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Planning the FM Stereo Installation

Broadcast Engineering, December 1963, Vol 5 no 12

Broadcast Engineering, December 1963, Vol 5 no 12

This is a reprint of an article by the same title first published in the December 1963 “Broadcast Engineering” magazine; volume 5, number 12. By George W. Yazell:

In planning a new installation, the broadcast station engineer will be called upon to evaluate the products of various manufacturers before an order is placed for new FM stereo station equipment. In preparing his recommendation, the engineer will review descriptive literature, advertisements, and instruction books. He will seek information and advice from his consultant, other station engineers with stereo experience, and sales representatives of broadcast equipment manufacturers. His thinking may also be influenced by magazine articles and advertisements.

It is unfortunate, but true, that during the engineer’s survey he will encounter many conflicting opinions and claims. Some “advisors” may go so far as to imply that their system of stereo signal generation is the only one worthy of consideration, and all the rest have so many shortcomings as to be impractical or even unworkable.

The simple truth is that any manufacturer offering a transmitter or associated device for sale to broadcast stations must obtain FCC type acceptance. In doing so, complete and authentic test data is submitted for the Commission’s review and approval. Type acceptance by the FCC is your assurance that the equipment will meet certain specifications.

Thus you can either draw straws, or accept the views of the “advisor” with the most forceful opinion and still feel safe that the equipment you recommend will work. A more practical solution would be to prepare a list of equipment and features you require, with careful attention to needs peculiar to your own station; then select the equipment which most nearly matches your requirements.

List What You Have

The first step is to list and evaluate any equipment, facilities, and assets already available for the proposed installation – even if it is only a construction permit, a bank account, and a plan of operations. Some items to consider include:

  1. Ask management for a budget. This is probably the most significant factor in your recommendation. You should set both a practical budget and an absolute top limit. If you find it impossible to do the job within the budget limitations, do not hesitate to say so. Point out that stereo is a two channel system and that in addition to special transmitting equipment, the studio installation will require two of each amplifier, loudspeaker, telephone line, etc. Therefore, a stereo installation will cost considerably more than monophonic facilities.
  2. Review the program plans for the station. The quantity, complexity, and flexibility of the audio equipment selected must adequately meet these needs, with some reserve facilities for future expansion.
  3. You may presently have an FM, AM, or TV station a combination of these. In this case you can probably count on using existing studio facilities, some of the technical equipment, the tower, remote control facilities, and technical manpower.
  4. Consider the abilities of your technical staff. You may be the only engineer, or may have available a large staff of technical personnel. In any event, select equipment having circuits and components your technicians can install and maintain.
  5. Survey the supply situation. Determine the location and stock capabilities of electronic supply houses in your area. Keep in mind that any electronic component must eventually fail; and an inexpensive component can cost hundreds of dollars if you are “off the air” several days while a replacement is being flown in from a distant source of supply. If the supply picture is discouraging, you can best protect yourself by selecting practical equipment employing readily available components – and ordering an adequate supply of spares for parts you cannot obtain locally.

List your needs

Your next step is to prepare as complete a list as possible of the total equipment requirements.

Broadcast Engineering, Typical Stereo diagram

Broadcast Engineering, Typical Stereo diagram

Sketch a block diagram of your proposed layout (Fig. 3). Then prepare a chart of all the equipment you will need with space provided for prices, data, and notes on each device. As you prepare these charts several things will become evident:

  1. You will probably discover more equipment is needed than you originally anticipated.
  2. In determining what must be purchased, you must carefully integrate your needs with equipment now on hand.
  3. Your ultimate decision will depend on many interacting factors rather than on one outstanding feature of a particular device.
  4. It will be wise to purchase as many items as possible from a single source to take advantage of: compatability of equipment that is designed to work together as a system, coordinated shipments and service, possible lower cost because of quantity purchase and -if required- simpler finance arrangements.

Making a Decision

After considering the points outlined above, and making the lists, you are ready to select equipment.

If the budget is limited you may investigate the possibility of some used equipment. However, since today’s FCC Stereo Specifications were only established as recently as 1961, there will be little used equipment available. In the majority of cases, converting old monophonic equipment will be difficult, costly, and the end result may be less than satisfactory. Old “dual channel” audio consoles have been successfully converted, but in the process usually require almost complete rebuilding. It is necessary to install dual faders, correct phase differences, and balance gain between channels.

Used FM transmitters are frequently advertised, but many are left over from the early days of FM. Some transmitter manufacturers of the late ’40s are no longer in business. Replacement tubes and parts are difficult, if not impossible, to get. Some older transmitters lack stability and some contribute to degradation of stereo separation, because they do not maintain the proper phase relationship between upper and lower sidebands. If such a transmitter is to be used, it probably will be necessary to purchase a new exciter and, of course, a stereo generator.

Since stereo listeners are a discriminating and critical audience, audio equipment should be chosen with care. It will be wise to settle for only the finest professional stereo turntable and tape equipment. It is better to have the minimum requirements of excellent equipment than a control room crowded with “make do” items.

