Marine Receiver – Skanti R5001

Dear Sparks,

under request of Radio Officer Sandro VIALE (Italy) and thanks to details supplied by him below a short review of one of the most popular marine receiver the Skanti R5001, this receiver has been produced also under Sailor and Debeg:

This is a marine receiver covering 0.01-30 MHz. It receives AM, USBl LSB (BFO), CW, and RTTY, and is a very good performer, especially using AM and on medium- and long-wave.
The R5001 marine and general purpose receiver is designed for use in a marine main radio station. The receiver has synthesized operation in the frequency range 10 kHz to 29,999.9 kHz.

The receiver is designed for reception of type F1, A1, A2, A2H, A3, A3H, and upper-sideband A3A, and A3J signals. It is fully transistorized, and widespread use is made of integrated circuits. These features, in connection with the fact that no crystal ovens are used, cause the receiver to be ready for operation immediately after having been switched on.

Depending on the power pack installed in it, the receiver can be powered from a 24 V battery, or from AC voltages normally occurring in practice.

The dimensions match a 19-inch standard rack.

Synthesized operation from 10 kHz to 29.9999 MHz
Fully digital read-out.

Modes of operation
A1, A2, A2H, A3, A3H, A3J, and F1. Simplex, semi-duplex and duplex with built-in duplex filters
-6 dB -60 dB
Wide +/- 4 kHz +/- 17.5 kHz
Intermediate +/- 1.2 kHz +/- 1.9 kHz
Narrow +/- 0.5 kHz +/- 3.5 kHz
Very narrow +/- 0.1 kHz +/- 2 kHz
SSB +350 and +2700 Hz -400 and +3400 Hz
F1 +/- 400 Hz +/- 850 Hz

Connection made for high input impedance. Sensitivity max input for 10 dB SINAD.
Frequency Mode Sensitivity
0.1-1.6 MHz A1 4 uV
0.1-1.6 MHz A2, A2H, A3 18 uV
1.6-4.0 MHz A1, A3A, A3J, F1 1 uV
1.6-4.0 MHz A2, A2H, A3, A3H 4 uV

Connection made for low input impedance, 50 ohm. Sensitivity max input for 10 dB SINAD.
Frequency Mode Sensitivity
0.1-1.6 MHz A1 2 uV
0.1-1.6 MHz A2, A2H, A3 9 uV
1.6-4.0 MHz A1, A3A, A3J, F1 0.5 uV
1.6-4.0 MHz A2, A2H, A3, A3H 2.5 uV
4-30 MHz A1, A3A, A3J, F1 0.5 uV
4-30 MHz A2, A2H, A3, A3H 2.5 uV

Audio output
10 mW to phones (400 ohm)
5 W to loudspeaker (4 ohm)
10 dBm to line (600 ohm)

Supply voltage
24 V battery with P5010 power pack
110/115/120 or 220/230/240 V single – or two phase AC 50-60 Hz with P5011 power pack
24 V battery, and/or 110/115/120 or 220/230/240 V single – or two phase AC 50-60 Hz with P5012 power pack

Supply voltage variations
DC: -10 to +30 %
AC: +10 %
24 V battery approx. 2 A
AC mains approx. 45 VA

The duplex filters bandwidth
Frequency band -1 dB bandwidth
4 MHz 4355 – 4445 kHz
6 MHz 6500 – 6596 kHz
8 MHz 8710 – 8840 kHz
12 MHz 13100 – 13350 kHz
16 MHz 17230 – 17830 kHz
22 MHz 22570 – 23430 kHz
25 MHz 25300 – 26300 kHz

Height 245 mm
Width 520 mm
Depth 306 mm
Weight 23.6 kg without cabinet




Radio room M/V Samuel L. Cobb

Dear Sparks,

below few seconds in the radio room of US M/V Samuel L. Cobb.. enjoy the video.




Marine Receiver – SAILOR R 1120

The following review and videos by Radio Officer Nino Paglialonga IZ7DJR (Italy)

Dear sparks now a real jewel :

SAILOR R1120 general coverage marine receiver made by  S.P. radio in Aalborg Denmark.

