My thoughts on HD Radio (IBOC) broadcasting

2013-post-hdHD Radio.  IBOC.  Two phrases that are sure to make the average DXer cringe—or at least sigh.

A reader and fellow DXer recently asked me how I felt about HD Radio/IBOC broadcasting.  I thought it would be interesting to write about my thoughts on the technology, which I have dealt with for 7 years.

When I started to DX in 1999, IBOC didn’t exist locally in the Washington, DC area.  After years of great tropo, I noticed a sharp decline in openings, distant station signal strength and new logs around 2006, when IBOC debuted locally.  I still received DX, but rarely got anything on adjacent frequencies to the northeast (in the direction of my new IBOC-carrying locals).

Me, and many other DXers, realized that the IBOC technology, which according to various reports broadcasts a digital radio station on the ‘sidebands,’ or adjacent frequencies of participating FM radio stations, ruined (or at least curtailed) the hobby for many.  A station running IBOC on 95.5 FM would actually be broadcasting its analog signal on 95.5, while its digital signal would be broadcasted, at a much lower power, on 95.3 and 95.7 FM.  An HD Radio would pick up either sideband, where available, and decode it on 95.5 FM, allowing the listener to enjoy a digital signal.

The technology most likely, at first, seemed to be great on paper for the general public.  Since nothing is broadcasted locally on adjacent-to-local frequencies, why waste the spectrum when it can be utilized?  But the manufacturers, executives, investors and others involved in making IBOC a reality didn’t realize that these empty frequencies were the livelihood of DXers.  When tuned to a frequency immediately next to a strong, local signal running IBOC, the listener hears static, but at a different pitch.  This static is not the same static that a distant analog station would fade in over—it was an analog representation of the fully-digital (and strong) IBOC signal.

As DXers well know, the ‘IBOC hash’ effectively prevents all but the strongest distant signals to be heard on the adjacent frequencies.  Personally, I was lucky in that my only true adjacent-signal interference was to the northwest toward my locals.  The IBOC hash is nonexistent, or severely attenuated, while my antenna is aimed elsewhere, so E-skip comes in just as great as pre-IBOC.  Tropo to the NE has been truncated and although it is still possible, it is nothing like before 2006.  But I can imagine those who live close to their local FM transmitters experience severe IBOC interference regardless of antenna orientation.

Understandably, most DXers openly criticized IBOC in hobbyist forums, email lists and elsewhere, myself included.

In 2008, Sony debuted the XDR-F1HD radio, which decoded IBOC.  From what I understand, I was one of the first few DXers who purchased, wrote a review and decoded IBOC with this radio.

For the first time, I saw IBOC had great benefits to the DXer.  The station’s call letters appeared on-screen in a field separate than radiotext, much like a displayed RDS PI code, and the calls were (most of the time) correct—something RDS is unreliable for providing.

An IBOC decode from KNCM Appleton, MN, at 1059 miles over local WAMU, which also broadcasts IBOC.

An IBOC decode from KNCM Appleton, MN, at 1059 miles over local WAMU, which also broadcasts IBOC.

But I didn’t notice the true benefit of IBOC until subsequent E-skip seasons, where I logged multiple IBOC signals directly over unrelated local signals, some which ironically also ran IBOC.  If it wasn’t for IBOC, I would have not logged 88.5 KNCM-MN, 89.3 KCMP-MN, 90.1 KNSE-MN, 91.9 WHRE-VA, 92.5 KSYN-MO, 92.5 KZPS-TX, 93.3 WQUE-LA, 93.9 WMIA-FL, 94.3 WZZR-FL, 98.7 WKGR-FL, 98.7 WSJT-FL, 99.1 WEDR-FL, 99.5 WRNO-LA, 99.5 KPLX-TX, 99.5 WQYK-FL, 101.1 WJRR-FL, 101.1 WNOE-LA, and 107.9 KQQL-MN over local signals.  I would argue that any technology allowing a distant FM signal to be easily received over a strong, otherwise-‘unbudgable’ local FM signal is a benefit to the DXing hobby.

Also, the dreaded sidebands that typically ruin tropo: these are beneficial during several Es openings.  Many a time have I logged an Es signal via IBOC by its sidebands when an unrelated, other signal (Es or not) occupied the analog frequency.  This is more pronounced on 88.1 and 107.9, where the 87.9 and 108.1 sidebands, respectively, have no analog signals to interfere with decoding.

Fast forward to 2012.  I just about forgotten how DXing was in the pre-IBOC days and considered the ruined FM band a ‘new normal,’ so to speak.  This changed in June during a vacation in Myrtle Beach, an area where no IBOC exists.  Next to a local non-IBOC blowtorch 100kw signal on 97.7 FM at 13 miles away, I picked up WRMF 97.9 FM from Palm Beach, FL, at 485 miles with clear stereo.  Imagine if the local 97.7 FM aired IBOC.  WRMF would’ve surely not have been received over IBOC hash.  Even with tropo reaching the 530-mile mark, I only decoded one IBOC signal while in Myrtle Beach, from Charleston.

My thoughts on IBOC started to change.  Although I was never completely pro-IBOC, this trip further solidified my disdain of the technology.  For years I enjoyed the service’s benefits, however it was simply amazing, for lack of better words, to DX in an area where every single non-local frequency was fair game without interference.

Although this is just a personal opinion, I don’t see IBOC’s benefit for the general public outside of song and program text IDs, something which is already done with RDS.  Sure, IBOC allows stations to multicast, but from what I’ve seen, most stations only simulcast their analog signal on HD.  Or, they simulcast another local FM or AM station on an HD subchannel which can otherwise be received strongly in the same area—a waste.  However, some stations, such as WAMU-Washington and WJFK-Manassas locally, take advantage of the extra subchannels by running formats not otherwise available on the local FM band, such as bluegrass country or co-owned sports stations from distant markets, respectively.

Nobody I know, outside of radio hobbyists, owns an HD Radio or cares to even know what it is.  They’d rather listen to their iPod, Pandora, satellite radio, etc.  I don’t think this is the fault of iBiquity, the company responsible for IBOC, save for a lack of HD Radio advertising.  It is simply the product of the current economy and radio listening habits.  Had IBOC debuted in the 1980s, or even early 2000s, I believe it would have picked up many more listeners and fans.  Personally, I don’t even listen to HD Radio outside of when I am dial scanning, mainly because the audio quality is, typically, very tinny and worse than the analog broadcast.

I don’t know if IBOC is going to last for much longer.  I’ve noticed some local Washington-area signals (102.3 WMMJ, 104.1 WPRS, 105.9 WJZW) turn their IBOC on and off over the past three years, as if the technology was an afterthought.  I predict in the future that the IBOC signals will go down, one by one, until only a handful in the top radio markets remain.  When a technical issue hits those stations, they’ll permanently go off-air, too.

Although probably not possible, I think it would be much more beneficial if the IBOC signal could physically reside on the same frequency as the analog, freeing up sidebands.  A separate IBOC radio band, possibly below 88.1 FM, would’ve been a better choice.  Imagine a full-powered IBOC signal with no sidebands during an Es opening!

Overall, I believe IBOC has its benefits and downsides.  Even with the ability to decode instant, positive IDs from distant signals often over locals, IBOC’s side effects have muddied the band, especially in urban areas.  Facing a seemingly uninterested and ignorant consumer base, a lack of advertising and on-again-off-again adaption of the technology by participating stations, I believe we’ll see a day when Myrtle Beach-style DXing would be possible even in inner New York City.  The question is not if, but when.

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