WSPR

WSPR is a ground-breaking mode that, for the first time in amateur radio, allows objective assessments of signal paths and antenna performance, free of human bias.

As I have written previously, WSPR arrived on the scene only recently, and as such, has adopted 'standard' frequencies towards the lower, digital end of the bands, without any coordination or assigning of protection such as is required by continusously-operating beacon-type modes.

Whilst most operators are aware of beacon modes, many are not.  A large number tune, hear a faint pure tone, assume it's just noise or something of no interest to them, and start operating some other mode, most commonly, RTTY.  Because RTTY uses LSB, the emissions frequently appear within the beacon segments.

Of course, for the most part, there is no 'correct' or 'legal' allocation to any particular mode, unless it's specificially included in the licence terms.  However, there is a wide, catch-all clause (section 7(3)) in the UK's Wireless and Telegraphy Act that prohibits interference, and in this legal context, 'interference' means just that - to interfere with other transmissions, whether on the amateur bands or otherwise.   

During a recent incident where SSB was destroying WSPR modes on 5MHz, I politely contacted one of the operators, simply to advise he had stamped on on-going transmissions by WSPR stations. 

The response wasn't favourable!

Whilst the person involved was of fairly advanced years, his aggressive defence, largely borne of feeling silly, I think, broke down into three basic parts:

(1) Ignorance of WSPR, and that he couldn't hear anything on the frequency.
(2) There was no breach of the licence or NoV terms, because the bandplan is voluntary.
(3) There was no other frequency available to use.

Let's take them in reverse order:

It is possible that (3) is true, but I did in fact listen across the band, and with S9+40 signals from the southern England station in question, it seems much more likely that other frequencies were, in fact, clear at the time.

(2) looks appealing, but without recourse to close legal argument, it's clear that simple protocol and the ability to use the ham frequencies effectively means that one operator should not 'stamp' (interfere) with an ongoing transmission.  WSPR operates continuously, and so commencing a transmission when one or several are already underway would appear to be, or could certainly be argued to be, a breach of s7(3).

(1) Is simply a non-starter.  Ignorance of a mode is perhaps understandable.  But amateurs are granted licences on the basis, like all citizens, that they keep themselves abreast of new laws and regulations, and that they do not breach them by causing interference.  So, ignorance of WSPR is no real defence.

If, as appeared to be the case after a couple of bun-type exchanges on e-mail, the operator still won't accept any error, then a question must be asked.  Is he saying that I can just jump on a frequency, claim ignorance of SSB because I'm a CW or digimodes-only operator, and then start transmitting away over an ongoing QSO, without any legitimate cause for complaint from anyone?  That, in fact, is precisely what he was trying to argue, ladled heavily with a value judgement on modes other than his own as being undetectable and of less worth.

It is true that WSPR, to the uninitiated, can be somewhat difficult, at times, to detect by ear alone.  But mostly, WSPR signals are strong, and readily detected as some form of digital transmission.  It is a new, but not that new a mode.  It is clearly allocated to a narrow segment of the 60m band, as part of the beacon modes, although it is not legally a beacon mode in itself.  That issue itself needs attention, because it's obvious that many, if not most operators transmit WSPR signals whilst unattended, and do so 24/7/365.

WSPR is a mode, because of its immense and universal utility, that needs a special allocation where it may not be interefered with by those who can't be bothered to listen, watch, or pay due respect to a crucially-important digital mode.  I have argued this case to the RSGB and IARU, to no real avial thus far...

Yagi, Yagi, Yagi...

And for those who know Max Boyce from the days of old, the response might be "Terrain!  Terrain!  Terrain!"

Many moons ago, I wrote about a comparison I ran alongside an operator in south Wales - about 125 miles away from me.  He's near the sea, runs a 4-element SteppIR, and runs about 400W.

So, it was a bit of a surprise - not accepted by some - that my simple delta loop was being heard at the same signal strength by the same operator, at the same time, on the US east coast, as the south Wales station.

