September 2011 – Page 4 – Engineering Radio

Ford begs Broadcasters: “Please install our wonderful HD Radio product.”

In an open letter to broadcasters, the entirety of which can be found here: Ford Exec Writes Open Letter to Broadcasters, Jim Buczkowski, whose official title seems to be “Henry Ford Technical Fellow and Director, Electrical and Electronic Systems Research and Innovation Ford Motor Company,” nearly begs broadcasters to install HD Radio technology at their radio stations.

One thing that seems to be missing from the open letter, is something mildly important called: Disclosure. According to iBiquity’s own website, Ford Motor Company is an investor in the technology. Other investors include:

Clear Channel
CBS Radio
Grotech Capital Group
J.P. Morgan Partners
New Venture Partners
FirstMark Capital
Harris
Texas Instruments
Visteon

Not an inclusive list by any means, but something to keep in mind when reading the letter or the latest iBiquity advertising in various trade magazines.

Back to the letter; the cliff notes version is this:

Through the use of HD Radio, AM/FM broadcasters can now embrace the digital age
Drivers now have many choices for in-car entertainment, including satellite radio (Sirius XM) and online services (Pandora, et.al) that offer “Crystal Clear” audio
Through Satellite radio, MP3 players, and IP streaming services, drivers now have extra features like Title, song, and artist; Song tagging; iTunes; album art, etc which they have become accustomed to
Installing HD Radio will be a big upgrade and make AM/FM stations on par with those “digital age” services

For the first part, there is not a single broadcaster in the country that is not already aware of HD Radio. Every radio station manager and owner knows that it exists, but most people in the general public do not. Radio stations are hesitant to install HD Radio equipment because it is expensive, has a questionable return on investment, is unimpressive, and technically dubious.

Making the comparison to Satellite Radio and or IP streaming services, which all require subscriptions or data plans, is a bit of a stretch. Someone who will pay a fee for in-car entertainment is usually a tech geek. As the subscription rates for Sirius XM show, that works out to about seven percent of the US population (~20 million subscribers/~300 million people). It is a bit harder to nail down those who listen to streaming products like Pandora, iHeartRadio, or other webstreams in their cars, but I’d estimate not more than ten percent do.

While 3G and 4G wireless services are great, it still does not have the same coverage as standard and FM broadcasting stations. The last time I tried to listen to Pandora in my vehicle, it kept dropping out and was not easy to deal with. With TuneIn radio, I had the same experience during urban, suburban, and rural driving. Thus, the “Crystal Clear” reception is also a bit of a misnomer.

Further, fooling around with iPods, iPhones, TuneIn, Pandora, etc while driving is not the best idea. Even on vehicles with built-in IP connectivity or satellite radio, looking for song titles and other information while driving is not recommended. Thus, the value-added services of HD Radio are of questionable at best in a moving vehicle.

I hate to keep beating a dead horse, but for as long as the iBiquity crew continues to spout disingenuous bull sh!t about their failed technology, I’ll keep posting about it.

Modulation Dependent Carrier Level

Coming to an AM transmitter near you. The FCC announced that starting immediately, stations can employ Modulation Dependent Carrier Level or MDCL technology on AM transmitters. According to Public Notice DA 11-1535 (.pdf):

Use of MDCL technologies requires a waiver of Section 73.1560(a) of the Commission’s Rules, which sets upper and lower limits for an AM station’s operating power. We hereby establish procedures for AM broadcasters to seek a rule waiver in order to use energy-saving MDCL technologies.

Several transmitter manufacturers offer some version of MDCL in their newer models with the ability to update some older models. Harris Corporation offers something called “Amplitude Modulation Companding” (AMC) and “Adaptive Carrier Control” (ACC). While Nautel includes an option called “Dynamic Carrier Control” (DCC) on all NX series transmitters with the ability to upgrade some older transmitters. Continental offers Controlled Carrier Level Modulation (CCM) on later-model shortwave transmitters by installing SSM modulator, which can be retrofitted.

