Certain naturally-occurring minerals can be used to detect radio signals, including galena, zincite, silicon,bornite and others. Carborundum was unique among the early crystals because it was synthetic. It was durable, and at 9 mohs much harder than most available crystals. More here. Also interestingly it requires it requires a negative potential of 1 volt to be used as a diode. Carborundum was not created with this purpose in mind. It was created in the early search for artificial diamonds

Like many things in early radio, there are several plot twists in this story and if one is interested in radio history, it is work a click to read.  While you are there, check out “It’s 105 degrees and rising“

Click on picture for original memo (.pdf)

I was digging through some old manuals at the shop today and I found this June 1987 memo from Orban to AM stations titled “AM radio CAN sound almost like FM.”

The main purpose of the memo was to get AM radio stations to implement the NRSC standard for pre-emphasis and high frequency roll off to improve the sound of AM broadcasts on ordinary radios.

I am not sure why the receiver manufactures never designed an IF filter that would be compatible with NRSC, it seems like a fairly simple design.  Instead, what we have is “digital” AM radio (IBOC) which does not work well, creates many more problems with interference that of pre NRSC broadcasting.

If one were to look at the entirety of AM broadcasting history, one would find some striking parallels with what is happening with IBOC today on both AM and FM.

To start, the NAB began petitioning the FCC to allow more AM broadcasting stations, even as it was known that these stations would create interference with existing stations, especially at night.  Still, the NAB persisted and the FCC relented and through the fifties, sixties, seventies, and eighties many more class II and III stations were established on what used to be clear channels (classes I and IA).

Once the AM band was chock full of stuff, they began going to work on the FM band with 80-90 drop ins.

You see, for the NAB, more radio stations means more dues money, greater lobbying power because of the larger size of the industry.   Then came deregulation of ownership limits.  By this time, Big Group Radio was calling the shots and they wanted more.  This led to the great consolidation rush of the late 1990’s from which the radio industry is still reeling.  The consolidation rush led to highly overpriced radio stations being leveraged to the absolute maximum, leading to the recent bankruptcies.

Finally, the NAB’s great push toward adopting IBOC digital radio in the early years of the 00’s.  IBOC was supposed to save the day, greatly improving quality of both AM and FM and bring radio into the 21st century.  Except that the promised technical advances never materialized.  IBOC remains a great expensive boondoggle and I am beginning to think that perhaps we should stop listening to the NAB.

The memo itself is a fascinating thing, which were one could substitute AM with RADIO and come to some of the very same conclusions today regarding analog and IBOC digital radio.  For example, this paragraph on AM stereo:

AM stereo was thought to be an answer (to improve AM), but AM stereo was embraced with the false assumption that having ’stereo’ automatically meant having ‘high fidelity’.  While AM stereo did provide somewhat better fidelity, it was not comprehensively engineered to get the best fidelity from AM.  It was hoped that the gimmick of having two channels would be enough to save AM.

AM stereo could have been an improvement, had it been properly implemented.  Unfortunately, the underlying problem of bad sounding receivers was never addressed.  About which, the same memo notes:

Receiver manufactures did what they could to reduce listener complaints – - they narrowed the bandwidth (thereby reducing audio fidelity) until the complaints about interference stopped.  Listeners clearly indicated, through their buying habits, a clear preference for lower fidelity over continuous irritating static, buzzes, whistles, and “monkey chatter’ from adjacent stations.  People accepted this situation for a long time – - until the simultaneous advent of improved receiver technology and the FCC’s anti-simulcasting rules created the FM boom of the late 1970’s. (ed note: I remember listening to FM because there were fewer commercials, not better sounding audio)

Then the memo goes on to stress the importance of implementing NRSC standard for AM broadcasting that included the sharp frequency roll off at 10 kHz, noting that receiver manufactures would design “fine new receivers” that would take full advantage of the new standard, but only if broadcasters first showed good faith by widely and promptly implementing it.

As I recall, NRSC-1 was adopted as rule of law by the FCC in 1989, about two years after this memo was written.  One could reasonably expect that receiver manufactures then started producing radios that took advantage of the NRSC pre-emphasis curve with IF filters that did not cut off audio frequencies above 3.5 kHz, but rather rolled them off in a gentle slope until about 7 kHz, more aggressively after that until 10 kHz, where they cut off.

