History of the WGY broadcasting tower

To any who live in the capital region, the WGY tower near the intersection of I-90 and I-88 in the town of Rotterdam is a familiar site.  It is big, tall, and conspicuously marked with a huge “81 WGY” on the southwest face of the tower.   At night the call letters used to be lit up by a spot light but that may have been turned off in recent years.

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
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
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
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
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
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.

Backup generator fuel tank
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.

AM transmitter site maintenance check list

As promised, here is the AM transmitter site maintenance check list.  This is for a generic directional AM station with a backup transmitter, generator and an RF STL.

Broadcast Electronics AM6A transmitter
Broadcast Electronics AM6A transmitter

Usual disclaimers apply.

AM site Maintenance checklist

Weekly Maintenance:

A.  Visit site, Check following:

  1. Check critical transmitter values against last logged value
  2. Check forward/reflected power on main transmitter
  3. Check and reset any overloads
  4. Check signal strength on STL against last logged value
  5. Check generator fuel level
  6. General check of building, look in all rooms, inspect for damage from vandalism, Leaking roofs, obvious signs of trouble, take steps to correct.

Monthly Maintenance:

B.  Visit site, Check following:

  1. Do a full multi-meter log, (includes tower phase angles, loop currents), run backup transmitter into dummy load.
  2. Start and run generator for 5 minutes, check block heater, hoses, belts, oil and antifreeze levels
  3. Calibrate remote control meters with transmitter meters, log it*
  4. Check all tower fences for integrity and locked gates*
  5. Complete Items 3, 4 and 5 under weekly maintenance.

Quarterly Maintenance:

C.  Visit site, Check following:

  1. Complete 1 through 5 under monthly maintenance.
  2. Check all air filters, clean or replace as needed.
  3. Check frequencies of all transmitters, STL receiver, and log.
  4. Complete quarterly tower lighting and painting inspection*

Bi-yearly Maintenance:

D.  Visit site, Check Following:

  1. Complete 1 through 5 under quarterly maintenance.
  2. Conduct monitor point readings for all directional antenna patterns*
  3. Check base current readings for day/night towers.  Ratio.*
  4. Clean backup transmitter
  5. Place backup transmitter on air and clean main transmitter.

Yearly Maintenance:

E.  Check all licenses and authorizations for accuracy. Make sure that all renewal cards etc are in public file and are posted at control point.*

F.  Visit site, Check following

  1. Complete 1 through 5 under Bi-yearly maintenance
  2. Equipment performance measurements (NRSC, Harmonics, frequency)*
  3. Complete service of generator
  4. Complete Inspection of towers, check for vertical and plumb, check guy wire tensions, retension as needed.
  5. Check property for anything out of the ordinary
  6. Repair driveway as needed

General maintenance that is completed on an as needed basis

  1. Re-fill fuel generator fuel tank when drops below 50 percent
  2. Empty trash, sweep floors, dust.
  3. Cut/remove vegetation inside tower fences, spray herbicide as needed
  4. Water proof tower fences every 2 years
  5. Paint exterior of building
  6. Replace tower lights*
  7. Paint towers*

*These are FCC inspection items, pay close attention if you do not want a fine.

That is it, a .pdf version of this file can be downloaded here.

How stupid do you have to be?

I read through the news coverage of the vandalism at the KRKO transmitter site.  Apparently there is some group of idiots people running around insisting that radio towers are bad for the environment and people’s health.  These are the same ones who have torched SUV’s and burned high end housing developments down.  Naturally, no pollution is released into the environment during these acts, else they would be hypocrites.

They make these claims with no merit or scientific basis, instead relying on base fears to make people go crazy, either temporarily or permanent like.  It is actually a pretty good motivator as both political parties and all sorts of fringe truthier, birthier, and others have discovered.  If enough people insist that it is true, than it must be so.

Unfortunately there is always some idiot around who thinks it is his or her duty to take action, to protect the rest of us from some terrible fate.

In the meantime, some security cameras at the transmitter site might be a good investment.  Chances are, these Earth Liberators that sneak around with bolt cutters and hack saws will likely think twice if there is any chance of themselves going to jail.

By the way, those KRKO towers looked like self supporters which would have been very difficult to get down.  Did they rent that excavator, or was that some construction equipment left unattended?

American Airlines Flight 723

File under: Why we check the tower lights every day (or have an automated tower light reporting system):

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
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
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
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
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.