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Author Topic: DNB irregularities and call signs 25 May 2019  (Read 1458 times)

Offline Looking-Glass

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DNB irregularities and call signs 25 May 2019
« on: May 25, 2019, 0155 UTC »
May has been an interesting month for Drift Net Beacons in the Pacific region.  Some signals have reached 599 report at various times of the late night/early morning monitoring sessions. 

Some call sign variants have also popped up, normally in this region I only hear 2X1 (two letters one number) but this month some surprises have been heard:

1.776      CW 2AFFG      0810z   529  22nd May 19.
1817       CW  TTT         0854z  529  22nd May 19.  Possible misfiring beacon, can be heard as TMT on occasions, irregular character spacing.
1922.5    CW  FP919     1119z  549  24th May 19.
1978.5    CW  FK221     1020z  569  22nd May 19.
1978.5    CW  FQ85?     1024z  559  22nd May 19.  (? indicates missed number)

2005       CW  7G         1935z  539   22nd May 19.
2005       CW  8F          1634z  559   24th May 19.

2122       CW  DO63     1810z  519   02nd May 19.
2139       CW  4FRL      1933z  569   19th May 19.
2218       CW  AN94      2030z  519   19th May 19.

2307       CW  BMD1     1039z   519   19th May 19.
2317       CW  BMP9      1042z  519   19th May 19.

A line of call sign series has also emerged, often only a few Kilohertz apart:

1831     CW    OB2     0746z  569   24th May 19
1842     CW    OB3     0942z  519   21st May 19.
1853     CW    OB4     1320z  539   22nd May 19.
1863     CW    OB5     0859z  559   02nd May 19.

1811    CW    OA0     0831z  519    21 May 19.
1801    CW    OA9     0830z  529    21 May 19.
1789    CW    OA8     1450z  519    02 May 19.
1779    CW    OA7     1603z  559    20 May 19.
1748    CW    OA4     1117z  529    20 May 19.
1717    CW    OA1     1421z  559    24 May 19.

Only need OA2, OA3, OA5 and OA6 to complete the above "OA" series.

The above observations make logging and chasing DNB's all that much more interesting, especially call sign block patterns and variants in call sign make up, in saying that, around 98% of all DNB's logged comprise of the two x one format (two letters plus one number).

Also the beacons logged on 1922.5 and 1978.5 are not the usual standard DNB.  There is no preceding nor ending carrier and there is no two to four minute key on/off period, they are a new type of "Tropical Ocean Tuna Longline Fishing Buoy" made by Ryokuseisha Electronics in Japan, with just a three watt transmitter.  They are also restricted to use "Movement Range: Pacific".

Likewise, the two on 2005 (7G and 8F) also exhibit similarities to the two frequencies mentioned above, no preceding/ending carrier, no four minute cycle and appear at random.

So unless you monitor those two frequencies for extended periods you have little chance coming across them by accident.  I see to think they are only activated by the Mother Ship using Selcal transmission and thus conserve battery energy.  I looked at these beacons on the company website which was in Japanese.

« Last Edit: May 25, 2019, 0157 UTC by Looking-Glass »
Hermitage Flat, NSW.

Grid Square:  QF56dm.

Yaesu FT-1000D, Yaesu FT-2000D, ICOM IC-736 HF/50MHz, ICOM IC R75 & Tecsun S-2000 to 450 feet of wire, 27MHz 1/2 wave CB antenna converted to 21MHz & a multi band vertical of dubious reliability.