Beacons and Aerials

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In our final NDB DXing outing for this year, Robert Connolly investigates Fishnet, Channel Marker and Cluster Beacons

 

 

In our final NDB DXing outing for this year, Robert Connolly investigates Fishnet, Channel Marker and Cluster Beacons, evaluates Mini-Whip aerials, prepares for Winter DXing and offers his loggings.

 

Generally, the non-directional beacons I refer to in this column are those used by aviation. There are also the few remaining marine NDBs, along with former marine NDBs that are now used to transmit DGPS signals.

However, there are also some other non-directional beacons, which monitors come across from time to time. These may be heard on MF and HF frequencies. These are used by fishing industries in many parts of the world and are referred to as ‘Driftnet Beacons’, although the use of driftnets is now restricted.

Nevertheless, these transmitters are still used by long-line fishing vessels and may also be referred to as ‘fishnet beacons’. It is thanks to reader Kevin, who recently emailed me regarding these, that I remembered that this was an area I had not looked at for some considerable time.

These lines may run for many kilometres and can have secondary lines branching off them using thousands of baited hooks. They are deployed by the fishing vessel and left for a period of time before the vessel returns to haul the line back on board with the catch.

Driftnet beacons are radio beacons deployed in the sea by commercial fishermen using these long lines. The beacons enable them to easily locate their lines for retrieval, and they operate in just the same fashion as a normal marine NDB. The transmitter unit is a compact, waterproof, and battery powered, device of just under a metre in height, with a 0.2m aerial deployed at one end of the long line and floating on top of the water.

The normal battery life is around 500 hours, and the image in Fig. 1 shows an example of a fishnet beacon.

Fishnet beacons operate on frequencies between 1.6 and 28.5MHz, although operation between 1.6 and 4 MHz is most common. Their transmission mode is A1A (Morse code) with a power of either 4 or 10W. This provides a practical working range of up to 200km.

Their identification signal consists of a combination of letters and numbers: Two letters and one number for Class 3a; two letters and two number for Class 4a; one number and three letters for Class 4b; two letters and three numbers for Class 5a; and one number and four letters for Class 5b.

The ident is transmitted three times over the period of one minute, followed by a silence period of three minutes, and then the cycle begins again. Although their official range is 200km, they can often be received over much greater distances.

While I am not aware of any official registry for these beacons, some amateur loggings may be found at the following websites:

www.qsl.net/n2sln/driftnetbeacons.htm

www.hfunderground.com/wiki/Fishnet_beacon

www.genesisradio.com.au/VK2DX/fishnet.html

Given the fact that these beacons are used in a maritime environment, it is not possible to establish their location, or, for that matter, their country of operation. Countries that use them include North and South America (Atlantic, Arctic and Pacific waters), Asia, Australia and New Zealand. I am also led to believe that some are used by Norway and Russia in the Arctic region.

Many of these beacons operate continuously when deployed, but there are some that only operate when activated by a Selcall transmission from the vessel, using the buoy. Their general specification and service range is the same as the others, but they are fitted with a Selcall receiver that operates on either 2331.5 or 1902.5 kHz. In addition, the battery of the beacon will last for up to ten times longer.

Amateur DXers know that locating an MF/HF transmitter and aerial on saltwater increases its receivable range by up to ten times, possibly even more during darkness; hence the reason why these are received by amateurs from long distances away.

 

Channel Markers and Cluster Beacons

There are other types of beacon that is commonly receivable in various parts of the world, including the British Isles and Europe. These normally take the form of transmitting a single letter, and some will occasionally break into fairly high-speed Morse code transmissions.

The two main types of these are referred to as channel markers and cluster beacons. Like fishnet beacons, they can be heard on a number of MF and HF frequencies. It is believed that they are operated by the Russian Military, mainly the Navy, and that the letters refer to their various bases. Their exact function is not known, and it is probable that they are being used to ensure nobody else can use those frequencies, leaving them clear for when the Russian Military wishes to send operational signals.

They are possibly also used as propagation beacons to allow Russian naval vessels to select the optimal frequency for operational communications, given their current location and prevailing propagation conditions.

Channel markers only transmit one letter constantly, while cluster beacons will transmit several letters constantly and all within a few Hz of each other.

Table 1 details the suspected locations of the letters used by channel marker beacons and the frequencies used by cluster beacon stations.

 

Mini-Whip Aerials

September’s Storm Ali hit hard here, and I am considering replacing my damaged Datong AD 370 active aerial with a mini-whip alternative (see my report in this month’s Maritime Matters).

So, what exactly is a mini-whip active aerial? Most current mini-whips are based on a design by Roelof Bakker PA0RDT, for low-frequency reception in a city environment and for use in small gardens.

