snip
One humorous but serious side effect of having dual patterns, one for the standard FM signal and another for the HD signal
snip

Are you saying the radio station can transmit (somewhat) separate reception footprints ("dual patterns") for FM-stereo and HD? If so, can you please say more?

Ben

Depends on the station involved.

Some have separate antennas, one for FM and one for HD, which of course often leads to the station ending up with different patterns.

Some stations have purchased newer transmitters that transmit both FM & HD together, whereby the same antenna can be used.

And, as I've mentioned before, the stations that present the most difficult situations are those that share antennas with other stations, and have their transmitters feed into combiners to allow each stations transmitter to see the antenna without "knowing" other things are connected to the same antenna. All that stuff is quite carefully designed around an FM signal, and a digital signal will behave differently and require different combining equipment or if nothing else, a complete re-tune of existing equipment. Can we say costly.....

Cameron

Just went from a Winegard 4-element to a Winegard monster 6065 10-element, 9 foot jobbie. Went from occasional forays into HD on PBS 94.5 to frequent forays. That is worse!

(Anybody added an HD-defeat switch to their Sony?)

We have some big trees in the way but my feeling is that HD from PBS is a lost cause. Transmitter is south of Buffalo and not high. However, pop station 102.5 was full-time HD before and, maybe my imagination, seems cleaner now on the Sony with bigger antenna.

I'd have trouble hearing the difference between HD and FM-stereo based on my limited PBS experience, at least based on experience.

Seems like a good idea, I suppose, for the Canadian stations try it. Does that sound half-hearted?

Ben

There's been changes at WTSS (102.5).

They dropped the blues on HD2 (unfortunately), and stuffed Newsradio 930 in it's place.

The HD1 signal almost sounds the same as the FM feed, no more breaking glass top end... and is a lot more natural sounding (within the confines of today's over processed audio).

Signal strength appears unchanged here.

The bigger antenna will be better at aiming at a particular station and avoiding multipath. The added gain, as you found out can be problematic.

One way of cutting back the signal is put in a splitter with unused taps having terminators on them. Not ideal, but a solution.

I once had one of those "FM Sleuth" tunable amplifiers for FM. Worked a charm. That, combined with a TFM-2 double tunable trap filter worked wonders. I had a 6 element beam fed with 300 ohm shielded beldon cable... That was quite the setup.... Many many moons ago... :-)

Cameron

Thanks for WTSS update. One of the benefits of HD is that stations can do that trick: music on HD1 and talk/news on HD2. Esp. nice with PBS music and APR talk/news. In south Florida, we get West Palm Beach with APR on HD1 and Miami with APR on HD2.... so even without HD, you get both or with HD, like we get half-way between the cities, roughly 3.5 separate broadcasts to choose from.

Got PBS HD all Sunday afternoon without noticing a single break. Maybe big trees in line of sight stopped sending sap or weather or something. Buffalo FM signal strength doesn't seem closely correlated to Buffalo TV/UHF.

But as long as on some days there is more-than-occasional switching in-and-out, some means of defeat is needed. (Easy to add a manual defeat switch to Sony if you have profound soldering skills and eagle eyesight.)

Gawd, I hate working with any hobby where I can't MEASURE what is going on. The Sony tuner has a meager 1, 2, or 3-bar signal strength meter plus "HD" flashing or solid.

My loose impression is there is no "happy medium" where there is insufficient signal to trigger HD sometimes yet there is sufficient signal to get great FM-stereo.

So just adding attenuation means HD isn't triggered but the FM-stereo is too weak to be high-class sound.

A particular strength of the famous Sony is that it has trick circuitry downstream that makes weak FM-stereo (and weak HD????) sound far better than the competition.

That's nice and just maybe there is a bit of "happy medium."

Ben

HD Radio uses sideband above and below the analog signal so if stronger analog station on same frequency will block the analog signal but allow the HD signal part thru of the weaker signal.Thus I can receive HD WYRK only and if it drops out i get AVR Toronto.Bad management by Industry Canada here.Before AVR went on air WYRK analog came in fine even in my car in mississauga.

