July 2015
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GE BT-25 Mystery transmitter site

Update: Thank you, Jim.  The mystery site is KFIG (formerly KFRE) in Fresno, CA.  This is what the transmitter building looks like from the outside today:

KFIG transmitter, circa 2011

KFIG transmitter, circa 2011

In the previously mentioned the rescued file cabinet and along with the WFLY transmitter site construction information, I also found these interesting photographs:

Mystery AM transmitter site

Mystery AM transmitter site, plate 9296

I do not know what transmitter site this is. From the photo, it has a two tower (guyed) directional antenna. It looks to me to be somewhere out west. The transmitter is a General Electric BTA-25 or BT-25, same as the former WPTR and WCKY transmitter. I know this back hallway well:

Mystery AM transmitter site, back hallway of GE BT-25.  Plate 9300

Mystery AM transmitter site, back hallway of GE BT-25. Plate 9300

This is the transformer vault:

Mystery AM transmitter site, transformer vault.  Plate 9297

Mystery AM transmitter site, transformer vault. Plate 9297

Modulation transformer and three pot plate transformer:

BT-25 modulation transformer.  Plate 9299

Mystery AM transmitter site, GE BT-25 modulation transformer. Plate 9299

I would say that these may be promotional photos, because of the spotlessly clean installation and the plate numbers on each print.  Unfortunately, there are no pictures of the front of the transmitter, including the operator console.

Does anybody know where this is?

Horby and Solvesborgs transmitter site

This is a video of Radio Sweden’s shortwave and medium wave transmitter sites:

Håkan Widenstedt at Hörby and Sölvesborgs Transmitter sites from HamSphere on Vimeo.

This was filmed in 2006. In 2010, Radio Sweden ceased broadcasting on medium and shortwave, thus I believe these sites have Horby (HF) has been dismantled.  Medium wave installation Solvesborg is visible starting at 15:30. Two tower directional array 180 degree towers with 600 KW carrier power. Quite impressive.

There is an effort to at save the Solvesborg site, perhaps as a museum.

Transmitters were in Skane, Sweden:

View Larger Map

h/t Shortwave Central

Wikipedia Articles

Wikipedia-logo-v2Type the call letters for almost any radio or television station in the country into a search engine, and the second or third result will be a Wikipedia article.

Try it.

This is both an opportunity and burden.  Since the Wikipedia articles place so well in most search engine results, it would be a benefit to radio stations to keep an eye on them; keep them up to date, make sure that no one vandalizes them and fix it when they do.  Most importantly, keep the station website link and streaming link information up to date.  That is the burden but it is relatively small.

The opportunity comes from the ability to document the history of individual radio stations. In the grand scale, the history of any individual radio station is like a grain of sand on the beach. It is only pertinent to those who care.  But then there are those who do care and for some of us, reading a well written, well sourced article about some station we are familiar with is interesting.  To be sure, there are many crappy radio station articles on Wikipedia.   Some of them read like advertisements, clearly written from non-neutral party.  Others do not have sections, have poor grammar, improper or no source citations, etc.  Those poor articles should be fixed.

In my time as a broadcast engineer, I have found radio station to be like ships; they all have a certain personality.  It is difficult to explain how an inanimate collection of equipment and buildings can have personality, but they do.  Of course, with time, format and ownership changes those personalities change.  Documenting operating histories, formats, unique occurrences, famous past personalities, incidents, accidents, and technical discoveries in one place takes a little bit of time.  Having that information available for fellow radio people to read about is valuable service.  The one thing that I notice about most radio station Wikipedia articles; there are no pictures.  There should be more pictures.

Voice of Russia to cut shortwave

Another government shortwave broadcaster calls it quits.  The Voice of Russia (Голос России, Golos Rossii) will cut its shortwave service as of January 1st, 2014. Originally known as Radio Moscow, it has been on the air continuously since 1922. It will be sad to see yet another shortwave station pull the plug.

Radio Moscow stamp, courtesy of Wikimedia

Radio Moscow stamp, courtesy of Wikimedia

I can remember Radio Moscow being one the first shortwave stations I tuned across on my Uncle’s Zenith Transoceanic shortwave radio.  It was fascinating to me to hear the news from the far away and all too scary Soviet Union.  After a short bit of interval music and a series of beeps counting down to the top of the hour, a man with a deep, sonorous voice came on and said “Zis is Moscow…” It was very dramatic.

The economics of HF broadcasting are daunting to say the least.  Minimum power levels in the US are 50,000 watts into a highly directional, high gain antenna.  Most stations use greater than 50 KW transmitters, which will very quickly use gobs of electricity, becoming an expensive operation.  Other expense include maintenance on transmitters, buildings, land and antennas.  With little or no opportunity to commercialize, it becomes difficult to justify a shortwave operation.  Sadly, those are the state of affairs in HF broadcasting today.

Troposcatter communication system

I found this interesting article on the inter-tubes the other day and thought that I would share.  It is about a dis-used site from the Soviet era Troposcatter communication system called “SEVER.” There are many more pictures of equipment including MUX, transmitters, antennas, buildings etc, at that link.

