• Get involved.
    We want your input!
    Apply for Membership and join the conversations about everything related to broadcasting.

    After we receive your registration, a moderator will review it. After your registration is approved, you will be permitted to post.
    If you use a disposable or false email address, your registration will be rejected.

    After your membership is approved, please take a minute to tell us a little bit about yourself.
    https://www.radiodiscussions.com/forums/introduce-yourself.1088/

    Thanks in advance and have fun!
    RadioDiscussions Administrators

HD radio directory?

DavidEduardo said:
They should not cut our sooner, as they differ in bandwidth allocation, but not the power of the HD signal.
Click to expand...

They definitely do, and it's a trait I've observed on multiple stations in different markets. For example, the public radio station in Pensacola, whose transmitter is southeast of the city in Gulf Breeze, has an HD signal that I can pick up dropout-free almost all the way into the middle of Baldwin County Alabama, a distance of about 40 miles. But the HD3 will start to experience dropouts right at the state line, which is only 25 miles from the transmitter. It never cuts completely out, but it becomes unlistenable much quicker than the HD2.

The same thing happens with iHeart's HD transmissions from their Spanish Fort tower in the Mobile market. Both WRKH and WMXC have HD3s running lower bitrate talk formats, and both cut out noticeably more than the HD2s. I'm only about 18 miles from that site and walking around the house it drops out constantly, but only the HD3.

I've noticed this both on a portable Insignia FM-only radio and an OEM Mazda car radio, so I know it's not just one particular chipset's quirk.
 
tomservo said:
They definitely do, and it's a trait I've observed on multiple stations in different markets. For example, the public radio station in Pensacola, whose transmitter is southeast of the city in Gulf Breeze, has an HD signal that I can pick up dropout-free almost all the way into the middle of Baldwin County Alabama, a distance of about 40 miles. But the HD3 will start to experience dropouts right at the state line, which is only 25 miles from the transmitter. It never cuts completely out, but it becomes unlistenable much quicker than the HD2.

The same thing happens with iHeart's HD transmissions from their Spanish Fort tower in the Mobile market. Both WRKH and WMXC have HD3s running lower bitrate talk formats, and both cut out noticeably more than the HD2s. I'm only about 18 miles from that site and walking around the house it drops out constantly, but only the HD3.

I've noticed this both on a portable Insignia FM-only radio and an OEM Mazda car radio, so I know it's not just one particular chipset's quirk.
Click to expand...

I think there is some control of power budget in the broadcast sidebands that allow stations managers to shape where the power goes. Any broadcast engineers here?
 
rbc said:
I think there is some control of power budget in the broadcast sidebands that allow stations managers to shape where the power goes. Any broadcast engineers here?
Click to expand...

I have not seen any feature like that in our Nautel HD equipment, other than the settings for overall HD power level.

I would guess the higher-number HD streams would be more susceptible to adjacent-channel interference, since they are farther away from the main channel.
 
awsherrill said:
I have not seen any feature like that in our Nautel HD equipment, other than the settings for overall HD power level.

I would guess the higher-number HD streams would be more susceptible to adjacent-channel interference, since they are farther away from the main channel.
Click to expand...

Thanks for that. The adjacent-channel interference make sense to me. Maybe I was thinking about the power budget between the analog and digital signal.
 
A narrow band antenna and/or bandpass filter will have an effect on HD sidebands. The HD injection level will also play a part.
 
I'm not an engineer, but I know that different stations decide how to allot their HD channels. If they use only standard HD mode all channels would prabably cover the same area. However, some stations might be using extended hybrid, which adds about 24kbps. A channel assigned to this extra resource might see a slightly lower coverage due to the extension actually being closer to the station's own center analog signals.

We use extended hybrid for our HD4 and there is a slightly lower coverage on that channel. It should be noted that we also employ an analog SCA service at 67khz so that's even closer to the extended hybrid, but they still seem to coexist quite well. We use Nautel equipment.

KVCB-LP
 
I live in the Springfield, IL area and I can receive WILL Urbana, IL 90.9 HD3 (news/talk) much better than WILL-HD2 (Classical). The HD3 often comes in when the HD2 does not which is disappointing because I would listen to the HD2 if it came in better but do not care about the HD3. I have always wondered why the HD3 comes in better than the HD2 which is the opposite of what was said above.

I have been curious for awhile if WKNP (90.1) was in HD but doubt it.
 
brian marchand said:
I live in the Springfield, IL area and I can receive WILL Urbana, IL 90.9 HD3 (news/talk) much better than WILL-HD2 (Classical). The HD3 often comes in when the HD2 does not which is disappointing because I would listen to the HD2 if it came in better but do not care about the HD3. I have always wondered why the HD3 comes in better than the HD2 which is the opposite of what was said above.

