ANTENNA MEASUREMENT COMPETITION

Update of information and Clarification of Rules

Date: 31st October 1999

RAST would like to welcome members and non-members to take part in this interesting competition, believed to be the first of it’s kind in Thailand. To make the competition fair to everyone we need some rules, and technical standards, but we don’t want to discourage anyone from bringing an antenna along. If you are not sure about the rules or the category of your antenna, don’t worry just bring it along, and the RAST Technical Staff will help you. We hope to make the testing interesting and informative. To conclude the event we will have some very distinguished guests to present awards, and a very good party. Would RAST members please spread this information as widely and quickly as possible.

ACTIVITY DATES.

Friday 12th November 1999: Deadline for receipt of postal entries to RAST PO Box 2008. Bangkok, 10501. Late entries can be brought by hand on Saturday 13th November 1999 to the Antenna Test Range. The entry fee is 200 Baht for any number of antennas (no limit).

0800 - RAST Technical Staff prepare antenna test range.

1000 - Deadline for hand delivered entries from Bangkok Metropolitan Area

1000 - RAST Technical Staff begin testing

1400 - Deadline for hand delivered entries from outside Bangkok

1800 - RAST Technical staff finish testing

Location: Antenna Test Range adjacent to Muang Thong Thani, Building T1

0900 onwards. Continuation of testing by RAST Technical Staff until all antennas completed. Location: as above.

There will be a full day of events at Sipathum University, starting at 8 am, and finishing at 9-30 pm. This will include an opening ceremony, the final judging of the antennas, on design, .construction technique, cost/materials, and quality. There will be interesting lectures by experts, and shops selling interesting things. There will be of course the presentation of results and awards, followed by a party. A separate programme of these events has already been distributed. Tickets for the party can be obtained from any committee member.

Basis of scoring:

The competitor can forward a simple drawing with his application form by post to arrive at RAST PO Box 2008, Bangkok, 10501 by 12th November 1999. This will help RAST prepare for testing. Late entries can be made by filling in an application form on arrival, and bringing the antenna(s) by hand on the testing day (13th November 1999). RAST Technical Staff will help with the application form and drawing.

The entry fee will be 200 Baht, per person, or per group. The person or group can enter any number of antennas, no limit. This fee can be paid on 13th November 1999 on the Antenna Test Range.

1st Prize: Trophy by HRH Maha Chakri Princess Srindhorn

Any antenna which is not a pure single Yagi or not a single vertical. Examples: cubical quads, quagi’s, delta loops, stacked arrays, bays of elements, side by side verticals, yagi loop antennas, loop antennas of any kind, vee beams, rhombics, long wires, turnstile, skeleton antennas, corner reflectors, ZL Special, HB9CV, W8JK, hentanna’s, and any new ideas! Don’t forget a new idea could get high design points.

Category B + E (Yagi). A single vertically polarised yagi, with 2 or more elements. No stacks or bays, can be entered in this category.

Category C + F (Verticals). A single vertical structure, with omni-directional radiation pattern. E.g. Ground Plane, half-wave dipole, folded dipole, 5/8th Wave antenna, collinear verticals (like Ringo Ranger etc.)

Category G (Multiple Entry). Any person or group who enters more than one antenna is automatically entered into this category. The person or group who’s best two antennas’ scores are the highest, wins. Antennas can be from any category, mixed, CB or Amateur Radio.

All antennas will be tested with 50 Ohm Non-Reactive test equipment. Therefore each competitor should aim to make the antennas a good match (low SWR) to 50 Ohms. Otherwise, performance may suffer in the testing. RAST technical staff will not attempt to match the test antenna to the test equipment.

Competitors should assemble their antennas ready for testing, but RAST Technical Staff will help if necessary.

Each competitor will be allowed to adjust the height and direction (rotator), and matching of his antenna (for limited time period) during test to achieve maximum gain.

For Amateur Radio 2m Band = 145.000 MHz

For CB Band 78 MHz = 78.5 MHz

For CB Band 245 MHz = 245.5 MHz

A 60 metre test range will be used. The received signal level of the competitors antennas will be compared with a calibrated reference dipole antenna. (0 dB gain). The measured gain/ loss will be calculated in dBd. The competitors antenna design will be modelled on a computer. The actual gain/loss measured, will be compared with the computer model, and marked according to the deviation from the model. E.g. If the computer model says the antennas should have 5 dBd gain, and the measured gain is 4 dBd, this constitutes a 1 dB difference I.e. 1/5 or 20% reduction from maximum marks.

Ray Gerrard

HS0/G3NOM

Secretary International RAST

Tel 037 328 041

Fax 037 328 042