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Studio renovation, WBLI

A quick humorous video shot by the staff of WBLI, Patchogue, (Long Island) NY. I was personally not involved with this. The old console looks like a PRE (or Harris) Airwave. I did not see the new console.

h/t Skywalker

Do radio transmitters have the capability of electrocuting copper thieves?

I found that question while perusing my search engine statistics today.  The short answer in theory is yes.  If you are a copper thief, it will most likely look like this:

That being the case, however, it is much more likely that an RF burn will result if one comes in contact with an energized antenna or transmission line.  Even small RF burns are painful, large ones can be nasty things.  RF burns occur because of the skin effect, that is to say, the higher the frequency of the AC waveform, the closer to the surface of any given conductor the current will flow.  It is the reason why five watt STL transmitters on 950 MHz use 7/8 or 1 5/8 inch cable to reduce losses.

When a human body part comes in contact with an energized RF antenna, the body part becomes part of the circuit, thus it follows the same principals.  The extremity that is making contact will have its skin burned off.  It also smells bad.

Getting an RF burn is a painful lesson on what not to come in contact with around a transmitter site.  But, that is not all.  Simply being in close proximity to radiating elements of antennas will induce body tissue heating, just like a microwave oven.  This can lead to all sorts of short term and long term damage to organs and other problems.

Therefore, the best thing is to avoid radio and cellular towers if you do not know what you are doing.   Stay out of fenced in areas around tower bases.  No matter how tempting that copper may look, you could be seriously injured or killed if you cut the wrong thing.

The Telos NX-12 Talkshow phone system

I have worked with my Telos telephone interfaces in various studios. They are well designed and intuitively designed pieces of equipment. The Telos NX-12 is no different.  The first thing different about this telephone system is the web interface.  I have commented before on this; eventually all broadcast equipment will have some type of http interface.  For configuration and monitoring, it makes life much simpler.

Telos’ NX-12 web interface allows the users to define phone lines, call directors and studios:

Telos NX-12 http interface

Telos NX-12 http interface

The NX-12 itself is just a box residing in the rack room.  This is where all of the pots lines or the PRI-ISDN line is installed, firewire, network interface, etc.

The studio end is the call director, which is connected to the NX-12 by a cat 5 cable.  There can be up to four call directors per NX-12.

The nice thing about the NX-12 is that the hybrid can be split into completely separate units, thus one NX-12 can be used for two separate stations, each with up to six lines.  Splitting the hybrid thus requires the use of Firewire or the unit must have an AES card.

This particular unit was installed at WFAS-AM/FM in White Plains, NY.

The General Electric XT-1-A AM transmitter

I found this photograph in a filing cabinet the other day as a part of a sales proposal dated 1948. I have never seen one of these in the field. They look like very sturdy units:

General Electric XT-1-A Standard Broadcast transmitter

General Electric XT-1-A Standard Broadcast transmitter

Back in the day when AM was king, no expense was spared on transmitting equipment.  I remember the GE BTA-25 transmitter from the same era, it was build like a tank.  Once, while we were repairing the Harris MW-50A main transmitter, the old GE burped, sputtered and threw an IPA overload, then returned to air.  I looked in the IPA cabinet and found a mica capacitor had been blown in half.  It was in the tuning circuit, but apparently there was still enough capacitance in the circuit for the transmitter to keep running.

This unit looks similar to that one.  The simplified schematic:

General Electric XT-1-A schematic diagram

General Electric XT-1-A schematic diagram

Like other 1 KW AM transmitter designs, this unit uses the venerable 833A triode.  There are some advantages of this tube, as extra circuits for PA stage neutralization are not needed.  The full sales brochure can be found here (medium sized .pdf).  These were manufactured in Syracuse, NY.

The asking price in 1948 was $8.730.00, tax and shipping extra.

The PIROD PRLC-A tower lighting controller

PIROD tower company has been around for a while, thus there are likely many of these tower light controllers out in the field.  They perform a vital service in controlling and monitoring tower lights at remote transmitter sites maintaining a safe operating environment for aircraft and compliance with FCC rules.

