The HD Radio callsign: How it has evolved over the years

HD Radio, also known as IBOC (In Band-On Channel), is the United States’ choice for digital radio broadcasting.  It debuted locally in my area in 2006.  One of the (few) benefits of HD Radio for listeners is the ability for capable stations to display their callsign on the screen of any HD Radio.  For DXers, this is a major plus, because during an intense tropo or Sporadic E event, one could theoretically identify any received IBOC signal immediately without the need to listen to the station for several minutes for an audio ID, potentially during a time when the signal would fade out, never to be heard (or identified) again.

The Sony XDR-F1HD radio displaying an HD Radio decode from 95.5 WPGC Morningside, MD, in 2008.
5/29/08, HD Radio

I purchased my first HD Radio, the Sony XDR-F1HD, in 2008.  The first HD Radio signal I received via Sporadic E was in May of that year, 97.5 KMOD Tulsa, OK, at 1045 miles away.  The distance didn’t matter–I knew it was KMOD the moment I tuned to 97.5 FM, since the station’s callsign flashed on my screen, as seen in the picture to the right.

Oops! Errors in the display

2008, HD Radio

Occasionally, I would come across a station broadcasting an incorrect callsign in the early days of HD Radio, such as my local 93.9 WKYS identifying as “KHRS-FM” for the better part of one day in 2008.

Ironically, a friend of mine in the Houston, TX area found the same incorrect KHRS callsign on his local 97.5 FM, whose real callsign was KFNC, in 2011.  Other stations occasionally displayed some variant of “HD-FM” or “HDHD-FM” at some point, too.  Just like the appearance of the KHRS calls on multiple stations, the error was often quickly fixed to the correct callsign.  Even still, it posed an issue for listeners wondering the true identity of what station they had tuned in.

The move to name-based callsign displays

For a few years it was a given–if your radio decoded an IBOC signal, you could positively identify it with minimal effort.  Although the aforementioned errors were rare, things started to change in the first half of the 2010s.  During a Sporadic E opening in 2010, I received a callsign from an HD Radio signal that said “RRR.”  Knowing that “RRR” was not a valid United States callsign, I had to listen to the signal to see what it was and where it was coming from.  I quickly learned that “RRR” stood for “Red River Radio,” a public radio network in Texas and Louisiana.  The station itself was 88.9 KLDN Lufkin, TX.  A year later, I picked up a station identifying on my radio screen as “TROY-FM,” which was later found to be 88.7 WRWA Dothan, AL, a signal broadcasting from Troy University.

By 2015, the sheer majority of HD Radio signals I encountered both via DX and while traveling in other cities largely still had their actual callsign displayed when tuned in.   This slowly began to change.  I noticed more and more stations showing their station name instead of their callsigns when tuned to HD Radio, most notably stations named “Kiss FM.”  Instead of callsigns, the HD Radio displayed “KISS-FM” on many of these stations.

In the following years, many radio groups switched their entire portfolio of HD signals in certain markets from callsign displays to name displays.  It isn’t happening in every city in America, but it is common enough that most major cities have at least two or three stations now with name displays.

The phenomenon was most obvious in Pittsburgh, PA.  I first visited Pittsburgh in 2016 and established an extensive DX log during my stay.  At the time, 10 of the city’s HD Radio signals had callsign displays, while two (96.1 WKST & 104.7 WPGH) had name displays, “KISS-FM” and “BIG -FM,” respectively.

When I returned to the market in 2019, four more of the same stations that previously had callsign displays switched to name displays, bringing the total of stations utilizing name displays in the market to six.

Washington: A rarity in HD Radio markets

My local market of Washington, DC is unique in that all 21 HD Radio signals currently broadcasting still display their callsigns in their HD displays as of 2019.  None have name displays.  Even so, there have been many changes in exactly what callsign appears on each signal.

Over the years, most of the signals in Washington flip-flopped between displaying their callsign with the “-FM” prefix at the end, to simply displaying the four-letter callsign itself.  This had no bearing on if the station’s actual callsign legally had “-FM” as a part of it or not.

In 2018, three Washington signals had “-FM” at the end of their callsign display: 88.5 WAMU, 93.9 WKYS, and 102.3 WMMJ.

Less than a year later, these stations removed the “-FM.”

Interestingly enough, I also noticed local 96.3 WHUR’s usual HD Radio display was replaced with an errornous “HD” callsign on April 4, as seen on the right screenshot below.  I predict this will be fixed in the coming days.

My take

Personally, I prefer the actual station callsign to be always visible on HD Radio signals.  Although it is always amusing to see how creative station owners can get with fitting a station name into a four-digit “spot” on stations that do have name displays, I think that it takes away from the intended purpose of HD Radio in terms of being able to identify which signal is being received.  It also makes DXing much harder because there is the chance of a distant signal coming in and disappearing before it is identified–even if its IBOC signal is fully decoded.

My prediction: within the next few years, at least one Washington HD Radio signal will switch to a name-based digital screen ID.  We will see how right I am in the coming years.