Nautel’s Dynamic Carrier Control (.ppt) (.pdf available here) reduces the carrier level during moderate modulation periods. The effect of this is to increase the perceived loudness at the receiver. During higher modulation periods, the carrier is increased to prevent distortion. The net effect is between 3 – 6 dB carrier reduction. During quite periods, the carrier is returned to full power to reduce noise.

Nautel AM Dynamic Carrier Control wave forms — Nautel Presentation on Dynamic AM carrier control

The potential savings are from 20-40%, which for a 10 or 50 KW station, would represent a significant reduction in the power bill. For a 50 kW station running an older transmitter, the savings would fall in the $37,000 to $56,000 per year range. In some cases, smaller stations may be able to get rid of a demand meter, which would also represent significant savings. The threshold for demand meters around here is 5,000 KWh per month.

The FCC further notes that:

The reduction in AM signal power at certain modulation levels inevitably exacts some penalty upon audio quality. Depending on the content of the audio program, MDCL algorithms may introduce some audio distortion or may decrease the signal-to-noise ratio in the receiver. In addition, MDCL algorithms may erode coverage slightly at the fringes of the AM station’s protected service area. Both the long experience of transmitter manufacturers and broadcasters abroad, and the initial reports from experimental operations in Alaska however, indicate that such adverse effects are generally imperceptible.

This would be especially true for higher-powered stations that stand to save the most money.

The malfunctioning STL antenna

Right after Tropical Storm Irene, it was noted that the STL signal strength at the WHUD transmitter site was low. Normally it was 300+ µV, but now reading around 100 µV, which is a problem. Upon further investigation, it was revealed that the STL transmitter on the intermediate hop had higher than normal reflected power.

Time to call the tower crew.

The STL transmit antenna for WHUD’s STL (WPOU464) hop is a Scala Paraflector (PR-950), mounted at the 280-foot level on this tower:

The fact that it happened after a major storm and the transmitter was showing higher than normal reflected power indicates a problem with either the antenna or the jumper between the 7/8″ Cablewave coax and the N connector on the antenna. A measurement with a spectrum analyzer shows very high return loss:

This shows the distance to fault 413 feet, with a return loss of -7.4 dB. That distance is either near or at the antenna and -7.4 dB indicates a lot of reflected power. We had the tower climber take apart the jumper connections and terminate the jumper with a known good 50-ohm load. The return loss did not change. We then had him swap out jumpers and reconnect to the antenna. That did the trick:

Much better, most of the power is now being radiated by the antenna, the VSWR is 1.02:1. The impedance bump at 51 feet is a sharp bend in the coax where it is attached to an ice bridge. Reconnecting the transmission line to the transmitter and turning it on confirms that all is normal again. The problem with the jumper was found in one of the connectors, it was full of water.

Water contaminated Andrew flexwell connector — Water-contaminated Andrew flexwell connector

I cut away the boot, water had entered the connector from the back because waterproofing and tape was not applied all the way to the coax. This was installed in 1998 when the station moved from Peekskill to its current location in the town of Fishkill. The fact that it happened now in the nice weather when Mt. Beacon is still accessible and not in the middle of winter means the radio gods are smiling on us.

NAB thinks Translators offer more value than LPFM

Alternate title: “I love Stupidity,” somebody else’s, usually not my own. It’s a bit hard to reconcile the NAB’s desire for translators against the need and strong community support for local radio. The original intent of translators was to fill in coverage areas of existing FM licenses within the parent stations’ protected contour. Very few translators are actually used for that purpose today. They have, instead, morphed into vast over-the-air relay networks for NPR and religious stations or are relaying programming of HD-2 channels that would otherwise not be heard. Why we would need more of that, I don’t know.

The unfortunate part of all that stupidity is the side effects. Think of the stupid driver who cuts off a tractor-trailer on the interstate and causes a big pile-up. There are potential injuries to those involved in the accident but also the inconvenience to all those stuck in miles of backed-up traffic. That is a fairly minor occurrence.