Soviet SEVER troposcatter communications antenna

Soviet SEVER troposcatter communications antenna, courtesy ralphmirebs.livejournal.com

Like many of it’s counterparts in the US, this system has quite a bit of information available, including an interesting blog and associated web site which has lots of interesting information.  Some of it is in Russian, which mine is a little bit rusty, but here is what I could find out:

This is site 6/60, call sign Poloska and is located in Amderma, Nenets Autonomous okrug. That is way up north along the Barents Sea.  This site was in use from about 1965 until 2001, when it was closed down.  It communicated with site 5/60, which was 264 km away.

Amderma map with SEVER 6/60 location

Amderma map with SEVER 6/60 location, courtesy of trrlsever.org

Troposcatter was used widely before satellites came into availability.  It used decimeter wavelengths (approximately 2 GHz) and lots of power with very high gain antennas. Basically the earth and the troposphere were used as reflectors, creating a type of duct.  It is noted the the SEVER and the GOREEZONT (HORIZONT) systems used both space and frequency diversity as a part of their system.  Frequency diversity means that there were as many as five identical signals transmitted on different frequencies at the same time.  Space diversity means that two or more transmit and receive antennas were used, as can be seen in the picture.  This site was run by the military, but would have likely carried civilian communications as well.

SEVER troposcatter communication system

SEVER troposcatter communication system

Basically it was a way to maintain communications across vast distances when wired or microwave systems were not practical or possible. The US used such systems on the DEW line and across the Pacific Ocean between Hawaii and Okinawa.  I remember the big Troposcatter dishes up on the hill behind the Navy housing area above Agana.

US Pacific Troposcatter communications system

US Pacific Troposcatter communications system, courtesy of Wikipedia

These systems were massive and expensive to build, operate and maintain.  From the looks of the pictures, site 6/60 generated all of it’s electricity with diesel generator sets. Fiber optic cable is an improvement of several orders of magnitude over this technology.

It is always interesting to see how things used to be done and give thanks to those that went along before us.  Last night I was grumbling about the network latency when watching a youtube video.  It was terrible, but in retrospect, not really that bad.

The Raytheon RL10 Limiting Amplifier

Update: Apparently this is quite interesting to a number of people.  I have rescanned the manual, properly compressed it and which you may find it here.

Found this manual at one of the older transmitter sites:

Raytheon RL10 limiting amplifier manual cover

Raytheon RL10 limiting amplifier manual cover

Entire manual is available for your reading pleasure here: Raytheon RL10 limiting amplifier

As this is an older design than either the Gates Sta level or the Collins 26U, it may not be as useful to tube audio enthusiasts.

Raytheon RL-10 Schematic diagram

Raytheon RL-10 Schematic diagram

The main issue with the Gates and Collins unit is the GE 6386 remote cutoff triode used, which were great tubes, but very difficult to come by these days.  This design calls for a 1612 or 6L7, which is a pentagrid amplifier.  Feedback is provided by the screen of the following stage, a 6SJ7GT.  Anyway, perhaps it will give somebody some idea on how to make a good tube compressor limiter.

Suppression of ideas

I found this video called Empire of Noise about broadcast radio jamming. It seems to be about ten years old and is a post cold war documentary about the jamming of radio signals by the USSR, Warsaw Pact counties and China.  It is an interesting look into the extent and expense that governments will go to to suppress counter thought and ideas.

The video is quite long, and there are stretches of jamming noise that can be annoying, but perhaps that is the point.  It is worth the time if interested in history and radio broadcasting.  You know what they say about history; those that do not understand history are destined to repeat it.

A few of the highlights:

  • The former Soviet Union had the most extensive jamming network of anyone on Earth.  There were groundwave jamming centers in eighty one Soviet cities which consisted of approximately 10-15 transmitters each in the 5 KW covering the medium and shortwave frequencies.
  • Each groundwave jamming station consisted of a transmitter site and a receiver/control site.  The receiver site possessed lists of frequencies to monitor, when objectionable material was heard, the jamming transmitters were turned on.
  • There was a skywave jamming network consisting of 13 jamming stations with 10 or more 100-200 KW transmitter in each.  There were some transmitters in the 1,000 KW power range.  These were located in Krasnodar, Lvov, Nikolaev, Yerevan, Alma-Ata, Grigoriopol, Sovieck, Novosibrisk, Tashkent, Khanbarovsk, Servdlosk and Moscow (some of these names may have changed).  These operated in a similar fashion to the groundwave jammers.
  • After sign off of government stations, Soviet jammers sent a blanketing signal on the IF frequency (most likely 455 KHz) of receivers to effectively block them from receiving any station while USSR government stations were off the air.
  • Baltic states had 11 jamming stations with approximately 140 transmitters
  • Ukraine had approximately 300 Jamming transmitter.
  • Warsaw Pact countries had extensive medium frequency jamming networks.
  • It is estimated it takes about 20 times the transmitted power to jam any one signal.

