency and Mode

CQ 474.5 kHz CW and alternately tuning 472 kHz - 475 kHz for signals.

VK4YB experienced a good night of reports across North America as geomagnetic storm conditions and elevated solar wind velocities continue; QRP CW Skimmer reports for several on RBN; Generally good domestic propagation but a bit noisy in some areas; W5EST presents: ”How Equatorial Path Loss Can Be So Low”

– Posted in: 630 Meter Daily Reports, 630 Meters

The details for October 12, 2016 can be viewed here.

The UTC amateur registration database is hereEven if you don’t think you will use these bands, REGISTER!  Doing so prevents UTC from future PLC coordination in these bands near your QTH.  While amateur interference to PLC systems is a myth and PLC systems are migrating away from RF, there is no reason to give them a reason to do something weird in the future.

HERE are a  few mode specific comments addressing where modes are located now and probably where they are best placed in the future.

 

Most of North America was in the clear, at least as far as lightning-rich storms were concerned.  Rain continues to be a factor in many areas, including at WG2XKA in Vermont, increasing rain static significantly.  A few storms were present from the mid-Atlantic region out to sea in addition to active weather off of the East coast of Florida.  From Mexico and along the US Gulf coast, a few more storms continue to create noise this morning.  I am hopeful that Central America will quieten down shortly.  Its not terribly noisy but it seems noisier than it should be for mid-October.

11-hour North American lightning summary

 

Geomagnetic conditions continue at G1 storm levels as a coronal hole remains geoeffective according to Solarham. The Bz is pointing to the South and solar wind velocities are averaging near 530 km/s.  DST values have decreased to relatively deep negative levels for a few reporting periods but its easy to seen when the Kp was at unsettled levels versus above storm limits.  In spite of the storm conditions, its all been relatively orderly compared to some recent much stronger events.

 

 

 

Roelof, PA0RDT, reported that VO1NA’s CW signals 477.7 kHz deteriorated during this session:

VO1NA at PA0RDT (courtesy PA0RDT)

 

Reverse beacon network reports for the session follow:

Courtesy Reverse Beacon Network

 

John, WA3ETD / WG2XKA, operated a CW beacon through the session in order to test the CW skimmer / RBN from his QTH in Vermont.  He received reports from WZ7I located in Pennsylvania.  John was operating with just 60-watts TPO.

Trans-Atlantic report details can be viewed here.

Dave, AA1A / WD2XSH/17, received reports from 44 unique stations including DH5RAE, DK6UG, DK7FC/P, DL4RAJ, EA2HB, F1AFJ, F4DTL/2, F59706, G8HUH, ON5TA, PA0RDT and PA7EY.

Doug, K4LY / WH2XZO, reported that he decoded thirteen WSPR stations and he received reports from 43 unique stations including two-way reports with WH2XCR.

Neil, W0YSE/7 / WG2XSV, reported that he “…was heard by 23 this time, including Florida, but I heard only 5, maybe due in part to the fact that I used a T coax coupler to share the e-probe with the 2200m receiver. I did catch many decodes of Ron’s 137 kHz wspr beacon as a result.This morning I sent out some CW and was immediately decoded by Don’s (ve6jy) skimmer.” (data posted earlier in this report)

WG2XSV session WSPR activity (courtesy W0YSE/7)

 

Ernie, KC4SIT / WI2XQU, reported that “All things considered WI2XQU had a good night being heard as far as Hawaii, WH2XCR.. 46 unique stations decoded my signal last session and I decoded 8 stations.”

Al, K2BLA / WI2XBV, provided reports for fourteen WSPR stations including three reports for VK4YB and sixteen reports for WH2XCR.  Al received reports from 33 unique stations including stations in VE3, VE4, VE6, VE7,  and two-way reports shared with WH2XCR.  Al also reported my CW at RST 589  through moderate  noise but  he indicates that signals on the band were strong this morning.

Mike, WA3TTS, reported that he decoded fourteen WSPR stations overnight, including “…XCR, XGP, XXP, ZF1EJ. missed VK4YB, NE ant early, SW antenna late to past SR…”

Dave, N4DB, reported that he decoded thirteen WSPR stations.  He also reported my  CW at audible levels in Virginia.

Courtesy N4DB

 

WG2XIQ CW at N4DB (courtesy N4DB)

 

Trans-Pacific report details, excluding KL7 and KH6, can be viewed here.

Hideo, JH3XCU, submitted this link detailing DX -> JA decode totals and DX -> JA S/N peaks for the session, as reported on the Japanese language 472 kHz website.