Except they didn’t.

Instead, twenty years later, AM radios universally sound bad, with audio bandwidth of about 3 kHz or so.

I believe that AM receivers could be made with three IF bandwidths, automatically selected based on signal strength.  Within the 5 mv contour, full (10 kHz) audio can be reproduced using a high frequency roll off described above.  In the 1 – 5 mv contour, a 6 kHz bandwidth and less than 1 mv a 3 kHz bandwidth.  The automatic selection could be defeated with a “wide/narrow” IF bandwidth selection switch like the GE superradios have.  Of course, if one where listening to stations transmitting AM IBOC, the “narrow” setting would be the best.

Half of me thinks that the ship has already sailed on AM broadcasting.  The stations on the air will continue to decline until they are no longer able to broadcast due to expensive repairs or replacement, at which time they will be turned off.  The other half thinks that AM radio, as evidenced by the huge public response to WEOK and WALL broadcasting the true oldies channel, can be revived.  With the impending inevitable FM IBOC power increases, translator shoe ins, LPFM, etc; the FM band may become worse than the AM band.  At which point the public will have to decide whether free radio is important to them, or 3G/4G services will become the new method of broadcasting.

It is a thick book and covers AM, FM and TV broadcasting technology as it was understood in 1975.  There are several chapters about “current” things that no longer apply, there are also many very useful items, such as studio construction, AM and FM broadcast antennas, tower maintenance and so on.

I will keep this on my shelf because it is an interesting primer on AM broadcast antennas with all attendant formulas and charts.  It is quite interesting and fun if one is looking for the theoretical efficiency of a 185 degree radiator at 1 mile.  I remember WPTR (now WDCD) in Albany had a three tower with 206 degree radiators, 50 KW carrier power on 1540 KHz.  It seemed to be quite effective, when I was chief engineer there, we used to get reception reports from South Africa.

Perhaps one day, I’ll put some of that information to good use with an AM station of my own.

Radio London air studio aboard the MV Galaxy

These were broadcast platforms that were usually anchored in international waters broadcasting popular music to several European Countries including Great Britain, Holland, France and Spain in the late 1960’s through late 1980’s.  The reasons for these peculiar operations was strict government control of all broadcast outlets and programming in those particular countries. The BBC was known to be stodgy and repressive of new music, particularly rock music from bands like the Rolling Stones, the Beatles, the Who, the Kinks, and others.

At the time, there was no specific law preventing ships anchored in international waters from broadcasting to shore based listeners, a loophole in the government control was found and exploited.  That loophole has been closed in most places, so as they say, don’t try this at home.

At one time there were several ships out there in the English Channel and coastal Denmark. The first and best known of these was Radio London or “The Big L.” It broadcast on 1133 KHz from December 16, 1964 to August 14, 1967 using a 50,000 watt RCA ampliphase transmitter. The ship itself was the M/V (motor vessel) Gallaxy, a converted WWII minesweaper formerly known as the USS Density.  After Radio London went off the air, the ship was transfered from port to port until it ended up in Kiel, Germany, were it was finally scrapped in the late 1990’s.

Radio Caroline was the main offshore competitor, broadcasting on 1520 KHz and several other frequencies off and on from 1964 until 1990 or so using several different vessels to transmit from.

MV Galaxy with radio mast

One incident in off shore broadcasting that has always fascinated me was the burning of the Mebo II, then transmitting Radio Northsea International off the coast of Holland (this ship moved around quite a bit) in 1971. Later investigations revealed that the staff of an offshore competitor, Radio Veronica, was responsible for the firing of the ship.  Apparently, in those days the competition was brutal.

I like the nice calm music with the increasingly frantic DJ (West, no East). In any case, the ship remained afloat and returned to the air the next day.  The final European offshore broadcaster was something called Laser 558 on M/V Communicator.  It broadcast using to CSI 25 KW AM transmitters on 558 KHz in 1983, again, off and on for several years until 2004.  The CSI grounded grid transmitters may have been inexpensive to purchase, but I’ll bet they cost a lot to run.  This would be especially true if one were using diesel generators as the main electrical power provider.  As a result, they were usually run at about 1/2 power.  Eventually, M/V Communicator ended up beached in the Orkney Islands off of Scotland.