The entire jamming network was hugely expensive to equip and operate, costing several tens of millions of dollars per year.

It is interesting that the US position in all of this was:

Everyone has the right to seek, receive and impart information through any media and regardless of frontiers.   Jamming of radio broadcasts is condemned as the denial of the right of persons to be fully informed concerning news, opinions and ideas.

Sounds perfectly reasonable.  The free exchange of ideas and information over the internet is something that should be guarded carefully and should not be restricted or censored.  Perhaps somebody should inform congress.

As requested: The old WSBS studio building

Alan asked that if I should ever find a picture of the old WSBS studio building to publish it.  Here it is:

WSBS old studio building

WSBS old studio building

I found this above the coffee machine in the lobby, nicely matted and framed.  I didn’t want to ruin the framing job, so I took a picture of the picture under glass and cropped it, thus the quality could be better.

I believe this is the original tower from 1959.  The current tower stands on a taller concrete pedestal and is further away from the road.  I think the roadway was widened and raised at some point, thus the new building sits higher in relationship to the tower base.  In any case, it little bit of radio history.

Radio Caroline, 49 years after

Radio Caroline went on the air forty nine years ago this weekend, broadcasting from the MV Caroline off the coast of England.  Why is this important?  Before off shore broadcasting was attempted, in Europe the only radio stations (and TV) were government owned.  As such, they had a monopoly over the air waves and were very restrictive on which groups or types of music they allowed to be broadcast.  Many of the so called “British Invasion” groups like The Beatles, Rolling Stones, The Who, The Kinks, etc got their first airplay on offshore radio stations like Radio Caroline or Radio London.

This video “Radio Caroline – A day in the life,” shows what it was like to be an offshore broadcaster:

By the haircuts and music, that appears to be sometime in the eighties.

Check out the Radio Caroline website for more information.  From 1983 onward, Radio Caroline was broadcast from the MV Ross Revenge. This is an overview of the Ross Revenge transmitter hold.  The movie “Pirate Radio” is loosely (very loosely, by most accounts) based on Radio Caroline/Radio London composite.

Radio London was the one of the other well known offshore radio ships.

I am sure that there are other tribute sites with lots of technical information on how they broadcast. Much of offshore radio was outlawed in the late 1960’s by several European countries. Radio London signed off August 14, 1967. Radio Caroline continued on in various iterations until about 1991 or so.

WBCQ is airing a radio ships special on Sunday March 31, 2013, 5,110 KHz starting at 6 pm eastern daylight time (2200 UTC).

Restoration work on an RCA transmitter

I read through this article about the ongoing restoration work of an RCA SSB T-3 transmitter and found it interesting.  The RCA T-3 transmitter is a 20 KW SSB/ISB HF (2-28 MHz) unit designed for point to point telephony service.  Because SSB requires class A or AB low distortion amplifiers, this is a large unit, even for its age and power levels.

From the looks of the before pictures, this transmitter was in sorry shape.

Here is a brief video of transmitter start up:

These units were designed to be switched on and run at 100% duty cycle from most of their operating lives. That is some heavy iron there.  This particular unit was made in 1959. More here and video part 2:

Anyway, before geosynchronous satellites, HF point to point transmitters were used to make long distance phone call connections and send data and pictures back and forth over long distances. Out in Hicksville, Long Island, Press Wireless ran a data and fax system that used HF for long haul data transmission.  Much of the WWII reporting from Europe and the Pacific Theaters was carried over this system.

Text would be printed out on a mechanical teletype machine at something like 60 words per minute, which was considered fast for the time:

Tuning across the band, one can often hear Radio Teletype (RTTY or RATT) which uses a 5 bit baudot code, 170 Hz shift with 2125 HZ representing a Mark or 1 bit and 2295 Hz representing a Space or 0 bit, which is bit different from the Bell 103 modem specifications. This is what it sounds like at 75 Baud:

So slow you can almost copy that by hand.

The RCA H (SSB T-3) unit above was independent side band (ISB), which means that either side band or both could be modulated independently of the other, thus two channels of information could be transmitted.  SSB bandwidth is about 2.7 KHz, which is good for telephone grade audio or low speed data.

I sort of wish I was living in California again, I’d lend a hand.


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Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
~1st amendment to the United States Constitution

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~Benjamin Franklin

The individual has always had to struggle to keep from being overwhelmed by the tribe. To be your own man is hard business. If you try it, you will be lonely often, and sometimes frightened. But no price is too high to pay for the privilege of owning yourself.
~Rudyard Kipling

Everyone has the right to freedom of opinion and expression; this right includes the freedom to hold opinions without interference and to seek, receive and impart information and ideas through any media and regardless of frontiers
~Universal Declaration Of Human Rights, Article 19

...radio was discovered, and not invented, and that these frequencies and principles were always in existence long before man was aware of them. Therefore, no one owns them. They are there as free as sunlight, which is a higher frequency form of the same energy.
~Alan Weiner

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