Elecraft

Broadcast band interference

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Gary Auchard

Broadcast band interference

I'm having occasionally issues with broadcast band interference on my KX3, SN. 564. It seems to come in at random times throughout the day on multiple bands. All of my antennas are tuned to the band I'm using them on and not just a random wire type. I tend to see the problem mostly on 30, 20 and 17 meters. Any reason I'm getting this type of interference and is there any way I can take care of it or block it. Sometimes it's loud enough to be a problem when trying to copy weak CW signals. Gary A. - W0MNA
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mzilmer

Re: Broadcast band interference

Use the RX SHFT function.

Matt Zilmer
Consultant - Product Management Dept.
Magellan Navigation / MiTAC Digital Corp.
Tel: (909) 394-6052
Cell: (909) 730-6552
In status quo voluntas non sufficit

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of [hidden email]
Sent: Tuesday, January 08, 2013 11:42 AM
To: [hidden email]
Subject: [Elecraft] Broadcast band interference

I'm having occasionally issues with broadcast band interference on my KX3, SN. 564. It seems to come in at random times throughout the day on multiple bands. All of my antennas are tuned to the band I'm using them on and not just a random wire type. I tend to see the problem mostly on 30, 20 and 17 meters. Any reason I'm getting this type of interference and is there any way I can take care of it or block it. Sometimes it's loud enough to be a problem when trying to copy weak CW signals. Gary A. - W0MNA ______________________________________________________________
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N5GE

Re: Broadcast band interference

In reply to this post by Gary Auchard

Check the addresses of your local AM radio broadcasters. You may
have one very close to you and not know it.

Here's a way to find where and who the broadcaster is.

If you have an AM radio in the house compare the signal on the KX3
with those you hear on the AM radio to see if you can identify the
station you're hearing.

If a station is very close, you may have to use a filter at the shack
end of the feedline to notch it out.

On Tue, 8 Jan 2013 19:41:57 GMT, "[hidden email]" <[hidden email]>
wrote:

>I'm having occasionally issues with broadcast band interference on my KX3, SN. 564. It seems to come in at random times throughout the day on multiple bands. All of my antennas are tuned to the band I'm using them on and not just a random wire type. I tend to see the problem mostly on 30, 20 and 17 meters. Any reason I'm getting this type of interference and is there any way I can take care of it or block it. Sometimes it's loud enough to be a problem when trying to copy weak CW signals. Gary A. - W0MNA
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
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>Please help support this email list: http://www.qsl.net/donate.html
73,
Tom
Amateur Radio Operator N5GE
ARRL Lifetime Member
QCWA Lifetime Member

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Amateur Radio Operator N5GE

Mel

Re: Broadcast band interference

Hello Tom,

I find it hard to understand how AM broadcast station in the lower BC band could be your problem. I am thinking since you have the problem on the higher bands, it might be overload from the SW BC bands also on AM where propagation is the cause of the randomness of the interference. I would use your KX3 to tune the adjacent SW bands when you have the interference and see if any of them sound the same. Or better yet use another SW receiver to compare the audio content.

Also, if you insert the ATT does the interference go away?? Once you identify the source you can decide on what remedies are possible. Just some thoughts,

Mel, K6KBE

--- On Tue, 1/8/13, Tom H Childers <[hidden email]> wrote:

From: Tom H Childers <[hidden email]>
Subject: Re: [Elecraft] Broadcast band interference
To: [hidden email]
Date: Tuesday, January 8, 2013, 12:10 PM

Check the addresses of your local AM radio broadcasters. You may
have one very close to you and not know it.

Here's a way to find where and who the broadcaster is.

If you have an AM radio in the house compare the signal on the KX3
with those you hear on the AM radio to see if you can identify the
station you're hearing.

If a station is very close, you may have to use a filter at the shack
end of the feedline to notch it out.

