April 2011
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Transmitter trips main breaker

Received a call last night, after a particularly bad thunderstorm, that WGHQ in Kingston, NY was off the air.  Earlier in the day, the transmitter had tripped the main breaker after a thunderstorm.  I arrived at the transmitter site and found the breaker tripped again.  Once the breaker was reset, the transmitter came back on and ran without any overload indications.  The transmitter is a 10 year old Nautel ND-5.

WGHQ Nautel ND-5 transmitter

WGHQ Nautel ND-5 transmitter

I was thinking breaker fatigue as the breaker is the original 1960 breaker installed when the building was built.  I reset the breaker and turned the power output down to 3 KW, thinking the reduced load might not trip the breaker until we could get a replacement.  The transmitter was on the air running as I was about to lock up and go home when I heard, but more felt through the floor, a THUMP! There I stood and watched the transmitter go dark.

At least it happened when I was there looking at it.  Because of the lightning, I was thinking something in the output network.  I reset the breaker and once again, no faults and the transmitter came back on.  Strange.  Obviously some sort of power supply issue.  Here are the clues:

  1. The B- voltage was right where it should be at 72 volts.
  2. All other readings, reflected power, forward power, power supply current are normal before and after the breaker trip
  3. No fault lights
  4. The service panel breaker, which was tripping, is rated for 70 amps, the transmitter front panel breaker which did not trip, is 50 amps.

The Nautel factory rep was thinking either breaker fatigue or the big transformer in the base of the transmitter had gone bad.  According to him, no one had ever heard of a transformer going bad in these transmitters, which makes a certain amount of sense.  Unlike a tube transmitter, which steps the B+ voltage up several times, these transmitters reduce the B- voltage by about 2/3rds or so.  With a step up situation, a surge would be multiplied many times and could very easily punch a hole in the transformer’s secondary winding insulation.  I have, in fact, experienced this on at least two occasions.

That leaves the wiring between the transmitter and the service panel.  I double checked the panel breaker with my volt meter to ensure that the voltage was indeed off.  Then I removed each phase from the connection lugs in the transmitter and tested the wire to ground with my Fluke 77 DVM.  Sure enough, two of the phases showed resistance of 1.2 and 1.7 MΩ to ground were it should have been infinite.  Further, when I took the cover off of the service panel, I found a dead mouse.  Unfortunately, I didn’t have any #4 THHN and all the home improvement stores were closed by that time, so it had to wait until morning.

The thunderstorm seems to be a coincidence.

After we pulled the wire out of the conduit, we found this:

mouse chewed feces encrusted electrical cable

Mouse chewed feces encrusted electrical cable

It is a little hard to see, but that shiny spot is copper.  The cable jacket is chewed back quite a ways and the entire thing is encrusted in mouse feces and urine.  I love to work on stuff like this.  LOVE IT!  Hantavirus, here we come!  That reminds me, I need to get some of those blue latex exam gloves and throw them in the truck…  Anyway, far back in the conduit running through the concrete floor where it bends to go up to the service panel, the mice apparently had a nest.  They got into the conduit under the transmitter, where it transitioned from 3 inch rigid to 1 1/4 inch flexible metal without benefit of a junction box or proper fitting.

We pulled new copper conductors in and installed a proper junction/transition between the 3 inch and 1 1/4 inch conduit.  The service panel was also missing several knockouts of various sizes, which were sealed with knockout seals.  The transmitter was back on the air at full power about 16 hours after it went off.  Unfortunately, the station has no back up transmitter, so they were off for that period of time.  Perhaps now they will look into a backup transmitter or at least an exterminator, but probably not.

Opting out of Smartphone Spyware

A while ago, I was extolling the virtues of my Android smartphone. I have to say, I am still pleased with the unit, having a mini-computer/camera/phone/calculator etc is handy. It makes life easy to find a needed part on Mouser.com, order it and get it the next day.  I can snap a picture of something and send to somebody in less than a minute.  When trouble shooting a transmitter, sending a picture to the factory rep cuts down on the back and forth and brings the effort directly to the point.

