The Voice of America on Mediumwave at Poro in the Philippines

The third relay station for VOA, the Voice of America in the Philippines, was located at Poro Point, 150 miles north of the national capital, Manila.  Interestingly though, that one VOA relay station at Poro was in reality four different radio broadcasting stations all clustered together.  We go back to the beginning.

The Wallace Air Force Base at Poro Point on Luzon Island in the Philippines was originally acquired by the United States for use as a Cavalry Base back in the year 1903.  It was subsequently taken over for use as an American Air Force Base.

During the year 1950, at the time when China was supporting the North Korean attempt to take over the entire Korean peninsula, the Poro location was in use as a radio listening base for monitoring Chinese and North Korean broadcasts.  Tents and other temporary housing was hurriedly erected, and sophisticated electronic equipment was installed.

In an attempt to cover the same Far Eastern areas with their radio programming, VOA announced its plan to install a massive one million watt mediumwave transmitter at that same Poro Point location.  The radio behemoth they chose was an American made Continental transmitter Model 105B.  It was in fact two 500 kW transmitters combined in parallel to make a single transmitter in the one huge metal shell.

Part of the transmitter room of the VOA Philippines Relay Station showing the Continental 1 MW medium-wave transmitter which broadcast to Asia on 1140 kc (1965). Photo: Cathode Press 1965

The first 1,000 kW Continental Model 105B was built for VOA as a longwave transmitter on 173 kHz, and it was installed in Munich-Erching in Germany in 1953.  The intended coverage area from this super powered longwave transmitter was Eastern Europe, and in particular Russia. 

Later in the same year in June (1953), the huge one megawatt mediumwave transmitter, which like the longwave transmitter was manufactured in Dallas Texas, was inaugurated at Poro in the Philippines with a single tall transmission tower.  It is probable that this transmitter was the first one megawatt mediumwave transmitter Model 105B constructed by Continental.

The signal from that one megawatt unit on 1140 kHz was heard far and wide, loud and clear.  The transmitter was accorded a Philippine callsign, DWVA, though that designation was never used by VOA, not in their on air announcements and not in their publications.  The callsign DWVA indicates the  following information:-

  • The two letters DW indicate the regional area in the Philippines
  • The two letters VA indicate ownership, as the Voice of America

In 1971 VOA sent this QSL card to New Zealand DXer David Ricquish confirming his reception of VOA Poro on 1140 kHz.
© David Ricquish Collection, Radio Heritage Foundation

In 1978 new international radio regulations required 9 kHz channel spacing in Asia, and accordingly the operating frequency for VOA DWVA at Poro in the Philippines was changed from 1140 kHz to 1143 kHz.

During the year 1995, a new one megawatt mediumwave transmitter was constructed at the Harris radio factory in Quincy Illinois in the United States in preparation for installation at Poro in the Philippines.  At 5 pm on Monday June 26, 1995, this new one megawatt Harris mediumwave transmitter was activated at the factory in Quincy on 1143 kHz for a series of preliminary test transmissions.

That new Harris transmitter was their first one megawatt mediumwave transmitter and later in that same year 1995 it was duly installed at Poro in the Philippines, most likely in the shortwave transmitter building.  At that stage, the original Continental was taken into active retirement, as a back up if necessary for the newer Harris transmitter.

An aerial view of Wallace Air Station, Poro Point, San Fernando (1981). Photo: US National Archives

However there was one major problem.  The mediumwave frequency for VOA Poro 1143 kHz now suffered from severe interference in the Far East due to a Taiwan transmitter on the same channel 1143 kHz with a power of 100 kW. 

Beginning on December 6, 1997, a series of test transmissions lasting nine days was conducted at Poro on what was considered a more successful mediumwave frequency 1170 kHz.  These test broadcasts which were on the air via the Harris transmitter at VOA Poro in the Philippines, simply used instrumental music, rather than the regular VOA programming feed.

Nevertheless, VOA Poro still remained on 1143 kHz, though a new four tower directional antenna system was installed in an endeavor to propagate a stronger directional signal into the Far East.  Then again another series of similar weekly test transmissions was conducted six years later (2003), with both superpower mediumwave transmitters on the air simultaneously, the Continental on 1143 kHz and the Harris on 1170 kHz. 

In 2005, the Harris transmitter was removed from its first location (in the shortwave transmitter building?) and reinstalled into a new and specifically constructed building where it began operation at the full power of almost one million watts on the new and now regular channel 1170 kHz.  At that stage, the Continental was finally retired forever, after a half a century of lifetime service.  It was both the first and the last Continental one megawatt to remain in active service.

VOA-IBB Poro Point, Luzon, Philippines on 1170 kHz captured at sign-off, 15.58 UTC on 18 March 2012. Heard in West Central Malaysia.

However the lifetime for the newer Harris super power transmitter was also coming to an end.  In March 2013, VOA DWVA was noted in Asia and the Pacific as off the air, silent.  The issues of the  WRTVHB for the next few years showed the station as inactive, and then in the 2016 issue, it was no longer listed. 

VOA superpower mediumwave at the Wallace Air Force Base on Poro Point in the Philippines  was now totally silent, off the air and gone for ever.  So whatever happened to those two super power one megawatt mediumwave transmitters?  We would guess that they were simply sold off locally as scrap metal.

You can see what remains of the VOA station at Poro on Google Maps.  The two mediumwave station buildings and sets of antenna systems are still visible, in what appears to be a double overlay rendering dated in 1985 as well as more recently.

This feature was written by Adrian Peterson and originally aired on Adventist World Radio’s “Wavescan” DX program of April 10, 2022

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