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Something I never understood about this...

J

jras20

On my antenna, I am about 32 miles as a crow flies to Austin's FM towers, I have my outdoor antenna about 27' up, and its going to San antonio. I dont understand though is why cant I pick up, KLBJ, KAMX, KVET, KPEZ, clear? It just seems very distorted and staticy. All others KFMA, KUT, KDHT, KKMJ, KHFI, KASE, KROX, KBPA, KXXS, KFMK, KGSR, all come in clear. Would they possibly be working on the towers? or is it just my antenna? I have a 12 element FM antenna from Radioshack Is expose to pull in stations 110 miles away. Anyone have any suggestions on what I can do to improve the Austin reception? I can pick up San antonio like a local.
<P ID="signature">______________
jras20</P>
 
It sounds like you have placed the Austin towers at a 90 degree angle to the reception pattern of your antenna. You may be putting them in a deep null.

You might find that just turning your antenna a few degrees more towards Austin has little effect on the SA stations, but a huge effect on the Austin.

Did you ever get your Superadio 3 to get 1520?

I forgot that HD transmitters add power to the broadcast spectrum - no doubt that would compensate for any of that 6 dB per octave power factor with bandwidth. Unless one transmitter handled it all, and wasn't boosted to compensate for the digital portion by boosting the power. I assumed the digital on most stations was summed in a combiner. So the analog will work as usual with only combiner losses, and the digital will sum into it.

The engineering gets complex in a hurry when you put combiners into the signal chain! It would be really easy to get it wrong.
 
> It sounds like you have placed the Austin towers at a 90
> degree angle to the reception pattern of your antenna. You
> may be putting them in a deep null.
>
> You might find that just turning your antenna a few degrees
> more towards Austin has little effect on the SA stations,
> but a huge effect on the Austin.
>
> Did you ever get your Superadio 3 to get 1520?
>
> I forgot that HD transmitters add power to the broadcast
> spectrum - no doubt that would compensate for any of that 6
> dB per octave power factor with bandwidth. Unless one
> transmitter handled it all, and wasn't boosted to compensate
> for the digital portion by boosting the power. I assumed
> the digital on most stations was summed in a combiner. So
> the analog will work as usual with only combiner losses, and
> the digital will sum into it.
>
> The engineering gets complex in a hurry when you put
> combiners into the signal chain! It would be really easy to
> get it wrong.
>
Thanks Bruce for the quick reply. I'll half to try to move it later today to see if it will help, Its just a pain, I need to get a rotator for it someday. I never could get my Superradio to pull in 1520. They finally got the audio fixed on 1520 though, it sounds a lot better now. I usually listen to KCTI with my super radio now, it picks it up almost like a local.
<P ID="signature">______________
jras20</P>
 
Well I moved it more, it did improve KLBJ, but still KVET was distorted. I dont remember ever having this problem with them. Wonder if its that stupid HD stuff comming in? I also cleared up 102.3 though it was a little worse than kvet.
<P ID="signature">______________
jras20</P>
 
> Well I moved it more, it did improve KLBJ, but still KVET
> was distorted. I dont remember ever having this problem
> with them. Wonder if its that stupid HD stuff comming in?
> I also cleared up 102.3 though it was a little worse than
> kvet.

Check the list of stations that have converted over on the Ibiquity web site. They love to advertise the list. I'll be willing to bet that the ones you are starting to have trouble with have converted.

Since you are obviously a very competant broadcast engineer, maybe we could try to figure this problem out. I agree with your observations that theoretically, there should be no losses with the HD conversion - provided that they use a combiner properly with a separate digital transmitter. And provided that they boost the signal to the correct degree with a combined digital / analog transmitter.

So where could these losses be happening? Maybe the antenna bays themselves? Perhaps they are becoming saturated? Transmission line effect - maybe some reflection coefficient that escaped everybody until now?
 
