"Well" she replied "they may have the facts, but we have alternative facts".
Her interviewer quickly pointed out that there are only facts. "Alternative facts" are, in fact "falsehoods", the interviewer retorted. I agree with him. The only facts are ... the facts.
I may have got the wording of the quotation a bit wrong - after all who cares about the truth (see later)? But that was the gist of it.
A weighty amateur of many years standing remarked to me that I could hardly keep saying that this QTH is not good for tropospheric propagation (tropo) when I had recently worked the Canary Islands on 2 metres, a (now corrected) distance of 3264km. Fair point.
It is true that I have said many times that this location is not good for tropo. If you were to be mad enough to look back in this blog you would find me saying that lots of times. I also fretted for years over "not being able to" work into France on 2m, due to the presence of "the headland", an outcrop of higher ground to the south of me.
How can I square the "fact" that I still feel that this QTH is not good for tropo and (the alternative fact) that it has proved itself to be rather good for tropo? I think that that both of those things exist at the same time - it depends what you mean by "tropo", but saying both of them looks a bit daft.
I decided to look at a map of my 2m tropo contacts since my last posting on this site (click to enlarge if necessary) ...
|144MHz band FT8 contacts at GM4FVM from 14 to 25 August 2018|
Taking the contacts per 100km increase in distance from me...
0 - 100km NIL
100 - 200km 1 GM0NRT
200 - 300km 5 MI6XZZ, MI0KOA, M1AVV, G4JIX, G8EEM
300 - 400km 5 MW0RSS, G7RHF, G8EFU, M0JDK, M0NPT
400 - 500km 2 G3RMD, G4TRA
500 - 600km 1 M0WGF
600 - 700km 1 F1IEE
700 - 800km 2 ON4POO, ON4KHG
800 - 900km 1 F6DBI
There could be all sorts of explanations for this result including the proportion of the area which is sea, and the geographical distribution of amateurs. The 0 - 100km circle has almost 50% land and the 100 -- 200km has more, but in general the total area of land in the other circles does not vary too much. Each more distant circle is larger than the closer ones, but the ever larger ones tend to include more of the Atlantic Ocean and the North Sea which have very few amateurs operating from them.
As for the distribution of amateurs, this often follows city size. Even the 0 - 100km circle has Edinburgh, Dundee and Newcastle upon Tyne in it - though I have never heard a station from any of those cities. Most UK cities are at sea level or very low, and that plays a part too. The 100 - 200km circle has Glasgow, Aberdeen, Leeds, Bradford, Hull and so forth in it. Yet I do not hear from these cities. Just about the only nearby place I do get into as well as I might expect is Fife.
You can only take this city thing so far. I do not live in a city myself. Nevertheless, in general there are more amateurs where there are more people.
I am drawn to the conclusion that I am right that this location is not good for what an FM operator might think of as tropo propagation, but yet it is good for distant tropo from 200km out to 500km and beyond. When I describe this distant propagation I do not mean tropo ducting (of the type which brought in EA8 from over 3000km), but simply "flat band" working. There were no discernible "lift conditions" during the 12-day period covered by that map.
I think that I am not alone. I suspect that others have been fooled by this effect and have also assumed that their site is not good for VHF, whereas in fact for more distant contacts they may be in a fairly good position.
When I do come on for 144MHz contests I am always surprised by noting from the serial numbers that many other stations work dozens (yes, dozens) of stations close to them before turning their attention to dx. These are stations local to them and maybe I just do not have those stations around me. I certainly have no local stations to work. What I think is most likely is that such local stations as there were have given up on 2m dx.
When I arrived here 10 years ago there were local stations on 2m. Now there are almost no stations within 75km of me in any direction. For example to the south the station I would first come across would be Jeremy M0XVF who is 137km away. There may be nearer stations in Newcastle upon Tyne or Gateshead, but I cannot hear them. Even working Jeremy can be a struggle due to the difficult path between us. Yet, in that 12 day period covered by the map I easily worked ON4POO three times and ON4KHG (709km) twice. These long distance results are not a fluke.
I cannot blame anyone for giving up when faced with the evidence. I almost fell for it and abandoned 2m. When I arrived here I put up a 4 element yagi and did badly. Even after I put up a 10 element I did not do well. I took the absence of stations out to about 200km as a sign that this QTH was not good for tropo. I was under the impression that if there was not much to hear on tropo at that range then there was not likely to me much to hear further away. This was because I knew that tropo has no "skip zone" and that events such as ducting were few and far between. Whilst I did not give up, I certainly relegated 2m down my priorities.
It has taken years for me to realise that I was wrong about that. The evidence is still there - I have a half wave vertical and an FM rig constantly scanning around and generally I hear nothing at all. The hills mean that I cannot hear any stations from Glasgow (maybe 120km) or Edinburgh (about 60km). I cannot get into Berwick upon Tweed (12km to the south) or Dunbar (15km to the north). It is hardly surprising that I thought tropo was no good from here.
Why complain about not being able to hear any locals? There are lots of dx and contest stations who would love to get rid of their local QRM. Well, the absence of locals almost caused me to give up on the 2m band entirely.
Part of the problem with understanding this is that everybody seems to mean something different when they refer to "tropo". For this purpose I am excluding ducting. I tend to lump in assistance from aircraft scatter with general tropo propagation, though that is not correct. Many of my middle-distance QSOs are a mix of tropo and aircraft scatter. All of the contacts on the map were made during a period when there was no unusually high barometric pressure, no noted temperature inversions, no fog and none of the features associated with a tropo "lift". They were what I call "flat band" QSOs.
So there it is. My view that this site is not good for tropo was based on solid observations that the standard fare of tropo, up to about 200km, was more or less absent. I could have given up at that point, and I suspect that many others around me have already given up years ago (which only makes everything seem quieter). Somehow I kept at it and now I have the help of FT8 to corral all the dx into one place.
I feel fairly sure that several local amateurs who put up a vertical for FM, and who then heard nothing, have concluded that their location is no good for 2m tropo dx. They may well be wrong.
I am going to stop suggesting that this location is not good for tropo. That is an alternative fact. In other words, it is not true.
Of course, more recently another political figure said that "the truth isn't the truth".
P.S. Grand Tour cycling is on again. The 2018 Vuelta a Espana is underway and Uran, Aru, Nibali, Quintana, Porte, several guys named Yates, and the main favourites are all in action. I will be watching them all closely, but especially Michal Kwiatkowski.