FMExtra was discussed heavily a few years ago...now that the dust has settled, has anyone actually used this system? And if so, what is the coverage like? Does it make it to the 60dbu contour? Or farther? Or not as far? What is the stereo sound quality like? The brochure leads me to think that a stereo signal on this is at 32K...which on an Internet stream sounds pretty bad. Don't have an application for this, but as time goes on and more stations consolidate, it's good to know what works and what doesn't.
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DRE/FMExtra
- Thread starter BobOnTheJob
- Start date
I got a demo of it a few years ago. We tried it on a 74 watt LPFM, figuring that would be a challenging situation. It worked quite well, even past the 6o dbu contour. The audio quality was very good too. I think it used AAC, so 32 KBs is not bad.
It was very easy to set up, taking maybe 15 minutes or so. Just put it in the rack, plug it into the SCA input, set levels and set up what encoding rate you want to use. I couldn't find much to not like, except for a lack of radios and not being accepted as an FCC standard. If I was allowed to use it to feed translators, like you can with a HD-2 signal, I'd have one of these in place right now. Unfortunately, when I asked Jim Bradshaw at the FCC he said "absolutely not." That ended the adventure.
It was very easy to set up, taking maybe 15 minutes or so. Just put it in the rack, plug it into the SCA input, set levels and set up what encoding rate you want to use. I couldn't find much to not like, except for a lack of radios and not being accepted as an FCC standard. If I was allowed to use it to feed translators, like you can with a HD-2 signal, I'd have one of these in place right now. Unfortunately, when I asked Jim Bradshaw at the FCC he said "absolutely not." That ended the adventure.
Thanks Chuck...was the beyond 60dbu performance with a T antenna hanging from the receiver or with an outdoor yagi?
We've got one on the air for program delivery (not public use).
Two independent mono channels for talk programming. Had to use AMRWB+ codecs as satellite delivered programming (already bit starved from multiple ISDN hops) suffered more degradation through AAC than AMRWB+. That said, it's fairly decent quality when heard rebroadcast on FM.
With RDS protection mode, we get about 48 kbps. You can configure it to use that bandwidth pretty much any way you like. Delay is around 2 seconds at medium density (error correction). I believe there is newer software / firmware to squeeze a few more kbps out of the same bandwidth.
It's basically a industrial rack-mount PC with proprietary software, a high end input card, and a proprietary generator card.
Once you have the injection set correctly, it works well. I haven't ever drive-tested the range, but I have a couple of fixed receiver points in less than perfect signal areas that stay solid.
The radios are just software-based table radios with custom firmware. Similar in size to the Boston Acoustics or Tivoli radios. It can get dicey if you try to use them in a high RF environment as the case is just pressboard. I asked them if they might consider making a rack-mount version (same guts, in a metal rack mount case), but they didn't seem to have any interest.
Since iNiquity...uh...iBiquity bought a share of their company a number of years ago (now known as ViewCast Media), their drive to compete suddenly waned... I wonder why :
It this were still a competitor to iBiquity with the dollars to market (and, dare I say, "lobby"), I believe it would be a far better alternative to the existing HD system. Just the pure simplicity and flexibility. Unfortunately that possibility passed many moons ago...
Two independent mono channels for talk programming. Had to use AMRWB+ codecs as satellite delivered programming (already bit starved from multiple ISDN hops) suffered more degradation through AAC than AMRWB+. That said, it's fairly decent quality when heard rebroadcast on FM.
With RDS protection mode, we get about 48 kbps. You can configure it to use that bandwidth pretty much any way you like. Delay is around 2 seconds at medium density (error correction). I believe there is newer software / firmware to squeeze a few more kbps out of the same bandwidth.
It's basically a industrial rack-mount PC with proprietary software, a high end input card, and a proprietary generator card.
Once you have the injection set correctly, it works well. I haven't ever drive-tested the range, but I have a couple of fixed receiver points in less than perfect signal areas that stay solid.
