Short answer: The OK/OM DX Contest is a well-known European contest in which stations around the world work stations in the Czech Republic and Slovakia. In general terms, the home stations send a district code, and stations elsewhere send a serial number together with the signal report, but the current rules decide every detail. Copy the district letters carefully, log the exchange in the right fields and check the log before submitting it.
What the contest is about
The OK/OM DX Contest invites amateurs everywhere to work stations in Czechia (OK) and Slovakia (OM). Like other national DX contests, it gives a chance to make contacts with a single group of countries and to compare results with other operators in the same category. The contest has its own regulars, who watch for it every year, and its own mood: a lot of European activity, a good deal of pile-up work for the home stations and plenty of calls from distant stations that are looking for a new country on a band.
The details of dates, modes, bands and categories change between editions, and the organisers publish them on their pages. This article therefore stays on general ground, and it gives you a way of thinking about the log. Read the current rules before you plan your weekend.
Two exchanges, two ways of logging
In general, the contest uses two kinds of exchange. Stations in the home countries send a signal report and a code that tells their district. Stations elsewhere send a signal report and a serial number. This means that your log has different information in the same field depending on who is calling. If you are outside the two home countries, you will mostly copy a district code, and you will send a serial number. If you are in the home countries, you will do the reverse.
The serial number is simple but needs care. It starts from one and increases with each QSO, and the logger should do the counting. The district code is the part that is new for many foreign operators. It is made of letters, and a code that is almost right is wrong. Compare this with the exchange of CQ WPX, where the serial number is the whole exchange, and with the zone exchange of CQ WW.
Copying district codes
A code made of letters needs a different technique from a number. In CW, letters can be confused when they are sent at speed: some pairs have similar rhythm, and a missing dit or dah gives another valid letter. In SSB, the problem is the sound of letters in a noisy band, and phonetics are the answer. The article on SSB letters that are confused and the one on CW characters that are confused list the usual pairs.
A few habits help in all modes. Ask for a repeat of only the letters that you missed. Confirm the code in your reply if the other station seems unsure. Use a printed or on-screen list of valid codes during the contest, but never replace what you hear with what the list suggests. If the logger can load the list and warn about an invalid entry, switch that on, since an impossible code is the cheapest error to catch.
Setting up the logger
Check whether your logger has a module for the contest. If it does, choose it and test the exchange fields before the start. If it does not, you may need to use a general mode that lets you define one text field for the received exchange. In both cases look at what the Cabrillo file will contain. The columns for the sent and received exchange must match the contest format, and the order of the fields matters. The article on the Cabrillo QSO line format explains the columns.
Also make sure that your own sent exchange is correct. If you are outside the home countries, your macros should send a serial number that increases with each QSO. A macro that sends a fixed number is a common mistake in the first hour. Test the macros before you start, and listen to the recording after the first few QSOs to be sure that what you send is what you think you send.
Common logging mistakes
- District code typed in the wrong field: the code ends up in the serial number field, or the number ends up in the code field.
- Code completed from memory: the same station worked on another band sent a code, and you copy it again without listening.
- Wrong country assumed: a station using a similar prefix from another country is logged as a home station.
- Report left at the default: in a fast contest it is tempting not to touch the report field, but check that it matches what the rules ask.
- Band set wrongly: frequency data from the radio is missing, and the QSO lands on the wrong band.
None of these is special to this contest, but each is more likely when the exchange changes depending on who calls you. A short break to check the first twenty QSOs is time well spent.
Rates and strategy in a regional contest
A regional contest often has a very different rate pattern from a worldwide one. For stations outside Europe, the contest is a search for a limited number of stations, and good openings are short. For stations in Europe, the contest is a sequence of local contacts with a strong signal, and the rate can be high. Look at your own hourly statistics to see how the contest behaves from your location. The articles on continent openings hour by hour and on rate versus band changes show how to read that picture.
If you operate from outside Europe and have a good signal, plan for the times when the openings to Central Europe are best, and be ready to move bands quickly when the signals fade. If you are in Europe, a good plan is to concentrate on bands where the Czech and Slovak stations are strongest and to avoid long periods on bands that are crowded with local signals.
After the contest
When the contest is over, check the log before submitting. Look at the header, the category, the exchange columns and the callsigns. A district code with a letter in the wrong place will not be marked by most logging software, and it may be removed during the official check. See checking your contest log before you submit for a full list.
Contest Analyzer checks every callsign and every zone against official license databases and several independent reference sources and shows only the few QSOs worth a second look. It gives full statistics (rates, QSOs by hour and band, countries, continents, CQ and ITU zones, WPX prefixes, distance, beam heading, breaks and off time, callsign length and structure) and year-on-year comparison with your own logs. You can edit calls, zones, time and frequency in the report, mark QSOs checked in your own audio recording, duplicate a QSO line and download a corrected Cabrillo. It marks QSOs outside the contest period and outside the band limits for your ITU region. Serial numbers are not checked, and neither are district codes, so those stay with you. See the contests page for the list of supported contests.
One more point concerns the callers who use the same exchange twice because they are not sure that you heard it. In a regional contest with a limited number of home stations, many callers will work you on several bands, and the codes you receive from the same station should be the same each time. This is useful as a quiet check: if the code you copied at 14 MHz differs from the code you copied at 21 MHz, one of the two copies is wrong. Compare them when you review the log, and use your audio to decide which one is right.
Think too about the pace of your own exchange. When you send a serial number, send it at a speed that suits the other station, and not at the speed that suits your keyer. A foreign operator who is not used to the contest may need a slower repeat, and a few seconds spent on a clear repeat often save a lost QSO. If you notice that many callers ask for repeats of the same part, change the way you send it before the problem spreads through your log.
Lastly, keep a short note of the codes that were new to you. Over several years the same districts return, and your note becomes a personal list that helps you recognise a code at the first hearing. A small habit like this is how experienced contesters build confidence in contests with unfamiliar exchanges, and it costs nothing but a few lines after the weekend.
Related reading
The bottom line
Know which exchange you send and which you receive, copy district letters with care, and check the log before submitting. Always read the current official rules for the details of this contest.
FAQ
Which stations send a district code?
In general the home stations do, but check the current rules for the exact definition.
Do I need a serial number?
Stations outside the two home countries usually send one. The rules tell you what is required.
Is a logger module necessary?
Not always. A flexible exchange field can do, but test the Cabrillo output before the contest.
What is the most common error?
A district code with a wrong letter. Ask for a repeat of the letters only.
Does Contest Analyzer verify the district code?
No. It checks callsigns and zones, and it shows only the few QSOs worth a second look.