The only such attempt in the US was Alan Wiener’s MV Sarah, known as “Radio Newyork International” anchored off of Jones Beach on 1620 KHz.  The owner’s figured 4 miles off shore was far enough to be in international waters, the FCC felt otherwise, I believe at the time, 12 miles was (and still is) the territorial limits for the US.  Four miles was not international waters, as the broadcasters claimed.  These guys were arrested and sent to trial.  After several years all charges were dropped.

Anyway, an interesting bit of radio history. Goes to show the lengths that some will go to when feeling repressed.

It is mostly just drag and drop the next element into the play deck, if anything needs to be done at all.

Technics SP-15 Turntable

I remember when DJ’s actually jockeyed disks, it was a sight to behold.  Back in the day when everything was on vinyl except the commercials, which were on cart, the DJ had his or her hands full.  Most of the songs where in the 2:30 to 3 minute range, so while the song was playing, the next song had to be cued up on the platter, the old song needed to be put back into it’s sleeve and shelved (most of the time), check the log to see what was on deck, pull the next commercial stop set, answer the phone and god forbid if the Program Director called on the hot line and it rang more than 3 times.  And hopefully the head wasn’t too far away, that coffee went somewhere, after all.  While all that is going on, timing, audience interaction, hitting the post and sounding fun.  In spite of what Howard Stern says, it was not easy.

Today, of course, if there is even a person in the studio, they may glance up at the computer screen every now and then to see when the next time they need to talk.  Otherwise, they would be engaged in talking on the phone with their girl friend, texting, surfing the internet, or watching the baseball game on TV.

RMS Titanic, April 10, 1912

Most of these early radio stations were owned by Marconi Company, which later became RCA.  One of the first Marconi Stations was in Wellfleet Cape Cod, original call sign MCC (for Marconi Cape Cod) later changed to WCC.

On April 14th about 11:45pm, the Titanic struck and ice burg and sank about two and a half hours later.  The RMS Titanic call sign MGY was equipped with a radio transmitters at a time when ships were not required to be.  Sadly, the finer details of distress procedures for radio equipped ships had not been worked out.   After this incident, radio distress procedures were codified and the SOS evolved into the internationally recognized distress signal.

On the night the ship sank, the Marconi employed radio operators were sending routine traffic to Cape Race, Newfoundland radio.  Because the radio apparatus used spark gap transmitters and crystal radio receivers, interference from other ship stations often caused problems.  Earlier in the evening, a Titanic radio operator had strongly rebuked the operator from the closest ship, the SS Californian, telling him to “Shut up, shut up, I am busy; I am working Cape Race.” About 11pm the SS Californian operator retired for the evening and the Californian never received the distress call.  Sadly, this incident probably led to the high loss of life because the Californian was just over the horizon to the west and would have likely been able to rescue many of the passengers before the Titanic sank.

Coast Guard radioman Jeffrey Herman has a good SOS story from the late 70’s.  Being stationed on Hawaii, he was on duty late one night at Coast Guard Radio Station Honolulu, call sign NMO.

John Davies, the radio operator on board the Eriskay also has a story about receiving an SOS while at sea. Fortunately, that one turns out a little better.

I remember one night, myself hearing an automated SOS on the international lifeboat frequency (8364 kHz).  I imagined some poor guy cranking the life boat radio not knowing if it was going out or not (I was right, it turns out).  We heard him on Guam and DF’d him to off the coast near Australia.  We notified the Australian authorities, who diverted a nearby ship that picked 26 survivors up the next morning.

I am sure there a quite a few old CW (morse code) radio operators out there that have similar stories.  By the 1990’s most maritime communications had moved to INMARSAT, CW and coastal radio stations became redundant.

The end of commercial Morse Code in the US came on July 13, 1999, when KFS, the last coastal radio station, signed off.  Most of them have been scrapped and the valuable coastal land sold off to developers.

The development of broadcast radio was a direct offshoot of these radio stations.  AM radio, or rather AM technology was developed by ATT as an adjunct for their long distance system.  ATT used High Frequency (HF) voice circuits to span oceans for several decades, up to about the mid 1960’s.  Amateur radio operators began fooling around with voice broadcasting, using ATT’s patented AM technology around 1915 or so, after tube type transmitters and receivers became available.   Somebody realized the money could be made with the new fangled radio contraption and commercial broadcasting was born.

