Will HD Radio eliminate even FM DXing?

[BamaWOLF]

> > I documented this on the Houston board a couple of weeks
> > back.  For years, I have been regularly going back and
> forth
> > to Houston.  KLDE 107.5 would always be one of the first
> > Houston stations I could get, around Centerville.  After
> > they went IBOC - they have trouble making it into
> > Huntsville.  While I doubt either city is in their ratings
> -
> > I was using a Pioneer Supertuner.  Ordingary radios are
> > probably dropping in the Woodlands and Conroe, or even the
>
> > Northern suburbs of Houston.  All very affluant areas,
> which
> > should be highly prized by any Houston station.  If I were
>
> > KLDE, I would immediately drop HD to get my coverage
> back!!!
> >  One estimate is that coverage is down just a few percent,
>
> > somebody else wrote that it can be down an astonishing
> > 60%!!!
> >
> > Station managers - BEWARE OF IBOC COVERAGE LOSSES!!!  Can
> > you afford to lose affluent suburbs for this pipe dream
> that
> > only enriches Ibiquity / Clear Channels pocketbooks?!  Do
> > you want your wealthiest listeners giving up on your
> > degraded signal to go to competitors, satellite, or iPods?
>
> >
> I didn't notice any coverage loss with WJJZ 106.1's IBOC
> before and after they got IBOC.  Maybe the coverage loss is
> due to an adjacent station's IBOC hash.
>
> If you DX an IBOC station with an HD radio, the ID will be
> displayed, so you won't have to wait for it.  You can just
> move on to the next station, so DXing will be easier.
>
I see absolutely no difference in WTAK 106.1 here in Huntsvlle AL, I live in a weaker area of their signal and any loss would be easily noticed here. it is also having no effect on 105.9 or 106.3, 105.9 being about 90 miles to the north in nashville, and 106.3 being a weaker station over in Muscle Shoals

Edited by BamaWOLF on 08/20/05 12:29 AM.

[Philip J. Smith]

> Station managers - BEWARE OF IBOC COVERAGE LOSSES!!!  Can
> you afford to lose affluent suburbs for this pipe dream that
> only enriches Ibiquity / Clear Channels pocketbooks?!  Do
> you want your wealthiest listeners giving up on your
> degraded signal to go to competitors, satellite, or iPods?

Unlike AM IBOC, FM IBOC's sidebands are so far outside the center frequency at significantly reduced power, that they should have zero effect on the analog FM Stereo signal on any properly-functioning receiver.  Stations transmitting HD Radio can even include RDS, 67kHz, and 92kHz subcarriers which are all well outside the FM and DSSC components of the main signal.  I would venture to say that if you are noticing problems on a receiver for HD Radio stations, the same receiver would produce noise and/or audio from stations with RDS or 67/92 kHz subcarriers.  I once had a Pioneer home stereo where RDS and SCA's could be heard "underneath" the baseband audio; for these defective receivers there is no hope, and likewise no concern.  I dumped that receiver years ago because of the RDS/SCA issue, long before HD Radio existed.

I am not an HD Radio advocate by any means.  Anyone who has read my posts probably already knows my opinion that is this is an inferior technology, which I feel should be replaced with an out-of-band or less harmful in-band solution.  Still, I have only once observed a change in coverage for any FM IBOC station in my receivers, most of which contain analog IF circuitry and one which has a DSP circuit.  That single instance of coverage loss was due to improper filter configuration at the transmitter, which was switched in specifically for IBOC.

Note that I'm only talking about FM IBOC's effect on the station actually transmitting the HD Radio signal, and I am assuming that the station hasn't mucked with their TX chain in some way for the IBOC implementation.  Adjacent- and alternate-channel effects, as well as AM IBOC, are separate topics for which I have mile-long rants on reserve.

[Philip J. Smith]

> If you DX an IBOC station with an HD radio, the ID will be
> displayed, so you won't have to wait for it.  You can just
> move on to the next station, so DXing will be easier.

That FM station will really need to BOOM IN if you're going to get their IBOC signal, and there better not be any stations on both of the first-adjacent frequencies (especially those with IBOC themselves).  I would venture to say that you would have better luck IDing a station from their RDS stream before IDing them via HD Radio, but that's just an educated guess.

[k9ez]

> > If you DX an IBOC station with an HD radio, the ID will be
>
> > displayed, so you won't have to wait for it.  You can just
>
> > move on to the next station, so DXing will be easier.
>
> That FM station will really need to BOOM IN if you're going
> to get their IBOC signal, and there better not be any
> stations on both of the first-adjacent frequencies
> (especially those with IBOC themselves).  I would venture to
> say that you would have better luck IDing a station from
> their RDS stream before IDing them via HD Radio, but that's
> just an educated guess.
>


I believe you are correct, but most of the HD radios I have seen dont offer RDS, just HD "RDS".

I did pull in a station 90 miles away in HD, so it is a start.