We have a few stations that are currently encoded with the Arbitron PPM encoders. I did a little research on the encoding method, since it is not immediately apparent how they are transmitting their data.
Arbitron PPM encoders
According to Wikipedia, which can sometimes be relied upon, Arbitron used Martin Marietta to help develop the technology. Martin Marietta (now Lockheed Martin) is mostly known as a defense contractor, they have helped develop several complex military communications systems over the years.
There are no fewer than 39 US patents that cover the technology used in the PPM. The most significant of these appears to be 7,316,025 which describes the psychoacoustic masking technique employed.
It really is pretty slick, using a sample rate of 8.192 kHz, it transmits 4 bits per second in the 300-3000 Hz range by hitting specific frequencies in that range at varying intervals, adapting to the audio levels to keep the encoding below the programming content. 4 BPS is very slow and thus very robust. After all, I believe the only formation transmitted is a six digit encoder serial number. I did not read all 39 patents to see if anything else was changed in the encoding method, so it may be slightly different.
This type of system would have fairly low overhead, not adding to the station’s bandwidth which is a consideration for FM stations, and in the correct frequency range for most AM receivers on the market today. Some people have said they have heard the encoding on one of our stations, most notably during silence or very quite programming. Perhaps, especially in a dead air situation, one might hear in nearly imperceptible low frequency slow fluttering sound.
If anything, the encoding is perhaps too robust.
Now for the deployment of the monitor technology, which has so many up in arms. As with other Arbitron ratings methods, the main bone of contention seems to be the size and distribution of the sampling hardware. Minority groups feel they are under represented because the PPM is unevenly distributed.
Ratings samples always seem to skew one way or another. The data samples themselves seem to be too small to accurately predict a station’s listenership. One anomaly and the entire month or quarter can be thrown off. The PPM seems to correct some if the issues with keeping an accurate written diary. One problem with the PPM however, it can also pick up incidental background noise and count it as time spent listening (TSL).
Think of the cubical environment where somebody several cubes away might be listening to a radio station. To the PPM wearer, it is unintelligible background noise, however, because of the perceptual encoding, the PPM picks it up and it counts as several hours of TSL.
A broader sample would dilute this with other more accurate representations of radio listening. A broader sample would also alleviate some of the complaints from the Minority Media and Telecommunications Council (MMTC). First year physics students would recognize that not enough sample data can make results wildly inaccurate. Or, as one emergency room doctor stated while washing my knee out with a liter of sterile water after a dirt bike accident, the solution to pollution is dilution.
In one of the better TV shows about radio, newsman Less Nessman reports live on the “WKRP Thanksgiving Turkey Drop give away”
Happy Thanksgiving – WKRP Turkey Drop – kewego http://www.sharkhost.com Happy Thanksgiving from Sharkhost.com! This is a blast from the past, WKRP in Cincinnati Famous Turkey Drop. Sharkhost does not own any copyright to this material. Web host, web design, marketing and promotion.
I always liked that show. “As god is my witness, I thought turkeys could fly!”
I tried to embed “Alice’s Restaurant” but you tube wouldn’t let me, so here is the link, if you haven’t heard it this year and are feeling so inclined.
The Senate seems to have it in their mind to release the LPFM genie from the bottle:
The Senate Commerce Committee unanimously approved a bill (Local Community Radio Act (S. 592)) today that would loosen regulations limiting low-power FM stations. It would abolish the third-adjacent minimum distance separation requirement except for stations that provide a radio reading service, as well as give FM translators and LPFMs equal access to spectrum. The House Commerce Committee has also cleared the bill.
The Local Community Radio Act (S. 592) official bill summary is:
3/12/2009–Introduced.Local Community Radio Act of 2009 – Repeals provisions in the Departments of Commerce, Justice, and State, the Judiciary, and Related Agencies Appropriations Act, 2001 that required the Federal Communications Commission (FCC) to: (1) modify rules authorizing the operation of low-power FM radio stations to prescribe minimum distance separations for third-adjacent channels; (2) prohibit applicants who have engaged in the unlicensed operation of any station from obtaining a low-power FM license; and (3) conduct a program to test whether low-power FM radio stations will result in harmful interference to existing FM radio stations if minimum distance separations for third-adjacent channels are not required. Requires the FCC to modify its rules to eliminate third-adjacent minimum distance separation requirements between specified stations. Requires the FCC to retain rules that provide third-adjacent channel protection for full-power noncommercial FM stations that broadcast radio reading services via a subcarrier frequency from potential low-power FM station interference. Requires the FCC, when licensing FM translator stations, to ensure that: (1) licenses are available to both FM translator stations and low-power FM stations; and (2) such decisions are made based on the needs of the local community.
