My own interest in it began when, while listening to the 6 o’clock news
one evening in the mid-1970s, an unusual, annoying interference swept through
the Radio 4 VHF frequency several times: it sounded like a machine gun,
did not stay for long, and was heard again on one or two other evenings
and then no more. We forgot about it.

But it all came back a few years later when a television programme featured
a mysterious interference that was affecting reception on the shortwave
radio bands. It was described as sounding like a woodpecker, and an exemplary
burst of the staccato bird noise was enough for me to recognise it as the
same animal as the intruder on the 6 o’clock news. The programme indicated
that the signal originated in the Soviet Union and suggested that its purpose
was probably sinister.

In a book, published in 1983, on the life and work of the Croatian electrical
engineer Nikola Tesla, this Woodpecker signal was cited as a possible current
application of one of Tesla’s unorthodox theories on the transmission of
electrical power over enormous distances through the Earth. The author,
David Peat, while admitting that the Woodpecker could be radar, preferred
to speculate about mind-bending with microwaves, weather modification and
cosmic power.

In 1985, an article in New ÐÓ°ÉÔ­´´ hinted that the Soviet Union could
use Woodpecker transmissions to nullify the communications on which the
American Star Wars system would depend. An accompanying piece by Barry Fox
set out what was known about the Woodpecker at that time. He contrasted
its enormous radiated power, said to be 50 megawatts, with the most powerful
BBC VHF radio transmitter’s 200 kilowatts, but did not say whether Woodpecker’s
power was the peak pulse power or the average power. If the former, then
the average power might be only about 500 kilowatts, the same power as some
of the BBC’s medium-wave transmitters. The article made no mention of the
possibility of Woodpecker being radar.

In 1987 Channel 4 put out another investigation into Soviet electronic
dirty tricks. A credulous interviewer had located two American experts on
electronic warfare. They, too, seemed to take it for granted the Woodpecker
transmissions had a sinister purpose, although one of them did admit the
possibility of it being radar but quickly dismissed it as unlikely. Among
the assertions made in this programme were the existence of a mysterious,
psycho-active magnetic component in the radiation and the fact that ‘intelligence’
had been detected in the signal.

That a magnetic component should be detected on an electromagnetic signal
is not surprising, and the ‘intelligence’ could be pulse coding, which is
a standard radar technique. Finally, egged on by the interviewer, one of
the experts agreed that this kind of activity could be a greater threat
than nuclear weapons, and there was no defence that he knew of. In fairness,
I should say that the other expert did mention ‘a rumour’ that the Americans
were up to something similar, aiming their signals at the Soviet Union.

I began to wonder why the ‘warfare’ was still going on after the advent
of Gorbachev and glasnost, and so on. And then I walked into Heffer’s and
spotted the book.

I couldn’t miss it: its title was Over-The-Horizon Radar, its authors
A. A. Kolosov et al. Originally published in Moscow in 1984, this English-language
edition was published in 1987 in Boston, US. It appeared to reveal all that
I needed to know, anyway. There were all these experts and commentators
doubting the reality of OTH radar while, all the time, there was a book
setting out its theory and practice, available in English since 1987 and
in Russian since 1984.

Although the book is sprinkled with references to the Soviet technical
literature, most of those on OTH radar relate to non-Communist publications.
Earliest explicit OTH references go back to the mid-1960s, and the only
discussion of OTH radar hardware in the main text relates to American systems.
Apparently the authors could only circumvent the dead hand of censorship
by writing what should have been the most interesting part of their book
in this vicarious fashion.

Despite this, the book demystifies the Woodpecker by clearly explaining
the operation of OTH radar. The frequency range used is 3 to 30 megahertz;
the pulse recurrence frequencies range from a few hertz to several tens
of hertz; the pulse width may be from hundreds of microseconds to several
milliseconds; the bandwidth of the signal can vary from a few hundred hertz
to many kilohertz; and, as with more conventional radar, the techniques
of frequency agility and pulse coding are used.

In references to American OTH radar, pulse powers of several megawatts
are said to be required, which suggests that the Russians are pushing it
a bit if they are using 50 megawatt pulses. All these characteristics, apart
from the power, are common to the Woodpecker signals and should (must?)
have been known to anyone seriously investigating the phenomenon. This opinion
was reinforced when I saw what had been published this side of the Iron
Curtain.

I found that most books on radar published in the past 10 years or so
had at least a brief reference to OTH radar. And closer to home came the
news that the US Navy wants to site an OTH radar in Wales, at Brawdy.

