Friday 26 August 2016

40m WSPR Challenge Results

Having done pretty well with 30m and 20m WSPR challenges recently, I tought I'd try 40m.

Again, the basic antenna is pretty simple - just a half sloper against the tower with a 3-element 12m Yagi on top.  Luckily, it's on sloping ground and appears to be 15m tall from just 80 m away horizontally.  So this, plus the far field ground, does yield very good gain - about +7dBi over the inherent gain of the antenna, with no obstructions.  The sea is a minimum of 2km away.

I was really pleased with the results, because there are plenty of very-well appointed 40m WSPR stations out there.  As you can see from the table below, I reached 12th position, with only a handful of extra spots gained by those up to about 4th position above me.

Not bad for a half sloper!

Whilst the antenna does have a very good native SWR for its type (1.4:1), the results do confirm that the location is very important.

So my station is doing pretty well, reaching near the top of the tables on each band. 

Tuesday 23 August 2016

Clean That Magmount!

I've recently gone back to doing some portable working from the car using a 20m AmPro vertical.  At £19.99, these are really very good value for money and, being just a wire up a stick, work well. 

Except, I've been having some problems.  First, the SARK-110 analyser was refusing to give sensible results.  There was a lot of noise on the signal, and I just couldn't approach a correct SWR reading.

Resorting to a simple analogue SWR meter, I found a good match, but then this went awry when I tried to key up at the rig.

It seemed like the magnetic mount, one of those Chinese three-magnet units, was at fault.

Many people report that these Chinese magmounts rust very quickly indeed.  I can confirm that this is so, which is very annoying and typically lacking in attention to detail.

Baby, I was born to rust...


The metal bar that connects the front two magnets with the rear one, and which forms the mounting point for the antenna, is aluminium.  Newer models tend to have a single fixed plate between magnets now, but the corrosion is much the same.

On removing the coupling where the coax is joined to two concentric rings (one for the sheath, the other for the inner), I found a good amount of aluminium corrosion, which I suspect was hastened by dissimilar metals (the coax coupling is brass.)

I cleaned all the connectors with light sandpaper and a stainless steel kitchen scourer (don't use normal steel wire wool - it will leave infinite amounts of rusting metal in your coupling - and probably lead to electrical shorts.)  A spray of WD40 and then cleaning this off with paper towel, and then the application of some aluminium conducting grease, avoiding any short between inner and sheath connectors (£6.00 from Innovantennas), completed the job.

I'm afraid that I didn't take any photos for lack of time, but don't be afraid to undo that coupling from coax to antenna mount - there is nothing to fall apart and it is quite robust to be handled roughly.

Suffice it to say that these units are not at all ideal for permanent exposure to the elements in countries that are anything other than deserts.  If you want a good mount for UK weather, you probably need to look at a drilled-in unit of some sort. Otherwise, you can just remove the magmount after each use, though these units do moderately scratch paintwork over time.

Sunday 14 August 2016

20m WSPR Challenge

Having come 15th in the 30m WSPR challenge earlier in the week, I thought I'd see what my 20m delta loop could bring in on Friday/Saturday 13-14th August, 2016.

I continued to contribute to others' results with an 8% transmission rate.  The delta is twin fed via a 6:1 homebrew voltage balun (unusual for this station), and is vertically polarised.

My 20m delta.


I was pleasantly surprised to reach 11th in the score table, out of what looks like a total world station list of about 220.  Being in the top 5% of WSPR sensitivity will do me just fine, thanks! 

Being a weekend, there were a fair number of periods where RTTY interfered badly with reception.  I'm also aware that signals that ought to be decoded sometimes aren't.  This may or may not be down to the old netbook computer I'm using, but the problem can't be too bad, given my relative position in the table.

11th on unique receptions, 19th on total distance.



Wednesday 10 August 2016

30m WSPR Challenge Results

Inspired by fellow blogger, PE4BAS, I surrendered my rig to 24 hours of continuous 30m WSPRing yesterday.

