November 1967 Popular Electronics
Table of Contents
Wax nostalgic about and learn from the history of early electronics. See articles
published October 1954 - April 1985. All copyrights are hereby acknowledged.
When this "Clandestine
Broadcasters" article appeared in a 1967 issue of Popular Electronics magazine,
we were at the height of the Cold
War era with Communist forces spreading all over the globe and inching closer
to the U.S. mainland with moves in the West, north of the Equator. The
Cuban Missile Crisis
occurred just five years earlier, and the spy game kept all sides busy trying to
hide their own secrets and discover the secrets of others. Mysterious radio
broadcasts were routinely picked up and reported by Amateur Radio operators and
Short Wave Listeners.
Their elusive broadcast content and station location enhanced the intrigue for people.
Of those, it was the "numbers
stations" that garnered the most attention because they issued a string of numbers,
then ceased transmission. It was believed to be a means of sending encoded messages
to spies. The practice continues to a lesser extent to this day. Side note: When I first
ran OCR (optical character recognition) on the article, Radio Libertad rendered
in a few instances as Radio Libtard - hah! Radio Libertad translates as
Liberty Radio. Bahamas radio station
ZNS is still broadcasting today.
and cloak-and-dagger stations make choice DX'ing for radio listeners.
By Thomas Kent
Clandestine broadcasters are the most fascinating and the most frustrating stations
on the short-wave bands. Usually operated by deposed governments or groups in exile,
these pirate stations encourage citizens to rise up in revolution against their
new governments; they urge soldiers to desert their ranks; they broadcast coded
messages to undercover agents; and they offer the SWL the thrill of hearing history
in the making.
Because of their sensitive political positions, these broadcasters go to great
lengths to conceal facts about themselves. They rarely provide mailing addresses
and transmitter locations are usually well hidden. To avoid jamming, clandestine
broadcasters change frequencies and schedules often and without notice. Much "information"
about such stations is usually no more than rumor, and the SWL must analyze
each piece of evidence to learn the real facts.
In the Bahamas?
Small islands in the Caribbean have long been suspected as hiding
places for clandestine broadcast stations. Radio Americas' transmitters are located
on Swan Island, and two new transmitter facilities located on Navassa Island will
soon be operational.
Operating at 1160 kHz on the standard broadcast band, and 6000
kHz on the international broadcast (shortwave) band, Radio Americas routes all program
material through control console shown at lower left.
Since the end of the Radio Americas' location controversy - it's definitely on
Swan Island - the number one mystery station has been Radio Libertad. This broadcaster,
which bills itself as "the anti-Communist voice of America," has been on the air
for several years, beaming anti-Castro programs to Cuba. It is generally believed
that the U.S. Government has an "interest" in the station's operations.
The biggest question about Radio Libertad is its true location. It is never mentioned,
and the mailing addresses given over the air have all proved to be false. However,
many DX'ers have long believed that the transmitter is on Andros Island, one of
the southernmost islands in the Bahamas group.
To check this theory, a letter was sent to the Bahamas Broadcasting and Television
Commission in Nassau asking if Radio Libertad operates from Bahamas territory. The
station's operating schedule and frequencies were included with the letter. The
reply, from H. R. Bethel, General Manager of Bahamas government station ZNS, was
surprising: although Radio Libertad's BCB frequency was monitored for three days,
said Bethel, no signal was heard! This is certainly peculiar since the station is
easily received in Puerto Rico, even farther away than Nassau from Cuba, Radio Libertad's
target area. Subsequent letters suggesting that Radio Libertad's short-wave frequencies
be monitored were ignored. Is it possible that ZNS is not telling all it knows ?
Direction-finding instruments and beam antenna headings indicate that the Radio
Libertad transmitter is in the general vicinity of Andros Island. The Bahamas have
always cooperated with U.S. Government operations. (It is believed that U.S. Armed
Forces bases are located in the Bahamas, and it wouldn't be difficult to hide a
radio station in the jungles of Andros Island.)
Radio Libertad is easy to log, though QSL's are obviously not available. Transmissions
are from 1100 to 1645 and from 0000 to 0600 GMT on many frequencies. Among the most
reliable frequencies are 15,050, 9295, 7308, 6250, 6000 kHz (a former Radio Americas
channel), and 1400 kHz. Broadcasts begin with chimes and the same anthem used by
Radio Habana Cuba. All programs are in Spanish; however, station identifications
are also given in English.
Incidentally, as this story goes to press, there is considerable fanfare concerning
a new station to be opened on Navassa Island, between Haiti and Cuba. This island
is a U.S. Possession and apparently, up until quite recently, has been uninhabited.
Transmitters are being shipped to Navassa for operation in the AM broadcast band,
as well as in the short-wave broadcast bands. The BCB transmitter is rated at 50
kW, and the short-wave transmitter at 20 kW. Programming is reported to be similar
to that of Radio Americas - all Spanish language broadcasts.
