Speaker 1: 0:00

Ah yes, hd radio. It's supposed to be the gold standard in digital radio transmission, right? Well, like any tech that promises to be the future, it's not without its quirks. In today's episode of Fully Modulated, we're diving into an ongoing mystery with one of our HD stations and, trust me, it's been a real puzzle. For some reason, our HD1 audio started dropping randomly. But here's the kicker HD2 never dropped. Let's get into what we've uncovered and why. Despite some of the best equipment, this was far from easy to figure out. The kicker here if it's a transport or an exciter issue, it should affect both HD1 and HD2, right? Well, that's not what we were seeing. Let's break down the issue, the head-scratching moments and the conclusion we're slowly but surely stumbling toward. So the first sign that something was off came from one of our nearby offices, which reported that HD1 audio was dropping intermittently. This wasn't your typical full-on dropout where the station just goes silent. This was more like a brief glitch lasting anywhere from 0.3 seconds to a full 3 seconds. But what made this problem especially tricky was the fact that HD2 wasn't dropping. Now you know the way I understand it. If the issue was with the transport or the exciter, or even a problem with the XGen card. It would take out all HD, not just HD1. It wasn't adding up for us.

Speaker 1: 2:10

We looked at all the gear in the air chain and the more we dove into it the more confusing it became. The Inovonix 632 HD receiver, which is part of the setup for our confidence, feeds back to the studio, to our partner organizations, that was constantly dropping hd1. But the inovonix 551 mod monitor that we just got didn't have any of these issues. Everything on the transmitter side, the nautil nv30, the nautil hd multicast and the omnia 9, it all checked out perfectly. Everything was up to date and there were no faults or errors in the logs.

Speaker 1: 2:51

It's moments like these when you start questioning everything you know about how radio should work. You're looking at one channel dropping and the other working fine and you're just kind of standing there left scratching your head going what am I missing? Now here's where things get even more puzzling. The enovonix 632 hd receiver was showing the dropouts. That was a clue. But the 551 mod monitor, no problem, it worked fine. It wasn't dropping hd1 at all. So what was going on? Was the 551 just better at handling the HD radio data or was there really an issue with the 632 receiver In troubleshooting. The key difference was the fact that the 632 doesn't blend back to analog FM like other HD radios, so when the dropout occurred we could hear it right away. The 551, however, might be a little more forgiving, hiding glitches because of how it processes the audio. If you've ever had issues with HD radio gear before, have you noticed similar oddities, maybe one channel misbehaving or a certain receiver acting up? I'd love to hear your experiences. Drop me a line. You can text the show using the link in the show description.

Speaker 1: 4:10

At this point we turned our attention to the core of the transmission chain the Nautil NV30 transmitter and all the related gear. After checking everything, we confirmed there were no faults, errors or lost packets. Everything was running smoothly with no issues flagged in the logs. The Nautil HD multicast was also operating as normal and the Omnia 9 had been rebooted without any improvement to the audio dropout issue. So if it wasn't the transmitter or the processor, it had to be somewhere further down the line. So, of course, next we went to the Anavonix Justin 808, which, for those that don't know, the 808 is responsible for automatic HD1 audio gain adjustments and time alignment to ensure everything blends smoothly when you lose HD1 and have to go back to the analog FM signal. So we bypassed the Justin 808 and while the dropout issue sort of decreased, it didn't go away entirely. Or it was just me hoping that it would be the culprit and solve things a little easier, which of course didn't work. This left us wondering maybe it's just a 632 HD receiver? This is the part where you get into that troubleshooting loop you know what I mean where you kind of tried everything rebooting the gear, bypassing components and were still no closer to figuring out what the root cause was. When something's dropping out intermittently like this, you can waste a lot of time chasing down red herrings and going in loops. It's enough to make you feel like you're in a maze with no exit.

Speaker 1: 5:55

As we continued digging, we learned that the issue might be related to the Inovonix 632 receivers, because nothing else made sense. The more we thought about it, the more it made sense overall to all of us. The tuners just couldn't handle the data properly in the way that the 551, the newer mod monitors could. A co-worker of mine at a partner organization mentioned something that kind of made us stop and think. Hd2 likely doesn't drop as often because it has a much larger buffer in the MP1 mode it's around about 40 seconds compared to HD1, which doesn't have as much room for buffering. Have as much room for buffering. This gives HD2 a bit more wiggle room to recover from when it has any sort of minor issues.

Speaker 1: 6:51

It turns out that the 632 tuners were known to have this flaw. The company had reportedly been aware of the issue, but never publicly admitted it. This was a big moment of clarity for us, but it also left us with a big question mark that may have bigger implications. Do we trust this company with future monitoring gear? And you know what. This is part of why HD radio feels so clunky. It's all proprietary gear that locks us into certain manufacturers, making troubleshooting harder than it needs to be.

Speaker 1: 7:29

What we really needed here in the US is an open digital radio standard, something like what they have done in other countries, instead of relying on one or two companies for all the equipment. We'd have multiple competitors in this space, driving innovation and making gear more affordable. And, who knows, maybe by now we'd have a full digital radio nation, like Norway, who went digital back in 2017. All digital, shut the FM off and everything, but here we are still tangled up in in proprietary systems and alright, you know what I'll get off my soapbox. But I think you get the point. It could have been better, much, much better.

Speaker 1: 9:07

Now, as we stare down this mystery, we're also eyeing up the new Anovonix 679 HD radio tuner to see if that will solve our problem. Maybe a newer HD radio chip, the 679, promises to address some of the issues that are nagging us with the 632. It might be the solution we've been looking for. But here's the thing. I'm also curious if anyone out there has experience with HD radio tuners commercial HD radio tuners that we could use to monitor our feeds. If you've got a favorite brand, a model or even just a good recommendation for reliable gear used to monitor your HD signals, drop me a line. I'd love to hear about it. You can text the show using the link in the episode description. Maybe in a future episode we could do a full gear comparison. So what do we do with all this info?

Speaker 1: 10:04

The takeaway here is that with HD radio, things aren't always as straightforward as they seem to be. In cases like this, where one channel works perfectly fine and the other doesn't, it's often a very certain issue with a single piece of equipment, in this case, the inovonix 632 tuner seemed to be the culprit, but it took some deep digging to figure that out, and even even after all that, we had to question the reliability of the gear we're using moving forward. That's it for today's episode of Fully Modulated. Sometimes, troubleshooting HD radio can feel like solving a puzzle, but the more pieces you get, the clearer the picture becomes. If you've run into similar issues with your HD1 or HD2 signals, or if you've had issues with HD tuners that weren't exactly advertised as quote-unquote junk, I'd love to hear from you. Stay tuned for more and, as always, check the description for links and extra details, and I'll see you next time.