Former ATT microwave site turned into a residence

If I were that guy, I’d take those antennas down a scrap them.  Looks like the wave guides are already gone.  I might have tried to put some windows in while I was renovating it.  It would drive me crazy to live in a house without any windows.  I guess if one where waiting for the big one, windows might not be a desired feature of a survival bunker.

I wouldn’t really call it a “communications bunker” though.  I’ve been in communications bunkers, they are mostly underground and are much more robust than that building.  Still, it is built better than an ordinary commercial building or a regular house.   It would take a special person to live out in the middle of nowhere like that.

WGU-20 logo

Back in the cold war days, the federal government took emergency warning quite seriously.  So much so that they spent about $2 million in 1972 to build a LF (low frequency) radio station WGU-20,  in Maryland designed to integrate into the public warning system.  This was known as the “Last radio station” because it was designed to operate after nuclear armageddon.  Using the first all solid state AM transmitter designed by Westinghouse, the station transmitted on 179 kHz (power 50 KW) with a loop that stated:

“Good evening. This is WGU-20, a defense civil-preparedness agency station, serving the east central states with emergency information. Eastern Standard Time seventeen hours, twenty minutes, twenty seconds.”

The greeting would change to “Good Morning…” or “Good afternoon…” as appropriate.

One small problem arose from this system, no one had long wave receivers.  The government attempted to persuade manufacturers to market, and the public to purchase radios that would only receive periodic tests or that they were likely going to die in the next 15 minutes. It was a tough sell from the start.

Military planners decided that they might integrate the DIDS (Decision Information Distribution System) information gained from surface to air radar that would give the approximate impact areas of incoming ballistic missiles. The idea was, the public would then know which areas to “avoid.”   It may have appealed to the military mind, but most others didn’t quite see the value in it, especially since reaction times would have been 10 minutes or less.

Plans were to build several of these radio stations throughout the US operating on Low Frequency, which would have replaced the EBS over the air daisy chain system that remains in effect today with the current EAS.   Unfortunately, the public never bought into the concept and around 1990 or so, WGU-20 was turned off for good.  The nearest thing was have to it today is NOAA weather (or all hazards) radio.

EBS and EAS have never had to work in a time of emergency and if the circumstances are dire enough for someone to attempt to activate EAS, it is very likely the system would fail.

In my time as chief engineer there, I found several file folders of memos and other materials about the building of the tower, which started in 1936.  Prior to that, WGY used a T top wire antenna, first from the General Electric plant in Schenectady (1922-25) then from the current tower site in Rotterdam.  Located with WGY were GE’s experimental shortwave stations W2XAF and W2XAD.

When the station increased power to 50,000 watts in 1925, may reports of fading were received from locations 20-50 miles away.  WGY engineers studied the situation by doing a full proof on the antenna.  They found an elliptical shaped pattern with nulls to the north and south.  This coincided approximately with the T arms of the T top antenna, likely due to the self resonating effect of the support towers for the ends of the T.

NBC, then owners of WJZ (now WABC) in NYC had studied this problem for years and came up with a new antenna design for Standard Broadcast, the uniform cross section guyed tower.  Starting in 1935, WGY began to investigate installing such a tower in South Schenectady, as the transmitter site was then known.  One report showed an efficiency gain of 430% over the T top antenna that was in use.  The General Electric construction and engineering department raised several objects to the standard triangular tower then and now commonly used for AM radiators.

WGY transmitting tower, Schenectady, NY

Much mechanical planning and effort went into the design of the tower, which is a square tower, 9 foot face, 625 feet tall.   During the planning phase, KDKA was installing a simuliar tower, which collapsed when it was being erected in 1936.  An analyisis of the failure showed that one of the guy anchor cable sockets pulled out of the concrete (which was improperly poured).  This may also be the reason why the KDKA tower collapsed in 2003, although I never read the engineering report on that failure.   Nevertheless,  GE engineering felt that forging the members of a triangular tower weakens them and was too risky, thus, a square tower was the solution.