Still in production on 1987 this great receiver was quoted more than 30.000 mk on a Finnish marine products  price list ( 11.000.000  italian old “ lire “). It isn’t well known and its sizes: 12 h, 45 w, 35 d _cms. (rack system 19’’). R1120 covers 10 kHz to 30 MHz continuosly and automatically switchs 7 front-end band filters. Great RF selectivity due to a tunable preselector on the front-end acting inside each band filter. It is a double conversion receiver 1st  if =10,6085 MHz & 16,6085 MHz, 2nd if = 600 kHz, all solid state.

Other filters: 7 (seven!) xtal filters:

2 dedicated to “roofing filtering” and 5 choosen for best mode filtering.

Usb/cw/rtty (Lsb by bfo). Digital display and synth. Down to 100/Hz.

Tuning by numeric dial or continuosly by tune/knob +  unlock  button.

It is a rock: frequency drift short time= 5 Hz, long time = 25 Hz… per year!

Now my opinions:

177 pages to describe a radio receiver, but 177 seconds o so to use it.

Ergonomic commands , maximum flexibility, one knob per action.

 Noise generator for front-end peaking.

 A solid, heavy tuning knob: smooth action, nice feeling (inside: optical rotation encoder).

Great efforts spent by Danish engineers to explain everything on the  user manual.


So after years, servicing is simple using common (well chosen) electronic components.

All boards are dedicated to a single function , detailed description and two sides board drawings on the service manual.

To keep inside noise low, Danish engineers preferred to limit the synthesizer step down to 100Hz (It is a real receiver not a lab instrument).

Tuning display by green LCD .

Restful cw reading, even by  internal loudspeaker. Choosing 600 kHz if frequency, filtering is excellent, deep sides much better than common 9000 kHz filters.

Signals coming out clean, even on wide filters.

It is impressive to compare cw signals even  on  a modern ham receiver.

The ssb filter shows a 6/60 dB ratio of less than 1,6. It means that a 2350 Hz channel becomes 3700 Hz only, down 60dB.

Cw filters are superb and  the very narrow filter BW = +/-190 Hz.

Quite unusual, but useful: a page dedicated to operational tips for AGC use and another page voted to noise blanking (NB not used ! ). This is a marine oceanic receiver and have to struggle against statics expecially in tropical zones.

Last but not least:  R1120 Sailor claimes an inside TCXO at 10 MHz: excellent and  guaranteed frequency stability .

A couple of videos filmed by me iz7DJR / Nino Paglialonga



Marine Receiver – ITT Mackay 3031A

Dear Sparks,

ITT Mackay, very popular between us, produced several radio gears for Merchant Marine, on the last productions realized very fine HF receiver and one of them was the model 3031A, below the video some features, unfortunately there are not online a clip for this model but has been decided to post one video of a modern Mackay receiver (3020 model) to have an idea about the quality of these apparatus:


The 3030A is a fully synthesized, dual conversion, maritime and fixed station communications receiver.  It covers a continuous frequency range from 15 KHz to 29.99999 MHz tunable in 10 Hz increments.  Operating modes are AM, USB, RTTY, and CW (fixed, variable, and preset).

The receiver is solid state and employs modular construction. There are printed circuit boards most of which are housed in chassis mounted plug-in modules. The 3031A is capable of fully synthesized high resolution tuning of 10 Hz increments, but by using features found on the receiver, tuning of resolution finer than 5 Hz can be realized.  In addition, the 3031A is designed with 1 ppm (part per million) high stability and this gives the user a maximum potential of error reading of 30 Hz of the exact frequency of the received signal at 30 MHz.

The Mackay receivers are highly regarded for longwave tuning.  While they perform quite well on the HF bands, they were designed for maritime use which included hearing signal beacons in the longwave frequency spectrum. Few commercial receivers can equal this performance using the combination of preselector and tuning and so the Mackay receivers have a strong following for DXers who enjoy hearing signals in the longwave range.

Another unique feature of this 3031A was the selection of CW modes.  Okay, you ask, so what is the difference.

CW Fixed: Allows the operator to center the CW signal to the middle of the IF bandwidth.  This allows both the ability to zero beat the signal, but also allows for the exact identification of received frequency. Thus, this is the first step to tuning a CW signal.

CW Preset: After tuning in a signal, the operator switches to this mode to get the proper audio tone for good copy of the signal.  Thus, this is a convenient method of quickly moving from the Fixed CW to a copyable CW.  The manual directs operators to use either the .4 KHz or the 1 KHz filters for regular CW reception, but that the wider 2 and 8 KHz filters may be used to help search and locate the signals when exact CW frequency is not known.