The radios are just software-based table radios with custom firmware. Similar in size to the Boston Acoustics or Tivoli radios. It can get dicey if you try to use them in a high RF environment as the case is just pressboard. I asked them if they might consider making a rack-mount version (same guts, in a metal rack mount case), but they didn't seem to have any interest.
Since iNiquity...uh...iBiquity bought a share of their company a number of years ago (now known as ViewCast Media), their drive to compete suddenly waned... I wonder why :
It this were still a competitor to iBiquity with the dollars to market (and, dare I say, "lobby"), I believe it would be a far better alternative to the existing HD system. Just the pure simplicity and flexibility. Unfortunately that possibility passed many moons ago...
I think it's worth noting that, because DRE/FMExtra rides on a subcarrier channel, it is considered an SCA service under FCC rules. As an SCA service, anyone that receives it has to have written permission from the originating station. Theoretically, SCA receivers are supposed to be fixed-tuned to one station, though frequncy agile ones have been common for decades. As an SCA service, you cannot do certain things such as broadcast them on the main channel of a translator like you can with HD2 channels.
Kmagrill said:
That's all true, but a system similar to DRE/FMExtra would be an easy way to make the transition to digital. Since digital streams are nothing more than 1 & 0's that sound like audio when transmitted (they can pass through a 56 K modem) then putting that stream on a subcarrier is an almost "no brainer." It would work for the next ten or twenty years as receiver penetration increased. If you ever got enough digital listeners, you could simply put the digital stream on your main carrier. That may be an over-simplification, but basically, I think we have been sold a bill of goods by the folks at Ibiquity....
Based on the research I did, and demo's I heard, FMextra is superior to IBOC in every way. A mono FM station, ie, News Talk or Sports, could have something like 192kbps for ancillary streams using FM extra. And the system can even be used on a station running IBOC HD streams.
The best part about FMExtra is that it DOESN'T hog the adjacent channels!!! I have two stations, either side of one transmitting in ICRAP and the digital subcarriers wipe out the two on either side.
I have no clue why it was reasoned that a digital radio service on FM needed to turn the neighboring FM channels into hiss and garbage. Makes a lot of translator off-air pickups a lot harder than they need to be as well, when you have a class B IBOC blasting away.
I've been on the fence about it for awhile, but have finally come around to SHUT IT ALL OFF. Had a station lose its HD carriers due to the BE exciter having a "burp". Airstaff didn't notice for a day and a half. Got it back up a day after that. Not one call, email, text, smoke signal, semaphore or otherwise from the listening public. About the only good that I can see from an HD is using it to feed an analog translator. Of course, if the rules were changed, you could do the same thing with FMExtra, and not have to pay the licensing fees to iBrokequity.
As for IBOC AM, while it does provide quite an audible difference in sound quality, it's about as stable as Jell-O on a trampoline. One fart near the receiving antenna and it loses lock. Look the wrong way at the radio and it loses lock. A butterfly flaps its wings in Japan and it loses lock. And again, it's really IBAC, not IBOC. In Band Adjacent Channel. Take a listen to the hash that WBZ throws around the eastern part of the country every night. For what? The station engineer who put an almost unobtanium HD radio in his car and maybe the GM and PD. And a few radio geeks and hams. Seriously, go into a Best Buy and ask for HD radio. You'll be pointed right to the Sirius/XM section every time.
I have no clue why it was reasoned that a digital radio service on FM needed to turn the neighboring FM channels into hiss and garbage. Makes a lot of translator off-air pickups a lot harder than they need to be as well, when you have a class B IBOC blasting away.
I've been on the fence about it for awhile, but have finally come around to SHUT IT ALL OFF. Had a station lose its HD carriers due to the BE exciter having a "burp". Airstaff didn't notice for a day and a half. Got it back up a day after that. Not one call, email, text, smoke signal, semaphore or otherwise from the listening public. About the only good that I can see from an HD is using it to feed an analog translator. Of course, if the rules were changed, you could do the same thing with FMExtra, and not have to pay the licensing fees to iBrokequity.