I have been curious for awhile if WKNP (90.1) was in HD but doubt it.
Click to expand...
The extended hybrid is a separate resource that could be assigned to any sub-channel. A station normally gets about 96kbps to share between all HD channels they use. The extended hybrid adds another 24kbps but it can't be combined with the rest. A station could assign any sub-channel to this extra resource or choose to not use it at all. We use it for our HD4 but we could have assigned HD2 there if we wanted. In that case, HD2 might have had a slightly lessened coverage. It's mostly a matter of content (music, all talk, etc.) and how much the channel might need.

At least, that's how I understand it. NOTE: Our station is an LPFM and I'm actually a music teacher by trade.

Here's our resource breakdown for those radio nerds like me:

KVCB-LP / HD
HD1 - 48kbps - stereo (main student channel)
HD2 - 32kbps - stereo (student produced music and sound art)
HD3 - 16kbps - mono (classic radio shows and student produced dramas)
HD4 - 24kbps [extended] - mono (school and community announcements in loop)
 
KVCB-LP sounds pretty sophisticated as school stations go. Thanks for sharing the details. It's very interesting.
 
Thanks Ralph. So if an HD sub-channel operates as an extended hybrid you are saying it will not have as good of coverage.

Do any of your channels play classical music and how much?
 
brian marchand said:
Thanks Ralph. So if an HD sub-channel operates as an extended hybrid you are saying it will not have as good of coverage.
Click to expand...

Yes, a sub-channel assigned to the extended hybrid resource could experience a bit less coverage on that channel. In our case the difference isn't big, but in the fringes of our service contour, that channel might not be heard. We still find it very useful.

brian marchand said:
Do any of your channels play classical music and how much?
Click to expand...

The kids choose what goes on the air. Classical music is fairly popular with them, so it's not uncommon to hear it on HD1. Our radio station also has an in-house orchestra called The VCS Radio Symphony. They play a good quantity of music on the station; particularly on HD2. Their specialty here is film scoring; especially silent films.

These are the websites:
www.vcsradio.com
www.vcsradioconservatory.org
 
Not an engineer, but I once complained to a station about this very issue.
The CE explained that some of the HD channels are closer to the analogue sidebands than others.

Reminded me of the time I was shopping in a supermarket and the store's 67KHz SCA feed had a LOT of splatter.
I went out to my car and put the station on that carried their SCA. They were playing Isaac Hayes's "SHAFT".
Contrary to popular wisdom, I have NEVER heard such problems with 92KHz SCAs; they have always sounded better.
 
ai4i said:
Not an engineer, but I once complained to a station about this very issue.
The CE explained that some of the HD channels are closer to the analogue sidebands than others.
Click to expand...

That's right -- at least it's in our case for HD4. It's a really small difference though.

ai4i said:
Reminded me of the time I was shopping in a supermarket and the store's 67KHz SCA feed had a LOT of splatter.
I went out to my car and put the station on that carried their SCA. They were playing Isaac Hayes's "SHAFT".
Contrary to popular wisdom, I have NEVER heard such problems with 92KHz SCAs; they have always sounded better.
Click to expand...

We run an SCA service at 67Khz. It coexists fairly well with even the extended hybrid.

It's amazing how many services a single FM station can broadcast from their channel. Since we're a school radio station, we use every speck of our elecctromagnetic space.

RADIO GEEKS ONLY BEYOND THIS POINT:

Our LPFM broadcasts nine services, both analog and digital, from our Radio station; some secret / some public :)

Here's an article I wrote about the mystery of our hidden broadcasts -- for the curious:

https://www.kvcb-online.com/home/blog/the-mystery-of-hidden-broadcasts-on-fm-radio
 
Nice article!
Do you carry a radio reader service for visually challenged news hounds
and can you run a 92KHz SCA in addition to HD, or would they conflict?
 
spiritof67 said:
Ralph, do you stream the HD subchannels? I cannot find the links on your website.
Click to expand...

We only stream the main channel, but most of the programming in the HD channels are also carried on our main channel at various times.


ai4i said:
Nice article!
Do you carry a radio reader service for visually challenged news hounds
and can you run a 92KHz SCA in addition to HD, or would they conflict?
Click to expand...

We have the capability of a 92Khz SCA, but our extended hybrid digital partitions start very close to 100Khz. This could be an issue at times, so we keep that area as a sort of "guard band" for the HD4 channel. Our 67Khz SCA channel is primarily for studio-to-remote talk-back (even though, because of the HD radio diversity delay -- by default -- the SCA is several seconds delayed with our other analog services), and special introductory class programs for our beginner broadcasters. We've even experimented with using it for classroom PA options, but we couldn't produce an SCA receiver with a reliable squelch to make the sets perfectly quiet between messages.

I'm not sure if SCA is that useful for reading services any longer when so many alternatives are available such as text-to-speech apps. But, wouldn't it be cool to have the kids read the local newspaper as an SCA (and online) reading service? If anyone knows if this is still done on SCA, please let me know. I'd love to look into it!
 
Status
This thread has been closed due to inactivity. You can create a new thread to discuss this topic.


Back
Top Bottom