According to Electronics World and Wireless World (July 1990), ‘The
radar’s range will be at least 1800 miles, focused on the Baltic Sea . .
. and will form part of the US Navy’s worldwide network of over-the-horizon
radars.’ This seemed to confirm the American expert’s rumour!

The siren voice of the Woodpecker has drawn me back to my old shortwave
receiver, and I have found some very strange goings-on. Of course, Woodpecker,
now rather old hat, is there, and so are lots of other, regular signals.
But, especially in the range 20 to 28 megahertz, there are some very irregular
happenings. Most obvious, because of its strength and unusual modulation
bursts of overlapping oscillations of different frequencies is a transmission
that has come into existence within the past year or so.

Having established that the Woodpecker signals are virtually certain
to be OTH radar, what is special about this kind of radar?

It uses the property of ordinary broadcast shortwaves, which have the
ability, by refraction in the ionosphere, to travel beyond the horizon,
thus increasing the range of the radar station. As well as the detection
of hostile aircraft and missiles, there are a number of other important
uses for OTH radar, such as studies of the sea surface and the ionosphere,
and the observation of meteor trails.

Now that we know that the US has been operating OTH radar for some time,
it may be that some of the signals attributed to the Soviet Woodpecker originated,
instead, from the West. After all, the characteristics of OTH radar set
out above have come, in the main, from US sources; so, if they fit the Woodpecker
signal, which they do, they might also be expected to produce a similar
signal from an American OTH station. Of course, the Americans may be using
more sophisticated techniques, like the new, absolutely unsinister signals
I have been picking up around 25 megahertz.

Raymond Harrowell is a freelance physicist living in Cambridge.

Known as ‘midi’ systems, today’s uncomely black boxes sit incongruously
on polished living-room tables and sideboards. Their black control knobs
and buttons merge invisibly into their surroundings and are identified only
by legends in dull red or grey-white type, about the size of the print on
this page. Back-illumination of the tuning dial is, of course, a thing of
the past; so, in subdued lighting for relaxed listening, it is virtually
impossible to read the frequency of the desired radio station.

When did these betes noires first appear? Looking through my file of
back numbers of Which?, I see that that magazine’s regular reports on stereo
systems began to feature all-black models in the period 1985-86. Before
then, most systems were in anodised aluminium (and had clearly visible legends
and illuminated dials).

Discovering who initiated this dismal design change is a more difficult
exercise, for they were all at it: Akai, Amstrad, Philips, Sharp, Sony,
Toshiba – they all came out with their lookalikes in concert. Here, surely,
is a new field for conspiracy theorists.

It is much easier to discern the reason for the manufacturers’ choice
of this unlovely package for their new product, which they introduced with
apparently no explanation. It was, no doubt, an attempt to transform the
earlier ‘rack and panel’ system, with its separate record-player, amplifier,
tuner, and so on, into a compact table-top unit. And, presumably, the only
suitable mouldable material for the cabinet was the depressing black plastic
that we now have. (If not, then there must have been some satanic influence
at work.) However, like an intrusive weed, the material has now spread to
other items of KK electronic furniture, and with less justification. Television
sets, video recorders, loudspeakers – we can have any colour we want, provided
it’s black! Henry Ford, where art thou now? (I find it slightlyironic that,
if you want to buy a car in black these days, you usually have to pay a
surcharge.) Ever since the first varnished-wood and ebonite crystal sets
and bright-emitter valve radios, there has been a steady evolution in the
materials and design of radio and record-player cabinets, but we have now
clearly arrived at an evolutionary cul-de-sac. If this kind of design were
to be found only in the shops of Eastern Europe, I am sure that returning
travellers would have it at the top of their horror lists as a prime example
of state-generated drabness. Over here, perhaps it is a prime example of
the hollowness of the freedom of choice that we are supposed to have in
the market place: as far as the cabinet is concerned all the companies cited
above seem to be offering more or less the same article, as anyone can see
by scanning the window displays of any high-street Dixons or Currys.

At the moment, it appears that all we can do is sit back and passively
await the next gimmick that is foisted upon us. Certainly, consumers’ organisations
such as Which? do not appear to be sufficiently concerned to make even a
passing reference to the appearance and design of audio equipment – or of
any other domestic appliance for that matter.

Any suggestions?

Raymond Harrowell is a freelance physicist living in Cambridge.