With big corporate government, the size and scale of stupidity can reach epic proportions. To wit: During the natural disasters that overtook the northeast, indeed other areas of the country as well, local radio was proven to be a reliable, sometimes life-saving means of communication time and time again. Yet, in spite of all that, the NAB seems to think that LPFM stations (community radio) should be second to cross-band translators broadcasting AM stations and HD-2 channels. Regarding FM translators on AM stations, the NAB says:

NAB first commends and supports the Commission’s proposal to eliminate the restriction on the use of FM translators by AM stations to translators that were authorized as of May 1, 2009. FM translators enable AM stations to overcome inherent technical disadvantages that limit audio quality compared to other services, thus limiting their service to the public and even threatening their economic viability.

Oh where to begin? First of all, AM stations do not have inherent technical disadvantages, that is a myth. Off-the-shelf AM receivers are of inferior quality and make a well-designed, well-executed AM station sound like a telephone. If one were to listen to an older AM radio or AM on a receiver with variable bandwidth IF, one would find that it can sound quite good, if not very good. The problem is that the receiver manufacturers never carried through with the promise to open up the bandwidth following the implementation of NRSC-2 in 1991. One should wonder why.

Second, there are many AM stations out there that are economically viable. Those stations have local programming and serve the community of license and have not been neglected or turned into an automated syndicated radio repeater. Now, could a class C or class D AM station benefit from a translator at night, sure? That may not be a bad distinction to draw, especially for those class D stations with no nighttime operating authority.

Regarding more translators in general, it is difficult to imagine what all those new signals will be used for, other than more of the same (relaying distant, out-of-market religious stations, NPR stations, or HD-2 programming which nobody cares about). The FM band is already full of such things and could actually use less, not more.

While unfortunate, the NAB’s position is not surprising. They do the bidding of their dues-paying members, after all. The anti-competition we are a monopoly stance of the NAB members is not new either. Remember the required economic impact study required by the LCRA on the LPFM vs full power commercial FM stations. To think that a 100-watt LPFM could significantly impact the business of a class A, B or C FM station is laughable. Yet, it was a requirement stuck into the bill at the behest of the NAB.

It is up to the broadband-minded FCC to see how to slice the remaining FM spectrum up and whether the corporatist NAB’s argument holds water or the rising call of the people who want a return of local radio and local community service will be heard.

This is a video of what happened during Tropical Storm Irene in Ulster County, where I live:

We are truly fortunate that no one here was killed. In the mean time, the waters around here are still receding, we had some additional flooding Wednesday (9/7) with another 6 inches of rain from Tropical Storm Lee with flood warnings still in effect for several local creeks.

In my neck of the woods, we have nine radio stations licensed within about a 16 mile radius. One is religious, one is a college station, the other is a classical music format programmed from Albany, 90 miles away, one is a LPFM run by a local high school and two are commercial AM or FM station. The commercial stations used to be located in downtown Ellenville but moved to Poughkeepsie, about 30 miles away in 1999. The religious, college, and classical stations are small and have no backup systems or interest in emergency programming. That leaves the high school LPFM, WELV-LP.

In the height of the storm, 11.53 inches of rain had fallen in the previous 8 hours, the power was out, cable was out, the internet unavailable, the Verizon telephone company office in town was almost underwater, we had two sources of local Ulster county information; WDST (100.1 MHz, class A) in Woodstock and WELV-LP in Ellenville. WDST studios are located in Bearsville, which is about 25 miles north of here. They are a locally owned, locally programmed station with a good record of community support. They did a good job updating emergency information, flooded roadways, emergency shelter information, power restoration information, dry ice, alternate emergency numbers in case 911 went out, rallying points for local fire departments, etc. Ellenville Central School district’s WELV-LP also did a good job, although much more confined to the local area around Ellenville and have a much smaller coverage area. Still, they were live on the air with up to date information. Thankfully.

Next time, who knows?