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Mighty 1190 - Simultaneously transmitting today from both xmit sites based on observations

J

_Jim

Guest
Mighty 1190 - Simultaneously transmitting today from both xmit sites based on observations

About 10 AM I noticed about a 4 or 5 Hz beat note -
from a pair of carriers present on 1190!

I also noticed cancellation of program audio, most
likely due to out-of-phase destructive cancellation
of the same program audio playing out from both
transmitter sites.

Observing Location: In central Plano east of US-75.
 
Re: Mighty 1190 - Simultaneously transmitting today from both xmit sites based on observations

> About 10 AM I noticed about a 4 or 5 Hz beat note -
> from a pair of carriers present on 1190!
>
> I also noticed cancellation of program audio, most
> likely due to out-of-phase destructive cancellation
> of the same program audio playing out from both
> transmitter sites.
>
> Observing Location: In central Plano east of US-75.

Sounds about right when the day and night sites are both on....
Hello, 1st Broadcasting!!???!! (we could include CC since legally they are the licensee and still responsible for its technical operation).

And who said noone listens to AM music anymore?? :)
 
Re: Mighty 1190 - Simultaneously transmitting today from both xmit sites based on observations

English, please. You saying that the nighttime towers were still on, and were 'competing' with the daytime ones? Suppose a prospective new owner was having some testing done?

I hooked up my oscilloscope just for laughs and here's what I got. The pattern was surprisingly predictable:

oscilloscope.gif
About 10 AM I noticed about a 4 or 5 Hz beat note -
> from a pair of carriers present on 1190!
>
> I also noticed cancellation of program audio, most
> likely due to out-of-phase destructive cancellation
> of the same program audio playing out from both
> transmitter sites.
>
> Observing Location: In central Plano east of US-75.
>
 
Re: Mighty 1190 - Simultaneously transmitting today from both xmit sites based on observations

> English, please. You saying that the nighttime towers were
> still on, and were 'competing' with the daytime ones?

I presume both daytime and nighttime sites were 'up' at the same
time, or, perhaps, some other transmitting site was active for
that brief observation period (I didn't DF/get bearings on the
source of the two signals - next time I will!)


> Suppose a prospective new owner was having some testing
> done?

I have noticed that the deep 'nulls' once exhibited by what I
presume had to be 1190's nighttime pattern don't seem as deep
or as noticable when driving my N-S route on Hwy-5 from Plano
northward, unlike what it was last year!


>
> I hooked up my oscilloscope just for laughs and here's what
> I got. The pattern was surprisingly predictable:
>
> - image snipped -
>
> > About 10 AM I noticed about a 4 or 5 Hz beat note -
> > from a pair of carriers present on 1190!
> >
> > I also noticed cancellation of program audio, most
> > likely due to out-of-phase destructive cancellation
> > of the same program audio playing out from both
> > transmitter sites.
> >
> > Observing Location: In central Plano east of US-75.
> >
>
 
Re: Mighty 1190 - Simultaneously transmitting today from both xmit sites based on observations

The day site had all its phone connections lost, thanks to a construction crew working on McArthur that snapped the cable. The Day site was on - but there was no audio coming out - since audio for those stations is carried over phone lines. The night site was brought up to stay on the air. Since all the phone lines were down, there was no way to turn OFF the day site remotely - so someone had to physically drive out there to turn it off.

Thats what you heard.<P ID="signature">______________
vide0 killed the radi0 star</P>
 
Re: Mighty 1190 - Simultaneously transmitting today from both xmit sites based on observations

> The day site had all its phone connections lost, thanks to a
> construction crew working on McArthur that snapped the
> cable. The Day site was on - but there was no audio coming
> out - since audio for those stations is carried over phone
> lines. The night site was brought up to stay on the air.
> Since all the phone lines were down, there was no way to
> turn OFF the day site remotely - so someone had to
> physically drive out there to turn it off.
>
> Thats what you heard.
>

Thanks for the 'fill'.

> The night site was brought up to stay on the air.
> Since all the phone lines were down, there was no
> way to turn OFF the day site remotely

Hmmmm ... no cessation of transmitting the 'carrier' on
the loss of program audio for an extended period of time
apparently ...

> Thats what you heard.

Yes, a 'beat' note indicating the prescence of two carriers
about 4 or 5 Hz (cycles per second) difference in frequency
from which I inferred that the two different transmitting
sites (day and night) used by 1190 were on the air concurently
(not everyone reading this board may know that 1190 employs
different sites for day and night).

And, I could swear I heard other 'artifacts' such as 'phase'
distortion due the audio cancelling ... wish I had recorded
that now.
 
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