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Last updated: 16 Sept 2012

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Proposal for Distance based scoring for VHF/UHF/Microwave contests

by Andrew Davis VK1DA and Colin Hutchesson VK5DK



1. The VHF/UHF field days are run by the WIA and administered by the VHF/UHF Contest manager, John Martin VK3KM. The rules have been fairly stable throughout the history of these events, with rule changes adopted only when it was believed there was wide support for a change, or if changing operating techniques called for change, such as the introduction of the rover category and the spring and winter events. The contest manager has defended the rules effectively, ensuring stability and a steadily increasing participation level. However support and interest from some parts of Australia is still low. The WIA would like to see more activity in these contests and is looking for ways to increase participation.

2. VHF/UHF- focussed field contests have existed in VK nationally since Jan 1989, with the introduction of the Summer VHF/UHF Field Day. An additional "spring" event was introduced in 1998 and a winter event was trialled in 2008. Prior to the introduction of VHF/UHF field contests the only field event catering for portable VHF field stations was the John Moyle National Field Day. The scoring for the John Moyle event was originally the same for HF and VHF, but was modified in the 80s to introduce distance based scoring, with distances grouped into ranges for scoring purposes. A table of scores awarded to various distances was introduced in the late 80s.

3. Scoring for the VHF/UHF field contests has been based on a combination of band scores and multipliers to create incentives for operators to activate higher frequency bands. The score on each band was based on a point per contact, plus a bonus of 10 points for each grid square worked or activated. This scoring scheme is referred to in this document as "the current rules".

The objectives of the Field Day events

4. The WIA website's VHF/UHF Field days page provides the following statement of objectives:

The overriding aim is to get away for the weekend and have fun! But next after that, the aims are:

  1. to encourage more activity on VHF and microwave bands;
  2. to encourage people to work greater distances than usual by operating portable, and
  3. to provide opportunities for people to activate or work into new grid squares.

Do the contest format and rules meet its aims?

General aims

5. Examining each of the general aims:

Operational aims

6. These aims are about the contacts made.

  1. The event provides an opportunity for working greater distances due to suitably located portable stations. While the rules reward the first contact into each grid square, they do not otherwise reward contacts on the basis of distance. The rules only indirectly support this aim through the next aim (grid squares) since working more grid squares generally involves making contacts at greater distances.
  2. provide opportunities for people to activate or work into new grid squares: the rules give bonus points for each additional grid square worked. The bonus points directly support this aim.

7. The score formula includes multipliers based on the band on which contacts are made. The multipliers range from 1 on 50 Mhz up to 10 on 2.3 GHz and higher. There is therefore a great incentive for higher frequency bands to be used. This part of the scoring formula apparently meets an unstated aim of encouraging activity on the higher frequency bands and indeed the multipliers have a double impact because the multiplier applies not only to the contacts made but to the bonuses given for each grid square.

8. We can conclude that the rules:

  1. directly support the broad or non-technical aims of the event (getting away, having fun, encouraging activity),
  2. include incentives for the aim of activating or working into new grid squares,
  3. include substantial incentives for (an unstated aim of) using higher frequency bands,
  4. but do not directly support the aim of working greater distances other than incidental bonuses for the first contact in each new grid square.

Achievements of the VHF Field Days

9. Some operators record "personal best"contacts on these Field Day weekends. These events have become a feature of the calendar for many VHF/UHF operators as they are the primary "QSO opportunity periods" where heightened activity can be expected on all VHF/UHF and microwave bands.

10. Compared with operation from home or portable locations on other weekends, Field Day weekends increase activity level greatly, creating increased interest in these activities among participants.

