If being heard over a wide area, intermodulation is probably occurring near the
transmitter. It may or may not be the broadcast transmitter, though, as many
transmitters are often co-located at any given site. The broadcaster is
probably the one best suited to unravel this one.
Ed, W1RFI
________________________________
From: RFI <rfi-bounces+w1rfi=arrl.org@contesting.com> on behalf of Don Kirk
<wd8dsb@gmail.com>
Sent: Monday, January 9, 2023 6:10 PM
To: Bob Kozlarek WA2SQQ <wa2sqq@gmail.com>
Cc: rfi@contesting.com <rfi@contesting.com>
Subject: Re: [RFI] 160m spur
Hi Bob,
I’m the person who determined that The third order IMD product of WWRU and
WKDM could cause the spurious signal on 1940 KHz and then I provided my
recommendation as follows.
—————
If the IMD is being generated within their hardware and they exceed the
emission limits as stated in section 73 of the FCC rules then the station
must address the problem (no need to prove harmful interference to anyone
for it to be a problem that needs to be fixed). If I were in the area I
would try and confirm the IMD is originating from the property of the
transmitter site, and then make an attempt to measure the spurious emission
signal strength relative to the carrier frequency signal strength (an
approximation is fine) to show that the spurious emission likely exceeds
the allowable limits. After achieving this I would then contact the
station general manager to explain the situation including the fact that
ham radio operators over a pretty large geographic area are hearing their
out of band spurious emissions and then have him put you in direct contact
with the chief engineer of the station to look into the problem (this
sometimes requires a lot of digging before you are able to make contact
with the right people).
—————-
I would not get the FCC involved as a first step, only if the station does
not address the problem after it’s shown to be coming from their property
would I get the FCC involved.
You might discuss offline with K2XT and W3LPL as they have been following
this closely. Since you are so close to the suspected AM broadcast
stations you would be a good candidate to follow up on this with them.
73,
Don wd8dsb
On Mon, Jan 9, 2023 at 5:46 PM Bob Kozlarek WA2SQQ <wa2sqq@gmail.com> wrote:
> So that’s where it comes from! That spur is S9, I live about 5 miles from
> those towers. So has anyone contacted the two stations? Is this something
> the FCC could be involved in? FYI I’m two air miles from WABC and luckily
> they don’t give me any problems. My Flex radio is tight as a crabs butt!
>
> Date: Fri, 6 Jan 2023 18:36:26 -0500 (EST)
> From: Frank W3LPL <donovanf@starpower.net>
> To: topband <topband@contesting.com>, rfi <rfi@contesting.com>
> Subject: Re: [RFI] The 160 meter spur
> Message-ID:
> <1169758511.11327047.1673048186910.JavaMail.zimbra@starpower.net>
> Content-Type: text/plain; charset=utf-8
>
> Hi Rick
>
> I've attached a photo of the four 237 foot towers used by 1660 kHz WWRU
> and the four 237 foot towers used by the 1380 kHz WKDM.
>
> The two directive antenna arrays share the same site at
> 350 Paterson Plank Rd, East Rutherford NJ
> <https://www.google.com/maps/search/350+Paterson+Plank+Rd,+East+Rutherford+NJ?entry=gmail&source=g>
> <
> https://www.google.com/maps/search/350+Paterson+Plank+Rd,+East+Rutherford+NJ?entry=gmail&source=g
> >
>
> The 1940 kHz intruder is the third order intermod of 1380 and 1660 kHz
> --
>
>
>
> *Best 73 de WA2SQQElmwood Park, NJ"The only dumb questions are those we
> don't ask"*
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
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