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OFF AIR - but back tonight after dark for more CW

The widespread trans-Atlantic openings of previous sessions dissolved but didn’t disappear completely; Strong storms in Oceania mean poor receiving conditions down under; WI2XSV grant approved while WI2XUD assigned to W6IEE

– Posted in: 630 Meter Daily Reports, 630 Meters

The details for March 16, 2016 can be viewed here.

It was a super-quiet night across much North America after I declared last week that the last quiet nights of the season were behind us.  Who knew?  There were a few storms reported in the Northwestern US and British Columbia but I have not heard from anyone in the region this morning indicating that the noise conditions changed any of their medium wave activities during the evening.  Propagation was relatively good across North America but there has been a shift as many of the trans-Atlantic openings that spread into the South and West in previous session disappeared, leaving New England with the bulk of the reports.  It was also a difficult night in Oceania as major storms with lots of lightning impacted many of the population centers along the East coast of Australia during the evening.  John, VK2XGJ, reported that he was doing his best to listen for WSPR and JT9/65 through the noise.

11-hour North American lightning summary

 

Geomagnetic conditions remain quiet although not as quiet as the previous session.  The Bz continues very near the centerline, ranging slightly to the North and South through the course of the session.  Solar wind velocities continue in the low category, averaging near 375 km/s.  DST values were tempered during this session, trending downward after a few days that showed some improvements.  I suspect this is a temporary setback.

 

 

 

Trans-Atlantic openings were down for this session, with no Europeans reported in North America and only WG2XPJ and WD2XSH/17, both located in New England, making it across the pond.  Report details can be viewed here.

WG2XPJ -> DL4RAJ, F1AFJ, F59706, G0LUJ, G0MJI, G3XKR, LA2XPA/2, PA0O, PA0RDT, PA3ABK/2

WD2XSH/17 -> DF2JP, DH5RAE, DJ0ABR, DK7FC, DK8FTA, DL/PA0EHG, DL0HT, DL4RAJ, DL6II, F1AFJ, F59706, G0LUJ, G0MJI, G3XKR, G4CPD, G4ETG, G8HUH, G8LCO, M0XDK, ON5TA, PA0O, PA0RDT, PA1SDB, PA3ABK/2, PA3EGH, PA7EY, PE1RKT, PI4THT

Paul, N1BUG, reported very low noise but is left wondering what happened to all of the trans-Atlantic openings.  He provided decodes for  thirteen WSPR stations, including VE7BDQ and WH2XGP on the high latitude transcontinental path.

Al, WI2XBV, reported near record cold in Florida so base current must have been through the roof.  He decoded nine WSPR stations and was decoded by 39 unique stations.  He also reports that he shared two-way reports with WH2XCR and Canadian stations in VE2, VE6, and VE7.

Doug, K4LY / WH2XZO, reported that he decoded fifteen WSPR stations and he was decoded by 46 unique stations. Doug adds that this session was “not quite as good as night before as strong winds continue to blow down branches on my wire antennas here.”

Rick, W7RNB / WI2XJQ, enjoyed transcontinental openings to the East coast and ZF1EJ for the third night in a row.  Rick provided reports for ten WSPR stations and was decoded by 35 unique stations.  Rick’s unique report details can be viewed here.

Mike, WA3TTS, reported improvements on transcontinental paths to the Pacific Northwest, British Columbia and Hawaii.  Mike indicates that in the previous session, he could only report a single decode for WH2XCR.  He provided these statistics:

Trans-Pacific openings were diminished through this session as well as poor weather conditions in Oceania. Report details, excluding KL7 and KH6, can be viewed here.

Hideo, JH3XCU, posted links to two tables showing NA/VK -> JA DX totals and NA/VK -> JA peak S/N for the session.

Roger, VK4YB, reported extremely strong storms in his area and very high noise, requiring him to take a break in the late evening.  He was able to return to air after weather conditions calmed down a bit.  By 1251z, he indicated that, “QRN is finally on the wane. WH2XCR should come in later. No DX heard at this time. JA beam is like a dummy load tonight.  630m/160m stats with VE6XH, 160m 8 spots, best -9, 630m 3 spots, best -21.”  Roger received reports from VE6XH, W7IUV, and WI2XBQ.

Ward, K7PO / WH2XXP, received reports from 61 unique stations including JA1NQI.  The path to VK and ZL appears to be completely cutoff.

WH2XXP 24-hour WSPR activity (courtesy NI7J)

 

Larry, W7IUV / WH2XGP, provided reports for thirteen WSPR stations and was decoded by 49 unique stations.  As W7IUV, Larry provided reports for twelve WSPR stations including VK4YB.

WH2XGP 24-hour WSPR activity (courtesy NI7J)

 

The OET website indicates that the grant application for Joe,  WA9CGZ / WI2XSV, has finally been approved after quite a delay.  I suspect that the delay was a byproduct of the administration change as well as internal changes at the FCC plus other factors.  Also notable, Jason, W6IEE, was assigned WI2XUD.  Hopefully his grant moves through the system quickly.  I expect that N1BUG’s grant will be approved shortly.