CW Var (variable): This mode is used if the operator desires a tone that is different than the standard fixed CW tone.  In this mode, the operator would tune the BFO control to the listener preference of receiving tone. Thus, this mode of CW is typical of most receivers and is less convenient than the CW preset mode.

If you look at the mode selection knob, you will notice something unusual….there is no LSB!  This is due to the fact that since this was designated as a marine receiver, it had no need for LSB as all maritime communication is in USB.  In fact, by not having it available prevents operator error in receiving such maritime signals by inadvertently selecting the incorrect receiving mode.  However, not to worry.  CW Var mode and tuned the BFO for clarity so that getting the LSB was possible and sounds great.

Another feature that seems very unique to this 3031A receiver is the Speech Clarifier.  By pulling out this knob, the operator unlocks the synthesizer and can vary the tuned frequency. Because the receiver can tune in 10 Hz increments without the clarifier, this knob is not normally used.  But if desired or necessary, the user can literally fine tune with extreme precision.

At this point additional standard features and specs of this Mackay 3031A receiver:

  • Tuning to 10 Hz resolution
  • Selectivity of 8 / 2.0 / 1 / .4 KHz
  • AGC of fast / slow
  • RF gain
  • S /AF meter
  • Internal speaker 3.5 watts
  • Headphone / line out / speaker connections
  • Operating voltages of 90 – 130 or 195 – 260 VAC
  • Operating temp range of 5 degrees to 131 Fahrenheit (-15 to 55 centigrade)
  • Power consumption of 62 watts
  • Can sustain an input signal EMF of 30 volts for 15 minutes without damage
  • Speaker switch

The 3031A comes with a standard IEC power connector and a 3031A operation manual.




Marine Receiver – RCA AR-8516

Dear Sparks,

the United States had own factories producing famous radio gears but not devoted only for their own use, also ships or shore radio stations of foreign Countries used these equipments but not so largely than European or Japanese productions.This short review to remember the famous RCA receiver model AR-8516 both for shore or sea applications:

Producer RCA Radiomarine Products Department; Camden (NJ

Year                     1961

Tubes 18:  3BZ6 3CB6 3CB6 3BZ6 3CB6 7AU7 3CB6 3BZ6 3BZ6 3BZ6 3AL5 7AU7 5U8 3BE6 5U8 3AL5 7AU7 12CU5
Principle Supereterodyne double / triple conversion; ZF/IF 1090-3090/455/45 kHz
Bands Long waves, Medium waves, Short waves
Power Supply AC/DC 115; 230 Volt
Audio power 1 W
Model Communications Receiver AR-8516 – RCA Radiomarine Products
Materials Metal rack
Dimensions (LxHxD) 558 x 289 x 444 mm / 22 x 11.4 x 17.5 inch

RCA Radiomarine Communications Receiver AR-8516: triple conversion receiver covering 80 – 30’000 kHz in 18 continuously tuneable bands, reception modes A1 (CW), A2/A3 (AM), SSB, sensitivity above 3 kHz 2 uV AM, 1 uV CW mode. IF filter (-6/-60 dB) 6/20 kHz, 3/7 kHz, 1,5/6 kHz, 0,8/4 kHz, 0,1 kHz. Tuneable BFO in shortwave bands, noise blanker.

Triple conversion superhet, 1st IF 1090-3090 kHz (or 2000-4000 kHz) tuneable, 2nd IF 455 kHz (mechanical IF filter), 45 kHz.

Powered by 115 V DC or AC 45-65 Hz, 230 V with optional RM-288 Resistor unit, to be used from different power systems onboard ships. Accessories: RM-288 resistor unit for 230 V use, RM-289 isolation transformer 115/230V AC, RM-290 loudspeaker unit. Desktop cabinet or 19 inch relay rack. The sister model RCA Radiomarine CRM-R6A with different tube is the standard AC mains version. Of the receiver AR-8516, only one small badge is reported to be made in 1961.

