TF1/M1CFN

The family managed to get away from it all this past week, in one of our fairly regular visits to Iceland.

Strokkur erupts!

On this trip, I decided to take a WSPRlite transmitter along, putting 200mW from a 20Ah lithium battery pack into a simple, 2-radial elevated 1/4 wave vertical.  

Would all this make it through the ever-increasing steps of security at the airport?

The lithium battery has to be carried in hand luggage, which I knew about and complied with.  Other than the usual rummage through the bag, there was no problem with this.  My antenna analyser was unfamiliar to security staff, but they just said "I won't even ask what this is", which seems a bit of an odd thing to say when they are supposed to be doing exactly that!  The WSPRlite wasn't even examined.

The antenna and coax went into hold luggage, and wasn't apparently a cause of concern, as the bag had not been physically examined.

On arrival, radio matters were the first priority!  My son is a good tree climber, and there were plenty of birch trees of a good height from which to hang the vertical.  But, because of the density of branches, it was actually very difficult to climb any tree.  All the rocks are, because of glacial and water erosion, rounded in Iceland, so a 'sling' was also rather difficult to arrange in a hurry.  

No problem!  We then realised that we'd completely failed to see a fibreglass flag pole (which was obvious, as you can see, just a few steps away from the car parking!)  Like most Scandinavian countries, just about every house has a flagpole in Iceland.  So, up went the wire on the lanyard, which was of perfect 7m height to hold the vertical wire above ground.  A small amount of trimming the wire, and we were down to 1.2:1 on the analyser.  Off we go!

Spot the antenna!

For the first few days of the trip, geomagnetic conditions were fairly quiet.  As a result, my signal was heard with typical regularity and consistency across Europe from early morning, and then into the US and Alaska in the evening.

The week's spot trace looks like this (the green box indicates a few hours of battery recharging):

As you can see, nothing much to write home about in the first four and a half days.  Propagation conditions are not so good, so DX distances are not great.  

All spots of TF1/M1CFN (1 week) courtesy DXplorer

But in the last two days or so, a coronal high speed stream impacted the Earth, taking us up to G1-G2 levels.  The effects are very clearly evident in the above plot.  

The best receiver for my signal, reporting over 400 spots, was DK6UG, plotting out like this:

DK6UG hearing TF1/M1CFN, 200mW, 14MHz WSPR.

Another very consistent spotter was 2E0PYB, who has a good, quiet rural location for receive.  Very curiously, his reception of my signal did not seem to suffer very much at all in response to the geomagnetic disturbances, and in fact, relative to at least two of the earlier (quiet) days, actually saw an enhancement (which I have reported upon many times in the past):

2E0PYB receiving TF1/M1CFN, 200mW, 14MHz WSPR.

It's worth restating that difference during disturbed periods between 2E0PYB and DK6UG, which is reinforced by looking at the reports from OZ7IT, a very respected and long-term WSPR operator.  My signal drops off a cliff as the disturbance takes place:

OZ7IT receiving TF1/M1CFN, 200mW, 14MHz WSPR

The real outlier in the whole dataset was from just 76km away, i.e. my groundwave, as reported by TF1VHF.  As you would expect, his reports were essentially flat throughout the week, typically around the -27dB mark.  Then, between 17:46 and 19:10UT on August 06, a huge pike in signal strength, reaching -10dB:

TF1VHF receiving TF1/M1CFN, 200mW, 14MHz WSPR.

What was the cause of the spike?  Whilst I thought it could be the weakening geomagnetic effects, the local magnetometer in Iceland (and other data) doesn't seem to support this theory, because the field was largely uneventful and the time:

I did consider whether seismic activity might have caused the spike.  There were some minor tremors at the correct time locally (you could feel their gentle shaking if sitting down or lying in bed).  But minor tremors are essentially constant in Iceland, so one would expect more spikes like this.  My dataset is too short to make any firm conclusions. 

That said, if we look closely at the TF1VHF reports, we can see there is another spike, much smaller, representing a ~6dB enhancement, at 01:32UT on August 04.  It seems we might be able to rule out geomagnetic effects for this event, because the field in Iceland was as flat as a pancake all day:

All told, I think the spike was probably an enhanced patch of ionisation against a background of a relaxing magnetic field.  Even so, it's quite an event.