It was another strong session due to very low noise conditions here in Texas.  Initial reports seemed later than previous sessions but I started earlier so I think thats why it seemed that reports took openings longer to begin.  There was a lot of activity on 160-meters due to the number of African DXpeditions on the air.  I had intended on calling CQ, which I really should have done, but opted out due to a significant amount of diverted activity and operators on 160-meters.  Overnight WSPR activity yielded no trans-Atlantic reports although two-way reports with WH2XCR were solid.  The path to WE2XPQ has been eluding me for a few weeks now, however.  WSPR reception report details were improved over the previous session, which can be viewed here and my WSPR transmission report details can be viewed here.  This morning’s CW session was uneventful.  There were a few pings heard but nothing definitive in spite of very quiet band conditions.  I will be back  on 474.5 kHz CW in the morning and possibly in the late evening tonight.

WG2XIQ 24-hour WSPR activity

 

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, provided reports for fourteen WSPR stations and was decoded by thirty unique stations including two-way reports with WH2XCR.

ZF1EJ 24-hour WSPR activity

 

Laurence, KL7L / WE2XPQ, was watching ionosondes this morning looking for answer about why the band was such a bust this morning.  He got a late start due to high winds but managed reports from JA1NQI and shared two-way reports with WH2XCR.  Report details can be viewed here.

WE2XPQ 24-hour WSPR activity

 

Merv, K9FD/KH6 / WH2XCR, reported a late start due to his time wading through the pileups on 160-meters.  Merv managed reports from 7L1RLL4, JA1NQI, JA3PKG, and JE1JDL.  He provided reports for VK3ELV and shared two-way reports with VK4YB and ZF1EJ.  Coverage of North America continues to be pretty good.  DX report details can be viewed here.

WH2XCR 24-hour WSPR activity

 

Jim, W5EST, presents, “GET A GRIP ON 630M GROUND WAVE: PART 6, GW REFLECTIONS”:

“The last several days have discussed ground wave from the standpoints of actual reception on 630m, GW  in presence of hills, EIRP, the TX antenna and interference between sky wave (SW) and ground wave (GW), and FCC GW E-field curves.

Today, let’s turn to more FAQs:

Question 5: If ground wave losses are I2R in the ground along which the ground wave travels, does geography beyond some distance that suddenly has low conductance stop ground wave?

JH Answer: In reply, I’d suggest that the impedance discontinuity at least partially reflects the ground wave. Here’s how.

First of all, RF current in the ground is vital for supporting ground wave, not just a lossy byproduct.  Otherwise, low conductivity ground would support as much or more ground wave as high conductivity ground does.  Compare GW with sky wave (SW).  SW propagates well through a vacuum, which has zero conductivity.  That’s just the opposite of the way GW works.

Turning to the matter of ground impedance discontinuity now, picture a vertical antenna mounted over a very large circular disc of conducting ground, with zero conductivity beyond its edge. See today’s illustration.  The ground current at the edge of the disc is zero, which you can also say is equal to incident ground current minus an equal and opposite ground current to cancel it. The latter ground current would establish a GW reflection that returns incident ground wave energy inward.

For another example, think of a vertical antenna mounted at one end of an infinitely long rectangular conducting ground plane that’s only a few wavelengths wide.  Since ground current must be zero at the boundary of the ground plane, and the ground wave energy must go somewhere, I presume a reflected wave having an opposite phase distribution would result at the long edges and cause ground wave energy to zigzag. Each reflection would bounce off at an angle to satisfy the zero- current condition at the boundary.

So GW works not unlike a transmission line that is terminated with a shorted end or an open end. One also analyzes the reflection process in a transmission line with a canceling voltage or canceling current to meet the zero voltage or zero current boundary condition in each case.

Question 6:   Is ground wave partially reflected off a moderate discontinuity in ground conductivity?

JH Answer: Yes, for similar reasons as in reply to the previous question.  By analogy, some reflected power likewise occurs on a transmission line terminated with just a moderate mismatch at the far end.

Laport (1952, p. 15)* recognizes ground wave reflections, as do the results of Zhou et al. (2011)** doing advanced modeling of back-reflection of ground wave encountering hill terrain. In the case of ground wave, the discontinuity should be several wavelengths wide and long. Otherwise the ground wave will diffract over or around the discontinuity.

*Laport:  http://www.athm.net/andreas/RadioAntennaEngineering-printer/

**Zhou, L., Xi, X., Liu, J. and Yu, N. “LF Ground-Wave Propagation Over Irregular Terrain,” Antennas and Propagation, IEEE Transactions on, Vol. 59(4): 1254–1260, April 2011. (Requires subscription or institutional access.)

Question7:   Is ground wave affected by a moderate discontinuity in properties of the air above the ground even over uniformly conductive flat terrain?

JH Answer: Yes, for similar reasons a partial reflection or bending of the GW can happen, as with a transmission line that is terminated with a moderate mismatch at the end.  On 630m I think folks would like to understand whether such reflection is at all significant and if so, what happens under what circumstances.

Cold fronts and warm fronts can affect the effective capacitance of the air in which the RF electric fields travel.  We could use a lot more experience about what frontal geometries enhance or disturb LF/MF prop of either sky wave or ground wave type.  At the RX end, I think the fronts that would be particularly interesting would be the ones not associated with noisy storm systems.  Nearer the TX end, stormy and non-stormy fronts would be interesting provided they are far from the RX.  Presumably, the fronts could have an effect on propagation anywhere along a ground wave path. For sky wave, the effect would presumably occur in places where RF is traversing the troposphere on either side of surface reflection locations where a ground bounce happens in sky wave n-hop mode.

If you have some 630m experience with any of these reflections or refractions, please tell us for this blog.  TU!”


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