For those who travel with HD

[jras20]

I got a question for those who travel with HD, how far can you go before it starts droping out? I'm about 30 miles south of Austin, just driving around, sometimes it drops out, Kind of annoying when listening to a HD-2 channel. My truck antenna system isnt all that great, but it did ok with analog.

 

[KB1OKL]

I don't own one in but have read quite a bit on the subject and 30 miles is pretty good compared to most reports I read because you live in flat terrain. Here in MA with all it's hills I'm sure it would be much worse.

 

[rbrucecarter5]

I don't own one in but have read quite a bit on the subject and 30 miles is pretty good compared to most reports I read because you live in flat terrain. Here in MA with all it's hills I'm sure it would be much worse.

I took an HD tuner with me down to Houston, operated it with a dipole on an inverter. 70 miles with a dipole is about it - the same as Dallas. Analog signals were solid as a rock at the Huntsville rest area, but not a trace of HD on any of them that far out. A good car HD tuner might do about the same, but my wife won't let me install one. The steering column controls on the stock car stereo are too convenient and she doesn't want to lose them. That - may be a microcosm of why more after market radios aren't sold these days - the stock radio is too integrated into the car and there are too many convenient interfaces.

 

[ve3jf]

I got a question for those who travel with HD, how far can you go before it starts droping out? I'm about 30 miles south of Austin, just driving around, sometimes it drops out, Kind of annoying when listening to a HD-2 channel. My truck antenna system isnt all that great, but it did ok with analog.

There is no simple answer to this question, as there are a number of variables. When NPR measured digital coverage on a number of HD FM stations, they found that reliable coverage extended out to about the 50 dBu contour in the best case, and to only the 85 dBu contour in the worst case. The main thing determining coverage is the presence of stations on the adjacent channels. On average, digital coverage probably goes out to the 60-65 dBu contour. To get an idea of what this means for a specific station, you can go to http://www.radio-locator.com, look up the station, and view its coverage map. The red contour is an approximation of the 60 dBu contour.

BTW, I believe the NPR measurements were done using a whip on the roof of a van - if your antenna is significantly worse than that (such as an in-glass antenna), your results won't be as good.

This is yet another illustration of why the NAB et al are pushing the brute force solution of a digital power increase. Think about it: if your digital coverage is limited by adjacent channel interference (because you're using those channels for your digital), and you increase your power to overcome it, then you're also increasing interference to those same stations. Bleah!

 

[Savage]

And there you have it: behold the beautiful simplicity of a truly dumb idea. There's too much interference which is limiting coverage? Just increase the power to increase the interference to overcome the interference that shouldn't have been there in the first place!

Not to argue with my friend, but my sources say that the NAB ENGINEERING section is pushing for the FM digital power increase. But the LEGAL beagles are warning that everyone should slow down, fearing a repeat of the HD-AM debacle. Thus the IBOC FM digital "hike" poses an apparent internal conflict.

While the AM problem has been massaged (note I didn't use the term "finessed") by self-regulation (as in the cases of the Citadel and CCU stations which have voluntarily turned IBOC-AM off to mitigate interference), very low implementation rate and general disinterest and lack of commitment to the band by both owners and listeners, the FM adjacent-channel issue poses far greater potential for generating lawsuits of either the individual or class-action variety.

IBOC interference problems plaguing the creaky old AM in a cluster are one issue. But when an operator buys a Class C in Arizona and does a rimshot move-in with a 100kw signal, representing an investment of $15 million or more, and that investment is suddenly worth bupkis because of an adjacent HD-FM issue, you can bet that owner's not just gonna shrug his shoulders and say, "oh well, sucks to be me. Guess I'll go buy some bowling alleys or a car dealership." Bet on him to trot down to the law firm and engage the legal ICBMs. (EAS header: better head for the bunker, iBiquity and NAB and Alliance!)

Besides, from what I hear NPR opposes the digital power increase.

 

[jras20]

I don't own one in but have read quite a bit on the subject and 30 miles is pretty good compared to most reports I read because you live in flat terrain. Here in MA with all it's hills I'm sure it would be much worse.

I took an HD tuner with me down to Houston, operated it with a dipole on an inverter. 70 miles with a dipole is about it - the same as Dallas. Analog signals were solid as a rock at the Huntsville rest area, but not a trace of HD on any of them that far out. A good car HD tuner might do about the same, but my wife won't let me install one. The steering column controls on the stock car stereo are too convenient and she doesn't want to lose them. That - may be a microcosm of why more after market radios aren't sold these days - the stock radio is too integrated into the car and there are too many convenient interfaces.

Houston Radio, I can recieve 84 miles away a good FM stereo with a dipole antenna, HD I cant. I can hardly get it with my outdoor antenna.

 

[hipporadio]

My Mother and Father have a home on Fripp Island, SC – forty-miles across ocean and ruler-flat tidal marsh from the HD FM stations in Charleston, SC—MOST at 100kw up from 750-1000 feet. In a recent evaluation of a Sangean HDR-1 HD table radio on the second floor of a home elevated on 16-foot stilts, HD and HD-2 reception were undependable on a second generation HD-capable radio connected to a CCrane premium FM dipole antenna. BTW, the analog reception on this receiver was AWESOME – best adjacent-channel selectivity I have ever seen on a “table radio”!!!

Interestingly, those HD Zombies who signed on to this despotic and defective technology, and since its obvious failure, now champion its salvation with a further rape of the prudent technical rules—the infamous “ten-db power increase” in the OFF-CHANNEL originally NON-ALLOCATED and formerly interference-protected ADJACENT CHANNELS... What an intelligent fallback for you desperate near-penny stock corporate radio types who have engaged in a serial-ruination of this business but for your shameless self-promotion since TelComm!!!

The public has NO CONSUMER INTEREST IN HD RADIO, and they have rapidly-diminishing interest IN YOU and your “chest-beating”—more like chest-hair yanking in general...LOL! GET A GRIP QUICK, before you sacrifice the fortunes of that final and unfortunate group that foolishly holds out for your baseless bluster in regards to their sacred 401k, and finally decides brings you down. You are "textbook" in what is wrong with business given a "free pass" by the regulatory body!

This HD experiment [especially on AM radio] HAS to soon experience a final fallen curtain!

 

[KB1OKL]

This is yet another illustration of why the NAB et al are pushing the brute force solution of a digital power increase. Think about it: if your digital coverage is limited by adjacent channel interference (because you're using those channels for your digital), and you increase your power to overcome it, then you're also increasing interference to those same stations. Bleah!

That is similar to the reasoning my lead guitarist took during the late 60's playing in echoing high school auditoriums: turn up the volume and you won't hear it ;D