Following tests using an active whip aerial, designed by G4COL, it became clear that, at LF, an active whip is a capacitance, coupled to the electric field, and that the whip length could be reduced from 100 to 30 cm without loss of performance; the shape becomes irrelevant, if the required capacitance is available.

In practice, the ‘whip’ can be, for instance, a small piece of copper-clad, printed, circuit board. A small die-cast aluminium box can also be used, with the buffer amplifier mounted inside.

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Tests were performed to find the optimum dimension for what became the PA0RDT-Mini-Whip. To prevent receiver overload, the maximum output has been set to about - 20dBm. The buffer amplifier has been optimised for good strong-signal-handling performance.

Unfortunately, these days, my eyesight is not just the best for close-soldering work, especially with surface- mount components, so I decided that I would purchase one that had the circuitry already built, leaving me with minimal work to complete the connections and secure them in a suitable casing.

There are a number of ready-made mini-whip aerials available for sale on eBay, with most seeming to come from Russia or Ukraine. For various reasons, I preferred to purchase from either the UK or Europe.

I came across a UK-based supplier who sells an IP 33 Mini-Whip Active Aerial, which may be purchased as a kit, with all the components to be soldered onto the circuit boards, or already assembled, with just the final exterior connections (power supply, two SMA sockets on the power board for coaxial cable connection, along with a female BNC connector that should be soldered to the mini-whip board) to be carried out for just a few pounds more. I opted for the assembled version (Fig. 2).

The aerial board is 110x30mm and is supplied with a 40 x 10mm power interface board that connects the aerial to the receiver. The 12V DC power is conducted from this board to the mini-whip board, via the coaxial cable. Complete assembly instructions can be downloaded from this website:

https://tinyurl.com/ASSEMBLEDMiniWhip

The UK seller, Mike, provides support here:

[email protected]

General specifications for the IP33 Mini-Whip are as follows: frequency range: 10kHz-30MHz; power: 12-15V at 38 mA; second order output intercept point: > + 74 dBm.; third order output intercept point: > + 33 dBm; dimensions: length: 110mm, diameter: 33mm. The feed line is 50-100Ω coaxial cable, up to 100m.

These specifications are very similar to the original PA0RDT mini-whip, and my twenty-year-old Datong AD370 active aerial. It does not come with an enclosure, but a short length of 40mm plastic pipe fitted with end-caps will provide a suitable outdoor case.

I used a small plastic project box for the interface and a slightly larger waterproof project box for the aerial unit. It should be noted that mini-whip active aerials should be used outside and mounted as high as possible, and as far away as possible from potential sources of interference.

 

Winter DX Season

We are now into the main winter DX season, so it will be interesting to see what propagation conditions will be like over the coming months.

Rob Evans e-mailed me at the end of September to let me know that he had received 372 kHz OZN Prins Christian Sund from Greenland and also 274 kHz SAL from Cape Verde at 0500 UTC. Reception of these is always a reliable indicator of the fact that that the main NDB DS season is starting to get underway.

I received a report from a DXer in the Czech Republic who recently received the following remnants from marine NDB chains located in the Black Sea, confirming that they are still active: SW - Mys Khersonesskiy and EYa Mys Yevpatoriyskiy Light (note Ya is a Russian special Morse character .-.-), both from Ukraine on 309.5 kHz. Received on 312.5 kHz: DB Doobskiy, Black Sea Russia and AT - Mys Aytodorskiy Ukraine. There is a third NDB believed to be still active in this chain, TR Mys Tarkhankutskiy.

To stand a chance of hearing these NDBs you have to listen to the frequency carefully for at least six minutes. These marine beacon chains normally have six NDBs on the same frequency, with each allocated one minute, during which interval it would transmit three times, followed by a long tone, and then by a single identification transmission at the end of the allocated period.

Time slots for these beacons on 309.5kHz are as follows: EYa slot 1, TR slot 5 ,and SW slot 6. On 312,5kHz, it is AT using slot 1 and DB slot 4.

Until next time, good DX.

 

DXers this month’s log table:

NDB reception this period during daylight (*).

A: Rob Evans, South Wales, Icom IC-R8600 with a long wire aerial.

B: Andy Thomsett, Southwest England. Airspy HF+ or SDRplay RSPduo and a PA0RDT Mini-Whip.

C: Robert Connolly, Co. Down, Northern Ireland. NRD 525, Datong AD370 active aerial, Timewave DSP+9.

 

Table 1: Suspected locations of the letters used by Channel Marker Beacons and of the frequencies used by Cluster Beacons.