Further, every component of the tower was tested individually.  Often, two of a type where build, with one being tested to destruction.  Two base insulators were made for this specific tower.  The first was tested to destruction at the National Standards and Institutes laboratory in Washington DC.  It was found that the insulator withstood slightly more than 1,200,000 pounds of pressure.  The working load (tower dead weight) of the base insulator is calculated to be about 430,000 pounds, thus almost a 3:1 safety margin.

The wire rope used for the guy wires was also tested to destruction.  The working load on the upper guy is about 24,000 pounds, the wire rope broke at nearly 120,000 pounds.  The concrete, guy anchor sockets, T bars, and all other parts were likewise tested.

Base insulator, WGY 625 foot square faced transmitting tower

Electrically, the tower is 186 degrees (it was 180 degrees on 790 kHz, the former WGY frequency).  It had a 40 X 40 foot ground mat with 120 buried ground radials.  The ground radials were #4 hard drawn stranded copper.  When we investigated the system in 1999, it was complete and unbroken.  The radials, ground screen, strap and all other metal component showed no signs of deterioration.  It helps that the soil surrounding the tower is a sandy loam and well drained.

WGY open transmission line between transmitter building and tower base

The tower was fed with 600 ohm open transmission line, 180 degrees long.  Initially, the system had been designed for high power operation up to 500 KW.  However, when the transmitter was replaced in 1980, a new Harris ATU was installed, which can only handle 50 KW.  I recall the base resistance to be 192 ohms with -j85 reactance.

A concrete wall surrounds the base insulator.  This was installed in early 1942 to prevent the base insulator from being shot out by sabbators during WWII.

Harris MW-50B, WGY Schenectady, NY

When I worked there, the station had a Harris MW-50B transmitter.  This unit was in slightly better shape than its counterpart at WPTR across town.  I did find some of the same quirky things with it, however.  Our consulting engineer had a good line, “Harris, where no economy is spared…”

WGY transmitter site backup generator

The site had a FEMA owned backup generator installed in the 60’s.  This was an Onan 225 KW diesel powered unit.  225KW is likely a conservative estimate as those units were way overbuilt.  The original fuel tank was buried out behind the building.  FEMA contracted for it’s removal in 1995 because of concerns of leaks and soil contamination.  When they dug it up, the primer was still on the tank.  After getting the tank out of the ground, the contractor cut a large hole in it and lowered a person into the tank to clean it out.  Something that should be profiled on the Dirties Jobs TV show.

5000 gallon backup generator fuel tank

The new tank was installed in the old outdoor transformer vault.  It is a 5000 gallon double walled above ground tank with monitoring system.

It has been several years since I have been to this site.  I know they installed a Harris DX-50 sometime in 2001 or so.  They also may have replaced the open transmission line.  WGY now transmits in HD radio, which they are able to do because the tower was well designed and installed.

56 years ago, on September 16, 1953 American Airlines flight 723 flew between the center and northeast towers of the WPTR antenna system while attempting to land at Albany County Airport.  The plane crashed about 3/10 mile away near NY route 5 (Central Avenue) killing all 28 persons on board.  To date, this is the worst aviation accident in the Albany, NY area.

Several years ago while cleaning out different AM transmitter site, I found a bunch of files about this accident in the trash bin.  It seems that some engineer had moved a file cabinet during the great consolidation of the 1990’s to the wrong transmitter site.  In any case, I rescued the file and for your reading pleasure, have scanned the following documents:

Original telegram to FCC in Washington DC regarding tower/aircraft colision

Retel WPTR north and center towers struck three hundred foot level 0930 morning 16 September by American Airlines Convair.  Damage inspected afternoon 16 September by representative Zane Construction and afternoon 17 September by engineer Ideco tower used in array.  Both report slight damage to center tower requiring straightening above 300 foot level.  North tower has two legs bent result of wing passing through tower 18 inches above top guys at bolt intersection.  Tower above bent and twisted but all right unless subject to high east wind.  Impact sheered north beacon clevises and shattered glass.  Replacement ordered and beacon restoration expected early next week.  Measurements of directional pattern afternoon 16 September show pattern unchanged and mulls, base currents and loop currents within tolerances except center loop current which reads ten percent low.  Indications are center pickup loop has been jarred and pattern unaffected.  FCC representative Turnbull who arrived noon Wednesday concurred.  No time lost.   Operating at full power

George Wetmore, Assistant Genl Mgr, Radio Station WPTR

This is the statement of the transmitter engineer on duty at the time of the crash.