PIROD was sold to Valmont in 2004, Valmont no longer manufactures or supports the product.  All is not lost, however, as XCEL Tower Controls does support it and parts are still available through them.

These units were fairly rugged, had good surge suppression on the incoming AC lines and are designed for easy access to service parts.

PIROD PRLCA tower light controller, WRKI Brookfield, CT

PIROD PRLCA tower light controller, WRKI Brookfield, CT

This particular controller is being installed at WRKI in Brookfield, CT.  We are adding toroid cores to the tower lighting circuits coming off of the tower because the last controller has been mostly destroyed by lightning.  It is a tall tower, on top of a tall hill, thus it gets struck by lightning many times over the course of a year.

WRKI tower, Brookfield, CT

WRKI tower, Brookfield, CT

The block diagram looks like this:

PIROD PRLCA block diagram

PIROD PRLCA block diagram

Click for higher resolution.

The basic schematic looks like this:

PRCLA tower light controller schematic

PRCLA tower light controller schematic

Click for higher resolution.

The entire manual can be found here, (medium sized .pdf) courtesy of John Brickley of EXEL tower controllers.

The Rabbit Hole

The internet is a wonderful technical achievement. It has truly changed the course of human history in ways incalculable. The amount of information available to anyone with access is simply astounding.  Then there is this:

Demotivator

Demotivator

I am supposed to be doing research for my technical writing class, but I keep getting sucked back in. Some of these are quite funny:

Demotivator

Demotivator

GAH! Someday, if I could figure out how to get that cloaking device to work, I would like to seek into all those conference rooms and replace the standard issue motivational poster with this one:

Standard issue demotivator

Standard issue demotivator

And the minutes still tick by, with my paper undone.  These are from despair.com,

Demotivator

Demotivator

The professor is going to have my butt.

It has been relatively light blogging these last few weeks, for several reasons; some of them obvious, some of them not so much.

WVTQ Mount Equinox, Vermont

The transmitter for Vermont Public Radio, WVTQ 95.1Sudbury is located on Mount Equinox, near Manchester Vermont.  Mount Equinox is one of the better mountain top transmitter sites to get to as it has a good access road, no jeep trails through the woods or ski lifts, etc.  The Summit is 3,580 feet (1,175 m), which is the third highest peak in the green mountains.  On a nice day, the view from the top is spectacular:

South view, Mount Equinox, Vermont

South view, Mount Equinox, Vermont

The southern view with US Route 7 cutting through the valley below.

WVTQ is a part of VPR’s classical music network.  They had a Nautel VS-1000 that had developed issues with the directional coupler.  This unit was repaired and re-installed:

WVTQ Nautel VS-1000 transmitter, Mount Equinox, Vermont

WVTQ Nautel VS-1000 transmitter, Mount Equinox, Vermont

The transmitter has a 7/8 EIA flange on the back, which had an elbow, then an adapter to a type N connector all unsupported. My boss felt that perhaps that perhaps too much weight on the EIA flange caused the crack in the directional coupler.

WVTQ transmitter racks and STL equipment

WVTQ transmitter racks and STL equipment

The transmitter site used to be in the basement of the hotel, but as that building no longer exists, it was moved over to the former RADAR site.  The RADAR site consists of four 80 foot towers arranged in a square around a building.  These towers now support two way radio equipment and the like

WVTQ transmitter site, Mount Equinox, Vermont

WVTQ transmitter site, Mount Equinox, Vermont

Finer points of GPS antennas

Finer points of GPS antennas

Your author (left) with Rich Parker of VPR discussing the finer points of GPS antennas.

Stairway to heaven

Stairway to heaven

Ladder to the top of one of the towers.

Hang Glider's view, east side pulloff, Mount Equinox, Vermont

Hang Glider's view, east side pulloff, Mount Equinox, Vermont

View from the turn off on the east side of Skyline Drive.  Known as “hang glider’s view” with good reason.  This is on the saddle that connects little Equinox with big Equinox.

On a nice day, such as yesterday, it is very pleasant.  When the road is covered in ice and snow, not so much.