Roger, VK4YB, indicated that “More storms forecast for Brisbane for the next 4 days. Heard 5, heard by 35, including VE4XC (first time), WG2XXM, KU4XR, and WI2XBV (best DX).”  Roger received reports from CF7MM, JA1NQI, JA1PKG/2, JA3TVF, JE1JDL, JR1IZM,  KL7KY, KU4XR, VA7JX, VE4XC, VE6JY, VE6XH, VE7AB, VE7BDQ, VE7CNF, W7IUV, WE2XPQ, WG2XXM, WI2XBV and WI2XJQ.   He shared two-way reports with WH2XCR and WH2XGP.

Ken, K5DNL / WG2XXM, provided reports for fifteen WSPR stations including VK4YB and he received reports from 54 unique stations including nine Canadian stations.  He also shared two-way reports with WH2XCR and ZF1EJ.

Rick, W7RNB / WI2XJQ, indicated that “Band appears to be in good shape here. TA was pretty good and VK4YB was back in again.”  Rick  provided reports for six WSPR stations and he received reports from 22 unique stations.  His unique report details can be viewed here.

Ward, K7PO / WH2XXP, received reports from 57 unique stations including ZL2AFP and VK4YB

WH2XXP session WSPR activity (courtesy NI7J)

 

Larry, W7IUV / WH2XGP, provided reports for fifteen WSPR stations and he received reports from 43 unique stations including ZL2AFP and VK2XGJ.   He shared two-way reports with VK4YB.  As W7IUV, Larry provided reports for eight WSPR stations including VK4YB.

WH2XGP session WSPR activity (courtesy NI7J)

 

I started CW early, well before sunset at 2220z to test some ground wave paths.  Nothing earth-shattering to report for this session but WG2XXM reported me at RST 589 about 30 minutes before sunset at a distance of 200-miles.   I QRT’ed for the night at 0038z, after dark.  This morning was a bit better in spite of a few nagging lightning crashes from phantom storms that don’t appear to be all that close to Texas and specifically the US mainland.  Dave, N4DB, reported me at strong, audible levels, as evidenced by his screen capture presented earlier.  AA4VV started off my reverse beacon network reports at 1059z after a bit of a dry spell with reports that peaked at +7 dB S/N at his sunrise. K2BLA reported me at RST 589.  The band was in good shape but maybe a bit unstable.

Regional and continental WSPR breakdowns follow:

North American 24-hour WSPR activity

 

European 24-hour WSPR activity

 

Asiatic Russian 24-hour WSPR activity

 

Japanese 24-hour WSPR activity

 

Oceania 24-hour WSPR activity

 

Eden, ZF1EJ, returned to air after completing antenna repairs.  He provided reports for eleven WSPR stations and he received reports from 38 unique stations.  Eden shared two-way reports with WH2XCR.

ZF1EJ 24-hour WSPR activity

 

Laurence, KL7L / WE2XPQ, experienced a weird juxtaposition from the previous session but after an explanation, it makes sense: “…reduced tx power by 10dB and down to 20%ish (25W carrier to ant) overnight for test – reports down because of this but PNW way down”.  He provided reports for two WSPR stations including VK4YB and he received reports from two unique stations. He shared two-way reports with WH2XCR.  The ionic fog remains pretty thick at his latitudes.  DX report details can be viewed here.

WE2XPQ 24-hour WSPR activity

 

Kevin, KL7KY, provided reports for three WSPR stations including VK4YB.  DX report details can be viewed here.

KL7KY 24-hour WSPR activity

 

Merv, K9FD/KH6 / WH2XCR, provided reports for twelve legitimate WSPR stations. He shared two-way reports with VK4YB, ZL2AFP, ZF1EJ and WE2XPQ. Merv received reports from 41 unique stations including 7L1RLL4, JA1NQI, JA1PKG, JA1PKG/2, JA3TVF, JE1JDL, JH3XCU, JR1IZM, KL7KY, VK2XGJ, VK3ALZ, VK5AKK, VK7TW and ZL4EI.  DX report details can be viewed here.

WH2XCR 24-hour WSPR activity

 

Jim, W5EST, presents “How Equatorial Path Loss Can Be So Low“:

“Yesterday’s analysis suggested remarkably low 630m path loss in the KH6-VK/ZL path portion of N.Am.-VK/ZL propagation—due to propagation 7000-9000 km that’s loss-equivalent to 2-hop multihop in the half-as-lengthy N.Am.-KH6 path portion.  How can one explain it?

Perhaps there’s some low-loss mode like chordal hop, very long F-hop, or ducting over much of the equatorial distance?  Any one or more of these conceivably could play a role.  But the not-unlimited altitude of reflection for chordal hop or F-hop does impose a limit on distance that even a chordal hop or F-hop can occupy.

