ZS6EZ on Dupes

Last updated: 2001-01-23

Duping is defined as someone working a station again, on the same band and mode as a previous contact. You may find that the dictionary mentions something about deliberate deceit. While I'm also opposed to that kind of duping, this article is mainly about the ham radio kind. You'll probably work out fairly quickly that 'duping' is simply a lazy man's way of referring to duplicate contacts.

Clearly, if chatting to long-time friends is your thing in ham radio, you are duping all the time and there is clearly nothing wrong with it. If you're a contester, your definition probably differs from the standard one, in that you will gladly 'dupe' a station that you've worked before, provided you haven't done so in that particular contest.

However, the moment you start getting involved in DXing, you will quickly see the bad side of duping. You've all heard the phenomenon. A DX station is having a hard time coping with the pileup, and working relatively few stations per hour. The operator might even be flustered, and might be at the verge of quitting in disgust. You're yelling your lungs out, hoping to make it into the log in those desperate moments before the elusive operator pulls the plug. The pileup is getting bigger, and your chances are rapidly vanishing. Yet, you hear several operators in succession making remarks that make it patently clear that they have worked the station before, and are just stopping by to say hello.

Clearly, at this point you are a victim of injudicious duping. If you're asked at this specific moment, your opinion will be fairly straightforward and very well defined. Yet most people seem somewhat unclear under other circumstances.

Personally, the milieu in which I'm most regularly exposed to harmful duping is on 50 MHz. The path from South Africa to the Mediterranean is relatively easy, and during sunspot maxima we have easy access to Italy, Spain, Greece, Portugal, Israel and a few other spots by TEP. Occasionally, for a few minutes, we have propagation further north. The signals are generally much weaker than those from the mentioned areas. Why, then, do those same stations from the same areas keep calling? Why are they adamant that their umpteenth contact is important enough to deprive those further north of possibly their only crack at a new country? Any W9 or W0 will recognise this situation w.r.t. the East Coast into Europe!

Another particularly poignant example for us is the African backscatter path. Late in the evenings during the TE season, we can sometimes hear stuff like 7Q, 5H, FH, FR and ZD7. The scatter signals are normally just barely audible. At the same time, Europe is S9 both into South Africa and into the target location. It is especially painful to have to listen to one European after the other making yet another duplicate contact, trampling our puny signals in the process. Every southern African 6 m DXer has missed at least one new country in this way, I'm sure.

Although we all like to believe (or maybe pretend) that we're acting exclusively for the greater good, there is a much more important reason why this destructive duping irks me. Personally, I would much rather be working new stuff than re-working the same stuff. Yet this solid wall of repeat callers generally makes it all but impossible to hear the weaker signals resulting from more exotic propagation paths.


Bitching is not much good if we can't come up with a solution. Let's examine some that I've heard:

Let's allow the DX station to control things, and announce that he doesn't welcome dupes. Doesn't this 'solution' put the cart before the horse by forcing the vast majority of operators to waste time to accommodate the few that would like to exchange niceties? I would argue that most people would prefer new stuff if it is available. Therefore, the default condition should be that dupes are not welcome, and those that welcome dupes should say so. Besides, they are clearly not as pressed for time as the rest of us!

There's no harm in saying hello occasionally. Granted. Provided, that is, that you can categorically say that the frequency is clear of other callers that you might be depriving of a contact. I would argue that you are seldom if ever in a position to make such a judgement. Furthermore, I think we generally overestimate the extent to which other people would love to hear our voices. If the DX operator hasn't named one of his children after you, chances are he can do without your company. If he doesn't know your dog's name, it's an almost certain bet.

It's the DX station operator's choice. Couldn't agree more--as long as it's a conscious choice. More on this subject later.

My contention is that real life requires some discretion. If you are absolutely certain that the guy has no takers, and that he would appreciate the company, there is no reason to refrain from saying hello. However, it is a known fact that discretion as a commodity is extremely hard to come by. Most people simply monkey-see-monkey-do. If you are a 'serious' 6 m DXer, and you are heard saying hello to a rare DX station, you will start an avalanche of duping. Those that turn their radios on only rarely, and who perceive you as a perennial denizen of the band who appears to know what's going on, are very likely to emulate your technique at every opportunity. I guess they'll just be hoping that some of your grandeur might rub off on them...

Which brings us back to the matter of personal choice. After all, it is the DX station operator's prerogative to make the choice whether dupes are welcome or not. I fully agree. I have even gone on public record as stating that the DX operator has the fullest right to sleep through great openings, chat to his buddy across town during once-in-a-lifetime propagation, and even (God forbid) to check into a DX net. However, few people are obsessed with amateur radio, and DX stations are rare for geographic or political reasons rather than for their devotion to amateur radio. That being the case, I think we can assume that few if any rare DX stations' operators will ever sit down and consider their attitude to duping. They will simply roll with the punches, and work all comers.