HD Radio uses sideband above and below the analog signal so if stronger analog station on same frequency will block the analog signal but allow the HD signal part thru of the weaker signal.Thus I can receive HD WYRK only and if it drops out i get AVR Toronto.Bad management by Industry Canada here.Before AVR went on air WYRK analog came in fine even in my car in mississauga.
Sorry, I can't understand what you are saying. Can you re-phrase your comment, please?

Thanks.
Ben

Sorry, I can't understand what you are saying. Can you re-phrase your comment, please?

A picture is worth a thousand words. Here is a spectral analysis of a typical hybrid HD Radio broadcast:

http://ham-radio.com/k6sti/fig1.jpg

The analog broadcast is in the centre and the HD broadcast is on the two (left and right) side bands. Since AVR (Toronto) uses the same frequency as WYRK (Buffalo), it obliterates the analog FM signal, but the HD broadcast is not affected. If WYRK's HD signal becomes too weak to receive, the radio will switch to back to analog, which in this case will be AVR.

I am pretty much dt Vancouver. Any point in attempting HD radio?

Interesting, if weird. Thanks.

Is that a good image or simulation of the signal from an HD station?

Ben

^^^It is a photograph of a spectrum analyzer (http://en.wikipedia.org/wiki/Spectrum_analyzer) measuring a real hybrid HD radio broadcast.

That was an interesting display.

I wonder what a display of HD Radio looks like when transmitting in digital only mode (minus the FM carrier component)...

Cameron

stationg, I only occasionally got HD Radio from SeaTac when driving near UBC or in the Langley area. You won't have any luck with it in downtown Vancouver.

I wonder what a display of HD Radio looks like when transmitting in digital only mode (minus the FM carrier component)...


Ask and you shall receive. These are simulations:

https://encrypted-tbn1.google.com/images?q=tbn:ANd9GcTaspVnPNXbJq5N2nFPiBF1TEQLklQtRCA8EG1Rt81 IwVIRFtQm
from: Overview of HD Radio Technology (http://www.ibiquity.com/international/general_overview)

For a better explanation of the All-digital waveform :

http://ecee.colorado.edu/~liue/teaching/comm_standards/2011F_HD_Radio/index_files/image011.jpg
from: HD Radio Tutorial (http://ecee.colorado.edu/~liue/teaching/comm_standards/2011F_HD_Radio/)

Has anyone noticed that on WTSS (102.5) from Buffalo that their HD2 stream with the Newsradio 930 feed has audio that is out of phase?

The FM and HD1 feeds sound fine... Just the Newsradio feed on HD2 has gone wrong... It was fine at one time...

(I still think that Delta Blues was a much better use of HD2.... But what do I know... :-) )

Cameron

A disappointing trend putting am talk radio onto HD radio.This does not add any new content to the airways.It does sound strange hd2 wtss

It shows that broadcasters see more value in extracting an extra 0.2% share point for their legacy brands than making something of new brands.

Unfortunately, they're probably right. They made the right decision in the first place to put the content there first to sell the technology, but it's gone on long enough without being monetized.

HD radio advertized about extra channels but now its becoming get your am talk radio in HD.Not much of a selling point.I am perfectly happy with talk radio on the am band.

One station, folks. No need to extrapolate from that for all of broadcasting.

Well... Almost... :-)

Another station in the Buffalo area on 107.7 MHz did a flip last year... Primary FM signal was a rock format along with the HD1 feed. HD2 *was* Newsradio 930...

After the flip, FM and the HD1 became Newsradio 930 and the rock moved to HD2.

Apparently (I can't get all the HD's in Buffalo to confirm) but that I seem to remember Newsradio 930 showing up on other HD2's as well as on 930KHz AM...

So... to me, not a great use of technology. If the bitrate had been lowered to something better than AM, and put in mono, then it would make sense on an HD3 stream, but in stereo, out of phase kinda takes the cake for wasted bandwidth....

Reminds me of the DAB days from Toronto.... :-(

Cameron