I have also blogged about my mediocre Pandora experience.  Now, it seems there is another reason to be weary of the mighty Pandora machine.

The Wall Street Journal has a good article about what these companies are doing with your data.

Both the Android and iPhone versions of Pandora, a popular music app, sent age, gender, location and phone identifiers to various ad networks.

Read the whole thing, it is enlightening.

Is my Smartphone spying on me?  Apparently so.  Frankly, I’ve had enough of this.  There is nothing compelling or even terribly unique about Pandora.  I’ve found the Pandora listening experience to be adequate, but certainly not worth all the hoopla it gets.  Being constantly bombarded by advertisers selling all sorts of garbage is becoming annoying.  I’ve gone through and deleted all apps that access personal data of any kind, including Pandora.   There are a few which are hard rooted in the phone such as Skype mobile and Facebook which can’t be deleted.  Skype mobile can’t even be deactivated, as soon as the program is ended, it restarts on it’s own.

So, is Skype mobile recording everything I do and sending to some black hole somewhere?  I don’t know.  If it is,  it is likely boring somebody half to death as most of my life is pretty mundane.

Update: I rooted my phone, which was far easier than I thought it would be, and deleted all the programs I didn’t like.

Heads? Tails? I don't really know

When confronted with something like this:

Transmitter Remote Control Wiring

Transmitter Remote Control Wiring

It is often faster to cut all the old wiring away and start over.  This is a transmitter remote control system which was initially installed in the early 70’s.  Over the years, it was added to, subtracted from, divided, multiplied, sliced, diced, etc.  In the end, the existing wiring documentation did not match most of what was there.  Additional to that, several of those terminals have 120 volts and I found at least one instance of 208 volts.

Therefore, we began by removing all of the wiring from the backup transmitter, running a temporary audio wire and switching to the backup.  Then, with all the breakers turned off, all the wiring was removed from the main transmitter, phasor and remote control interface and we started over:

Transmitter site remote control interfaces

Transmitter site remote control interfaces

Once upon a time, some engineer built these remote control interfaces, which are quite nice.  We decided to re-use them where 120 volt control is required.  When completed, I will tape over the terminal and label them accordingly.  The main transmitter uses open collector control, therefore, it can be wired directly to the Burk ARC-16 IP-8 panel.

Burk IP-8 Remote Control interface panels

Burk IP-8 Remote Control interface panels

The Burk unit, as wired with the main transmitter, common point, tower lights, phasor and antenna monitor.  The project has not been without some small off air incidents, once while we removed a metal name plate that had fallen into an inductor in the phasor.  All in all, progress is being made.

Emergency AM Replacement Antenna

Eventually, disaster will strike. It can range from a fire at the transmitter site to a tornado at the studio.  Someday, every station on the air will be knocked off at the worst possible moment. It is the law of nature.  Perhaps the most difficult disaster to recover from is the loss of a tower at a transmitter site.  An FM tower holds the antenna, therefore, finding a tower or building nearby and placing a temporary antenna there will get the station back on the air in a reasonable fashion.

An AM tower is the antenna, which is much harder to replicate.  One possible solution is to use a temporary wire antenna while the tower is being rebuilt.  This is allowed in FCC 73.1680 emergency antennas, provided the commission is notified of the situation by informal letter.  Directional stations must operate at 25% or less of the station’s licensed power, or demonstrate that radiation limits are are not being exceeded in any direction.  That usually can be accomplished by taking a set of monitor points.

A wire antenna can come in several configurations:

  1. Fastest to deploy is the random length end fed wire.  This can normally be attached to the existing ATU and tuned up with components on hand.  It requires having an OIB, generator and receiver to tune, which not every station has.  In addition to that, extra components may be needed in the ATU for tuning purposes.
  2. Next easiest is a tower length wire ready to deploy.  This is a length of wire equal to the height of the tower, with insulators and supports.  Wire should be supported as high above ground as possible using trees, wooden poles, etc.  Still requires having an OIB, generator and receiver to tune.  Likely to be within the tuning limits of the ATU components on hand.
  3. A 1/2 wave dipole tuned for 50 ohms.  This can be connected directly to the transmitter output, thus is the best solution if the ATU’s were damaged or otherwise not serviceable.  In this situation, two 1/4 wavelengths of wire are coupled at the center using a 1:1 balun.  Again, this antenna should be supported as high above ground as possible using trees, poles and other non-conductive supports.  Can be installed in a V, inverted V, or L shape as required.

