Marine Radio – Main transmitter Standard Radio ST1200

Dear Sprks,

following article by Technical Journalist Dr. Marcin Marciniak – SP5XMI

This masterpiece of old tube technology is quite rare comparing to Marconi, Mackay or even Dansk Radio (the Elektromekano brand). It came from a Swedish company „Standard Radio & Telefon AB” in the 50s, it was installed on three Polish vessels including s/s SOŁDEK callsign SPCJ (, now a museum ship. You can see this ship as a part of National Maritime Museum in Gdańsk, Poland. Unfortunately none of the original radio sets onboard are in working condition. A group of enthusiasts wanted to restore main transmitter and one of the receivers but the process is very complicated as of now.

There were also three sister ships that had similar radio setup: s/s BRYGADA MAKOWSKIEGO/SPCN (written off in 1979) and s/s JEDNOSC ROBOTNICZA/SPCK (written off in 1978). It’s Standard Radio ST1200 *)  that covers maritime bands 4-6-8-12MHz (A1/A2), telegraphy on whole 500kHz band and AM coastal telephony on 1,8MHz band. Therefore its range and modes were more than adequate for voyages all over Baltic Sea or the English Channel. This is where s/s SOŁDEK sailed.

It’s comprised of separate modules: exciter and final stage of HF CW transmitter, MF AM coastal telephone transmitter, 500kc main transmitter, power supply and A2/A3 modulator for W/T and R/T. It uses standard chain on HF W/T: crystal oscillator, frequency doubler/tripler chain, separator, driver and C-class power amplifier. One stage of the doublers is bypassed on lower bands. MF R/T is also crystal controlled, uses standard principle with Class-C PA, anode modulated. The 500kc main transmitter uses free running oscillator. The HT is in the kilovolt range. Power supply requires AC converter (a dynamotor perhaps) and separate voltage regulator because many vessels of that time used DC power supply. The s/s SOŁDEK/SPCJ was no exception – it was a DC ship.


The radio room of s/s SOŁDEK/SPCJ

not to be confused with ITT ST1200, the American one works SSB, this one comes from the 50s and is only CW and AM.


Two racks of the main transmitter. On the left-hand side: local power supply and modulator for A2 mode, exciter and driver and the finals. On the right-hand side: power supply and charging panel, AM radiotelephone transmitter for medium wave and main 500kHz CW transmitter.


Main transmitter for 500kc band. Uses free running oscillator with a tuning lock knob. This transmitter uses oscillator, separator and C-Class power amplifier. Tuning switch enables transmitter on low power settings.


Exciter of the shortwave W/T transmitter. It’s crystal controlled – 6 pcs of 2MHz crystals can be used (on SPCJ only three of them were inserted). Frequencies used: 4178, 4201, 4222 ; 6268.5, 6301.5 , 6333; 8358, 8402, 8444 and 12537, 12603. Third crystal on 12MHz after doubling and tripling was 12666 MHz therefore outside of the usable 12Mc maritime band in Poland.
Signal from oscillator is fed into the doubler that works also as a tripler for 6MHz band. Changing the band swich position bypasses one of the doublers in chain. It’s similar to the doubler/tripler chain used in Marconi Oceanspan transmitter. Then the driver stage is tuned to resonance. All voltages and currents can be measured using a selectable meter. Cathode current of the last driver stage is measured by a separate meter. Tuning procedure: set a proper crystal to be used, set the band switch to position depending on the band and tune doubler to resonance within band (cathode meter should deflect some, tune for maximum deflection). Then tune final stage, then tune the driver stage to maximum deflection and correct doubler tuning if needed. Take care of maximum reading of anode current in the final stage.


Final stage of W/T shortwave transmitter. Tx uses direct heated tubes in parallel working in class C. Final stage tuning is typical – set the band switch to proper position and then tune the output tank for maximum aerial current. Correct final drive by driver tuning if needed.


This is the transmitter for R/T on medium wave (1,8MHz). It is also crystal controlled, tuning is similar to W/T module. Besides crystals that are installed inside, there is a socket for external crystal. Frequencies used: 1960, 2049, 2056, 2090, 2107, 2182 and additionally external crystals: 2411, 3331. All in AM of course.

wt modulator

Power supply, modulator and mode selector for W/T. Power switch enabled filaments (“START”), enabled screen and HT but with lowered voltage (“TUNE”) and finally full HT voltage (“SEND”). A2 mode enabled oscillator for A2 W/T mode.