Perhaps, if the masses can act in the public interest, the DX station operators will eventually come to the right conclusion. That is, if they ever bother to think about it at all!

If this premise is true, we as semi-serious DXers have a duty to set a good example and to educate those who may not be devoting as much time to thinking about amateur radio issues. Example is by far the most powerful mechanism for education.

Personally, I have taken a policy decision to decline all dupe attempts politely but firmly. I am occasionally taken to task by a rabid duper, and I have seen the odd snide comment on the DX Summit, but by and large I'm hoping that I'm at least enticing one or two European DXers to think about duping. I've certainly had several favourable comments from 6 m DXing stalwarts, who often comment the next day by email that they support the technique.

Results have been encouraging. Many of the regular dupers have stopped calling me. I guess part of the reason is that duping is often driven by the ego trip of cracking yet another pile-up in competition with hundreds of other callers. Perhaps being declined is not quite the ego trip they are looking for. Perhaps Pavlov (does the name ring a bell?) had a point. Whatever the reason, I have been more successful than most ZS DXers during major openings, for only one reason: My frequency is less cluttered by would-be dupers, and I can often hear very weak stations from fringe areas that do not make it through the roaring pileups of some of the other locals. As we all know: The most efficient pileup handling technique is to have no pileup at all!

How do you make it happen?

Finally, I might mention a word or two about how to practically avoid dupes, especially if you are at the DX end. I personally log on paper, as I don't like to have to fire up a computer each time I want to make a contact. In contests, I always use a logging computer. However, I don't have a single computer log covering all my QSOs, so I can't use the logging software to provide real-time duping. Obviously, the ideal solution is to have a computer log and to use it during all QSOs.

What I do have is a QSLing database. I type my paper logs into the computer once a month or so, using a log-entry program that I have written in C. The log files are in ASCII. I then use a simple DOS batch file that invokes find.exe (one of the standard DOS utilities) to find specific records in my database. My batch file can take up to three command line parameters and return all records containing those strings. For example, if I type:

q zs6 030c 990

the batch file q.bat returns all QSOs with ZS6 stations during the first 10 months of 1990 on 10 MHz CW. Records are of the form:

ZS6AL;030C;990813;2149;Please QSL!

These records facilitate easy handling in DOS, including alphabetical sorting and dupe checking for QSLing purposes.

I have written a special batch file that enables me to dupe-check 6 m QSOs more quickly, without having to sort through the entire log file. Simply typing

6 3a

instantly returns all callsigns in the 6 m log that contain the string "3A". Examples might be G3ABC, 3A/OH2BC or IK3AMQ. This way, even with the most inadequate typing skills one could probably come up with a quick dupe check on any caller. The main purpose is to reduce the amount of information shown on the screen to manageable proportions, so that one can do a manual scan and identify the caller. I have a secondary use for this procedure, too; I can identify partial callsigns in the pileup that I may have worked on the other mode (CW or SSB), so that I can pull them out and work them without having to wait for the full callsign to become audible. Ah, the delights of having information at one's fingertips!

If you don't have access to a computer at the operating desk, you might resort to even more mundane techniques. The simplest is probably an alphabetically-sorted list of stations you've worked. The list is probably manageable, as all but the most rabid DXers have probably worked at most a few thousand stations. Using a laser printer, one can easily fit 50 callsigns into a column, and 8 columns to a page, so 2000 contacts will comfortably fit onto 5 sheets of A4 paper.

If you are serious about finding callsigns quickly on paper, you could even resort to sorting the callsigns by the last letter. This arrangement makes for a more equal distribution, so you could organise your callsigns into 26 easily-manageable blocks of roughly equal size. Obviously, prefix-sorted records are not as well-behaved. For example, a very large proportion indeed of my VHF log consists of callsigns starting with I!

Once you can identify dupes instantly, you have to find a way to tell them off firmly but politely. On CW, most stations use 'QSO B4', and on SSB I normally just tell them 'We've worked before', and immediately proceed to call CQ or QRZ to indicate quite firmly that no correspondence on the decision will be entered into. The occasional dyed-in-the-wool duper will come back for another iteration, but most will accept their fate with exemplary stoicism and continue on their merry way.

What are we hoping to achieve? Hopefully less of the situation where someone on a fringe path has the opportunity to work a really earth-shattering contact, but gets beaten out by comparative locals hogging the DX station. Examples of the past weeks include 5A1A being reported frantically calling TF3FK without success, and ZS6PJS being unable to attract T97V's attention due to loud European signals. You can bet your bottom dollar that both T97V and TF3FK would have appreciated the QSOs, but were re-working loud stations that they've worked before. Bet ya! The backscatter conditions I've mentioned before are also a prime example.

If we can make only a handful of these truly exceptional QSOs happen, it will definitely have been worth it. All it takes is just a modicum of self-restraint from the big guns. The rest will gradually follow.

Thanks to Peter Bowyer G4MJS for some lively debate that prompted me to sit down and compose these thoughts in writing. Guys like me don't get much done without prompting!

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