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Let me get this straight...

J

JM_pstar

Guest
As I have mentioned before on this board, I live about 115-130 miles north of Albuquerque, New Mexico. The area that I live in is very mountainous and hilly. I've noticed that whenever I am in a part of town that doesn't have as many hills/mountains to block the radio signals from Albuquerque, many of those Class C FM stations (there are a lot of them in Albuquerque!) almost sound local. HD radio is supposed to do away with multipath interference, right? Is it safe to say, given these conditions, that I can have more hope of being able to pull in Albuquerque HD stations (at least FM...maybe KKOB-AM, as well)?

Is it remotely possible that HD Radio signals would make it into areas previously not accessible to analog signals due to multipath interference, such as a canyon between here and Albuquerque? I doubt it, but it couldn't hurt to ask.

I know that I've asked how possible it'd be to receive HD signals, particularly in my case, a couple of times before. Sorry of it's getting annoying, but I need to figure out whether it'd be worth working or something to buy an HD Radio at this point in time. The chances of my local stations broadcasting in HD soon is very slim, I would imagine, so it doesn't make sense to invest in an HD Radio at this time if I can't pull in HD signals from Albuquerque. Thanks.
 
> As I have mentioned before on this board, I live about
> 115-130 miles north of Albuquerque, New Mexico. The area
> that I live in is very mountainous and hilly. I've noticed
> that whenever I am in a part of town that doesn't have as
> many hills/mountains to block the radio signals from
> Albuquerque, many of those Class C FM stations (there are a
> lot of them in Albuquerque!) almost sound local. HD radio is
> supposed to do away with multipath interference, right? Is
> it safe to say, given these conditions, that I can have more
> hope of being able to pull in Albuquerque HD stations (at
> least FM...maybe KKOB-AM, as well)?
>
> Is it remotely possible that HD Radio signals would make it
> into areas previously not accessible to analog signals due
> to multipath interference, such as a canyon between here and
> Albuquerque? I doubt it, but it couldn't hurt to ask.
>
> I know that I've asked how possible it'd be to receive HD
> signals, particularly in my case, a couple of times before.
> Sorry of it's getting annoying, but I need to figure out
> whether it'd be worth working or something to buy an HD
> Radio at this point in time. The chances of my local
> stations broadcasting in HD soon is very slim, I would
> imagine, so it doesn't make sense to invest in an HD Radio
> at this time if I can't pull in HD signals from Albuquerque.
> Thanks.
>

Boy, that's a tough one! The best bet is to see if you can order a radio from a place with a good return policy. That way you can try it out and return it if it doesn't work.

I know I certainly don't want to be the one to tell you to go ahead, only to find out it didn't work!

:)<P ID="signature">______________
</P>
 
I have serious doubts about most HD Radio claims.
The digital signals of both AM and FM HD stations are very low compared to the broadcasting stations analog licensed power.
I agree with RadioDoc that if you are really interested, try an HD radio and get back to us. Also, get that iron clad 100% satisfaction return guarantee from a reputable seller.

> > As I have mentioned before on this board, I live about
> > 115-130 miles north of Albuquerque, New Mexico. The area
> > that I live in is very mountainous and hilly. I've noticed
>
> > that whenever I am in a part of town that doesn't have as
> > many hills/mountains to block the radio signals from
> > Albuquerque, many of those Class C FM stations (there are
> a
> > lot of them in Albuquerque!) almost sound local. HD radio
> is
> > supposed to do away with multipath interference, right? Is
>
> > it safe to say, given these conditions, that I can have
> more
> > hope of being able to pull in Albuquerque HD stations (at
> > least FM...maybe KKOB-AM, as well)?
> >
> > Is it remotely possible that HD Radio signals would make
> it
> > into areas previously not accessible to analog signals due
>
> > to multipath interference, such as a canyon between here
> and
> > Albuquerque? I doubt it, but it couldn't hurt to ask.
> >
> > I know that I've asked how possible it'd be to receive HD
> > signals, particularly in my case, a couple of times
> before.
> > Sorry of it's getting annoying, but I need to figure out
> > whether it'd be worth working or something to buy an HD
> > Radio at this point in time. The chances of my local
> > stations broadcasting in HD soon is very slim, I would
> > imagine, so it doesn't make sense to invest in an HD Radio
>
> > at this time if I can't pull in HD signals from
> Albuquerque.
> > Thanks.
> >
>
> Boy, that's a tough one! The best bet is to see if you can
> order a radio from a place with a good return policy. That
> way you can try it out and return it if it doesn't work.
>
> I know I certainly don't want to be the one to tell you to
> go ahead, only to find out it didn't work!
>
> :)
>
 
> I have serious doubts about most HD Radio claims.
> The digital signals of both AM and FM HD stations are very
> low compared to the broadcasting stations analog licensed
> power.
> I agree with RadioDoc that if you are really interested, try
> an HD radio and get back to us. Also, get that iron clad
> 100% satisfaction return guarantee from a reputable seller.
>

There is a reason why the digital power levels are lower. You dont need as much power to carry as far with digital as you do with analog. If you take a look at cell phoens for an example, the old analog phones use up to 3 watts. Digital (which basically have the same coverage) have significantly lower power to cover the same area.
 