The XDS satellite receiver

I remember, back in the day, when we all used Scientific Atlanta 7300 satellite receivers. There were two flavors of decoder cards; DATS and SEDAT.  Starting about 1982 or so, satellite distribution of network audio was a quantum leap over the old TELCO circuits used previously.  The use of satellite downlinks allowed radio stations to receive an almost unlimited number of programs from every network under the sun.

The SA 7300 receivers gradually gave way to the SA 3640, which gave way to the Starguide, Starguide II and Starguide III series which finally lead to the XDS and MAX receivers used today.

XDS satellite receivers

XDS satellite receivers

The newest generation satellite receivers are yet another quantum leap over the last, with on board hard drive storage that allows time shifting of entire shows.  Another nice thing is the web interface.  Before you know it, everything in the broadcast plant will have a web interface.

The one issue I have had with nearly every single XDS receiver is the fan going bad.  The manufacture must have laid into a supply of defective fans.  A bad fan is noted with the fault light turns red and the unit will return a “Fan stopped” error message.  The network will send a replacement fan if you let them know.  I have carefully replaced several of these fans without turning the receiver off.

Otherwise, the web interface is pretty intuitive.  Drop down menus allow for programming the audio ports on the receiver and setting up the delayed recording and playback function.

XDS satellite receiver weekly programming grid

XDS satellite receiver weekly programming grid

Any required network closures are configured in the relay screen.  The programming clock provided by the network will specify which relays are used for each show.

XDS relay maping screen

XDS relay maping screen

Each receiver has two DB-37 connectors that have 16 relays each for a total of 32 output closures.  That should be enough to cover almost any programming situation.

Finally, the receiver’s overall operating condition can be monitored via the health screen:

XDS satellite receiver health screen

XDS satellite receiver health screen

Something like this can greatly speed up any remote diagnostic trouble shooting by eliminating (or pinpointing) a satellite system failure as the reason for a station being off the air.  I also make sure that all automation systems have some type of remote access like VNC so that I don’t have to needlessly drive to the studio to fix a silly computer problem.

Then there is one more neat tool, for those XDS receivers that do not have any front panel user controls (one certain network uses these), called the “XDS discovery tool.”  I have found this bit of software to be very helpful from time to time.

Studying for final exams this week

My apologies to the regular readers here. I have been busy studying, working, and managing family life.  The good news is my last final exam is this afternoon.  Even better news, the next semester is starting on May 22nd, during which I will be taking English 227, which is a Technical Writing course.  It is my hope that you all will be benefiting from my labor.

Electronic death

Good audio clip below of the WIYY’s (Rock 98, Baltimore) console melting down during the morning show.  These things happen from time to time. I often found, when it happened at one the stations I was working for, nobody would know anything about it. Nope. Just stopped working. What? No, I don’t know anything about the coffee dripping out of the bottom of the console.

Rock 98, (WIYY) Baltimore, coffee spilled into console courtesy of the Baltimore Sun.

If that link doesn’t work, try this one (7MB .mp3 file).

Pictures and stuff at their facebook page.

Off the air for twenty minutes during morning drive.  I wonder what kind of console it was?  From the pictures on facebook, it looks like Wheatstone stuff.  Ouch! That’s going to leave a mark.

I tried to enforce a no eating no drinking in the studio rule.  Most of the time I was successful, however, there were various incidents over the years.  The worst was the morning show spilling “distilled water” in the console, but not saying anything about it.  Months later, the air monitor stopped muting when the main mic was turned on. Nearly caused the guy who did the spilling to loose his hearing.  Karma.

At another station, someone spilled soda on all the remote mic on/off/cough switches for the guest positions.  That prompted an early morning phone call, which the morning show producer yelled at me and told me I must be at the station in five minutes (I lived about 25 minutes away at the time).  Ha!  I took my sweet time getting there.  The soda cooked all the +5VDC regulators on the guest microphone modules, thus, for the next several days, all the morning show DJ’s had to share one microphone.

Old time radio guys will tell you, do not mess with the engineer.

Axiom


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

Free counters!