Referring to today’s illustration, let’s consider a less mysterious explanation. Rays fan out laterally from the XGP transmitter in N. America and only a few of them (middle yellow arrow) reach Hawaii’s XCR RX (purple). Many more of the rays miss Hawaii altogether (two outsideyellow arrows).

Meanwhile, many RF rays (green arrows) from N. America that bypass Hawaii can indeed get to VK/ZL and augment TP SNRs “down under.” This multiple-ray idea was discussed and statistically analyzed in this blog http://njdtechnologies.net/092517/ .  For distance ratios under 2.0, the SNR is enhanced by low loss on equatorial path that goes through the formula to create higher loss on the N. America-Hawaii path and drive down the ratio of Equatorial path loss to N. America-Hawaii path loss for VK/ZL-destined TP signals.

Two related concepts of path loss are afoot here.  First, there’s comunications path loss that reduces SNR, which is what 630m operators care about.  If the ionospheric reflective contour surfaces near the equator are variously oriented to support many RF rays (green arrows), then you could say this first path loss is really a “physical” path loss partially compensated by a path gain represented by the many contour surfaces.

A second concept, the just-mentioned physical path loss, tells how many dB of XGP RF power get lost on the way from around Hawaii to Australia, not counting the effect of the many contour surfaces. That second path loss is perhaps of more interest to ionospheric scientists.

The formula I’ve been using (Endnote*) is focusing on that comunications path loss. The formula uses peak SNRs on each path in a trio like XGP-xcr, XCR-vk4yb, XGP-vk4yb.  If all XGP rays destined for Australia’s VK4YB were accounted for on their way past Hawaii, then the subtraction method would cancel out the number of rays so to speak and focus on the physical path loss in dB independently of them.  But since Hawaii only samples a few XGP rays, compared to all that are on the way to Australia, reception SNR in Hawaii causes the formula to understate the physical path loss those Australia-bound XGP rays encounter between Hawaii and Australia.

Meanwhile, Merv’s XCR-vk4yb rays (red) face more distance that permits more skew and brings more directions of such XCR TX rays (red middle arrows)  to Australia than could correspondingly get from XGP to the XCR RX itself (middle yellow arrow).  Compared to all the XGP-vk4yb rays (green arrows) the power in the XCR Australia-bound rays becomes less understated and via the formula doesn’t so much understate the physical path loss of Australia-bound rays fanning out from N.America toward and either side of Hawaii (green arrows between yellow arrows).

Plain old multihop, or multihop with some chordal hop or F-hop assistance, can explain why value 2.0 of Distance Ratio is a critical value. XGP-xcr is probably 2-hop. Whatever propagation modality is providing low equatorial path loss KH6-VK/ZL probably gives way to a mixture of prop modes near Distance Ratio 2.0.  At distance ratios over 2.0, a 15 dB lossier propagation mode such as 4-hop multihop predominates.  4-hop sky reflections would encounter the equatorial anomaly at much different reflection points and evidently permit far fewer rays to reach Australia than with distance ratios under 2.0.

If path length is not very critical to ducting, how can one explain critical value 2.0 by means of duct propagation?  One way would reject the conclusion that the graphs on Oct. 11 steeply ramp near value 2.0 of Distance Ratio.  If the more gradually increasing trend line truly describes the data points better, then a mode of propagation like ducting would imply gradually increasing path loss with distance.

How can we be sure what propagation is happening on this TP equatorial path portion when peak SNRs out of 36 days are exclusively used to create the graphs?  What kind of propagation is happening on other more ordinary nights and times of night? That’s where the convolution and statistical approach blogged on 9/25/17 supported the illustrated multiple ray idea. Nevertheless, discussion and proposed explanations of TP propagation will continue actively among 630m operators. Tell us what you think and how you reached your conclusions so this blog can carry the best reasoning for many points of view. Perhaps someday we’ll find out for sure what’s happening “up there!”

TU & GL on LF/MF!”

*ENDNOTE:  Recall from yesterday’s blog that loss difference is approximately represented by:
               L23/23 – L12/12 =  SNR12 –(SNR23 + TRP1–TRP2)
If fewer 630m RF rays compose SNR12 than SNR23, it means that SNR12 is understated. When SNR12 is understated, that also understates the left-side path loss L23/23 of the KH6-VK/ZL path relative to the path loss L12/12 of the N.America-KH6 path.  Such understatement underlies the otherwise puzzlingly low path loss calculated for the KH6-VK/ZL path when Distance Ratio is less than 2.0.

Click to Enlarge

 


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