Problems seen in the scoring system

11. Despite the success of the events, there are a number of situations in which the scoring method does not give adequate consistent recognition to the difficulty or the rarity of each contact. Examples of these situations are:

  1. There is a disparity in the points earned for contacts of similar difficulty or achievement. A station worked in a new grid square is awarded 1 point for the contact and 10 points for the new grid square. However subsequent contacts of equal difficulty, either with the same station or others in the same grid square, attract only 1 point each (prior to the band multiplier being applied). An example is a rare opening to say ZL from VK3, in which a field station works 5 ZL contacts. The first contact adds 11 points to the band score but subsequent contacts add only 1 point each.
  2. There is a corresponding disparity in the points the other stations can make by working you or someone else in your grid square, ie. after making the first contact with your grid square, there is little incentive for the dx operator to seek further contacts in your grid square.
  3. While it is generally accepted that microwave band contacts can be more difficult than those made on the lower bands, the points awarded to specific contacts can be out of proportion to the difficulty. For example the first contact on a microwave band can earn 210 points whereas subsequent contacts of equal difficulty could earn 10 points each, or 110 points for a contact into a new grid square. The effect of these bonuses and multipliers can be to distort the results when the number of contacts made on the microwave bands is relatively small.
  4. While the "grid square" bonus scheme does encourage operators to look for contacts further afield, it is only the first contact with each grid square that is given a bonus, so there is insufficient incentive to work greater distances.

12. In summary, our fundamental concern is that the scores earned by contacts are not consistent and are not proportional to the difficulty or rarity of the contacts achieved. We think the "better contacts" (greater distances) should receive more points than "ordinary contacts" (shorter distances) and that all contacts that are equal in achievement should be given the same points.

Distance and its significance to VHF/UHF

13. Distance worked is a fundamental measure of achievement on the VHF/UHF bands. Going back to the origins of our band allocations, the attitude of one government was "give them everything below 200 metres - they'll never get out of their backyards on that" and that became a challenge to amateurs to prove otherwise and of course we did. Ross Hull's major achievements were in extending the distances workable on VHF. Through careful experimentation he was able to prove that VHF propagation beyond line of sight was not only possible but was influenced by atmospheric conditions -behaviour that was not previously understood by the scientific community.

14. The WIA offers awards for distance records on VHF/UHF/Microwave bands. The Ross Hull contest also awards points on the basis of distance worked. It would be consistent to reward distance achievements appropriately in the principal VHF/UHF field contests run by the WIA. By encouraging operators to improve the performance of their stations so as to work longer distances, the WIA would be supporting and generating greater interest in the VHF/UHF awards scheme. The VHF/UHF field days are conducted at times when the chances of long distances are greatest. And as pointed out earlier, one of the aims of these events is to encourage longer distance contacts.

Are Grid Squares a good basis for a contest scoring formula?

15. Under the Maidenhead Grid Locator system, grid squares are defined as areas bounded by 1 degree of latitude (the vertical distance) and 2 degrees of longitude. 1 degree of latitude is exactly 60 nautical miles (111.12 km) but 2 degrees of longitude is a varying distance from its maximum of 1/180th of the circumference of the earth at the equator, which is 120 nautical miles (222.24 km), to its minimum of zero at the poles. The further you are from the equator, the smaller the distance between the 2 degree curves. The left and right "edges" of grid squares are thus curved lines which gradually approach each other, finally meeting at the poles.

16. Using VK1 as an example, at the latitude of the VK1 region, (35 south) the width of grid squares is about 180km. In North Qld (17 S at Cairns, 27.5 S at Brisbane) they are wider, and in Hobart (43 S) they are somewhat narrower. This effect is visible via an image included in the Wikipedia reference. The "unsquare" shape and inconsistent size is clearly visible. As this is a northern hemisphere sample, it needs to be inverted to apply to Australia. The fields like JM and KM, closer to the equator are clearly wider than those further towards the pole, such as JP and KP. Grid squares (JM00 to JM99) are equal divisions of those curved shapes so are therefore also curved and unequal.
Grid square example from Wikipedia

17. As grid squares are not an equal size across the country, the achievement of making a contact with someone in an adjacent grid square is different for each operator, as the distance and difficulty of the contact depends on the station's actual location relative to the grid square boundaries and on the station's latitude. A contact with a station in the next grid square due west of you could be as short as 1 km or as much as 200km. For stations north or south of you, they could again be as close as 1 km or as much as 112 km away. Thus it can be seen that making a contact into the adjacent grid squares is not a consistent achievement and depends on the location of each station.