 I'm not particularly well-equipped for 30m.  The antenna is a half-sloper, nominally cut for 40m and matched in the shack with a simple ATU, running from about 5m above local ground, sloping to about 1 metre.  The 'missing half' is provided by bonding to my modest lattice tower that supports a 3 element 12m LFA beam.

The 12m Yagi and tower, prior to the installation of the sloping wire antenna, that forms the 'other half' of the antenna used for the 30m WSPR challenge.

At 40m the SWR is remarkably good for such an antenna - just 1:1.4.  But at 30m, it's about 1:2.5.  Losses are pretty low at 10MHz, even with coax feed, so the theory was that the antenna would work reasonably well.  Sloping ground in all directions except to the north east, and an elevated aspect near the sea is known to help signals considerably, especially to the Americas.

After 24 hours, where I spent 15% of the time transmitting (probably a mistake in terms of the total stations received), I was really pleasantly surprised to find I'd reached 15th position in terms of unique spots, which numbered 163 over the 24 hours.  This was just a couple behind the likes of K9AN and GM4SFW, respected long-term stations with 'good ears'.

Here is the evidence, courtesy of PE1ITR's WSPR Challenge page:

Not bad, at 15th position (unique spots.)

Monday 8 August 2016

Amateur Radio: A Perfect Storm Ahead?

Things aren't so good on the HF bands of late.  Approaching solar minimum, we're seeing few sunspots, yet seemingly endless geomagnetic storms.  Even 20m is often difficult at times.

Of course, ham radio is already in troubled waters because of its inability to reach out to and recruit youngsters, who are permanently attached to their cellphones, tablets and consoles.  With each passing year, the age profile of ham radio, at least in the UK - and by the RSGB's own admission - is increasing by the same amount. 

Add to that the sad fact that many of the hams now reaching the end of their lives used to be professionally involved in radio and electronics.  There is almost nobody to replace them.

Spotless.


Wind on the clock about 10-15 years, and a big decline in ham enthusiasts seems almost inevitable.

In tandem with this period, we have to take into account the suppression of interest in ham radio that a solar minimum is known to bring.  When propagation is poor, operators tend to 'take a break', sometimes never to return.

The problem for the next few solar cycles, according to the best 'twin dynamo' theory we have of the Sun, is that we may well have to endure 30 or so years of very low solar activity - a repeat of the 'Maunder Minimum' seen during the Middle Ages.

Here's a plot of how the Sun is likely to play out, together with modelling results that have clearly accurately reproduced what happened in past cycles, enhancing our confidence in future predictive power:

The end of solar activity - and ham radio?  Image courtesy Prof. Valentina Zharkova.
This really doesn't bode well for ham radio.  True, the lower bands of 7-1.8MHz will be less affected.  But these need longer antennas - space that the average UK Joe often doesn't have.  Whilst one Joe will find a way, others will decide it's too difficult, and not bother.

And as if that wasn't enough, the hobby is suffering from rapidly increasing spectrum noise, often arising from directly-imported Chinese goods of poor quality.  LED lights, TVs, electric fences, CCTV power supplies - they're all taking their toll, with very little in terms of enforcement activity taking place.


This is a bit like amateur astronomy, where magazines are stuffed full of expensive telescopes and accessories that imply all is well, but that just about nobody has a dark sky under which they can be put to best use.  What's the point of a $4000 rig when all you can hear is next door's solar PV system?

So, I think the likes of the ARRL and RSGB need to wake up - fast - to these three problems that really could see a whole generation fail to take an interest in amateur radio.  If that happens, it will probably be impossible to promote a resurgence of interest once the Sun shows a little more life.


Friday 5 August 2016

'K' For Kernow - A Year On...

Yesterday, I put my proper journalist's hat on and went looking for a response to the following series of questions from the Managing Director of the RSGB.

