Tales from the southern hemisphere

A very welcome WSPRer has recently appeared on a regular basis - CP6EE - from Bolivia.  Welcome, because there are precious few WSPR stations anywhere in the southern hemisphere.  Even the former British colonies like ZL, VK and ZS and their ex-pat operators now have very few WSPR stations.

Both CP6EE and DP0GVN saw increases in signal levels as a small disturbance of the geomagnetic field passed around the local magnetic midnight period here last night.  Note the sharp spike in Z component direction at the centre of the plot. 

Z component, eastern Greenland.  Image: Tromso Geophysical Laboratory.

CP6EE's received signal here responded to this disturbance, rising from low levels at 21:00UT and peaking at 21:20UT.  The signal continues to be stronger than before the disturbance for a long time after it occurs, so the increased signal has nothing to do with the greyline at either point on the globe:

CP6EE heard at MW1CFN

DP0GVN, receiving my 1W signal, also saw a smaller level peak, occurring at 22:00UT:

DP0GVN hearing my 1W.

WSPR Anomaly - PY2GN

Last night was quite unusual at 14MHz, where there had been minor disturbances throughout the day.  This led to the band remaining open at short skip distances into mainland Europe and even some moderate DX from the Middle East (4Z and HZ).

The single unusual spot of the night came from PY2GN at 00:20UT, with a SNR/2500Hz of -20dB.  This station does feature relatively often in the unusual spots list.

Now, the distance to PY2 is over 9500km - making a consideration of the likely propagation path an interesting one!  Here's the planet's situation at the relevant time:

How to account for propagation at this time?  Image: DX Atlas, with permission.

Now, the question to ask first is: is there anything unusual about PY2GN's location that might help understand the propagation?  Well, there is certainly the South Atlantic Anomaly to consider, because this is quite a significant feature of the earth's magnetic environment.  This is how it looks, as measured at about 500km:

South Atlantic Anomaly.  Image: Wikipedia/Steve Snowden/NASA

Who knows what effect this has in practice?  Certainly, ionisation is enhanced in this area.  Could the signal be running up the grey line to the north, being bent towards Wales by the auroral oval?

Or perhaps along the grey line to the south, again undergoing bending by the auroral oval when it gets to the north?

Or perhaps there are auroral Es drifting northwards from the southern aurora, and equivalent Es drifting south from the northern aurora, yielding a path?

Or is the path more direct, with the field of the inner Van Allen belt conveying the signal from south to north?  Can a WSPR signal stay coherent under such complex paths?

Or, finally, could it be the equatorial electrojet that is responsible?  This paper provides interesting food for thought.

Well, all we know for sure is that some path is allowing a coherent signal to make it to the UK.  Only with a coordinated effort at both stations, to try and measure time delays, could we make some progress.  Because of the infrequent nature of the event, this is not very easy to organise without particular determination at both ends.

Also interesting to note that the (northern) auroral prediction last night showed a distinct and persistent patch as far south as Spain.  It's still not clear if these patches are anomalies in the model, but there certainly were plenty of short skip signals coming in from Europe all night, so the patches might well portray real auroral Es:

Image: NOAA.

Looking at the southern aurora, the model again predicts quite extensive patches extending to tropical regions.  This shot is a few hours earlier than the PY2 spot, but the predicted patch would be drifting over the coming hours to the right, towards Brazil.

More geomagnetic anomalies!

Last evening saw the onset of what was predicted to reach G1 geomagnetic conditions.  Unfortunately, things didn't get quite that rough, but a nice disturbance did take place, as shown below:

Image: IRF/Kiruna

At 19:26UT, N1ECP in Maine was the last station I heard on 14MHz WSPR.  I was actually watching the screen at the time, and the waterfall became quite dead, with not even much by way of partial traces appearing. I did notice the occasional strong WSPR signal burst (looking like a meteor scatter signal at VHF) that lasted only three of four seconds, followed by a natural 'whooshing' noise.

Aurora visibility at 23:30UT.  Image: NOAA.

