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By Paul Thurst, on May 11th, 2012
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 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 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 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 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.
By Paul Thurst, on May 10th, 2012
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.
By Paul Thurst, on May 7th, 2012
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.
By Paul Thurst, on May 7th, 2012
The FCC reverses it’s former position on EAS text to speech, permitting stations to begin using it today (May 7, 2012). The FCC’s main issue with Text To Speech (TTS) was that it may not render the text accurately enough to be understood, especially in emergencies. This can lead to confusing messages and defeat the purpose of EAS altogether.
I have played around with some text to speech software and indeed it can mangle words, mispronounce punctuation as a part of the sentence structure, mumble, etc. Further, as I have said before, listening to some robo voice is very impersonal. But, I suppose that is the point, isn’t it; some big government agency computers generating messages that no one person is really responsible for. Bureaucratic paradise.
By Paul Thurst, on May 3rd, 2012
It is surprising to me how many times I have seen this done incorrectly in the field. Summing a stereo source, whether it is balanced or unbalanced is not simply twisting a couple of wires together. This will effectively reduce the impedance of the outputs by one half. With newer, active balanced outputs, this may cause damage to the output amplifiers.
The parallel resistance formula is thus:
Therefore a 600 ohm stereo output tied together would look like:
Rt = 1/(1/600+1/600) or 300 ohms.
It also creates an impedance mismatch with the next piece of gear, which will effect the common mode noise rejection of the circuit.
The best way to sum is through a resistive network. That way stereo separation is maintained, the impedance of the output circuits is maintained and the output amplifier will not current cycle. That looks like this:
 resistive summing network Pretty easy to fabricate in the field. It is good to do things the right way, it sounds better on the air too.
By Paul Thurst, on May 2nd, 2012
 A potential LPFM (Low Power FM) filing window may be opening up as soon October/November. There is nothing official from the FCC about the date, however, several insiders have suggested that this is on the fast track and it may happen sooner rather than later.
This will likely be the last chance for community radio operators to get a LPFM license, as after this filing window, every available scrap of spectrum will have a translator shoe horned into it. Therefore, now is the time to do some research and get prepared.
To that end, there are two good LPFM channel finders that can be used to determine if a LPFM station can be put on the air. The first is the FCC’s official LPFM channel finder. For this tool, one will need to know the latitude and longitude of the proposed transmitter site. That information can be obtained from itouchmap.com, with which one can find the lat/long of any point on the face of the earth.
The second LPFM channel finder is from REC networks. This tool is a much more flexible. For finding possible transmitter location, a street address, zip code, or lat/long can be used. It also has much more information as it has a provision to use the proposed 250 watt station class and shows every available channel as well as possible available second adjacent channels.
Prometheus radio has a simpler zip code check, which does not give any technical information, it simply states that LPFM channels are available at the zip code which was entered. Prometheus has good primers on how to start and operate a LPFM station.
If you are a member of a group considering starting a community radio station, now is the time to get going.
By Paul Thurst, on May 1st, 2012
When they sold their Broadcast Equipment supply division to SCMS a few years ago, the handwriting was on the wall. Even so, it is a little surprising that they would exit broadcasting altogether.
The decision to divest in no way reflects the quality of the work Broadcast Communications performed in support of our customers and our company. Harris simply determined that Broadcast Communications could provide higher value and operate more effectively under a different ownership model.
They are spinning the broadcast division off to a new owner rather than completely shutting down the operation. In an e-mail received from Harris Morris, President, Broadcast Communications Division, clients and customers will still receive support for existing products:
In the interim, Broadcast Communications will continue to be a part of Harris Corporation and operate business as usual. Our valued relationships, both longstanding and new, remain our top priority. The global Broadcast Communications team will continue to work diligently to ensure our commitment to our customers and partners remains steadfast, our execution to fulfill commitments is flawless, and our progress against strategic objectives remains focused.
Well, there you have it. This effects such things as Harris transmitters (AM, FM, TV, HF) and support, Harris consoles and studio furniture (previously Pacific Recorders and Engineering or Pacific Research and Engineering, AKA PR&E), Intraplex STL systems, among others.
What does all this say about the future of terrestrial broadcasting?
We live in interesting times.
By Paul Thurst, on April 30th, 2012
This is a neat piece of kit, designed to save those late night/early morning call outs, which is the ultimate goal of all broadcast engineers, or at least it should be. This seems like a really good idea, however, BE has discontinued the product line, the last manual update is from 2000.
 Broadcast Electronics FW-30 exciter switcher innards A small four port coax switch is located next to the power supply transformer. This is controlled by the circuit board. The circuit board senses loss of excitation by detecting a forward power level below the threshold set on the board. The power sample comes from the exciter forward power remote metering terminals. Thus, it can be used with any exciter(s) that have a remote forward power sample.
 BE FW30 exciter switcher block diagram The idea is to use the RF fault function output of the FX-30 (later FX-50) exciter to automatically switch from a faulted exciter to one that is working. Finally, it can be hooked to a remote control for manual switching. The un-used exciter is muted and routed to a dummy load mounted on the back of the unit.
 Broadcast Electronics FW-30 front, mid 1980's BE blue An alternate configuration would be to route the backup exciter to the backup transmitter instead of the dummy load. This would create the best redundancy on a limited equipment budget. It also has a battery bank designed to hold the last state of the unit through a power outage. As we have a good sized UPS powering the remote control, STLs and satellite receivers, the batteries are not needed.