Stereo consoles are available with a wide range of prices and facilities. Some offer stereo channels only for record and tape inputs, while the more complete models even make provision for stereo network and remote circuits. Much of today’s programming is on records and tapes, but regional “off -the -air relay” stereo networks are springing up. Stereo microphone facilities are a must if you want your locally produced commercials to sound as impressive as your stereophonic music.

Current models of FM transmitters are highly efficient, trouble free, and easily remote controlled. All FM transmitters follow one pattern- a basic exciter and a number of amplifier stages to produce the required power output. The power amplifiers in the various models are somewhat similar, except in high power transmitters (20 kw and up).

A wide variety of FM exciters and stereo generators is offered, and this is one area in which confusion might occur. (Again, it should be pointed out that all these units are subject to FCC type acceptance.) A typical exciter and stereo /SCA generating system is shown in Fig. 5. The block diagram explains the signal path and function of the various circuits.

Broadcast Engineering, FM stereo exciter diagram

Broadcast Engineering, FM stereo exciter diagram


The selection, installation, and operation of FM multiplex stereo equipment requires the careful attention of a highly skilled technician. Installation, adjustment, and maintenance should be in exact accordance with the manufacturer’s instruction book. Following these instructions, the broadcast engineer can feel confident in planning a stereo installation that will be a pleasure to operate and a source of pride and profit.

Used by permission of the publisher; SAMS Technical Publishing, Inc.

I found a stack of these old Broadcast Engineering magazines from the early sixties when cleaning out the WUPE-FM (formerly WNMB) transmitter site.  I thought it would be interesting to see how Broadcast Engineers some 50+ years ago were planning for FM stereo.  One of the stations I worked for, WRVE (formerly WGFM) was the first station in the country to broadcast with the General Electric stereo system.  This was later adopted as the standard for FM stereo broadcasting in the US.

For more historical broadcasting publications, go to American Radio History.

ATT Long Lines Site, Rock City NY

Another one of those former ATT Long Lines sites which has been re-purposed. This site was known as Rock City and as the name suggests, it is a fairly remote location. These locations were chosen by ATT to facilitate microwave relay between cities.  Some of the more remote rural locations are so far off the beaten path that they do not make good wireless carrier sites today.  Such is the case here, there simply are not enough people around to turn this into a profitable cell site.

Former ATT long lines site, Rock City NY

Former ATT long lines site, Rock City, NY

This site is useful in other ways, the local township purchased it and has put it to use for E911 dispatch and other uses such as WKZE translator W290BZ.

Former ATT long lines Western Electric Tower, Rock City NY

Former ATT long lines Western Electric Tower, Rock City, NY

The tower is less than 200 feet tall, therefore it is no longer painted or lit. These old Western Electric towers were really built. Under that peeling paint, the galvanizing is still in near perfect condition. The tower dates from 1968.

Former ATT tower, Rock CIty NY

Former ATT tower, Rock City, NY

The Western Electric KS-15676 microwave antennas and waveguide have been removed. The top platform is quite large, one could build a house up there. The W290BZ antenna is the cross polarized LPA attached to the center pole which is barely visible.

Former ATT long lines site, Rock City NY.  The big empty.

Former ATT long lines site, Rock City, NY. The big empty.

This room held the switch gear and TD-3 microwave radios.

Former ATT site, Rock City NY 100 KW generator

Former ATT site, Rock City, NY 100 KW generator

The original General Motors 100 KW diesel generator. The fuel tank was removed before the site was transferred from ATT to the new owners.  If reconnected to a fuel supply and the block heater turned on, I’d bet this unit would start and run.

ATT Rock City NY generator, Detroit Diesel straight six engine

ATT Rock City, NY generator Detroit Diesel straight six engine

ATT Rock City NY fuel tank cathodic projection unit.

ATT Rock City, NY fuel tank cathodic projection unit.

The tank had a Cathodic protection unit installed, which ran a small DC current through the tank to keep it from rusting.

The original visitors log book is still there, showing every ATT person who visited the site from 1968 until it was decommissioned in 1994.  This site was unmanned and remotely monitored and controlled from somewhere else.  Maintenance personal showed up at regular intervals or to fix specific problems.

Like many of its rural counterparts, this site sits mostly empty since the microwave equipment was removed in the early 1990’s.  This one seems to be well taken care of, others are in terrible shape.

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.

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.

Clove Mountain

We take care of a non-broadcast radio site on Clove Mountain, NY. This is a fairly prominent terrain feature and has something else interesting next to the tower site. This old fire tower:

Clove Mountain fire tower, Clove Mountain, NY

Clove Mountain fire tower, Clove Mountain, NY

That is an Aermotor LS-60 fire tower, constructed in 1932. For an eighty year old structure, it is a remarkably good shape. In New York State, fire towers were used for spotting up until 1990, although I believe the last season this one was used was 1988.