I didnt think KVET was yet to be in HD or is it? I know 102.3 is in HD, 89.5 and 90.5, I'm not sure about the rest. My adapter broke off of my antenna today, had to go buy another one to hook up,, but that still didnt clear up my problem.
<P ID="signature">______________
jras20</P>
 
I swung an antenna south the other day - if KVET is 96.1, they are now covered up by IBOC hash from 96.3. I'm not generally a country music fan - so its no big loss, but that was about the last Austin station receivable in the DFW area. (KLBJ used to be a popular rim shot / DX target before being obliterated by a move-in.)

I am hoping this IBOC dies a quick death in the marketplace so stations will shut it off to recover their lost coverage.
 
> I swung an antenna south the other day - if KVET is 96.1,
> they are now covered up by IBOC hash from 96.3. I'm not
> generally a country music fan - so its no big loss, but that
> was about the last Austin station receivable in the DFW
> area. (KLBJ used to be a popular rim shot / DX target
> before being obliterated by a move-in.)
>
> I am hoping this IBOC dies a quick death in the marketplace
> so stations will shut it off to recover their lost coverage.
>

I agree, or is there a way they could fix the coverage to be more dxable? <P ID="signature">______________
jras20</P>
 
> I agree, or is there a way they could fix the coverage to be
> more dxable?

Most stations do not care for their DX audience, which is actually larger than most people think if you include in-car listeners that pick them up well out of the metro area by chance or design. If they figure out IBOC is costing them affluent suburbs - as is happening in Houston and I suspect Dallas, then IBOC may go QUICK, at least until there is a sizable number of receivers out there, and coverage issues are solved. Still - it does not take long, or far, until first adjacents come into play and start zapping the IBOC sidebands. This crazy idea of using first adjacent frequencies is crazy - especially in dense population areas where first adjacents are common on both bands.
 
> > I agree, or is there a way they could fix the coverage to
> be
> > more dxable?
>
> Most stations do not care for their DX audience, which is
> actually larger than most people think if you include in-car
> listeners that pick them up well out of the metro area by
> chance or design. If they figure out IBOC is costing them
> affluent suburbs - as is happening in Houston and I suspect
> Dallas, then IBOC may go QUICK, at least until there is a
> sizable number of receivers out there, and coverage issues
> are solved. Still - it does not take long, or far, until
> first adjacents come into play and start zapping the IBOC
> sidebands. This crazy idea of using first adjacent
> frequencies is crazy - especially in dense population areas
> where first adjacents are common on both bands.
>
They should care about there dx audiences, Look at Lavaca county (where I dx to houston at...) more than half is in a fringe area of any radio station, I acually baught a few things and went to a few restaurants from other towns by dx'n a far station.<P ID="signature">______________
jras20</P>
 
> > > I agree, or is there a way they could fix the coverage
> to
> > be
> > > more dxable?
> >
> > Most stations do not care for their DX audience, which is
> > actually larger than most people think if you include
> in-car
> > listeners that pick them up well out of the metro area by
> > chance or design. If they figure out IBOC is costing them
>
> > affluent suburbs - as is happening in Houston and I
> suspect
> > Dallas, then IBOC may go QUICK, at least until there is a
> > sizable number of receivers out there, and coverage issues
>
> > are solved. Still - it does not take long, or far, until
> > first adjacents come into play and start zapping the IBOC
> > sidebands. This crazy idea of using first adjacent
> > frequencies is crazy - especially in dense population
> areas
> > where first adjacents are common on both bands.
> >
> They should care about there dx audiences, Look at Lavaca
> county (where I dx to houston at...) more than half is in a
> fringe area of any radio station, I acually baught a few
> things and went to a few restaurants from other towns by
> dx'n a far station.
>

I agree Bruce. I've not heard what happens when the IBOC sidebands from say a 107.1 and a 107.5 overlap in their primary contours. Can receivers separate it out or do they just switch back to analog when the interference is occurring?
Trick_Magnet
 
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