To me, this is easily explained.  It's the terrain, stupid!

Living on a ridge, with ground that slopes initially steeply, then gently to the coast, is of enormous benefit in terms of ground gain.  According to the ARRL HF Terrain Assessment model, my 3-ele Yagi gets a ~7dBi boost from ground reflections, even with the antenna being set at no more than 6m high.  What's more, that total peak gain of over 14dBi occurs at just 2.5 degrees above the horizon.  By lowering the antenna to about 4 metres above ground (remembering we live on an elevated plot), the peak gain comes down to just 1 degree at 14dBi.  That is very tough to achieve from most sites.

True, DX doesn't always come in at such incredibly low angles.  But more often that not, access to very low angles is of benefit, not hindrance.

Now, I saw the same thing happen again this week.  A west Wales operator this time, operating a 3-ele SteppIR (the make of the antenna is irrelevant, of course).  I don't know the power in use, but that's OK, as I didn't have a chance to make contact with the US station, so it's a listening test only.

The result?  The station was a 5/5 to me on a delta loop with base at 1.8m, and 5/5 to the other operator on a Yagi up at about 10m.  No difference!

If we now look at the terrain, we see some profound differences.  The west Wales operator (red) is much nearer the sea than I am (blue) in the same beam direction for the USA.  But the terrain for me slopes away continuously, if not smoothly, whereas the other operator has land that rises significantly. That said, the mast puts the west Wales Yagi pretty much above most of the surroundings, if only just so.

OK.  You are probably not convinced just yet.  That's understandable.  So, let's look at how the ARRL HFTA software models the gain for both stations.  This time, I'm comparing identical Yagis, except mine is only 6m up on the tower, whereas the west Wales Yagi is set at 10m.

Are you starting to warm to the argument now?  My gain (blue) is +14.3dBi at 2.5 degrees, whereas the SteppIR in west Wales (red) is way, way down at minus 2.5dBi at the same elevation.  Rather self-evidently, the other station stays well down on gain until we reach parity at 11 degrees, beyond which the west Wales Yagi then has a marginal advantage for a while.

So, whilst I again stress and accept that not all DX comes in low, a lot of it does.  So, a lot of the explanation for the ability of my simple wire antennas to match the gain of big, expensive antennas atop big, expensive towers, is likely to be in the advantage of my terrain.

True, I haven't compared the delta loop against a Yagi, which was my original position.  That's because HFTA can only handle horizontal antennas; my delta is vertically polarised.  However, whilst ground gain is likely different, the delta is able to access very low angles, due to the sloping ground in front of it in most directions.

Antenna modelling with MMANA-GAL suggests that my vertical delta has anything between 4.4 and 7dBi gain, and real RF measurements confirm the radiation is at or only slightly above the horizontal, i.e. 0 degrees.

So, if we take the worst-case gain for the delta, at 4.4dBi, that still puts it at least 5-6 dBi ahead of the 3-ele Yagi at 10m in west Wales until at least 5 degrees elevation - and that's without any ground gain included for the delta!

In short, if you want the best location for DX, don't take my word on what to look for.  Take that of the great Les Moxon, who, according to an acquaintance of his, would only choose a hillside location for a new home - explaining his vivid accounts of milliwatt SSB QSOs between himself and VK land!

WSPR: Broken?

WSPR is a mode that has taken over the world of beacon-type transmissions, and taken the subjectivity out of antenna and propagation assessments.

Sadly, whilst WSPR must have a huge number of people hitting its servers 24/365, the WSPR net web site has slowly become quite degraded in its performance.  It's now quite common not to be able to get updated maps and database query results back for long periods during any given operating period.  This undermines the whole point of the mode.

It may be that WSPR net needs to start charging users in order to provide better server bandwidth.  If something isn't done to prevent the rot getting worse, this could well see WSPR fade away over time, at least in its present form.  As a concept and practice, it's too powerful and useful across the globe to vanish, so let's hope some improvements come about, one way or another.