All three of these choices would likely limit transmitter power output to 1-2 KW.  Choice 3 likely represents the most efficient radiator and can be fabricated ahead of time and stored at the transmitter site.

1/2 wave dipole with 1:1 balun

1/2 wave dipole with 1:1 balun

To make a 1/2 wave dipole, cut two lengths of wire using the formula L(feet)=246/F(MHz).  This formula does not account for a velocity factor of 90%, which is typical for stranded wire.  The reason being, since a MF dipole antenna is necessarily going to be lower than 1/2 wave length, it is better to start the antenna a little long and trim it to size for a 50 ohm impedance.  If commercially made insulators are not available, insulators can be made from non-conductive materials like PVC conduit, PEX, plexi-glass, etc.  The insulators on the ends of the wire need to account for the voltage peak that will occur there.  If small “dogbone” type porcelain insulators are used, string thee or four of them together using nylon or poly rope.  The insulator needs to be able to withstand 8-10 KW of power under full modulation.

A 1:1 balun will distribute the RF currents evenly on both wires, which will help improve efficiency and coverage.  Most Ham Radio Baluns are not designed to work below 1.8 MHz and therefore, will not work for this purpose.  A balun can be made with a ferrite torroid made from 68, 73, 77 or type F material.  A good choice would be Amidon FT-290-77 or FT-290-F.  The type F material has a higher AL value, thus fewer turns are needed.  In addition to that, high voltage insulated wire should be used to wind the balun.

1/2 wave dipole antenna current voltage distribution

1/2 wave dipole antenna current voltage distribution

Since, in a 1/2 wave dipole configuration, the voltage is at a minimum at the center of the antenna, and current is at a maximum, some attention needs to be paid to wire size as well.

Amidon ferrite torroid core

Amidon ferrite torroid core

To give a good idea of wire sizes required, some basic information is needed.  For a 1 KW station, it is assumed that the carrier will be modulated to 100 percent, therefore the peak envelope power will be 4 KW.  If the station is asymmetrically modulated, add another kilowatt.  Therefore, the maximum current formula is I=√(P/R).  P is the power in watts, or 5,000 and R is the radiation resistance or 50 ohms, thus I=√(5000/50) or 10 amps.   The maximum voltage is E=√(P x R) or E=√ (5000 x 50) or 500 volts.  For a safety factor, multiplying these values by 1.5 is recommended.  That will likely account for any impedance differences due to ground proximity and so forth.  Therefore for a 1 KW station, the dipole antenna should be designed for 15 amps and 750 volts.

For a 2 KW station the peak envelope power for an asymmetrically modulated transmitter is 10 KW, thus it follows that 30 amps and 1500 volts are safe working figures.

With the proper torroid core, a turns count of 7-10 turns bifilar will suffice.  Since it is a 1:1 balun, the turns count on both sides of the transformer will be the same.  The balun then should be placed in a suitable water proof housing designed to be attached to the center of the dipole antenna.  This is a good example of a commercially available 5 KW 1:1 balun for amateur radio use:

1:1 balun designed for center of 1/2 wave dipole antenna

1:1 balun designed for center of 1/2 wave dipole antenna

The antenna can be fed with RG-8, RG-8X, RG-8A, RG-214 or any other coax this is capable of handling the peak envelope power of the radio station.  The connector can be UHF, N, LC, etc.  In some cases, the may be easier to simply omit the connector and connect the coax to the balun using some type of strain relief on the cable coming out of the box.