As for IBOC AM, while it does provide quite an audible difference in sound quality, it's about as stable as Jell-O on a trampoline. One fart near the receiving antenna and it loses lock. Look the wrong way at the radio and it loses lock. A butterfly flaps its wings in Japan and it loses lock. And again, it's really IBAC, not IBOC. In Band Adjacent Channel. Take a listen to the hash that WBZ throws around the eastern part of the country every night. For what? The station engineer who put an almost unobtanium HD radio in his car and maybe the GM and PD. And a few radio geeks and hams. Seriously, go into a Best Buy and ask for HD radio. You'll be pointed right to the Sirius/XM section every time.
Sounds like the quality can be adequate...That leaves my biggest question being what the coverage is like with similar receive conditions to what Muzak had 35 years ago...a 6 element FM yagi on a grocery store roof. 60dbu, 54dbu, 40dbu? This could be a viable alternative for say a non-com empire where the group has a big Class B non-com and a much smaller non-com that wants to branch out on a network of translators. If it reaches the 40dbu circle, it holds a lot of potential. If it starts getting iffy just past the 60dbu, not so much. Anyone pushed this technology to the limit to see what it can do distance wise?
The advantage over an analog SCA is that you aren't slave to SNR like an analog SCA. I haven't tested it, but assume you can vary the injection level. If you can lock the digital signal with sufficient strength on a translator receive (even though the FCC says no on this), hypothetically speaking, it should work.
As for in-car, I've heard reports that it's usually good out to the 54dBu.
Honestly, IBOC is like Muzak in its coverage.
As for in-car, I've heard reports that it's usually good out to the 54dBu.
Honestly, IBOC is like Muzak in its coverage.
I think the FCC saying you can't feed a translator with FMeXTRA applies in terms of originating programming. In the non-com band, I believe you can get programming from the originating station to a translator by any method...OTA, phone lines, satellite, SCA, FMeXTRA, etc. I think what they specifically said no to is using FMeXTRA as a way to create a new station and air it on a translator. I'll stand correct if I'm mistaken, but that's how I understand the FCC declaration. Thanks for the 54dbu indication. I wonder if that is at 10% injection? Running it up to 20% would probably push it out a little farther.
DRE and related SCA feeds are not considered "broadcast services." Hence a translator cannot relay programming that only transmitted on these subsidiary services. HD2 channels are considered broadcast, so can be relayed by a translator.
Where the programming is broadcast, say on an AM station AND relayed by DRE, then the programming can be relayed by a translator. The DRE subcarrier is merely being used as a program relay for the AM station's programming, just as you might do with an STL, equalized telco loop, or internet relay.
Where the programming is broadcast, say on an AM station AND relayed by DRE, then the programming can be relayed by a translator. The DRE subcarrier is merely being used as a program relay for the AM station's programming, just as you might do with an STL, equalized telco loop, or internet relay.
We tried it at a location that was approximately 14 air miles from the 74 watt LPFM. I connected the Aruba receiver to a 6 element Yagi made by Samco, that was tuned to the LPFM's frequency. This antenna is roughly 75 feet above ground level. We were able to get a lock with the FMExtra receiver which was sitting on top of a 300 watt FM transmitter in the same rack. At that location, we were approximately 1.5 miles beyond the predicted 40 dbu contour. I was quite surprised that it worked.BobOnTheJob said:
Would it do this on a day in, day out basis? I don't know. I imagine tropospheric ducting would play havoc, no matter what you do. My interest was using this to feed a couple of translators. It did a much better job than the analog tuners we were using at the time. Unfortunately, because the originating station and the translators in question are all in the commercial band (even though they are non commercial) the FCC informed me that it would not be in keeping with the rules. That said, if the originating station was in the reserved band, then I think it would be OK.
Instead, I pretty well circumvented the problem by using BW Broadcast RBRX-1 tuners, and keeping things analog (and mono).
That's the real world test I was looking for. Thanks Chuck. Was that at 10% injection?Chuck said:
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