On the face of it, a pretty good idea. I have had a few exciters fail over the years, which normally means the backup transmitter is placed in service by remote.
I did download the manual, but since it is currently listed on the BE website, it’s probably not a good idea to post the schematic. Suffice to say, it is a tad bit complicated what with all the CMOS logic and that. It is very possible to duplicate the functions of this equipment with a simple RF forward power sample and set a failure threshold with a comparator circuit. Hook that to a small four port coax switch and a couple of RF mute/un-mute commands to each exciter and: Viola! Automatic exciter switching!
Perhaps a good rainy day project.
By Paul Thurst, on April 27th, 2012
Not really a technical thing, but is something that I have to deal with as a self employed contractor. The big change for me between being an employee versus someone who is self employed is the amount of driving I do on a day to day basis. The group of engineers that I work with cover an area from New York City all the way up to the Canadian boarder. On any given day, I can be in Bridgeport CT or Albany, NY or Burlington, VT or White Plains, NY. The miles pile up quickly.
While out driving around, I get to see many new things. For example, yesterday I drove by the County Sheriff’s car:
 County Sheriff's department armored vehicle, courtesy of NorthJersey.com Something has changed, but I can’t quite put my finger on it.
The fact that I drive so many miles means that there will almost certainly be some interaction with local law enforcement, especially on that late night trip to or from a transmitter site. As one State Trooper once put it, nothing good happens after 11pm, which seemed to be enough to trigger reasonable suspicion and a traffic stop.
Of course, the police officers executing traffic stops are doing their jobs and the best course of action is cooperate and maintain a polite, professional disposition. Usually, a traffic stop goes something like this:
While driving down the road, you notice a police car behind you. At some point, the lights will come on and you pull over, the police car pulls up behind you. At this point, you roll down the driver side window, put the car in park (or neutral) and turn off the engine. Do not start rooting around for the registration, get out your wallet, unlatch your seat belt or anything else, just sit there. The police officer will run your plate, which may take a few minutes. Then, after some period of time, he (or she) will get out of the police car and approach your vehicle on the driver’s side. When you see him approach, place both hands on the steering wheel, so that he (or she) can see them. The exchange will go something like this:
Police officer: Do you know why I pulled you over?
Yourself: No, I do not. (That is always the reply, even if you have a good idea why you were pulled over)
PO: You were (speeding, running a stop sign, red light or the general crossing road lines, unable to maintain lanes, unsafe lane change, etc) (fill in the blank).
Yourself: I was not aware of that.
From here, the interaction can take any number of routes; you may be able to explain what was going on, he may let you off with a warning, or you may get a ticket. As the driver, you will have to gauge the situation. Many times, I have found the best course is to explain that you are a radio (or TV) engineer on your way to or from some specific emergency somewhere. Many times, this will be enough, so long as the police officer does not suspect you of drinking or something similar.
Other times, the generic “you crossed the white (or yellow) line” will be used a fishing expedition and he is looking for drunk driving, warrants, drugs or something else to arrest you for. The most important thing to remember is not to give him that reason.
The police officer will ask you for your license and registration, he may ask you to step out of the car, take a field sobriety test, ask questions about items in the car, etc. Answer the specific question and no more, do not get chatty, volunteer information, etc.
If a traffic citation is issued, follow the directions, mail it in on time and plead not guilty. Some form of trial will take place, often, before the proceeding, the prosecuting attorney or police officer will approach you and offer a plea to some lesser charge. To avoid wasting a lot of time on a trial, make the best deal possible and pay the fine.
On the other hand, if there is time to spare, go ahead with the trial. There are many ways to get out of a speeding ticket, especially if RADAR was used in the traffic stop. The law of sines is a good way to shoot holes in a police officer’s RADAR testimony. I like this one, because, in order for RADAR to be accurate, the measurement must be taken from dead ahead. Any angle to either side and the relative speed of the vehicle to the RADAR gun is reduced as a function of the sine of the angle. The greater the angle, the less the relative speed. Other things like calibration procedures (which can be checked), last time the instrument was calibrated, time interval between the use of the RADAR gun and passage of vehicle(s), did the police officer loose sight of your vehicle, etc.
I have gone to trial twice for speeding tickets, lost one because the system was rigged (this was on Guam) and won the other because the police officer lost sight of my vehicle while he turned around to catch me. That was on a back road, where there were multiple places to enter or exit the roadway and I was something like two miles away from the point of the infraction.
With any profession that requires a lot of driving, especially late at night, some interaction with local law enforcement will take place. Be polite, use common sense, be professional, don’t take any shit but don’t create any bigger problems either.
By Paul Thurst, on April 26th, 2012
The old version of the software, that is. I like the graphical interface, just one glance is all that is needed:
 Burk auto pilot I have not had a chance to fool around with the newer version, the screen shots on the Burk website look a little bit different.
The set up and programming of macros is pretty easy; power/pattern change times, Pre-sunrise, post sunset functions, automatic tower light monitoring, AM Directional Antenna readings, and automatic transmitter restoration routines. If programmed correctly, the software can eliminate many of those late night/early morning phone calls, which is always a good goal.
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Axiom
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
Those who would give up essential liberty to purchase a little temporary safety, deserve neither Liberty nor Safety.
~Benjamin Franklin
...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
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
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Heard in the clear