Once this antenna is made, a bit of tuning may be required to bring it to 50 ohms.  This can be done with a bridge and generator, or with the transmitter on low power.  Either way, the measurements must be taken with the antenna at operating height as the distance to ground will effect the termination point impedance.  It may require some trial and error.

In all, a good backup antenna can be made for about $50-60 or so.  A little bit more if fancy transmission line is used.  Well worth the expense and effort to have something ready to go in a moment’s notice.

Update: I’ve been fooling around with this on EZNEC, it may not be that easy to do, especially with the lower frequencies in the AM band.  The antenna needs to be at least 0.06 wave length above ground to perform correctly.  Somewhat lower over better ground conductivity, e.g. ground radials.  Even at this height, it needs to be lengthened significantly to get the feed point impedance close to 50 ohms.


Sound Cards for Broadcast Use

Computer audio sound cards are the norm at nearly all radio stations. I often wonder, am I using the best audio quality sound card?  There are some trade offs on the quality vs. cost curve.  At the expensive end of the curve, one can spend a lot of money for an excellent sound card.  The question is, is it worth it?  The laws of diminishing returns states: No.  High quality reproduction audio can be obtained for a reasonable price.  The one possible exception to that rule would be production studios, especially where music mix downs occur.

I would establish the basic requirement for a professional sound card is balanced audio in and out, either analog, digital or preferably, both.  Almost all sound cards work on PCI buss architecture, some are available with PCMCIA (laptop) or USB.  For permanent installations, an internal PCI buss card is preferred.

Keeping an apples:apples comparison, this comparison it limited to PCI buss, stereo input/output, analog and digital balanced audio units for general use.  Manufactures of these cards often have other units with a higher number of input/output combinations if that is desired.   There are several cards to choose from:

The first and preferred general all around sound card that I use is the Digigram VX222HR series.   This is a mid price range PCI card, running about $525.00 per copy.

Digigram VX222HR professional sound card

Digigram VX222HR professional sound card

These are the cards preferred by BE Audiovault, ENCO and others. I have found them to be easy to install with copious documentation and driver downloads available on line.  The VX series cards are available in 2, 4, 8, or 12 input/output configurations.  The HR suffix stands for “High Resolution,” which indicates 192 KHz sample rate.  This card is capable of generating baseband composite audio, including RDS and subcarriers, with a program like Breakaway Broadcast.

Quick Specs:

  • 2/2 balanced analog and digital AES/EBU I/Os
  • Comprehensive set of drivers: driver for the Digigram SDK, as well as low-latency WDM DirectSound, ASIO, and Wave drivers
  • 32-bit/66 MHz PCI Master mode, PCI and PCI-X compatible interface
  • 24-bit/192 kHz converters
  • LTC input and inter-board Sync
  • Windows 2003 server, 2008 server, Seven, Eight, Vista, XP (32 and 64 bit), ALSA (Linux)
  • Hardware SRC on AES input and separate AES sync input (available on special request)

Next is the Lynx L22-PCI.  This card comes with a rudimentary 16 channel mixer program.  I have found them to be durable and slightly more flexible than the Digigram cards.  They run about $670.00 each.  Again, capable of 192 KHz sample rate on the analog input/outputs.  Like Digigram, Lynx has several other sound cards with multiple input/outputs which are appropriate for broadcast applications.