 

Channel Markers

 

ID Letter

Location

A

Astrakhan, Russia

C

Moscow, Russia

D

Sevastopol, Ukraine

F

Vladivostok, Russia

K

Petropavlovsk-Kamchatsky, Russia

L

Tirana, Albania (inactive)

M

Magadan, Russia

P

Kaliningrad, Russia

R

Izhevsk (Ustinov), Russia

S

Severomorsk, Russia

V

Khiva, Uzbekistan

   

Cluster Beacons

 

ID Letter

Frequencies (kHz)

D

3593.7, 4557.7, 5153.7, 7038.7, 8494.7, 10871.7, 13527.7, 16331.7, 20047.7

P

3593.8, 4557.8, 5153.8, 7038.8, 8494.8, 10871.8, 13527.8, 16331.8, 20047.8

S

3593.9, 4557.9, 5153.9, 7038.9, 8494.9, 10871.9, 13527.9, 16331.9, 20047.9

C

3594.0, 4558.0, 5154.0, 7039.0, 8495.0, 10872.0, 13528.0, 16332.0, 20048.0

A

3595.1, 4558.1, 5154.1, 7039.1, 8495.1, 10872.1, 16332.1

F

7039.2

K

5154.3, 7039.3, 8495.3

M

5154.4, 7039.4, 8495.4, 10872.4, 13528.4, 16332.4

 

Table 2: NDB Loggings (Part Four – December 2018)

 