At the moment, the Poldhu Club in Cornwall, who had a 'K' regional secondary locator granted for only a year after a ridiculous debacle between the RSGB and OFCOM, are seeking support for the RSL to be continued.

"Dear Steve,

Even if you would not wish to make comment on the 'K for Kernow'
(Cornish RSL) debacle that raged 18 months or so ago, I think you may
agree it wasn't handled by either the RSGB or OFCOM very well.

I am writing an update to the situation as we approach the end of the
year's grant of 'K', now that the calming effects of time have come to
pass. 

At the time of the RSGB's objections to the new RSL, it stated that, to
paraphrase, there would be "wide repercussions" and "confusion" in the
ham community, arising from such a grant. 

A number of people involved, and including myself as an observer and
commentator, found such banshee-esque comments rather silly, and
unlikely to be based on any evidence.  It did not help that the RSGB
claimed repeatedly that "significant numbers" of members had raised
"objections" about the new RSL, yet could not then provide those numbers
to me when I asked Graham Coomber on two occasions.  It smelled of rat,
you see?

Of course, you aren't under any legal obligation to respond to
journalistic enquiries like this, although I might expect, as a member,
I might get something meaningful in return. 

In pursuit of that aim, does the RSGB now regret making alarmist
comments about the consquences of a new RSL, and/or does it have any
proper, objective evidence that shows the year-long grant of the 'K' RSL
has led to any real "confusion" or "wide repercussions"?  Has any other
county, nation or ethnic minority made an application for its own RSL
since 'K'?

Does the RSGB, on reflection, now accept the extraordinarily rare
governmental grant of National Minority Status was never likely to be
repeated in a manner that would lead to a flood of similar applications?
 Alternatively, does the RSGB maintain this original position?

Does the RSGB now accept that, whilst being Cornish might loosely relate
to an association with a county,  the minority status grant was never
"county" based per se, but on an ethnic minority basis - just as being
welsh yields an association wih an ethnic 'nation', rather than a single
administrative county within that nation?  Did the RSGB allow itself to
think of Cornwall less as a very ancient nation, recorded consistently
as a constituent nation of Britain and distinct from England for
centuries, and more simply as a name for a modern administrative county?
 Was the RSGB aware of the legal distinctions arising, for example only,
from the 1337AD establishment of the Duchy of Cornwall?  Does it,
indeed, accept that the National Minority status granted is valid?

Does the RSGB regret making comments that could be perceived as
insensitive, at best, when it asserted that Cornwall was an integral
part of England, seemingly being rather dismissive of the new minority
status, and potentially insulting to those who declare themselves,
including officially (and validly) in censuses, to be 'Cornish', and not
'English'?    Was the RSGB not insensitive, also, in claiming a flood of
new applications would follow, when it failed to recognsie a key
distinguishing factor for Cornish difference from other parts of 
England was their Celtic language, strongly related to the other Celtic
nations, and a critical factor in ethnic identity?

If there is no comment you wish to make, that will be recorded in the
eventual article, but such silence does tend to result in an adverse
image for the organisation, especially when member-funded.  I realise
that this is a complex issue, but one must recall that the RSGB found no
difficulty or reluctance in wading into an ethnic-based issue with very
little evident sensitivity.  It must show itself to be circumspect and
alive to ethnic diversity, even where such ethnicities - mostly white
people in 'just another part of England' - don't outwardly differ as
much as we commonly believe."
 
The response came just over a week later, and doesn't say very much at all. 
It does, though, show something very wrong with the RSGB's understandin of
events, in that it was not the "EU" that granted minority status, but the UK
government!   
 