> > I have serious doubts about most HD Radio claims.
> > The digital signals of both AM and FM HD stations are very
>
> > low compared to the broadcasting stations analog licensed
> > power.
> > I agree with RadioDoc that if you are really interested,
> try
> > an HD radio and get back to us. Also, get that iron clad
> > 100% satisfaction return guarantee from a reputable
> seller.
> >
>
> There is a reason why the digital power levels are lower.
> You dont need as much power to carry as far with digital as
> you do with analog. If you take a look at cell phoens for
> an example, the old analog phones use up to 3 watts. Digital
> (which basically have the same coverage) have significantly
> lower power to cover the same area.
>

Darn...I was hoping that you might be able to help me, k9ez! :) Oh well...

Thanks, Doc and SuperSound. I will try that. Now to get the money for that HD Radio...
<P ID="signature">______________
16-year-old radio geek.</P>
 
> > > I have serious doubts about most HD Radio claims.
> > > The digital signals of both AM and FM HD stations are
> very
> >
> > > low compared to the broadcasting stations analog
> licensed
> > > power.
> > > I agree with RadioDoc that if you are really interested,
>
> > try
> > > an HD radio and get back to us. Also, get that iron clad
>
> > > 100% satisfaction return guarantee from a reputable
> > seller.
> > >
> >
> > There is a reason why the digital power levels are lower.
>
> > You dont need as much power to carry as far with digital
> as
> > you do with analog. If you take a look at cell phoens for
>
> > an example, the old analog phones use up to 3 watts.
> Digital
> > (which basically have the same coverage) have
> significantly
> > lower power to cover the same area.
> >
>
> Darn...I was hoping that you might be able to help me, k9ez!
> :) Oh well...
>
> Thanks, Doc and SuperSound. I will try that. Now to get the
> money for that HD Radio...
>


Sure wish I could help you but I do not have expereince in that kind of distances with HD, let alone a full Class C station. Most of the stations in my area are B.
 
I've built a couple of HD stations in the past year. And the real world of reception and coverage is different than any claims by Ibquity you might have read.

First of all, FM coverage by HD is generally good within the 70 dbu (3.16 mv/m) contour of FM, and fairly robust inside the 5 mv contour of AM stations. Outside of those general coverage contours, it falls apart pretty quickly. HD AM in particular is vulnerable to power line noise and driving under bridges and such, as is it's analog counterpart. HD FM seems to suffer the same problems as it's analog counterpart, except there is no multi-path. Dropouts, digital glitches, switching back and forth from analog to digital, yes. But no multi-path.

Whoopie...

I was surprised by the lack of robustness of the HD signal within the primary contours myself. At one of the stations, we rigged up a Kenwood HD Car radio into a nice display in the front office, put a set of rabbit ears on the antenna input, and despite a measured 80 dbu + analog signal, the HD portion came and went with people moving around in the office. The analog was fine as usual, never even a wisp of noise on the same radio. The staff was trying to figure out what we spent $120K on. So was I. The second digital audio channels are nice, but suffer the same problems as the main channel HD. They simply don't drive as well as the analog side.

If you are hoping to improve listening to stations far away, HD is not going to help you, unless you are at home with a high gain directional yagi on the roof pointed at the transmitter of interest. Then you might get something. KKOB-AM? Forget it at night. I'm not sure the FCC will ever authorize it. And if you drive past powerlines and noisy lights, forget it.

If you are trying to listen to HD radio in a car, I am afraid you might be disappointed. YMMV.

Been there, still doing it...

> Sure wish I could help you but I do not have expereince in
> that kind of distances with HD, let alone a full Class C
> station. Most of the stations in my area are B.
>
 