I would add to that list; Must be on the air at least 50% of the time and no more than 50% of that time is automated. Why not? If this is supposed to spur local (community radio) what would be the point of a whole bunch of low power automated stations? Just more clutter in the FM band.
This is an EIMAC 4CX3500A which came out of a Harris HT5 transmitter. As you can see it the ceramic cracked in half. When I arrived at the transmitter site, the unit was on, full plate voltage, no plate current, no overload lights. I figured it might be something with the tube, so I tried to pull it out, but only the top half came. One of those “Ah ha” moments.
Fortunately, there was a working spare at the transmitter site and we got back on the air relatively quickly. That, in and of itself is amazing considering the building that this transmitter lived in. One of those abandond former studio sites with the transmitter jammed into a back room somewhere. To get to it, one has to dodge pigons, beware of rats and wade through piles of garbage.
It is a little bit hard to tell in this photograph, but there are to “cages” which are the Screen and Grid. The post in the center is the filament/cathode and the top detached part is the plate/anode. In an FM transmitter, the exciter is coupled to the grid, the screen accelerates electrons toward the plate and therefore controls the power, the plate collects the electrons and is coupled to the output stages and the antenna. Good stuff.
Behold, I do not work for Clear Channel. I do not work for Cumulus, or Citadel. The company I work for is not about to go bankrupt, in fact, we have purchased a brand new FM transmitter for the wretched mountain top transmitter site featured here.
Nautel V 7.5 FM transmitter
Am I happy? Oh yes I am. New transmitter = fewer midnight phone calls thus better quality of life for me and my family. A solid state Nautel transmitter means fewer unscheduled trips to the transmitter site and better reliability.
As a result of consolidation and smaller engineering departments, almost my entire work day is now scheduled weeks in advance. One little hiccup in the schedule can throw things off for days, resulting in many apologies, phone calls to reschedule, and general wasted time.
This is a V 7.5 FM transmitter, very likely the last V series transmitter Nautel ever makes. They have moved on to the NV series.
It is replacing the Broadcast Electronics FM5A, which is 24 years old. The BE has been a good transmitter, we lost a few rectifier stacks due to lightning over the years, but over all, it has been reliable and easy to repair when problems did arise. This transmitter will be going into standby service.
Very similar to a TiVo, only works with radios. There are some very good radio shows out there, the kind that make you sit in the car long after you have reached your destination. The kind that you might schedule your day around if possible.
A few of them are syndicated on NPR a few are locally produced, some are interesting talk, some are perspective, some are new music, etc.
Radio Shark Digital Audio Recording Device
Wouldn’t it be great if you could time shift those shows and listen to them when you wanted to? Imagine this, you know that “This American Life” is airs on Saturday afternoon and it is a favorite. However, this Saturday you are busy working or what ever. Go to the Radio Shark and program it to record your show, then listen to it later. What a concept.
What this unit does:
Plugs into PC or Mac USB port.
Has AM and FM receivers built in.
Can record programming and play back later, or pause programming and resume playback while recording.
What this unit does not do:
Not very portable, unless the user want to lug a lap top around.
Does not integrate into cars or other playback devices, such as I-pods, etc.
Does not record internet sources directly, although there are a few links to shareware on the Radio Shark website that will do this.
This is a start, but what is really needed is something that is factory installed in cars. Say the Digital Audio Recording Device (DARD) can be in installed in the car, or in the house, or both. Then each DARD has a flash drive that can be moved from one unit to another, but only played back in DARD units (to thwart pirating music). It can even be an I-pod app.
This is the type of new technology that will bring listeners to radio and make radio stations create good quality local content, stuff you can’t get anyplace else.
Why aren’t these being marketed? Heck, radio stations should be giving them to listeners, I bet you could even get them manufactured with station logos. Seems like an opportunity lost to embrace some meaningful, understandable, young technology.
Update: Okay, there are others out there as well. What needs to happen is all these features tied together and offered in stock car radios.
I recently got into an argument about the requirements for transmitter readings with a fellow engineer. Said fellow stated that transmitter readings need to be taken every three hours and that all operators needed to sign on and off the station log. Time was when those things were supposed to be done, that is true. I believe the rules have changed a little bit since he last read them. The current FCC rules (part 73.1820) state that the following items need to be in the station log:
Tower light malfunctions and repairs
Emergency Alert System (EAS) tests and activations
AM antenna field strength measurements (73.61) (monitor points)
The logs are to be reviewed and signed by the chief operator
The exception to this is AM stations without an FCC approved antenna sampling system, which indeed require readings on the antenna system every three hours. Most AM stations have an approved antenna sampling system.
If an AM station has an approved sampling system, it will be noted on the instrument of authorization (license).