Main power supply panel – the input voltage after rotary DC/AC converter (s/s SOŁDEK/SPCJ was a DC ship) was fed into a voltage regulator for stabilizing input voltage. All voltages (mains, battery, bias, HT and battery charging) could be measured by selectable meter.




Marine Receiver – Receiver DEBEG 7284

Dear Sparks,

in the Mediterranean area we suffered a very hot summer keeping many out of the radio rooms, I am one of them HI!

I am back on and tonight with a good fresh air I propose a nice clip of a simple receiver mainly used in the past on board fishing boats or on coasters and nowadays in the hands of many collectors, I have not at the moment technical specifications but as soon as they will be available they will be included with this review.

Best regards,



Marine Receiver – I.R.M.E. RXU70

Dear Sparks,

in the past Italy had many important firms in the radio electronic field and some of them was involved in the production of equipments for maritime radio communications, of of the them was I.R.M.E. factory based in Rome. I.R.M.E. produced a wide range of marine radios and between them there was one receiver, very similar to the ATALANTA of Marconi Marine, the model RXU 70. This receiver has been used for long time and not only on Italian flagged ships, unfortunately on the web there is not much to report here, it was a receiver of good quality but with some drift trouble. If someone reading this post has some documents for picking up the main features of this radio, they are very welcome.




Marine Receiver – JRC NRD 91

Dear Sparks,

JRC firm has been established in 1915, the company produced a wide variety of products including marine electronics, measuring equipments for telecommunication, radio broadcasting equipments, and amateur radio equipments. For marine radiocommunications JRC produced a wide range of apparaturs both for ships and coast radio stations, from high perfomance receivers to high power trasmitters and today continue to have a leadership in the production of GMDSS equipments.

In this review it is showed the NRD 91 receiver which is the basic model followed by NRD 92 and NRD 93, today this equipments, not longer used in maritime communications, found a place in several amateur radio and SWL/BCL stations.

Here a clip with receiver tuned on the frequency of the Italian coast radio station NAPLES RADIO c/s IQH while trasmitting NW.



Country Japan

Factory  JRC Japan Radio Co., Ltd.; Tokyo

Year 1984

Principle  PLL, Phase-locked loop; ZF/IF 70455/455 kHz

Solid State Transistors and IC’s

Power Supply AC 100/110; 200/ 220 and DC battery 24 Volt

Audio output 1 W on 600 ohm

Materials  Metal rack

Dimensions (LxHxD) 480 x 149 x 294 mm / 18.9 x 5.9 x 11.6 inch

Notes Wave range: 90 kHz – 29.9999 MHz
Double superhet with up-conversion using a PLL synthesizer.
Reception modes: CW, MCW, DSB, SSB (FSK, FAX optional)
Selectivity: 6 kHz, 3 kHz, 0,5 kHz
Digital frequency display
Head phone jack.

Optional desktop cabinet (dimensions 489 x 190 x 305 mm, weight 11.5 kg).

Net weight 7 kg / 15 lb 6.7 oz (15.419 lb)


Marine Receiver – Marconi Marine Oceanic

By Radio Officer Riccardo MEMEO (The Netherlands)

Dear Sparks,

this is a receiver produced both by Elektromekano later Danks Radio (with name M3000) and by Marconi Marine (with name “Oceanic”) I have used this radio on board bulk carrier M/V Massimiliano c/s ICZV a great receiver indeed.

On the photo below M/V Massimiliano (FERRUZZI Fleet)


In the clip below a restoring of the M3000

Technical specifications:

Coverage:  100 – 30000 kHz


Selectivity:  5.4/2.4/1/.2 kHz -6dB

Stability:  ± 1 PPM 0° to 40° C

Sensitivity:  <2 µV 4-30 MHz 20 dB

IF Rejection:  >90 dB

Image Rej.:  >90 dB

Antenna Input:  BNC 50 ohm (>4 MHz)

Audio Out:  4 W 4 ohm

Environment:  0° to +50° C

Preset freq.: 500/2182 kHz

Memories:  75

Dimensions:  509x159x463 mm weight 15 kg

Voltages:  110/220 VAC 50/60 Hz 60W or 24 VDC 85W

73’s R/O Riccardo MEMEO



Marine Receiver – Elektromekano M97

Review by Radio Officer Riccardo MEMEO (The Netherlands)

Dear Sparks,

an excellent Rx that I had the pleasure to use on board two ships: it is the Elektromekano M97 that can be seen on the photo of the entire RT station that I include. It was like the Siemens 745 E310 with the bandspread every 100 kHz. However, it had the advantage over the latter that the bandwidth was selectable according to the type of modulation chosen. On A1 could be selected the 300 Hz filter in case of strong qrm.