Lynx L22-PCI professional sound card

Lynx L22-PCI professional sound card


  • 200kHz sample rate / 100kHz analog bandwidth (Supported with all drivers)
  • Two 24-bit balanced analog inputs and outputs
  • +4dBu or -10dBV line levels selectable per channel pair
  • 24-bit AES3 or S/PDIF I/O with full status and subcode support
  • Sample rate conversion on digital input
  • Non-audio digital I/O support for Dolby Digital® and HDCD
  • 32-channel / 32-bit digital mixer with 16 sub outputs
  • Multiple dither algorithms per channel
  • Word, 256 Word, 13.5MHz or 27MHz clock sync
  • Extremely low-jitter tunable sample clock generator
  • Dedicated clock frequency diagnostic hardware
  • Multiple-board audio data routing and sync
  • Two LStream™ ports support 8 additional I/O channels each
  • Compatible with LStream modules for ADAT and AES/EBU standards
  • Zero-wait state, 16-channel, scatter-gather DMA engine
  • Windows 2000/XP/XPx64/Seven/Eight/Vista/Vistax64: MME, ASIO 2.0, WDM, DirectSound, Direct Kernel Streaming and GSIF
  • Macintosh OSX: CoreAudio (10.4)
  • Linux, FreeBSD: OSS
  • RoHS Compliant
  • Optional LStream Expansion Module LS-ADAT: provides sixteen-channel 24-bit ADAT optical I/O (Internal)
  • Optional LStream Expansion Module LS-AES: provides eight-channel 24-bit/96kHz AES/EBU or S/PDIF digital I/O (Internal)

Audio Science makes several different sound cards, which are used in BSI and others in automation systems.  These cards run about $675 each.

Audio Science ASI 5020 professional sound card

Audio Science ASI 5020 professional sound card


  • 6 stereo streams of playback into 2 stereo outputs
  • 4 stereo streams of record from 2 stereo inputs
  • PCM format with sample rates to 192kHz
  • Balanced stereo analog I/O with levels to +24dBu
  • 24bit ADC and DAC with 110dB DNR and 0.0015% THD+N
  • SoundGuard™ transient voltage suppression on all I/O
  • Short length PCI format (6.6 inches/168mm)
  • Up to 4 cards in one system
  • Windows 2000, XP and Linux software drivers available.

There are several other cards and card manufactures which do not use balanced audio.  These cards can be used with caution, but it is not recommended in high RF environments like transmitter sites or studios located at transmitter sites.  Appropriate measures for converting audio from balanced to unbalanced must be observed.

Further, there are many ethersound systems coming into the product pipeline which convert audio directly to TCP/IP for routing over an ethernet 802.x based network.  These systems are coming down in price and are being looked at more favorably by broadcast groups.  This is the future of broadcast audio.

OET65? What is that?

Readers of this blog will know that I enjoy history.  Old photos are great things to study, as they say, picture… thousand words… etc.  Here is one that I found on the RadioMarine website:

WER radio, 192X?

WER radio, 192X?

Here we have three gentlemen at work at an early radio station.  It seems like a posed shot, nobody can study a meter that intently.  They are sitting directly in front of the transmitter and it looks like the antenna tuning coils are behind the operating position.  Notice the open wire and transmission line, presumably all under power when this picture was taken.  There seems to be no concern about RF or electrical safety, I suppose it was trial and error back then, with a heavy price paid for error.  Meter boy should be careful not to back up too far, if he does, he’ll get a little behind in his work.

We’ve been a little busy this last week, I’ll catch up on the blogging this weekend, there are many things to tell.

Friday Funnies

Thought I’d bring them back:

Via xkcd

2017 called, but I couldn’t understand what they were saying over all the screams.

Michael Copps Talks the Talk

The rest remains to be seen, of course.  I found this speech given by Commissioner Copps on April 9, at the National Conference for Media Reform in Boston, MA interesting.  He gets this part exactly right:

We see investigative journalism on the endangered species list, hundreds of newsrooms shuttered, reporters fired by the thousands, walking the street looking for a job instead of a story. And it didn’t start with the Internet because the process of media being high-jacked by the profit-at-all cost gang has been going on for decades. For the consolidated owners of radio and TV, the license to broadcast became a license to despoil. Visions of sugarplums danced in their heads–spectrum that belonged, they decided, to them rather than to the people.

And this:

Left to their own devices, these absentee landlords would put local and independent programming on a starvation
diet and feed us instead monotonous homogenized music and mindless infotainment masquerading as “news.”

And that has already happened in many places.  The issue with traditional media in general is that the public can smell a rat.  Watered down, syndicated “news” whether on the TV, radio, newspaper or news-magazine is not fooling anybody.  When he was the president, Bill Clinton chided the American public for being cynical.  I’d suggest that it wasn’t cynicism but fatigue due to lies.  The degree to which licensees have ceded control of their stations to bankster masters is not known.  I would hazard that it is far more common than not.