Statement from the Engineer on duty at the transmitter site

I, Robert S. Henry engineer for Patroon Broadcasting Co. would like to make this statement concerning the collision of an American Airlines Plane with our transmitting towers.

On Wednesday morning September 16, 1953 I was on duty alone at the WPTR transmitter when at approximately 9:30 A.M. a low flying plane was heard overhead. The carrier trip circuit which protects the transmitting apparatus from sudden overloads at the antenna almost instantly actuated and a low sound of explosion followed about 3 seconds later. I ran to the back door of the transmitter in time to see what proved later to be aluminum sheets fluttering down through the fog. I estimate the ceiling at the time to have been approximately 75 feet and not sharply defined. The centre (sic) tower of our three tower array swayed violently for approximately for approximately (sic) 1 minute. At the time I knew a plane had hit the tower but it was above the ceiling and invisable to me. I called W. R. David and George Wetmore and the incident was reported to the Albany airport.

Back in these days, the studios were located at the Hendrick Hudson Hotel in Troy, the transmitter site was manned by a licensed transmitter engineer when ever the station was on the air.

What is amazing is that the IDECO towers remained standing after being struck by Convair 240, a pretty good sized aircraft.

Convair CV-240

Official report by the International Civil Aviation Organization:

American Airlines’ Flight 723 was a scheduled flight between Boston, and Chicago, with intermediate stops among which were Hartford (BDL), and Albany (ALB). The CV-240 arrived at Bradley Field at 06:57. Weather at the next stop, Albany, at this time was below the company’s landing minimums, but was forecast to improve to within limits by the time the flight arrived there. Departure from Bradley Field was made at 07:14. Because of poor visibility at Albany, several aircraft were in a holding pattern. The special Albany weather report issued at 07:50 indicated thin obscurement, ceiling estimated 4,000, overcast, fog, visibility 3/4 miles. Two aircraft left the holding pattern, attempted to land, but both executed a missed approach procedure. A third airplane landed at 08:16 following an instrument approach to runway 19. Immediately following this landing, Flight 723 was cleared to make an instrument approach to runway 19. Three minutes later the flight advised the tower that its approach was being abandoned because the aircraft’s flaps could not be lowered.
At 08:30 Albany Tower reported:”All aircraft holding Albany. It now appears to be pretty good for a contact approach from the west. It looks much better than to the north.” Flight 723 was then cleared for a contact approach to runway 10. On finals for runway 10, the Convair descended too low. The right wing of the aircraft struck the center tower of three radio towers at a point 308 feet above the ground. The left wing then struck the east tower. Seven feet of the outer panel of the right wing including the right aileron and control mechanism from the center hinge outboard together with 15 feet of the left outer wing panel and aileron separated from the aircraft at this time. Following the collision with the towers, ground impact occurred a distance of 1,590 feet beyond the tower last struck. First ground contact was made simultaneously by the nose and the left wing with the aircraft partially inverted.
The weather reported at the time of the accident was thin scattered clouds at, 500 feet, ceiling estimated 4500 feet, broken clouds, visibility 1-1/2 miles, fog.

PROBABLE CAUSE: “During the execution of a contact approach, and while manoeuvring for alignment with the runway to be used, descent was made to an altitude below obstructions partially obscured by fog in a local area of restricted visibility.”

The above reports notes that the aircraft traveled 1590 feet and struck the ground partially inverted.  I do not know what the flaps up landing speed of a Convair CV-240 is but the cruising speed is 280 MPH.  It would be safe to say the aircraft was traveling in the 120 to 130 MPH range or about 220 feet per second.  At that speed, it was likely airborne for about 7 seconds after it hit the tower.  Enough time to look out the window, realize what was happening and say “Oh, Shit!”

IDECO towers WDCD antenna system, northeast tower is farthest

IDECO stood for the Internation Derrick Company, they build cranes, derricks and bridges as well as radio towers. Apparently they made pretty good stuff because those same towers are still standing today.

Not that checking the tower lights would have averted disaster in this case, it appears to be pilot error compounded by bad weather that caused this incident.  But there have been more recent aircraft/radio tower accidents, some of which have involved possible faulty tower lights.  I wouldn’t want that on my conscience.