Radio direction finding stations

General Information and Regulations

A direction finding service may be provided in either of the following forms: —

1. Where each D/F station is fitted with transmitting and receiving gear and works independently.

2. Where several D/F stations are linked together under the con­trol of one station which alone is equipped with transmitting apparatus. The latter is not necessarily a D/F station, but may be an ordinary coast radio station. In this case if a ship requires a single bearing only, she calls the control station, and specifies the D/F station from which the bearing is required.

Notes

(1) The frequencies used by D/F stations are classified as fol- lows: —

1. Frequency on which station (or control station) keeps watch.

2. Frequency for transmission of signals on which bearings are observed.

3. Frequency on which results are transmitted.

2. Unless otherwise stated, hours of service are continuous.

3. All bearings are true and are given clockwise from D/F station, the compass coil of which forms the centre for the "Calibrated sector".

Radio direction finding regulations

Important. — It should be remembered that where CEAR1NGS from a group of stations are required the signal "QTE" should be used in making this request. If the SHIP'S POSITION is required the signal "QTF" should be used instead.

Great Britain Hours of Service: Continuous.

Frequency: For calling the station: 500 kc/s; for making the signals on which bearings are observed, and for receiving the results: 500 kc/s or 410 kc/s.

Signals on Which Bearings are Observed: Two dashes of 10 seconds each, followed by ship's call sign.

Time Used in Messages: G.M.T., using the 4-figure notation (0000 = midnight).

Remarks: Bearings are classed as follows: A=accurate to within 2 degrees; В = accurate to within 5 degrees; С = accurate to within 10 degrees. If the station is provided with remote loops (Gonio A) and local loops (Gonio B) the appropriate indication is added to the bearing, thus: "QTE 196 Class A at 0937 GMT Gonio A."

"QTG" SERVICE

On receipt of the signal QTG, D/F stations in Great Britain will transmit for one minute signals to enable bearings to be taken by means of D/F installations on board ship.

RADIO DIRECTION FINDING STATIONS

Service Details

Great Britain

1002 Niton (GNI) Receiver: 50°34^,52^,,N. 1°17'59"W.

Transmitter: 50°34'42"N. i°17'10"W. Frequency: (A) 500. A2.

2. 500,410. A2.

3. 500,410 A2. 0.5 kw. Sectors: Calibrated: on 400 kc/s:

on 500 kc/s: 001°—360°

Bermuda Islands

1820 Bermuda (VRT)

"A" Station: Receiver: 32°18'49"N. 64°44'51"W.

"B" Station: Receiver: 32°18'49"N. 64°43'48"W.

Transmitter: 32°22'57"N. 64°40'02"W.

Frequency: "A" Station: (A) 500. AI,A2.

2. 375. AI,A2.

3. 484. AI,A2. 1.0 kw.

"B" Station: 17,025, 12,590, 11,125, 8,405, 6,555, 1,638, 500, 485, 333, 143, 133,3, AI,A2 1,0 kw.

Sector: "A" Station: Calibrated: 000°—360°.

Remarks: "B" Station is intended primarily for determination of bearings at long range on short waves (by special arrangement), but will, if necessary, provide bearings at short range, using the frequency 1,638 kc/s.

Hours: 1030—0230: Sundays, 1300—0130. Also, at any hour on

previous request.

Error: Normally within 2°.

RADIOBEACONS

General Information

Caution

Misuse of Radiobeacon Signals

The attention of mariners is directed to the serious dangers which may arise from the misuse of Radiobeacons, and particularly to the risk of collision with light-vessel and Ocean Weather Ships operating such signals.

Radiobeacons of themselves give no indication of distance off, and safety demands that every precaution should be taken. If such signals are carried on light-vessels, risk of collision can be avoided by ensuring that the bearing does not remain constant.