Elektromekano M97

Some features:

General coverage communications receiver, double conversion superheterodyne (single conversion below 3,7 MHz).

Range : 14 kHz to 26 MHz in 10 bands, 14-21.5 kHz; 96-230 kHz; 240-530 kHz; 600-1500 kHz; 1.5-3.8 MHz; 3.7-7.4 MHz; 7-11 MHz; 11-15 MHz; 15-19 MHz and 19-26 MHz.


Selectivity : 8.2/4/2/0.6 kHz -3 dB

Sensitivity : < 3 to 5µV 20 dB S/N (7-26 MHz)

IF Rej. : > 90 dB typical

IF : 1300-1200, 560 kHz

Image Rejection : > 65 dB

Audio out : 3.23 Ohm 1.5 W

AGC : Off/Short/Long

18 Tubes used : 2 EF85; 7 EBF80; 4 ECH81; 1 ECF 80; 1 EAA91; 1 EL95 and 2 OB2.

Calibration for bandspread every 100 kHz. (same as the Siemens E 310)

The M97 is supplied with 9 built-in crystals, plus sockets for additional 10 crystals, covering the complete  marine coastal frequencies in the 4, 6, 8, 12, 16 and 22 MHz for extra frequency stability.

Dimensions : Cabinet version 564x408x434 mm 44 Kg, 22.2x16x17” 97 Lbs

Best regards

R/O  Riccardo MEMEO



Marine Receiver – Eddystone 1830/1

By Radio Officer Sandro VIALE – Italy

Dear Sparks,

on this review it is showed the prestigious receiver 1830/1 made by Eddystone in the 70s. On many ships this receiver was dedicated as “Emergency Unit”. First time I have used this radio I was on board M/V “Jolly Marrone” c/s IBIM, below the picture of the vessel and a short clip I recovered by an old VHS cassette where the receiver is on the right side of the rack (bottom unit). After the clip are listed some features of this equipment.


Here the features of the receiver:

Year  1971–1977

Principle Superetherodyne double / triple conversion; ZF/IF 1350/100 kHz

Bands LW, MW and HF

Power supply AC 100-130 / 200-260 / Battery12 Volt

Audio power 1.5 W

Material Metal rack

Dimension (LxHxD) 502 x 164 x 376 mm / 19.8 x 6.5 x 14.8 inch

Notes General coverage receiver, covering 120 kHz – 31 MHz in 9 bands (120-250 / 240-480 / 480-950 / 920-1750 kHz, 1,5-2,9 / 2,9-5,5 / 5,5-10 / 10-19 / 18-31 MHz); AM, CW, USB/LSB.
10 crystal controlled preset channels. Optional plint loudspeaker unit 989 or cabinet speaker 935, optional anti-vibration mounting LP-2817/2. Standard production version, approved by MPT as Marine Reserve Receiver.
Also sold as S.A.I.T. MR1431 and under Hagenuk Label.

Weight 18.1 kg / 39 lb 13.9 oz (39.868 lb)

Frequency Coverage and Tuning Facilities
In the 1830/1 and 1830/2 models, a total of 9 ranges cover 120kHz to 31MHz thus:
Range          Coverage                                Conversion IF1 IF2
1.        18 to 31 MHz Double Tunable    1300-1400 kHz 100 kHz
2.        10 to 19 MHz Double Tunable    1300-1400 kHz 100 kHz
3.        5.5 to 10 MHz Double Tunable   1300-1400 kHz 100 kHz
4.        2.9 to 5 MHz Double Tunable     1300-1400 kHz 100 kHz
5.        1.5 to 2.9 MHz Double Tunable  1300-1400 kHz 100 kHz
6.        920 to 1750 kHz Single                            100 kHz
7.        480 to 950 kHz Single                              100 kHz
8.        240 to 480 kHz Single                              100 kHz
9.       120 to 250 kHz Single                               100 kHz
The 1830/3 and 1830/4 models cover similar frequencies on ranges 1 through 6 and 9, but cover the following on ranges 7 and 8, leaving a gap in the tuning range between 535kHz and 920kHz, ie. the lower half of the medium-wave or ‘Broadcast Band’:
Range           Coverage                               Conversion IF1 IF2
7.           400 to 535kHz Single                           100kHz
8.           200 to 400kHz Single                           100kHz


R/O Sandro VIALE


Marine Receiver – Eddystone 1837

Dear Sparks,

on this review some details about the marine receiver produed by Eddystone at the end of the 70s, no videos available on the web.