To some extent, “new media” has filled the vacuum.  People in search of information and things they have, in the past, found on radio and TV now look to the internet.  Youtube has become the launching platform for new music.  News from all over the world is available with the click of a mouse.  The problem with the internet is miss-information, either by ignorance or design.  The other issue is it can be hard to come upon local news.  I can read all about the tsunami in Japan, but try and find out what happened at the local school board meeting, good luck with that.

The question is; how to unscrew this mess, return competitive and credible media to this country.  Further, this should be done without increasing administrative burden to licensees or increased enforcement and other expenses to the FCC.  It should be a simple idea, like requiring a certain number of programming hours be live, from the main studio, putting the main studio back within the city grade contour, beginning to walk back the ownership limits, etc. The FCC is going to have to have the wherewithal to carry through.  In this day and age of political expediency, wherewithal seems to be in short supply.

So, we’ve at least acknowledged the problem, now back to the fiddling.

Mouser Mobile edition

Mouser Electronics has created a mobile web edition to their online store. This is a handy tool for searching, cross referencing and ordering parts.  Mouser has a large stock and they ship quickly.  Time once was that you could run down to the local electronics store and get just about anything you needed.  Even Radio Shack carried a fair amount of small parts, tools, connectors and so on.  Since then, the local electronics shop has closed and Radio Shack inventory gets smaller every year.  Using a large parts supply company like Mouser or Allied is necessary if any type of trouble shooting and repair is undertaken.

I like the Mouser Mobile site because there is no app to download and install.  One simply points the web browser on any mobile device to mouser.com and it will automatically redirect to the mobile site.  If that does not work, then m.mouser.com will.   The mobile website is easy to browse around, and if needed, a quick call can be made by hitting the little phone icon.  Here is more in a video:

Radio Before Broadcasting

Before anyone ever though to click a mouse and play the latest Ke$ha “song,” or spin Stairway to Heaven for the millionth time, radio was used for a different purpose.  Early radio was developed to transmit messages between ship and shore or between continents.  Radio apparatus consisted of spark gap transmitters, which were very simple devices only suitable for sending Morse code.  Some did experiment with voice modulation methods, but the quality was poor.  It was not until Lee Deforest developed the vacuum tube that the state of the electronics art was capable of transmitting voice and music.

ATT developed AM (amplitude modulation) for point to point long distance service over high frequency radio circuit.  This is how early inter continental long distance phone service was first established.  In fact, up until the early 1970’s much of the long distance telephone traffic was routed via high frequency stations like WOO, WOM and KMI to Europe and Asia.  It was this development that allowed Ham Radio operators to begin transmitting music and other programming to their neighbors and the idea of broadcasting was born.

The Coastal Radio stations that for years transmitted and received messages from ships and sea, transmitted navigation warnings, weather broadcasts, news and responded to distress calls have all but faded away.  The operators of those stations often become nostalgic with the memory of sitting in a small room late at night straining to hear what might be faint SOS call under all the other chirping CW notes.  Successfully “working” a distress call is considered the pinnacle of a shore operator’s career.  High Frequency Continuous Wave (HF CW)(Continuous Wave is the technical description of Morse code modulation) has several distinct advantages for distress work.  A small signal can travel long distances and still be well received.  The average life boat CW transmitter had 5 watt output and often they could be heard across an ocean, 1,000 miles away.

I put together a few lists of these Coastal (ship to shore) radio stations.  The first are commercial public stations, these were responsible for sending message traffic to and from ships at sea.  They often had other purposes like transmitting signals point to point or High Seas Telephone service.  High Seas Telephone is just the way it sounds, persons on board a vessel at sea could place a telephone call.  It was hugely expensive and was replaced by INMARSAT, which is only moderately expensive.