At 21:14UT, 8P9HA appeared and, over the coming few minutes built up to -20dB SNR/2500Hz.

Shortly thereafter, HC6PE appeared.  He built up to a remarkable -08dB SNR/2500Hz at 22:10UT.  Keep in mind the geometry of his station and mine, relative to the sunlit atmosphere, no part of which has been visible from Wales at this point for maybe 2 hours or so:

Path to HC6PE and terminator at 22:10UT, 2018 December 01.  Image with permission, DX Atlas.

My RX spots at the times relevant to this post.

Not only this, but you will note that WC2S - all the way from Los Angeles - makes an appearance, if only just, at -29dB SNR/2500Hz, at 22:32UT.

Even more intriguingly,  K6MCS appears shortly thereafter, but only briefly.  You may recall this post concerning K6MCS making an identical sort of appearance in early January this year.

The paths are interesting to consider.  The model for the aurora shows a small patch further to the south in the Atlantic than the main oval.  These appear regularly, so they don't seem to be artefacts of the model, though that is a possibility that needs checking out with NOAA.  If this patch is real, it might indicate a limited area that could have facilitated propagation to HC6PE.

The path for K6MCS seems to go through dense regions of the aurora.  Clearly, with so many (as of this morning, 300) WSPR stations active on 14MHz, there remains something to explain about how that station seems to make a regular appearance under disturbed conditions.

As always, any ideas welcome under comments!

The curious case of...ZL/K6KWI

WSPR always throws up something unexpected.  Last night, it was a New Zealand station (with the great callsign of ZL/K6KWI - indicating Neil's Kiwi origins) at 14MHz, throwing out a very high, 50W signal.

The strange thing was that I was the only station who heard him around that time (18:20UT) outisde the US and Antarctica, despite the very high output.  Oddly, though it appears on the map, I can find no reference at all to the HB9 spot in the WSPR database, either in TX or RX in relation to Neil's station:

The terminator is correct for the time of the spot.  I am not sure as to the path taken, as ZL is very near the precise antipodean point to the UK, and the geometry of the greyline seems to make either (or both) paths just as likely.  I tend to think it was a path involving antipodean focusing, which was just about enough to enhance the signal to detection limits (I heard him at -26dB).

I didn't hear Neil again until 06:52UT this morning, where a few other stations in Europe were also now hearing him.

Certainly something to look out for in coming days, if the very high winds of up to 130km/h over the next 24 hours permit!

Geomagnetic anomalies, 30m

My single turn magnetic loop has been out in the strong and very cold easterly winds over the past few days, doing very well on 14MHz.

Yesterday morning, I decided to re-tune the loop to 30m and see where the 200mW WSPR signal got to.

I am not sure what antenna other people are using at 10MHz, but my loop is doing better than any others I can find from the UK, by quite a big margin.  This is surprising, as a 10MHz antenna is not so large - just 7m per side as a dipole, or 7m tall as a vertical - as to preclude most people from having a full-sized, efficient radiator.

It's too early for a full analysis of spots yet.  But I did note that geomagnetic disturbances overnight generated interesting propagation enhancements throughout the dead of night.  Curiously, as the early morning period advanced, a periodicity between spots of an hour, or multiple of an hour, seemed to become apparent.  I will have to think about that one, but this paper is an interesting place to start, not least because the proposed modulation period occurs in agreement with my spots:

Magnetometer stackplot, 19-20/11/2018, Norwegian line.

Propagation anomaly, 2018 November 15

Last evening's Norwegian line geomagnetic stackplot looked like this, showing a relatively minor disturbance in the early evening, and some much smaller disturbances later in the morning:

The last that was heard of WJ1I anywhere other than the US was at 21:02UT - except for here at MW1CFN, where a single reception was made at 01:20UT (now reverted to the vertical delta loop antenna):

The fact that only one US station made it across the Atlantic at this time, and that he was not then heard again, shows there must be very localised and extremely transient propagation changes related to the passing of the auroral oval at mid-Atlantic longitudes.  Again, the anomalous spot comes at the time of field restoration.