Weight 41 kg / 90 lb 4.9 oz (90.308 lb)





Dear Sparks,

our friend OM Geoff POWELL – M1EDF –  from England had some correspondance with OM Zele on board M/V SIDER MOMPOX and reported me the following maritime mobile activity;

Hello Geoff,
thanks for all QSO and your QSL card. I receive your lettet but have not time to answer, i will do when I next time be at home.
Now I am on other vessel, Sider Mompox, in this moment in Barraquilla, Colombia. For few days we sailing to Turkey and I will be on the air again, so maybe catch you again

Best 73’s de Zele YU2AX/mm

Good Watch,



Marine Receiver – Marconi Marine APOLLO

picture from:

Dear Sparks,

largely used on cargo ships the APOLLO receiver made the history of marine communications, interesting features, two separated VFO and good filtering, the VFO for marine bands was extremely stable thanks to the Xtal oven, personally used I found it very reliable, For this receiver no videos around the web.

Here some carhacterictics:

Type: General purpose, SSB marine receiver ;  solid state.
Frequency Range: 10 kHz to 28 MHz in ten ranges.
Circuits: Single conversion superhet from 15 kHz  to 1.4 MHz. Above 1.4 MHz, it operates as double conversion superhet.
Power Mains:   105-130 VAC or  210-260 VAC .
Manufactured between:  1970 and 1982.
Comments: Although this is a solid state receiver, it is nonetheless the first of the main Marconi receivers used during the transitionary period from tubes to solid state. Apollo was basically a tube design but with
transistors substituted for the tubes.




Marine Receiver – Dancom R203

Dear Sparks,

some words about the well known receiver produced by DANCOM in the 80’s and largely used also on Passenger ships, not a real excellent receiver but much appreciated for easy operation.


Danish Marine Communications (Dancom) R-203 solid state receiver made in the early 80s.
Digital rack mount unit.
Covers 10 kHz to 30 MHz in 1MHz switched bands.
Uses crystal-bridge type filtering, where the crystals defined the upper and lower limits to the IF passband.

It will operate from mains or a 24 VDC supply.
Weight 24kg.

Main problems: medium quality mechanic expecially in the band switch and no good enough during SITOR operations too much noisy.

(In 1973 3 Danish engineers from S.P radio established a spin of company “Dancom producing maritime communication equipment. Dancom went through some financial difficulties in the 80s and was restructured and renamed Dancall radio in 1983).




Marine Receiver – Sait PR155

Dear Sparks,

here some informations about a really well made marine receiver SAIT/PLESSEY model PR155, this kind of receiver was used also in coast radio stations such as CAPE TOWN RADIO c/s ZSC.

Country           Gran Bretagna (Regno Unito)

Producer         Plessey; Ilford

Year                  1967–1970

Principle Wadley-Loop (supereterodyne double conversion); ZF/IF 37300 kHz, solid state
Bands Long waves, Medium waves, Short waves
Power supply (AC) / 110-125 / 200-240 / (DC) 24 Volt
Audio power 0,5 W excellent quality
Materials Metal cabinet
Dimension (LxHxD) 16.75 x 7 x 17 inch / 425 x 178 x 432 mm
Notes Triple conversion Receiver, coverage 15 – 30.000 kHz, AM/USB/LSB/CW, BFO ± 8 kHz, 0.5 µV sensitivity, analogue frequency readout (1/3 kHz!), “Wadley loop” technique with MHz selector and 0 – 1000 kHz film dial.
Weight 17.2 kg / 37 lb 14.2 oz (37.885 lb)




Marine Receiver – Drake MSR 2

picture from:

Dear Sparks,

DRAKE Company produced a long serie of general communications receivers, some of them dedicated to marine radio communications, the MSR-2 is one example of these very good equipments employed on several cargo ships of many flags, Drake has been one of the first Company to supply their receivers with the digital frequency readout.

On the video below it is showed the DSR-2 receiver very similar to the MSR-2 that’s because on the web a video of MSR-2 is not available

Country                    USA
Producer                 Drake, R.L. Miamisburg, Ohio

Years                       1974–1978

Type:                        solid state


Principle Supereterodyne double / triple conversion; ZF/IF 50500/50 kHz
Bands Medium waves and Short waves
Power supply AC 120/240 Volt
Power audio out 2 W
Materials Mobil mount
Shape Rack
Size  (LxHxD) 480 x 133 x 380 mm / 18.9 x 5.2 x 15 inch

Coverage 10 kHz – 30 MHz, AM, CW, USB/LSB, ISB;
Digital frequency readout through nixie tubes up to 100 kHz, integrated noise blanker.
Marine receiver also sold as DEBEG MSR-2, Hagenuk EE334, SAIT MR 1415, CRM 3928.

Weight 11.5 kg / 25 lb 5.3 oz (25.33 lb)