In many cases, Tim, AM station "harmonics" are generated by an overloaded
receiver. In that case, a high-pass or bandpass filter will resolve the
interference problem. In cases where AM-broadcast harmonics or intermodulation
is suspect, trying a filter on the affected receiver is an important step to
determining that the receiver is not being overloaded.
________________________________
From: RFI <rfi-bounces+w1rfi=arrl.org@contesting.com> on behalf of Tim Duffy
<k3lr@k3lr.com>
Sent: Wednesday, January 11, 2023 3:29 AM
To: 'AA5CT' <jwin95@yahoo.com>; 'ezrhino fastmovers.biz'
<ezrhino@fastmovers.biz>
Cc: rfi@contesting.com <rfi@contesting.com>
Subject: Re: [RFI] 160m spur
Not sure why we are talking about filters – that have no impact on the solution
to this problem
Has a local ham (skin in the game) contacted the broadcast station(s) general
manager or the contract chief engineer?
73
K3LR
CT [mailto:jwin95@yahoo.com]
Sent: Wednesday, January 11, 2023 3:19 AM
To: 'ezrhino fastmovers.biz'; Tim Duffy
Cc: rfi@contesting.com
Subject: Re: [RFI] 160m spur
re: " No RX filter can fix this."
I think that is understood; also understand that a 'broadcast' filter (of the
design I forwarded to the group yesterday), or two, ahead of a DF receiver
could allow DFing of the 'spur' in the vicinity of the broadcast transmit
antennas near the transmitter site. I don't know if that idea had occurred to
all persons, or not.
When a single filter can achieve 40 dB attenuation (minimum) in the BCB, TWO
filters in cascade can achieve 80 dB.
de AA5CT Jim
- - - - - - - - - - - - - - -
On Tuesday, January 10, 2023, 10:30:58 PM GMT-6, Tim Duffy <k3lr@k3lr.com>
wrote:
This issue is not a broadcast mix or overload in a ham receiver. No RX filter
can fix this. This is a problem at the broadcast station(s).
Listen to 1940 KHz and hear what is going on.
73
Tim K3LR
-----Original Message-----
From: RFI [mailto:rfi-bounces+k3lr=k3lr.com@contesting.com] On Behalf Of
ezrhino fastmovers.biz
Sent: Tuesday, January 10, 2023 11:25 PM
Cc: rfi@contesting.com
Subject: Re: [RFI] 160m spur
Broadcast band filters for 160m and 80m available here
https://surgestop.com/filter-products/index.html
Chris
KF7P
> On Jan 10, 2023, at 10:22 AM, K2GKK D C_Mac_ Macdonald <k2gkk@hotmail.com>
> wrote:
>
> Isn't this sort of thing usually an occasion of fundamental
> overload of the receiver front end? Attenuation is probably
> the only remedy.
>
> ICE made a high pass filter at one time as a possible aid.
>
> 73 - Mac, K2GKK/5
> (Since 30 Nov 53)
> Oklahoma City, OK
> USAF, Ret'd 61-81
> FAA, Ret'd 94-10
>
> ________________________________
> From: RFI <rfi-bounces+k2gkk=hotmail.com@contesting.com> on behalf of Bob
> Kozlarek WA2SQQ <wa2sqq@gmail.com>
> Sent: Monday, January 9, 2023 16:45
> To: rfi@contesting.com <rfi@contesting.com>
> Subject: [RFI] 160m spur
>
> 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://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.google.com%2Fmaps%2Fsearch%2F350%2BPaterson%2BPlank%2BRd%2C%2BEast%2BRutherford%2BNJ%3Fentry%3Dgmail%26source%3Dg
>
> <https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.google.com%2Fmaps%2Fsearch%2F350%2BPaterson%2BPlank%2BRd%2C%2BEast%2BRutherford%2BNJ%3Fentry%3Dgmail%26source%3Dg&data=05%7C01%7C%7C769f49c7410b453fa3be08daf2934f1a%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638089011749005354%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=Uz3ffnKeQkmjW8FvW1f%2BGK0%2FXUAUNAbeNaL%2F3EZwkWg%3D&reserved=0>
>
> &data=05%7C01%7C%7C769f49c7410b453fa3be08daf2934f1a%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638089011749005354%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=Uz3ffnKeQkmjW8FvW1f%2BGK0%2FXUAUNAbeNaL%2F3EZwkWg%3D&reserved=0>
>
> 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"*
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