The "Numbers" Game
More mysterious than Radio Libertad are the shortwave "numbers stations" - some
probably located in the Caribbean area. These stations begin their transmissions
with musical signals, chimes, or the sound of buzzers. Then, without any other station
identification, announcers read long lists of numbers in 4- or 5-digit groups. At
the end of the lists of numbers, the stations abruptly leave the air - again with
no identification. It is suspected that all of these numbers stations are somehow
involved in espionage activities and are transmitting coded instructions to undercover
Numbers stations have been heard in the German, Russian, English, and Czech languages,
but the most interesting ones to North Americans are those that broadcast in Spanish.
According to Cuban exile sources, the Spanish-speaking stations are used by the
Federation of Cuban Workers in Exile, a Miami-based organization, to send coded
instructions to anti-Castro guerrillas inside Cuba. The transmitter site is unknown,
but is most likely located in the Florida Keys, where many Cuban exile activities
have been based.
These Spanish numbers stations have been heard around 0400 and 0500 GMT in the
3-4- and 5-8 MHz bands. They change frequencies often, but among the channels most
consistently in use are 7390, 7010, 5680, 5630, 3380, and 3205 kHz. The song "Sesame
Mucho" is frequently employed for transmitter identification by some stations.
At one time, Radio Americas' operating expenses were paid by
funds from a sympathetic government. Now sale of advertising time pays these expenses.
Besides Radio Libertad and the Spanish numbers stations, there is another important
clandestine radio activity in our hemisphere. A number of unlicensed short-wave
stations have suddenly begun operation in Bolivia, most of them in or near the 49-meter
band. Communist insurgency in Bolivia has reached an all-time high, and it is possible
that these stations are a part of the "liberation" movement, especially since they
are all located in rebel-infested areas.
A partial listing of these stations includes: Radio Mandez, Huanuni, on 5790
kHz; La Voz del Minero, Llallagua, on 5850 kHz; Radio Busch, Uyuni, on 6500 kHz;
and Radio Copacabana, Sucre, on 6600 kHz. There are also two stations known as Radio
Libertad (no relation to the Andros Island station) operating from Santa Cruz and
Sucre on 6200 and 6600 kHz respectively.
In Europe, Too
One of the more interesting clandestine stations in Europe is Radio Euzkadi,
operated by the Basque resistance movement. The goal of this movement is to create
an independent state for the million-odd Basques now living in northern Spain, though
even among the Basques the idea has won little popular support. The movement claims
to be strongly anti-Communist, and "wants only to re-establish Euzkadi, the Basque
As is the case with other clandestine stations, Radio Euzkadi's transmitter location
is unknown. The unsuccessful attempts made by Spanish dictator Franco to silence
the station indicate that the transmitter is probably not in Spain. The station
may be in southern France, where there is a small Basque colony. Headquarters of
the Basque resistance movement is in Paris and the Basques evidently operate freely
It has been suggested by some DX'ers that Radio Euzkadi is in Latin America or
Radio Euzkadi itself denies that it is associated with Communist Cuba "or with
any other government." There really seems to be no reason why the Basques should
want to set up high-powered - and therefore very expensive - transmitters in Latin
America when they can operate safely and with low power from French territory. Radio
Euzkadi ( "La Voz de la Resistencia Vasca") broadcasts in both the Basque and Spanish
languages around 2145 GMT on 15,080 and 13,250 kHz. Reports are usually verified;
they should be written in Spanish, if possible. The address is 48, rue Singer F-75,
Paris 16e, France.
Less is known about two other European clandestine stations, Radio Portugal Livre
and Radio Espana Independiente. They are both Communist operations whose targets
are Generalissimo Franco and the Portuguese dictator, Premier Salazar. Radio Portugal
Livre is rumored to operate from Rumania, though Radio Bucharest denies this rumor.
The station is heard on 8333 kHz in Portuguese until sign-off at 2350 GMT. "A Portuguesa,"
the Portuguese national anthem, is played at the end of each transmission.
Radio Espana Independiente transmits on 6950, 7600, and 10,110 kHz around 1500
GMT and on 10,110, 11,260 and 12,140 kHz around 0600 GMT. The World Radio Bulletin
gives as its address, P.O. Box 359, Prague, Czechoslovakia.
The complex political situation in Southeast Asia has given rise to several new
clandestine stations there. The most recent is the Voice of the People of Thailand,
9425 kHz, which signs on with Oriental chimes at 1430 GMT. It broadcasts only in
Thai and is obviously Communist -supported.
The Associated Press reports from Saigon that a station identified as Radio Liberation
Army or "Voice of the Sacred Sword of Patriotism" has been heard urging North Vietnamese
soldiers to leave South Vietnam. It claims to be in Hanoi, but is almost certainly
operated by American or South Vietnamese personnel in South Vietnam. Of course,
there is no relation between this station and the various "Radio Liberation Army"
stations operated by North Vietnam and Communist China. Transmissions are at 0500-0600
on 7225 and 7216 kHz (Hanoi also uses the latter channel) and at 1400 GMT on 9425
kHz. The interval signal is a drum and cymbal call, and the Vietnamese ID may begin
"Guom Thieng Ai Quoc" or "Day la Tieng noi."
Posted October 3, 2022