For transmitter operations, a review of part 73.1350 shows that the licensees are responsible for insuring transmitting apparatus complies with all FCC regulations. Specifically:
73.1350 (b)(2)(c)The licensee must establish monitoring procedures and schedules for the station and the indicating instruments employed must comply with Sec. 73.1215.
And
73.1350 (b)(2)(c)(1) Monitoring procedures and schedules must enable the licensee to determine compliance with Sec. 73.1560 regarding operating power and AM station mode of operation, Sec. 73.1570 regarding modulation levels, and, where applicable, Sec. 73.1213 regarding antenna tower lighting, and Sec. 73.69 regarding the parameters of an AM directional antenna system.
One would assume that would mean some sort of logging. Further, a review of all recent NAL, NOV and citations from the FCC’s enforcement bureau shows that field agents investigating a radio station will make their own power measurements if they suspect a broadcast station is operating out of power tolerance. Most particularly with AM directional stations that are supposed to reduce power at night. I doubt very much that producing an operating log with in tolerance power readings would do any good in those circumstances.
For directional AM stations that change power/mode at night, some routine of checking the transmitter for proper power levels after power/pattern change needs to be established. If there is an auto logging system, such as a Burk Autopilot, then checking that system for proper time of day and/or proper pattern/power change functioning could take the place of checking the actual transmitter readings as long as there were an alarm (and notification) generated during an out of tolerance condition.
For most FM stations and AM non-directional stations, most modern transmitters have Automatic Power Control (APC) built in. As long as the APC is functioning properly and there is an alarm (with notification) generated when an out of tolerance condition occurs (under/over power), logging power output readings can be done on a weekly maintenance log.
Station logs are to be retained for two years (73.1840) and should be available to the FCC for inspection. After two years, throw the logs out because anything that you have on file is liable to be inspected. Any rules infractions found in the station logs can lead to a NOV or NAL, even if it happened more than two years ago.
For your reading pleasure:
73.1820
Sec. 73.1820 Station log.
(a) Entries must be made in the station log either manually by a
person designated by the licensee who is in actual charge of the
transmitting apparatus, or by automatic devices meeting the requirements of paragraph (b) of this section. Indications of operating parameters that are required to be logged must be logged prior to any adjustment of the equipment. Where adjustments are made to restore parameters to their proper operating values, the corrected indications must be logged and accompanied, if any parameter deviation was beyond a prescribed tolerance, by a notation describing the nature of the corrective action. Indications of all parameters whose values are affected by the modulation of the carrier must be read without modulation. The actual time of observation must be included in each log entry. The following information must be entered:
(1) All stations. (i) Entries required by Sec. 17.49 of this
chapter concerning any observed or otherwise known extinguishment or improper functioning of a tower light:
(A) The nature of such extinguishment or improper functioning.
(B) The date and time the extinguishment or improper operation was observed or otherwise noted.
(C) The date, time and nature of adjustments, repairs or
replacements made.
(ii) Any entries not specifically required in this section, but
required by the instrument of authorization or elsewhere in this part.
(iii) An entry of each test and activation of the Emergency Alert
System (EAS) pursuant to the requirement of part 11 of this chapter and the EAS Operating Handbook. Stations may keep EAS data in a special EAS log which shall be maintained at a convenient
location; however, this log is considered a part of the station log.
(2) Directional AM stations without an FCC-approved antenna sampling system (See Sec. 73.68). (i) An entry at the beginning of operations in each mode of operation, and thereafter at intervals not exceeding 3 hours, of the following (actual readings observed prior to making any adjustments to the equipment and an indication of any corrections to restore parameters to normal operating values):
(A) Common point current.
(B) When the operating power is determined by the indirect method, the efficiency factor F and either the product of the final amplifier input voltage and current or the calculated antenna input power. See Sec. 73.51(e).
(C) Antenna monitor phase or phase deviation indications.
(D) Antenna monitor sample currents, current ratios, or ratio
deviation indications.
(ii) Entries required by Sec. 73.61 performed in accordance with the schedule specified therein.
(iii) Entries of the results of calibration of automatic logging
devices (see paragraph (b) of this section) or indicating instruments
(see Sec. 73.67), whenever performed.
(b) Automatic devices accurately calibrated and with appropriate
time, date and circuit functions may be utilized to record entries in
the station log Provided:
(1) The recording devices do not affect the operation of circuits or
accuracy of indicating instruments of the equipment being recorded;
(2) The recording devices have an accuracy equivalent to the
accuracy of the indicating instruments;
(3) The calibration is checked against the original indicators as
often as necessary to ensure recording accuracy;
(4) In the event of failure or malfunctioning of the automatic
equipment, the person designated by the licensee as being responsible for the log small make the required entries in the log manually at that time;
(5) The indicating equipment conforms to the requirements of Sec. 73.1215 (Indicating instruments–specifications) except that the scales need not exceed 5 cm (2 inches) in length. Arbitrary scales may not be used.
