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Widget Of The Week
Viking ‘Sol Invictus’ Metal Detector, 1975?
 Metal detecting has always had a slightly nerdy
reputation, but it’s easy to understand the appeal when (very) occasionally a
lucky detectorist unearths a historic or valuable artefact or better yet, a
hoard of gold coins. In reality the vast majority of amateur metal detector
owners are lucky to find anything more exciting than a few ring-pulls and some
loose change, but for the determined few who put in the time and effort there’s
always the chance of striking it rich…
Nowadays it can be a very expensive business
with top-end equipment selling for thousands of pounds; but back in the 1970s,
when this Viking Sol Invictus model first appeared, it was an altogether more
modest hobby. The 70s and 80s was one of metal detecting’s periodic golden
ages, with dozens of affordably priced models coming onto the market. This was
due, at least in part, to advances in electronics and rapidly falling prices
thanks to the efforts of far-Eastern manufacturers. However, for once detectors
from British companies, like Viking were establishing a strong presence in the
market, often with high performance (though not always very pretty) designs
like this one from Viking. Incidentally, the name ‘Sol Invictus’ (unconquered
Sun) refers to a Roman Sun god and his likeness, along with the emperor of the
day often appeared on Roman coins, and the sticky label on the front of this
detector.
 It looks deceptively simple; essentially it is
a metal tube, bent at one end to form a handle, with a circular waterproof
detector head, containing a pair of coils, on the other end. A plastic box
houses the electronics and a battery, and this is mounted near the top of the
pole. There are just two controls, one for power On/Off and Fine Tuning, the
other for Course (sic) Tuning. It has a built-in loudspeaker, or if you want to
avoid scaring the horses, there’s a standard jack socket for a pair of
headphones. Setup takes just a few moments; after switch on the Coarse Tuning
control is adjusted to compensate for ground conditions (moisture, minerals
etc) by turning it to the point where the rasping tone from the speaker
completely disappears. The fine tune control is then used to set it to just
above the tone’s cut-off point. When the detector head passes over anything
made of metal it disrupts the magnetic field between the two coils and produces
a rising tone that falls off as it moves away. With practice it is possible to
determine the approximate size, shape and even the depth of the metal object
detected.
 The design and construction of the hardware is
relatively crude, even by the standards of the time. It looks almost hand made,
the sort of thing that a hobbyist might put together in their garden shed,
which may not be too far off the mark as it was almost certainly one of
Viking’s earliest products. In spite of the lack of polish it is sturdily
built, light, well balanced and in contrast to the rest of it, the circuit
board is a professional looking item, using what was then state of the art
components.
 I spotted this one at a large open air antiques
fair in the Midlands; it was hard to miss, looking decidedly out of place
underneath a trestle table groaning with lots of fancy, and expensive,
glassware. It turned out to be a relic from the stallholder’s youth who, like
most would-be metal detectorists, gave up on it quite early on. He clearly had
no emotional attachment with it and readily accepted my counter offer of £2.00
to his initial asking price of £10. It was in a bit of a state, though, and
looked like it had spent the past several decades gathering dust in his garage.
The layers of grime were so thick the metal and plastic parts all looked the
same dull grey colour and If I hadn’t bought it I suspect it’s final destination
would have been the rubbish bin.
Luckily it was the sort of grime that responded
well to a rub down with household detergents and a scouring sponge. The metal
pole regained its shine with the application of Brasso, elbow grease and
several yellow dusters. The plastic housings for the coil and electronics had
done an excellent job of protecting the innards from moisture and all it needed
to get it going was a few squirts of contact cleaner on the two tuning
controls. It works, probably as well as the day it was made, and was able to
detect a 5-pence piece at a distance of 5cm; 2cm when buried in light soil.
Having comprehensively swept my back garden with metal detectors in the past I
wasn’t hopeful of finding anything new but thanks to some recent weeding I
found a new bare patch to explore and swiftly located a long-lost teaspoon
buried at a depth of around 10cm and closer to the surface, a badly decomposed
pre-decimal penny, so it’s already starting to pay its way…
What Happened To It?
Metal detectors have been around for a
surprisingly long time, since 1881 in fact, when Alexander Graham Bell – of
telephone inventing fame -- designed a machine to locate a bullet lodged inside
US President James Garfield. He had been shot in an attempted assassination but
unfortunately it wasn’t found in time. Apparently Bell’s ‘Induction Balance’
apparatus was confused by the springs in the bed he was lying on and Garfield
later died of an infection from the wound. The first purpose-designed portable
instruments appeared in the 1930s and developments came thick and fast during
and after the Second World War as they were used by the military to find and
clear mines.
The next significant advance in the technology
came in the 1950s, following the development of the transistor in 1947. This
rapidly led to many new and increasingly advanced systems for locating and
identifying buried metal objects, though without doubt the biggest impact of
the transistor in the early days was to bring down prices and turn what was
previously a highly specialised military and industrial tool into an
inexpensive consumer product.
Viking
started making metal detectors in the1970s and they’re still at it, with some
smart looking and keenly priced designs, aimed at both recreational and
industrial users. The story behind this Sol Invictus model is still a bit
vague, at the time of writing the company had yet to respond to my enquiries
regarding its official model designation, launch date and subsequent
replacement but if and when I hear from them I’ll include an update.
Collecting vintage metal detectors has yet to
take off as a hobby in its own right but there is definitely a healthy market
for ex-military equipment, especially valve-based designs from WW II and
subsequent conflicts. Metal detectors from the 60s onwards do not generate
much, if any interest, yet they were an important part of the story of this
interesting technology. Moreover, providing they work, some models, and this
includes this early Viking, can still earn their keep. The lack of demand for
older examples also means prices are low and its not unknown for disillusioned
owners to part with relatively recent and much more advanced models at car boot
sales for just a few pounds.
First Seen:
1975?
Original Price:
£25.00?
Value Today:
£5.00 (0618)
Features:
Twin-coil VLF type
detector, rotary controls: On/Off & Fine Tune, Course (Coarse) Tuning,
standard Jack headphone socket, 55mm speaker
Power req.
1 x 9 volt PP3 battery
Dimensions:
length: 860mm, search
head: 165 x 20mm, main unit: 230 x 60 x 70mm
Weight: 1kg
Made (assembled) in: England
Hen's Teeth (10 rarest) 8
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