Call Sign Location Owner Services Notes
KFS Palo Alto, CA Federal Telegraph/ITT Coastal Sold to globe wireless, ceased operation 7/12/1999
KPH, KET (point to point) Pt. Reyes, CA RCA/MCI Coastal, point to point Sold to globe wireless ceased operation 7/1/1997
KLB Seattle, WA ShipComm, LLC Coastal In service
KMI Dixon, CA ATT Coastal, High seas phone service Ceased operation 10/8/1999
KSM Pt. Reyes, CA MRHS Coastal In service
WBL Buffalo, NY RCA Coastal (Great Lakes) Ceased operation 1984
WNU Slidell, LA Coastal Sold to globe wireless ceased operation 7/12/1999
WLC Rogers City, MI United States Steel Coastal (Great Lakes) Ceased operation 1997
WCC Chathem, MA RCA/MCI Coastal Sold to globe wireless ceased operation 1997
WLO Mobile, AL ShipComm, LLC Coastal, (oil rigs) In service
WOO, WDT (point to point) Toms River/Ocean Gate, NJ ATT Coastal, High Seas and point to point Ceased operation 10/8/1999
WOM Pennsuco, FL ATT Coastal, high seas phone service Ceased operation 10/8/1999
WSC Tuckerton, NJ RCA/MCI Coastal Ceased operation 1978
WSL Brentwood, Sayville, Southhampton, Amagansett, NY Federal Telegraph/ITT Coastal, point to point Ceased operation 1984

This is by no means an inclusive list as at one time there were hundreds of these stations licensed to the US.  There were many inland stations on the Great Lakes and rivers.  These are the most common ones that I’ve heard, heard of and or seen personally.


Most people mark the end of commercial Morse Code as July 13, 1999.  There is, however, one station, KSM, which still is open as a public coastal station.  That station is a part of the Maritime Radio Historical Society, which operates from the former KPH facilities in Pt. Reyes, California.  KPH suspended operations in July, 1997 while other station continued on for the next two years.

Rectifiers from PW-15 transmitter, courtesy of MRHS

Mercury Vapor Rectifiers from PW-15 transmitter, courtesy of MRHS

Press Wireless was a company used by newspapers to transmit articles and pictures. They developed their own transmitters and operated point to point sites in Hicksville, NY and San Francisco, CA. A few of their transmitters survive today at KPH.

RCA H series HF transmitter, courtesy of MRHS

RCA H series HF transmitter, courtesy of MRHS

The 1950s H and K RCA HF transmitters were built to last. The carrier power is 10 KW and can be used for CW, SSB, and RTTY.

KPH is the best preserved Coastal Station, when the facility closed down in 1997, the US Park Service took ownership and left it mostly untouched.  In 2004 volunteers and former station employees began to restore the equipment to operation.  Eventually, these efforts led to the licensure of KSM, the only operating commercial CW station in the US.  KSM uses restored donated equipment from KPH and KFS.  Restoration work continues and if I lived closer, I’d volunteer my services.  MRHS also operates amateur radio station K6KPH.


Other facilities survive in parts, the former WOO is home to the  Tesla Radio Foundation and Museum.  Anyone that knows anything about radio will recognize Tesla as one of the founding fathers, perhaps much more so than Marconi, who often gets more credit than is due.  During it’s day, this was a huge facility, connecting North America with Europe, Africa, South America and Asia.  Point to Point service included programming relays for the VOA, Long Distance phone service and so on.

WOO transmitter floor, courtesy of Tesla Foundation

WOO transmitter floor, courtesy of Tesla Foundation

ATT seemed to use the same design for their HF sites, the buildings at KMI, WOO and WOM all look alike, right down to the brown/yellow tile floors.

WOO transmitter, courtesy of Tesla Foundation

WOO (PW-15 ?) transmitter, courtesy of Tesla Foundation

Again, this facility was restored through the hard work of Radio Amateurs.  Unfortunately, unlike KPH, the old CW transmitters where scavenged for parts and none where restorable.

WOO antenna switching matrix

WOO antenna switching matrix

All of the transmitters were routed to this antenna switching matrix.  As you can plainly see, there were many, many antennas at this facility.  There were also several types, rhombics, verticals, inverted cones, etc.  They were (some still are) located in a tidal swamp.  From this matrix, with a few exceptions, the transmission lines were routed through BALUNs which then fed open wire transmission lines.

