486
Item nr.


Eddystone 870A Cabin Receiver

Small ship receiver in metal case


Data for Eddystone 870A
ProductionEngland, 1962.
Price was 33 Pounds.
BandsBand 5 (150-380kHz), 4 (510-1400kHz), 3 (1.3-3.5MHz), 2 (3.2-7.5MHz), 3 (7.5-24MHz); IF is 465kHz.
Tubes12BE6 (Conv), 12BA6 (MF), 12AT6 (det/AF), 19AQ5 (output), 35W4 (rect), 2 pilot lights.
CabinetMetal. Size 28x16x18cm. Weight 5.2kg.
PowerACDC 240/210/110V.

The Design

The Eddystone 870A is a popular small reciever and a lot is written about it on the internet. There are two versions, the older type with four bands and the newer type with five bands.

Caution: This is an ACDC set with metal case. The first means that all internal parts are connected directly with the mains and the second that your life and health (and of your family members) depands on insulation! Unfortunately there is a serious risk of internal parts getting into contact with the outer case. Therefore I recommend for your safety that you use this radio only in a grounded socket protected with a ground fault interruptor!

How can this set be so much more sensitive than other radio's with similar tubes? I see two reasons here. Various sources already report the use of high quality coils, making the set more expensive than a typical AA5 but leading to good response and image suppression. Second, I point towards the metal casing and mains RF filter, keeping a lot of noise out of the radio. Indeed, I find a lot of SW stations come in with lower noise that on many of my other sets.


Obtained9/2018 from Nico Romeijn; sn=F05592.
Condition9.
Sound samplePLAY SOUND   After fixing my antenna cable, I tuned in the 49m band using my 80m Loop and heard Radio Emmeloord on 6095kHz. Emmeloord existed 2 years on October 6, 2018, and celebrated this with a transmission with 150kW from Nauen, on top of the usual 1224kHz. We could hear the English singer David Bowie, singing in Spanish on a Dutch station broadcast from Germany.

This Object

In 2017 I advised a family about what to do with the sets of a deceased radio collector. The radios were sold following my advice with the exception of this radio, that came my way.

Looking inside I found a quite neat set, no rust or dust. Of the two fuses, one was replaced by a metal plug leg and the other was blown; I replaced both by 25mm fuses, which fit the larger holder when placed inside a 25mm holder. Also the plastic wheel driving the tuning capacitor was broken. It functioned, but gave a little play in the tuning so later I applied some glue, without even having to take the wheel out.

I found the two dial lights missing and put 6.3V/100mA lights there, bridged by a 220 Ohm resistor. I replaced C44 (mains filter), C38 (coupling), C16 (RF decoupling), and C4 (mains separation). I fired up the Eddystone using a series bulb and it played immediately on all bands. Voltages on filter caps and tubes were a bit low, and to remedy this I switched the power selector to 210V.

The antenna jack is just a bit narrower than the usual banana plug and I had some difficulty making a fitting cable. I ordered several banana plug announce as "3mm" but all turned out to be the common 4mm plugs. I succeeded with plugs I had in stock for years, the cheapest banana type with four metal strips around the pin to smoothly fit. With a screw driver and plier, I could remove two of the four strips and then the plug fits the Eddystone.


Part of Gerard's Radio Corner.
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