Clove Mountain fire tower, clove mountain, NY

Clove Mountain fire tower, clove mountain, NY

Clove mountain is about 1,400 feet above sea level and 800 to 1000 feet above the surrounding terrain. From the top, on a clear day, the view was approximately 30-45 miles depending on terrain obstacles. A forest ranger would be constantly scanning the area looking for signs of fire. If he saw something, there was a range finder that would give the range and azimuth. He would then reference a map and call the fire department responsible for that location.  The fire tower was equipped with electric and a wired telephone.

Clove Mountain view to Northwest

Clove Mountain view to Northwest

This picture was taken on a cloudy day, thus the view is somewhat restricted.

Stairs looking down

Stairs looking down

It would be nice if this were preserved and not allowed to deteriorate any further. Several of these sites have been placed on the National Register of Historic Places.

Clove Mountain Ranger cabin

Clove Mountain Ranger cabin

Below the tower is this ranger cabin. Presumably, during the busy season somebody stayed up here 24/7. There was electricity and a refrigerator, but no running water.  Off to the side is a bedroom.  Over the years, people have broken into the fire tower and this cabin and smashed things for no reason.  It would be nice to preserve all of this for future generations to see, but it is likely these pictures will have to do.

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.

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.

Radio Shack catalog archive

This is a trip down memory lane.  Someone has taken the time to preserve and document Radio Shack, its founding, history and all of the catalogs printed from 1939 to 2005. The website archive is Radio Shack Catalogs.

I remember reading these very catalogs cover to cover, when they came out in the mid 1970’s.  At that time, this stuff looked expensive and in relative dollar terms compared to today, it was.  We had one of these computers in our “Math Lab” in 9th grade:

Radio Shack catalog, TRS-80

Radio Shack catalog, TRS-80

In fact, when I found one of these computers stashed away in the corner of a transmitter site, I had a flash back of Mr. B scowling as yet another student made a mistake plotting x/y coordinates on the backboard.

Tandy TRS-80 Model 4D computer

Tandy TRS-80 Model 4D computer

Ahhh, memories.  Enjoy!

SAQ Grimeton

Historic VLF (Very Low Frequency) station SAQ Grimeton will be on the air to celebrate United Nations Day on October 24th at 10:30 UTC (6:30am EST) on 17.2 KHz CW.  This station was established in 1922 and is the last radio station in the world employing an Alexanderson transmitter.  More information at their website.

This is a great 2011 video of a tour of the station, including transmitter start up:

It is great to see that old gear come to life and transmit a message.  The electric motor/generator sounds like a jet engine spooling up.

Before solid state or even hollow state rectifiers, motor generators were used to create the DC voltages needed to transmit high power radio signals.  This method was used by high powered Naval shore stations through WWII and beyond.

By way of comparison, an average CW operator can send and receive Morse code at about 20-25 words per minute.  A good CW operator, about 30 words per minute and a Russian CW operator, somewhere near 50 words per minute.  This was the main wireless data transmission method until Radio Teletype came into widespread use in the 1950s.   Here is a comparison of data speeds through the years:

Method Speed Bits/S
CW 20 WPM 8.3
CW 35 WPM 14.58
Radio Teletype* 75 Baud/100 WPM 41.6
Radio Teletype* 100 Baud/133 WPM 55.41
Async data 300 Baud 300
Async data 1200 Baud 1200
Async data 9600 Baud 9600
Switched 56 (Switchway) 56KB 56,000
DS0 (POTS) 64KB 64,000
ISDN 64KB X2 128,000
DS1 (T-1) 1.54 MB 1,540,000
DS3 (T-3) 45 MB 45,000,000
Ethernet 10BaseT 10,000,000
Ethernet 100BaseT 100,000,000
Ethernet Gigabit 1,000,000,000

The Morse Code (CW) and Radio Teletype data rates are not a direct comparison, as most radio teletype systems use 5 bit Baudot code instead of 8 bit ASCII.  Morse code varied in length from one to five bits, if one thinks of each dot or dash as a data bit.  Back in the day, before “Netcentric” mindset, we used mainly radio teletype to communicate from ship to shore.  A premium was placed on brief, concise, operational communications.  Everything else was sent via the mail.

It is quite amazing to see the increase in data speed, which directly correlates to information exchanged (or the ability to exchange information) in the last 90 years.

To receive SAQ Grimeton, one needs a VLF receiver or converter capable of receiving 17.2 KHz and a very quite receiver location.  There are many VLF hobbyists that will be tuning in.

BBC “Tracking the Lincolnshire Poacher”

I have covered numbers stations before. This is a radio program from BBC Radio 4 first broadcast in 2005. It is an interesting look what is known and not known about various numbers stations around the world.

I found it interesting in a general way.


A pessimist sees the glass as half empty. An optimist sees the glass as half full. The engineer sees the glass as twice the size it needs to be.

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

Any society that would give up a little liberty to gain a little security will deserve neither and lose both.
~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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