> I've built a couple of HD stations in the past year. And the
> real world of reception and coverage is different than any
> claims by Ibquity you might have read.
>
> First of all, FM coverage by HD is generally good within the
> 70 dbu (3.16 mv/m) contour of FM, and fairly robust inside
> the 5 mv contour of AM stations. Outside of those general
> coverage contours, it falls apart pretty quickly. HD AM in
> particular is vulnerable to power line noise and driving
> under bridges and such, as is it's analog counterpart. HD FM
> seems to suffer the same problems as it's analog
> counterpart, except there is no multi-path. Dropouts,
> digital glitches, switching back and forth from analog to
> digital, yes. But no multi-path.
>
> Whoopie...
>
> I was surprised by the lack of robustness of the HD signal
> within the primary contours myself. At one of the stations,
> we rigged up a Kenwood HD Car radio into a nice display in
> the front office, put a set of rabbit ears on the antenna
> input, and despite a measured 80 dbu + analog signal, the HD
> portion came and went with people moving around in the
> office. The analog was fine as usual, never even a wisp of
> noise on the same radio. The staff was trying to figure out
> what we spent $120K on. So was I. The second digital audio
> channels are nice, but suffer the same problems as the main
> channel HD. They simply don't drive as well as the analog
> side.
>
> If you are hoping to improve listening to stations far away,
> HD is not going to help you, unless you are at home with a
> high gain directional yagi on the roof pointed at the
> transmitter of interest. Then you might get something.
> KKOB-AM? Forget it at night. I'm not sure the FCC will ever
> authorize it. And if you drive past powerlines and noisy
> lights, forget it.
>
> If you are trying to listen to HD radio in a car, I am
> afraid you might be disappointed. YMMV.
>
> Been there, still doing it...
>
>


I think a lot of it has to do with terrain, however. Here in the Midwest, where the terrrain is flat, I will generally get a good HD signal into the 50 dBu zone.

I can easily lock on Class B signals 40 miles out from the TX site, using a Kenwood car radio with an in-glass antenna.<P ID="signature">______________
</P>
 
> I think a lot of it has to do with terrain, however. Here
> in the Midwest, where the terrrain is flat, I will generally
> get a good HD signal into the 50 dBu zone.
>
> I can easily lock on Class B signals 40 miles out from the
> TX site, using a Kenwood car radio with an in-glass antenna.

Like I said, your mileage may vary. The question came from a person in the mountains of New Mexico. I know the territory very well, having built a Class C FM in Taos a little over a year ago. In California, FM HD hangs together as long as you have line-of-sight to the transitter. After that, it is not as dependable as analog FM. Don't get me started about AM HD.
In Hawaii, where I work about 50% of the time, it remains to be seen if it is going to be viable. It's all mountains and water there, and it's difficult at best to make analog FM cover everyone, using defraction over razor-back ridges, boosters and translators and other tricks of the trade. The budget is in place, HD will be built, but I can't tell you if it will work over there. I just don't know.
 
> > I think a lot of it has to do with terrain, however. Here
>
> > in the Midwest, where the terrrain is flat, I will
> generally
> > get a good HD signal into the 50 dBu zone.
> >
> > I can easily lock on Class B signals 40 miles out from the
>
> > TX site, using a Kenwood car radio with an in-glass
> antenna.
>
> Like I said, your mileage may vary. The question came from a
> person in the mountains of New Mexico. I know the territory
> very well, having built a Class C FM in Taos a little over a
> year ago. In California, FM HD hangs together as long as you
> have line-of-sight to the transitter. After that, it is not
> as dependable as analog FM. Don't get me started about AM
> HD.
> In Hawaii, where I work about 50% of the time, it
> remains to be seen if it is going to be viable. It's all
> mountains and water there, and it's difficult at best to
> make analog FM cover everyone, using defraction over
> razor-back ridges, boosters and translators and other tricks
> of the trade. The budget is in place, HD will be built, but
> I can't tell you if it will work over there. I just don't
> know.
>

Thank you, SML and k9ez.

SML, gee, that is exactly where I live! Did you happen to work on the KXMT project when they moved the transmitter to the base of San Antonio Mountain (at least I think that's where they moved it)?

So, given how you know Taos' terrain and how HD signals work, you don't think that HD will work very well out here? I know that it's not easy to say yea or nay unless you actually try it...but it can't hurt to do research before actually investing in the radio.
<P ID="signature">______________
16-year-old radio geek.</P>
 
> Thank you, SML and k9ez.
>
> SML, gee, that is exactly where I live! Did you happen to
> work on the KXMT project when they moved the transmitter to
> the base of San Antonio Mountain (at least I think that's
> where they moved it)?

KXMT is near the top of Mt. San Antonio.
Try this URL for the whole story:

http://www.well.com/user/dmsml/kxmt/index.html

> So, given how you know Taos' terrain and how HD signals
> work, you don't think that HD will work very well out here?
> I know that it's not easy to say yea or nay unless you
> actually try it...but it can't hurt to do research before
> actually investing in the radio.

Like I said, YMMV. In the Taos valley, even the analog signals from down south don't have enough punch to get through very well in the first place. Down around Santa Fe you might have a better chance. So far, from my direct esxperience, HD Radio is iffy in hilly terrain at a distance. What I am finding is that a higher power level for HD does overcome some of its limitations in hilly terrain. But so far, we are not authorized to run it that way.
If it was me, I would save my $$ for a time when either the money-back guarantee is assured, or the price comes down enough that you can afford to take the risk.
 
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