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:
Hi, 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 grey. 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. Richard UNQUOTE