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It might not look like it, but this apparently
quite ordinary Japanese 6-transistor AM pocket radio played a small but
important part in US public safety and Civil Defense (CD) operations during the
Cold War. If fact you have to look very closely indeed at the 
On the tuning dial, between the numbers 16 and
10 and 7 and 6, there are two tiny red triangles. They indicate a pair of very
specific Medium Wave frequencies of 640kHz and 1240 kHz, which belonged to the US Key
Stations System, later to become Conelrad (from CONtrol of Electromagnetic
RADiation), more recently the Emergency Broadcast System (EBS) and currently
the Emergency Alert System (EAS). 
It was set up in the early 1950s and in the
event of an emergency all TV and radio stations would be shut down and only
Government and Civil Defense sanctioned news, information and instructions to
the public would be broadcast on the two designated frequencies. All AM and FM
radios sold in the US were required to have so-called ‘CD-Mark’ symbols on
their tuning scales. Mostly they were white, the rest, like this Spica radio were red.
Some specialised radios even had a built-in alarm if an alert was activated.
Sadly this wasn’t once of them, in fact by most technical standards the Spica
is fairly ordinary but it does have a couple of features worth mentioning. 
The first is build quality; they really knew
how to make them in those days, which is probably why this one has survived for
so long, in such good condition. It’s deceptively heavy, and that’s largely
down to the hefty little speaker and several other components that, back in the
late fifties were only partway through the rapid miniaturisation process that
by the early sixties resulted in a deluge of shirt-pocket sized transistor
radios from scores, if not hundreds of far-eastern manufacturers. 
The actual radio is a fairly conventional
6-transistor superhetrodyne design, and as you can see from the internal photo,
densely packed with chunky components. Oddities that you rarely, if
ever, seen on modern portable radios of that era, include twin 3.5mm mono jack
headphone sockets. It’s a mono, AM-only tuner -- stereo FM portables took
another decade or so to appear – so in the absence of any solid evidence to the contrary, my
best guesses are that they were meant for sharing the sound, later a common
feature on first generation Walkman-style stereo tape cassette players, or
maybe it was some sort of pseudo stereo effect using two earphones or
headphones. If anyone knows, do tell!
There are only two controls, on/off volume and
rotary tuning. Power comes from four 1.5-volt type 915 cells. These are now
obsolete but they were the predecessors of the AA cells we know and love today.
They are broadly similar to AAs but a millimetre or so shorter. This makes
cramming modern batteries into this radio a risky business. The difference in
length is more than enough to fracture the brittle plastic battery contact
support pillars. A quick and dirty solution, which actually worked quite well,
was to flatten the positive end caps on a modern battery with few taps from a
small hammer. It probably doesn’t do the cells any good but they last long
enough to confirm that the Spica Transistor Six was in tip-top working order
and reception through the built-in ferrite antenna was good enough to pick up a
number of stations on the Medium Wave band without the need for an external aerial
(there’s a threaded socket on the top of the case for just such a purpose).
There’s no need to dwell on sound quality, it’s about as good as it gets on MW
transmissions on pocket radios, of any age…