18. Another factor is the spread of population and hence amateur activity in Australia. All coastal locations have empty/unpopulated grid squares in one direction (the ocean) and some have empty grid squares on both sides, either E/W or N/S. Clearly there are populations in places that are relatively isolated, with no likely contacts available in at least two directions, and sometimes three directions. For some areas of North Queensland there is almost no nearby grid square with activity or likely contacts on VHF bands unless there is sporadic E propagation on 6m.

19. The third problem with basing scores on worked grid squares in contests is that the borders of grid squares do not provide equal opportunity to all contestants. For city dwellers, grid square boundaries naturally do not occur in the same position relative to even the central business district. The grid square borders near Melbourne, Canberra, Sydney, Brisbane and Perth provide operators in those cities a wide range of different fortunes, some being able to reach other grid squares within the city borders but others needing to beam a long way east or west. The locations of these borders determine how many multipliers are within easy distances on VHF bands.

20. For stations on carefully chosen hilltops in these events, several grid squares in a large city with many potential contacts may be within easy contact distance only 50 km away, therefore making it easy to work additional grid squares on every band available. Conversely, a country station in Queensland, inland from Cairns, has very little opportunity to make contacts with grid squares in any direction but east, other than being lucky enough to have a sporadic E opening to other parts of VK or ZL that extends up to 144 as well as 50 MHz. Alternatively, to gain the requisite 3000 points typical of a high score in the contest, the northern VK4 would have to work some combination of international contacts on 6m in many grid squares to get a score of 3000, eg 2500 contacts into 50 different squares (2500 + 50*10) . The dx potential of 6m is good but it has never supported that kind of success in a vhf field day. 200 contacts into 20 grid squares - perhaps yes. That's 410 points (200 for the contacts plus 200 for grids worked plus 10 for activating your own square).

21. In summary, the Grid square locator system is a very useful and convenient international standard for identifying the location of a station. It can be used for calculating distances, and can be a basis for awards but as they are of different sizes and are inequitably distributed near population centres, they can unfairly discriminate between operators in different parts of the country.

22. For these reasons we suggest that the number of grid squares worked should not be used in scoring for VHF contests. Distance between stations is a much fairer and consistent way of assessing the value of each contact.

Proposed Scoring system

23. We propose a change to the scoring for each contact to one point per kilometre, based on the distance between the two stations. This is based largely on the scoring system used by European VHF/UHF contests. We also propose multiple band categories to allow for the large number of operators owning equipment capable of operation on 6m/2m/70cm. A revised band-based multiplier scheme is also proposed.