Country            Great Britain

Factory             Eddystone

Years                1977–1983 

Principle           Supereterodyne double / triple conversion; ZF/IF 1350/100 kHz

Bands               LW, MW, HF

Power supply   100-130; 200-260 Volts / battery 12; 24 Volts

Audio power      0.5 W

Materials            Metal rack

Dimensions (LxHxD)     483 x 133 x 334 mm / 19 x 5.2 x 13.1 inch


General coverage communication receiver covering 100 kHz – 31 MHz in nine bands AM, CW, USB/LSB, FSK optional. 840-1600 kHz segment single conversion, high stability frequency lock above 1600 kHz. Standard IF bandwidths 8/3/2,4/1,3/0,4 kHz. Digital readout 100 Hz resolution. Optional plinth speaker 989, optional panoramic unit 1061.

Weight                      16.8 kg / 37 lb 0.1 oz (37.004 lb)




Marine Receiver – RFT EKD 500

Dear Sparks,

here is a summary of the history of the East German factory RFT than one of her last receiver produced for East European market largely used in merchant marine communications:

VEB Funkwerk Dresden was a publicly owned company (VEB) in the city of Dresden during the times of the former DDR (East Germany). The company was founded under Russian occupation immediately after WWII, in 1945, and was initially known as Radio H. Mende & Co. Dresden. In 1948, it became a Volkseigener Betrieb (VEB) and was renamed to VEB Funkwerk Dresden . As the company was also part of the RFT consortium, it is also known as RFT Funwerk Dresden. Initially Funkwerk Dresden contentrated on the production of radio receivers for the domestic market, with bulk production starting in 1951. In 1962, the production of radios is cancelled and moved completely to Stern-Radio Staßfurt. From that moment on, the company concentrates on the production of measuring equipment and radio communication systems.
In 1969, Funkwerk Dresden is merged with two other VEBs, Vakutronik and Schwingungstechnik und Akustik Dresden, and moves on as VEB Meßelektronik Dresden (abbreviated as MKD).
A few years later, in 1972, the name ‘Otto Schön’ is added to the title and the company becomes known as VEB Meßelektronik ‘Otto Schön’ Dresden. This name lasts until the company is merged with the large VEB consortium Robotron in 1979, after which the name is changed to VEB Robotron-Meßelektronik ‘Otto Schön’ Dresden. On 30 June 1990, after a variety of problems in the supply chain, the company was dissolved in the light of the reunification of Germany .

Professional receiver  RTF  VEB  Funkwerk   DDR model EKD 500

10 kHz  – 30 MHz


keybord direct entry

triple PLL  synthesizer

16 selectable tuning steps

adjustable   BFO

all scan functions

filter bandwidth = 0,15/0,4/0,75/3,1/6  kHz

weight  25 Kg




Marine Receiver – Redifon R551N

Dear Sparks,

for long time this receiver has been employed on board merchant and passenger ships, it has been a great receiver but on the web there are not reviews and specifications, if any of you have detailed informations this article will be modified with your contribution:

This receiver was designed to a high specification and cover 10 kHz to 30 MHz with a resolution of 10 Hz, a sensitivity of 0.35 uV on the HF amateur bands and good selectivity due to 300Hz, 1 kHz and 3 kHz crystal filters.

After published this short review I received by Radio Officer Richard PHILLIPS the following message:

the  Redifon  R551N  that  you have on your site is not a commercial
radio  but one used by the British Royal Navy (and possibly other NATO
forces  too).  You  can tell this by the model number ending in N, the
NATO  spares number (5820-99-525-6189) and the fact that it is painted

The standard commercial radio is the Redifon R551. It is painted cream
and  black and does not have the ARU18 or ARU11 units.

I've  attached  a  picture  of  a  ship with a Redifon radio room that I
sailed on.
opal bounty rr