"I've followed-up with some of the Board members who were involved in the 
discussions and would offer the following comments:

Following the decision by the EU to award Cornwall Minority Status, Poldhu 
Amateur Radio Club asked the RSGB to support an application to Ofcom for
Cornish amateurs to have permanent use of K as a Regional Secondary Locator.
This was discussed with Ofcom who were not inclined to support this approach.
The Society received a number of inputs, both supporting and opposing the
proposal. There were strong views expressed against the permanent use of K 
on the basis that Cornwall is not a 'country' and that many of those belonging
to the EU recognised Cornish minority group are no longer located in Cornwall.
The RSGB Board took the view that a permanent change based on a county boundary
would mean other counties could follow suit and we therefore did not support
the proposal.

Ofcom eventually determined that the use of K would be permitted for a period 
of one year only for stations permanently located in Cornwall. The RSGB have 
been supportive of this temporary approach to mark EU recognition. We support 
the initiative by providing the administration, on behalf of Ofcom, of the 
issue of Notices of Variation (NoVs) which allow amateurs to operate with K 
as a Regional Secondary Locator.

Best regards,

Steve Thomas, M1ACB
General Manager
Radio Society of Great Britain "

Monday 1 August 2016

QRPp WSPRing - With a Strange Anomaly.

Over the past few weeks, I've been busy gathering 5W resistors for homebrewing a step attenuator.

Before I lose the graphic (courtesy of N2KI)  on which I based the design, here is the circuit, complete with resistor values needed:



5W resistors aren't that easy to come by in the UK, but Ebay sellers in China and Hong Kong provide them with admirable quality and speed for ludicrously good prices.

Having not yet received quite all the resistors needed to complete the project, I decided to throw together a fixed value attenuator, consisting of two pi-mounted resistor circuits yielding a total of about (mindful the resistors are tolerance rated only at +/- 5%) -10dB.

In practice, after using the admittedly very limited power meters at my disposal, I found the attenuation provided by this unit to be roughly 11 - 12 dB, which is perfectly acceptable.  This allows 2 Watts at the rig to be reduced, allowing for losses, to about 100 - 150mW.  Without a traceable, calibrated power meter, I can't be more accurate than that.

Here, for those who want to build their own, is the simple circuit, which, unlike the larger, switched unit, needs no special care in preparation, save for good soldering.  As you can see from the associated SARK 110 analyser plot, the impedance and SWR both come in at very good values.

The resistors, incidentally, are 200 Ohms (four needed, bonded to the case at one end), and 33 Ohms (two needed.)

A simple, fixed value attenuator of roughly -10dB.


Analyser shows good characteristics at 14MHz.
So, having connected-up and fired 2W, attenuated to about 100mW through the unit from 18:00UT on July 21 2016 overnight, I was pleased to find this tiny power level was getting across the Atlantic quite comfortably.

The overnight run into August 01 2016 produced an average reception SNR at K9AN, always my reference station in the US, of -19dB.  This value didn't change by very much for the whole run, except for one outlier, which showed a huge, 24dB enhancement in SNR, or a factor of 250 times above the average reception strength!   Here's the plot of the evening's proceedings, where you can see the enhancement to +5dB SNR at 23:12UT:



This anomaly is really interesting.  I've noticed similar enhancements in the past with WSPR and other digital modes, when signals are, broadly speaking, taking a path that yields a glancing blow with the auroral oval where local magnetic midnight is roughly half way between the transmitter and receiver.  It's interesting to note that the enhancement occurs shortly after connection with K9AN is re-established, after about an hour where I wasn't being heard.

The auroral situation on 2016 July 31d 23h12m UT (NOAA)


The grey line situation at the same time.  Courtesy DX Atlas, with permission.
 
The auroral involvement might be supported by looking at GM4SFW, transmitting 5 Watts from Scotland, where the auroral oval has a greater and more frequent effect.  Remarkably, his signal, more variable with time due to the aurora, shows an even greater enhancement an hour after mine (2016 August 01d 00h16mUT), of a whopping 29dB - or a factor of 795 times!

I'm not terribly clever at explaining radio propagation, and not many texts I've read fill me with confidence that anyone else does, either.  That said, I'm sure there will be someone out there with insight, whether theory or proven principles.