24. Details follow:

  1. Contacts will earn one point per km worked. Distances will be calculated from the 6 character grid subsquares of each station, eg. QF44MO to QF22AB. (This is not necessarily the precise distance between the actual stations, but is adopted as the reference for calculation purposes. Some distances will be overstated by several km, others will be understated. The net error will be low and is considered acceptable over when spread over 50 to 200 contacts. )
  2. The distance calculated from the 6 character grid subsquares will be rounded up to the next higher whole number. Therefore both 276.1 and 276.765 will be rounded up to 277. A contact of less than 1 km, ie. between stations in the same subsquare, will be rounded up to 1km, earning 1 point.
  3. The score earned on each band is multiplied by a number allocated to each band. It increases roughly with frequency and provides an incentive to operate on higher frequency bands.
  4. The multipliers proposed for the bands are as follows:
    Band50 144 432 1296 2.3/2.4G 3.4G 5.7G 10G 24G+
    Mult2 2 3 3 4 4 5 5 6
  5. The 6m band has not been popular with field stations due to the low multiplier given to that band in the current rules. This has led to field stations not putting much effort into operating on that band. As the entry point to vhf operation, 6m is a good band for field day use and it allows operators to get some experience with directive antennas and the different conditions under which tropo contacts are made. In the event of an Es opening, longer distances will be worked, providing more interest for the operators. For these reasons it is proposed that 2m and 6m be given the same multiplier.
  6. A further measure is proposed to deal with VHF/UHF and microwave band differences. To allow for operators who have equipment covering the 50, 144 and 432 MHz bands and to encourage them to take them into the field or use them from home in these events, it is proposed to provide categories for VHF/UHF, Microwave and All Bands. This allows for the VHF/UHF category operator to compete against others in that category without competing against microwavers who have higher band multipliers. It also allows for 6m specialists to take advantage of Es openings and enjoy the event knowing they are competitive with others in that band category.
  7. No changes are proposed to the timing, dates and other rules already established for these events. Eg, no repeaters, no satellites, repeat contacts every 3 hours, all modes permitted.

25. It is recommended that the grid locator is not considered part of the formal contest exchange. This is the current situation - the grid square is not a required part of every contact. When making repeat contacts with the same station, either on the same band or a different band, it would be impractical to transmit and receive the grid locator on each occasion. This is consistent with common sense. Most of the higher frequency contacts made in these events are a result of "throws" from an initial contact, typically on 2m. As part of that contact, each station's locator is exchanged and confirmed. It is not plausible that the locator is unknown when those stations QSY to a higher band. Therefore it cannot be regarded sensibly as a required part of the contest "exchange".

26. Some contest logging software requires the operator to record the grid locator on each contact. It is recommended that such software be updated so as to allow this data to flow automatically from previous contacts, in the same way that the operator's name would.

27. It is acknowledged that these changes would make rover operation much less attractive. The rover concept is derived from grid square based rules, so changing it to a distance based concept would be necessary.

Summary of Proposals

28. The proposed changes are:-

  1. Scoring is changed to a distance based formula, based on 1 point per kilometre or part kilometre. This allows the contest rules to support all of the stated aims of the event.
  2. Minor changes to band multipliers, increasing the multiplier for 6m and retaining greater weight for higher frequencies.
  3. Three main categories are provided: category A for the three lower bands 6m/2m/70cm, category B for the GHZ bands and category C being "all bands".

Status of proposal

29. This proposal has been developed by a group of experienced VHF/UHF field day operators who have all contributed to its development. It is now circulated more widely to enable all VHF/UHF Field day operators to discuss it and indicate their support if they wish.

30. After a month of discussion the level of support will be assessed and a decision made on whether to lodge the proposal with the WIA Contests manager for consideration.

The survey was open from 16 September 2012 to 15 October 2012

31. The survey has now closed.

Your participation is appreciated.

32. The results of the survey will be used to support a submission to the WIA Contests Manager requesting this change.

33. We are using this opportunity to gather opinions from as many active operators in the VHF/UHF field days as possible.

34. Your name and email are collected by the survey as they are required for the registration process. Your callsign is requested in survey question 1. These details will not be divulged to any other party except that your callsign may be included in a list of supporters, which will be a private communication with the contest manager Trent VK4TS and VHF contest manager John VK3KM. They need to know the extent of support for this change and a list of supporters is essential. Your email details will not be divulged to any other party except the sponsors of this survey.

Proposal authors and sponsors

Andrew Davis

Colin Hutchesson
Mt Gambier SA


1. http://www.wia.org.au/members/contests/vhfuhf/ The VHF/UHF Field day rules on the WIA website

2. The ARRL handbook quotes this comment about how amateur band allocations were made in the early days of radio. The Radio Amateur's Handbook, ARRL, Newington Ct USA, annual publication.

3. An explanation of the Maidenhead QTH Locator codes by Guy Fletcher VK2KU.

4. Wikipedia on Maidenhead Grid Locators