WOO Ocean Gate Radio transmission lines

WOO Ocean Gate Radio transmission lines

These lines went to various antenna fields pointed at Europe, South America, Asia and Africa.


The former WCC receiver site is now home to the Chatham Marconi Maritime Center and has the amateur radio call sign WA1WCC.  This is a museum that is open to public.  The town of Chatham, with donations from Qualcomm and Verizon, has endeavoured rehabilitate the old receiver site and operations building.  They have spent a fair sum of money on replacing plumbing, fixing the driveway and other necessary work to turn the site into a historical attraction and provide a center for Science, Technology, Engineering, and Mathematics (STEM) on Cape Cod.

WCC transmitting antenna, South Chatham, MA courtesy MHRS

WCC transmitting antenna, South Chatham, MA courtesy MHRS

We used to go to the public beach right next to this radio tower.  It looks like a Milliken tower similar to WICC ‘s towers in Bridgeport. I believe the transmitter site in South Chatham was bulldozed and turned into a wild life refuge.

WLO and KLB are in service with HF voice and SITOR, PACTOR and AMTOR modes but not CW.  These stations are operated by ShipCom, LLC.

Coast Guard Maritime Radio

The US Coast Guard operated a network of Coastal Radio stations as well.  These where to communicate with Coast Guard vessels and aircraft but also interfaced with civilian shipping.  They stretched up and down the east and west coasts, covered Alaska, Hawaii and territories like Puerto Rico and Guam.  They ceased CW operations in 1995 and are remotely operated by the two surviving stations, NMC at Pt. Reyes and NMN in Portsmouth, VA.

Call Sign Location Services CW close date Disposition
NMA Miami, FL Limited Coastal, Military 1/4/1995 Remoted to NMN Portsmouth, VA
NMC Pt. Reyes, CA Limited Coastal, Military 1/4/1995 In service GMDSS
NMF Boston, MA Limited Coastal, Military 1/4/1995 Remoted to NMN, Portsmouth, VA
NMG New Orleans, LA Limited Coastal, Military 1/4/1995 Remoted to NMN, Portsmouth, VA
NMO Honolulu, HI Limited Coastal, Military, Point to Point 1/4/1995 Remoted to NMC, Pt. Reyes, CA
NMQ Long Beach, CA Limited Coastal, Military 1980 Closed
NMN Portsmouth, VA Limited Coastal, Military 1/4/1995 In service GMDSS
NMP Chicago, IL Limited Coastal, Military 1975 Closed
NMR San Juan, PR Limited Coastal, Military 1986 Closed
NOJ Kodiak, AK Coastal, Military, Point to point 1/4/1995 In service, GMDSS
NRT Yokota, JP Point to point N/A Closed 1992
NRV Barrigada, GU Coastal, Military, Point to point 1993 Remoted to NMO in 1992, then to NMC in 1995

This is by no means a complete list, there are several more stations that existed but were closed by the mid 1970’s.

GMDSS is the Global Maritime Distress and Safety System, an automated system consisting of satellites and HF radio that replaced the use of manned listening watches on ship and shore.  A few years ago, the Coast Guard explored eliminating HF services all together, however the public outcry was loud and vigorous, thus they didn’t carry through with the plan.  Even so, the voice weather and navigation broadcasts are computer generated simulated human voices, which are not a good as the real thing, in this former operator’s humble opinion.

Unlike their civilian counterparts, most of these stations where disposed of without ceremony when they were turned off.  Some former Coast Guard Radio Stations were sold off for land, others which were part of existing bases, were dismantled.  The only exception to this is the remnant of NMY (New York) on fire island, now administered by the National Parks Service.

There are a fair number of former Coast Guard radio operators with fond memories of working at these places and the satisfaction of a job well done.

If you are interested in history, check out those sites and or pay them a visit if in the neighborhood.  You may learn something you didn’t know before.


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