How Is It That IBOC Can Make It Sound.....

[RJ Kanary]

Like you are listening to an AM station in a car and are driving in and out of the nulls in their directional array? This of course is occuring at home while listening to KDKA 1020 on any AM receiver that I have. And they DON'T have a directional array. It also sounds very similar to groundwave cancellation, but I find it hard to believe THAT is possible at 13:00 on a sunny afternoon. It's also available after sunset.

I live in Southeastern Butler County,not far from where KDKA was located until 1940 or so.

I'm told by station personnel that the blowtorch's hand cuffs have been removed and it is operating at full power. Could this newly noticed irritation be caused by some unanticipated interaction between their sectionalized radiator and the additional trash that IBOC tacks onto the RF ?

RJ

 

[TomT]

Not sure what you are hearing, but with the low point in the sunspot cycle we are getting daytime skip, particularly high angle skip.

So you may well be hearing fading caused by the interaction of the groundwave signal and this high-angle skip. We heard this on WWVA, Wheeling in northern WV, about 70 miles from their transmitter site at around ten in the morning.
Butler County seems too close, but who knows.

Common any time of year is fading caused by interaction between ground wave signal and re-radiation from power lines, especially high voltage lines which can carry AM signals like a long-wave antenna.

Another source of interference is WBZ. The IBOC sidebands have been heard interfering with KDKA at night in downtown Pittsburgh, early morning skip signal may be strong enough to add considerable hiss to the KDKA signal out in Butler County.

 

[RJ Kanary]

I'll have to get ambitious and put together an mp3 file of it.It's not just hiss, which is omnipresent now, but is more in line with listening to the distortion commonly associated with listening to distant shortwave broadcasts. Again, akin to driving through the nulls generated by KQV's night pattern if you happen to be North of the City.

RJ

 

[DanStrassberg]

I'll have to get ambitious and put together an mp3 file of it.It's not just hiss, which is omnipresent now, but is more in line with listening to the distortion commonly associated with listening to distant shortwave broadcasts. Again, akin to driving through the nulls generated by KQV's night pattern if you happen to be North of the City.
RJ

I live 10 miles from downtown Boston. About a year ago, I experienced what appear to have been the identical symptoms while listeing to WBZ. Problem lasted for several months, IIRC. Eventually, I e-mailed Mark Manuelian, WBZ's CE, who said that there was no problem at the station. I was listening on a Super Radio III, which was more than 10 years old but in good condition. Then one day, seemingly with no warning whatsoever, the varactor tuner in the SR III died--the tuning became totally unstable; the selected frequency was running madly up and down the dial and was completely not under control of the tuning knob. My conclusion is that the moribund tuner was responsible for the reception problems I was experiencing with WBZ. I think, prior to the failure of the tuner, the tuning of the radio became just unstable enough to cause the radio to simulate the "shortwave" effect. Can I prove that this is the case? No, but if the tuner problem wasn't the cause of the strange reception, it was a rather odd coincidence.

 

[RJ Kanary]

I have a multitude of receivers here, several transistor units dating back into the Sixties and Seventies.All exhibit the same behaviour.{I don't have the dexterity left to re-string the dialcord on my Farnsworth BT-600 series LW/MW/SW receiver or I'd try than one, too.} <VBG>

 

[Sgeirk]

The problem is probably IBOC itself. If I owned or operated a 50kw clear channel AM station, there is no way in HELL I would run IBOC.

 

[calstymes]

Sgeirk bristled:

The problem is probably IBOC itself. If I owned or operated a 50kw clear channel AM station, there is no way in HELL I would run IBOC.

And you are a SMART man! But sadly, it may not be up to you, particularly if you only operated (and not owned) the station and you had to answer to a higher corporate authority that was financially "involved" with iBiquity.

We shudder to think such a thing, eh?