FREQ

C/S

LOCATION

COUNTRY

DXer

274.0

SAL

Ilha Do Sal

Cape Verde

A, C

277.0

CHT

Chiltern

England

A

316.0

OE

Dublin

Republic of Ireland

B, C*

318.0

BE

Bordeaux - Mérignac

France

B

318.0

BPL

Blackpool

England

C*

319.0

VAR

Varhaug

Norway

B, C

321.0

ABY

Albert - Bray

France

B

321.0

STM

Scilly Isles

England

B, C

322.0

RL

La Rochelle

France

C

323.0

WPL

Welshpool

Wales

A

325.0

AST

Asturias

Spain

B, C

326.0

LM

Le Man - Arnage

France

B

327.0

LNZ

Linz

Austria

B

327.0

MVC

Merville - Calonne

France

B

328.0

CL

Carlisle

England

B, C*

328.0

HIG

San Sebastian

Spain

B

328.5

EGT

Londonderry

N. Ireland

B, C*

331.0

GLW

Glasgow

Scotland

C*

331.0

GST

Gloucester

England

B, A

331.5

TLF

Toulouse - Francazal

France

B

332.0

OY

Aldergrove

N. Ireland

C*

333.5

VOG

Voghera

Italy

B

334.0

GMN

Gormanstown

Republic of Ireland

B, C*

334.0

KER

Kerry - Farranfore

Republic of Ireland

B

335.0

TON

Torralba de Aragón

Spain

B

335.0

WCO

Westcott

England

B

337.0

EX

Exeter

England

A, B

337.0

MY

Myggenaes

Faeroes

B, C

337.0

WTN

Warton

England

C*

338.0

FNY

Doncaster

England

C*

338.0

GU

Brest - Guipavas

France

B, A

338.0

PST

Porto Santo

Madeira

B

339.0

BIA

Bournemouth

England

B

339.0

OL

Shannon

Republic of Ireland

B

340.0

HAW

Hawarden

Wales

B, C*

341.0

EDN

Edinburgh

Scotland

B, C

342.0

VA

Vannes

France

B

342.0

VLD

Valladolid

Spain

C

342.5

NWI

Norwich

England

B

343.0

YVL

Yeovil

England

B

345.0

CSD

Daouarat

Morocco

B

345.0

LN

Lannion

France

B

346.0

LHO

Le Havre

France

B, C

347.0

NQY

Newquay

England

C*

347.5

TD

Teesside

England

C

349.5

LPL

Liverpool

England

C*

350.0

FU

Hamburg

Germany

B

351.0

OV

Visby

Sweden

B, C

352.0

ENS

Ennis

Republic of Ireland

C

352.0

NT

Newcastle

England

C

352.0

WOD

Woodley

England

B

353.0

KIL

Kiel

Germany

B

355.0

PIK

Prestwick

Scotland

B, C*

356.0

SGO

Sagunto

Spain

B

356.0

WBA

Wolverhampton

England

B, C*

357.0

LP

Cholet

France

B

358.0

BRS

Biscarosse

France

B

358.0

LT

Le Touquet

France

B, C

359.0

LOR

Lorient 

France

B, C

359.0

RWY

Ronaldsway

Isle of Man

C*

360.5

MAK

Makel

Belgium

B

361.0

CFN

Carickfinn

Republic of Ireland

B, C

363.0

PI

Poitiers

France

A, B

364.0

KNK

Connaught

Republic of Ireland

C*

364.0

PU

Pau

France

B

365.0

VR

Gran Canaria

Canaries

A

366.0

UTH

Uthaug

Norway

B

367.5

OX

Oxford

England

A, B

368.0

WTD

Waterford

Ireland

A, B, C*

368.5

WHI

Whitegate

England

B, C*

369.0

GL

Nantes - Atlantique

France

B

371.0

STR

Sintra

Portugal

C

372.0

ODR

Odderøya

Norway

C

372.0

OZN

Prins Christian Sund

Greenland

A, B, C

373.0

MP

Cherbourg - Maupertuis

France

A

374.0

BGC

Bergerac - Roumanie

France

B

376.0

BJA

Beja

Portugal

B

378.0

KLY

Killiney

Republic of Ireland

B, C*

380.0

CBL

Campbelltown

Scotland

C*

380.0

FIL

Horta

Azores

B

380.0

RQ

Quimper - Pluguffan

France

B

380.0

VNV

Villanueva

Spain

B

382.0

LAR

Arruda

Portugal

B, C

382.0

SBG

Salzburg

Austria

B

383.0

ALD

Alderney

Channel Islands

A, B

384.0

SLG

Sligo

Republic of Ireland

B, C*

385.0

WL

Walney Island

England

C*

386.0

BZ

Brize Norton

England

B

387.0

AV

Asturias

Spain

B

387.0

BGP

Brest - Guipavas

France

A, B

387.0

CML

Clonmel

Republic of Ireland

B, C*

388.5

CDF

Cardiff

Wales

A, B

389.0

CP

Lisbon

Portugal

B, C

389.0

PX

Périgueux

France

B

390.0

DR

Dinard

France

B

390.0

SO

Santiago

Spain

B

393.0

BD

Bordeaux - Mérignac

France

B

394.0

DND

Dundee

Scotland

B, C*

394.0

NV

Nevers - Fourchambault

France

B

395.0

B

Bilbao

Spain

B

395.0

FOY

Foynes

Rep. of Ireland

B, C*

395.0

LAY

Islay

Scotland

C*

397.0

OP

Dublin

Rep. of Ireland

C*

397.0

BLB

Blois - Le Breuil

France

B

397.0

FV

Fuerteventura

Canary Islands

B

397.0

ZR

Béziers - Vias

France

B

398.0

MT

St-Nazaire - Montoir

France

B

398.0

OK

Connaught

Rep. of Ireland

C*

399.0

NGY

New Galloway

Scotland

B, C*

400.0

AG

Agen

France

B

401.0

COA

La Coruña

Spain

C

401.0

LA

Laval

France

B

402.5

LBA

Leeds

England

B

404.0

AGO

Angoulême

France

B

404.0

CNE

Caen - Carpiquet

France

B

404.0

LRD

Lleida

Spain

B

406.0

BHX

Birmingham

England

B

406.5

BOT

Bottrop

Germany

B

409.0

SG

Såtenäs

Sweden

B

410.0

C

La Coruña

Spain

C

410.0

ETN

Étain

France

B

412.0

GRN

Gerona

Spain

B

413.5

DLS

Berlin - Lubars

Germany

B

414.0

BRI

Bristol

England

A, B

414.0

HD

Sandnessjøen - Hestad

Norway

B

415.0

TOE

Toulouse

France

B, C

416.0

POZ

Po┼żarevac

Serbia

B

416.0

SA

Santander

Spain

B

417.0

AH

Ängelholm

Sweden

B

417.0

CVT

Madrid - Cuarto Vientos

Spain

B

417.0

SNO

Santiago

Spain

B, C

418.5

MT

Offshore Installation

North Sea - UK

B

419.0

EMT

Épinal

France

C

420.0

HB

Belfast City

N. Ireland

B, C*

421.0

BUR

Burnham

England

A

421.0

GE

Madrid

Spain

B, C

422.0

PAM

Pamplona

Spain

B

423.0

TS

Toulouse - Blagnac

France

B

424.0

PHG

Phalsbourg - Bourscheid

France

B

424.0

PIS

Pisarovina

Croatia

B

425.0

EVR

Évora

Portugal

B

426.0

CTS

Castets

France

B

426.0

SH

Shobden

England

A

427.0

RY

Royan

France

B

428.0

BST

Lanvéoc 

France

B, C

428.0

CTX

Châteauroux

France

B

430.0

SN

Saint-Yan

France

B

431.0

SAY

Stornoway

Scotland

B

432.0

PK

Pardubice

Czech Republic

B

433.0

VON

Vigo

Portugal

B

433.0

VNS

Castor Platform

Spain (offshore)

B

433.5

HEN

Henton

England

A, B

468.0

FTZ

Fritzlar

Germany

B

488.0

ILM

Illesheim

Germany

B

 

 

This article was featured in the December 2018 issue of Radio User