(c) In preparing the station log, original data may be recorded in
rough form and later transcribed into the log.
73.1350:
Sec. 73.1350 Transmission system operation.
(a) Each licensee is responsible for maintaining and operating its
broadcast station in a manner which complies with the technical rules
set forth elsewhere in this part and in accordance with the terms of the station authorization.
(b) The licensee must designate a chief operator in accordance with Sec. 73.1870. The licensee may designate one or more technically competent persons to adjust the transmitter operating parameters for compliance with the technical rules and the station authorization.
(1) Persons so authorized by the licensee may make such adjustments directly at the transmitter site or by using control equipment at an off-site location.
(2) The transmitter control personnel must have the capability to
turn the transmitter off at all times. If the personnel are at a remote
location, the control system must provide this capability continuously
or must include an alternate method of acquiring control that can
satisfy the requirement of paragraph (e) of this section that operation
be terminated within three minutes.
(c)The licensee must establish monitoring procedures and schedules for the station and the indicating instruments employed must comply with Sec. 73.1215.
(1) Monitoring procedures and schedules must enable the licensee to determine compliance with Sec. 73.1560 regarding operating power and AM station mode of operation, Sec. 73.1570 regarding modulation levels, and, where applicable, Sec. 73.1213 regarding antenna tower lighting, and Sec. 73.69 regarding the parameters of an AM directional antenna system.
(2) Monitoring equipment must be periodically calibrated so as to
provide reliable indications of transmitter operating parameters with a
known degree of accuracy. Errors inherent in monitoring equipment and the calibration procedure must be taken into account when adjusting operating parameters to ensure that the limits imposed by the technical rules and the station authorization are not exceeded.
(d) In the event that a broadcast station is operating in a manner
that is not in compliance with the applicable technical rules set forth
elsewhere in this part or the terms of the station authorization, and
the condition is not listed in paragraph (e) or (f) of this section,
broadcast operation must be terminated within three hours unless antenna input power is reduced sufficiently to eliminate any excess radiation. Examples of conditions that require termination of operation within three hours include excessive power, excessive modulation or the emission of spurious signals that do not result in harmful interference.
(e) If a broadcast station is operating in a manner that poses a
threat to life or property or that is likely to significantly disrupt
the operation of other stations, immediate corrective action is
required. In such cases, operation must be terminated within three
minutes unless antenna input power is reduced sufficiently to eliminate any excess radiation. Examples of conditions that require immediate corrective action include the emission of spurious signals that cause harmful interference, any mode of operation not specified by the station license for the pertinent time of day, or operation substantially at variance from the authorized radiation pattern.
(f) If a broadcast station is operating in a manner that is not in
compliance with one of the following technical rules, operation may
continue if the station complies with relevant alternative provisions in
the specified rule section.
(1) AM directional antenna system tolerances, see Sec. 73.62;
(2) AM directional antenna monitoring points, see Sec. 73.158;
(3) TV visual waveform, see Sec. 73.691(b);
(4) Reduced power operation, see Sec. 73.1560(d);
(5) Reduced modulation level, see Sec. 73.1570(a);
(6) Emergency antennas, see Sec. 73.1680.
(g) The transmission system must be maintained and inspected in
accordance with Sec. 73.1580.
(h) Whenever a transmission system control point is established at a location other than the main studio or transmitter, a letter of
notification of that location must be sent to the FCC in Washington, DC, Attention: Audio Division (radio) or Video Division (television), Media Bureau, within 3 days of the initial use of that point. The letter
should include a list of all control points in use, for clarity. This
notification is not required if responsible station personnel can be
contacted at the transmitter or studio site during hours of operation.
(i) The licensee must ensure that the station is operated in
compliance with Part 11 of this chapter, the rules governing the
Emergency Alert System (EAS).
Another picture from my collection, this one is the back side of a power supply module from a Broadcast Electronics AM6A transmitter:
Bang!
It happened during power up from 1 KW to 5 KW and it was quite loud, as I was standing right next to the transmitter. The exploded part is a 0.1 uf capacitor that looks like an add on. In fact, some of the other power supplies don’t have it. It also took out the 20 amp slow blow fuse.
I like the exploded look of the board, kind of like on The Road Runner, when Wyle E. Coyote looks into a box and something explodes.
This is the only problem I have had with this particular transmitter.
I spent hours and hours working on this theory while I was in college and after college as well, including developing a theorem and practical filed testing:
Girls are Evil proof
And here is the practical application:
Looks fun, doesn’t it? Be aware, dangerous curves ahead, don’t ask me how I know.
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
...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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