On Tue, 8 Jan 2013 19:41:57 GMT, "[hidden email]" <[hidden email]>
wrote:

>I'm having occasionally issues with broadcast band interference on my KX3, SN. 564. It seems to come in at random times throughout the day on multiple bands. All of my antennas are tuned to the band I'm using them on and not just a random wire type. I tend to see the problem mostly on 30, 20 and 17 meters. Any reason I'm getting this type of interference and is there any way I can take care of it or block it. Sometimes it's loud enough to be a problem when trying to copy weak CW signals. Gary A. - W0MNA
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html
73,
Tom
Amateur Radio Operator N5GE
ARRL Lifetime Member
QCWA Lifetime Member

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Chip Stratton

Re: Broadcast band interference

At one QTH (Key Largo) I have noticed a problem similar to Tom's with the
KX3. On a number of quiet bands, I can just hear a broadcast station whose
volume is not affected by spinning the VFO. It wasn't a real problem so I
didn't make an effort to eliminate it. The nearest AM broadcast antenna I
can find with an online antenna search engine is 13 miles away on the
mainland, however there is a large tower only one mile away - I just can't
find an AM station that is broadcasting from it.

In any event I have experienced what he is talking about. Don't know if
using IF shift would have eliminated it.

Chip
AE5KA

On Tue, Jan 8, 2013 at 3:28 PM, Mel Farrer <[hidden email]> wrote:

> Hello Tom,
>
> I find it hard to understand how AM broadcast station in the lower BC band
> could be your problem. I am thinking since you have the problem on the
> higher bands, it might be overload from the SW BC bands also on AM where
> propagation is the cause of the randomness of the interference. I would
> use your KX3 to tune the adjacent SW bands when you have the interference
> and see if any of them sound the same. Or better yet use another SW
> receiver to compare the audio content.
>
> Also, if you insert the ATT does the interference go away?? Once you
> identify the source you can decide on what remedies are possible. Just
> some thoughts,
>
> Mel, K6KBE
>
> --- On Tue, 1/8/13, Tom H Childers <[hidden email]> wrote:
>
>
> From: Tom H Childers <[hidden email]>
> Subject: Re: [Elecraft] Broadcast band interference
> To: [hidden email]
> Date: Tuesday, January 8, 2013, 12:10 PM
>
>
>
> Check the addresses of your local AM radio broadcasters. You may
> have one very close to you and not know it.
>
> Here's a way to find where and who the broadcaster is.
>
> If you have an AM radio in the house compare the signal on the KX3
> with those you hear on the AM radio to see if you can identify the
> station you're hearing.
>
> If a station is very close, you may have to use a filter at the shack
> end of the feedline to notch it out.
>
> On Tue, 8 Jan 2013 19:41:57 GMT, "[hidden email]" <[hidden email]>
> wrote:
>
> >I'm having occasionally issues with broadcast band interference on my
> KX3, SN. 564. It seems to come in at random times throughout the day on
> multiple bands. All of my antennas are tuned to the band I'm using them on
> and not just a random wire type. I tend to see the problem mostly on 30,
> 20 and 17 meters. Any reason I'm getting this type of interference and is
> there any way I can take care of it or block it. Sometimes it's loud
> enough to be a problem when trying to copy weak CW signals. Gary A. - W0MNA
> >______________________________________________________________
> >Elecraft mailing list
> >Home: http://mailman.qth.net/mailman/listinfo/elecraft
> >Help: http://mailman.qth.net/mmfaq.htm
> >Post: mailto:[hidden email]
> >
> >This list hosted by: http://www.qsl.net
> >Please help support this email list: http://www.qsl.net/donate.html
> 73,
> Tom
> Amateur Radio Operator N5GE
> ARRL Lifetime Member
> QCWA Lifetime Member
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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alorona

Re: Broadcast band interference

In reply to this post by Gary Auchard

There are at least two other ways of knocking down interference from nearby AM
broadcast stations. Each requires the choice of a particular type of antenna.

The first is to use a balanced tuner of the link-coupled type (the Johnson
Matchbox and Annecke Coupler are the most famous examples) which has a highpass
response and can add some 30 dB to reject AM BC signals.

The second is to use a small transmitting loop (STL) which has a very narrow
bandwidth and rejects all signals more than a few kHz away.

Al W6LX

> If a station is very close, you may have to use a filter at the shack
> end of the feedline to notch it out.
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Jim Brown-10

Re: Broadcast band interference

On 1/14/2013 11:05 AM, Al Lorona wrote:
> There are at least two other ways of knocking down interference from nearby AM
> broadcast stations. Each requires the choice of a particular type of antenna.

The BEST way to kill AM broadcast interference coupled via the antenna
is with a high pass filter. This concept is far from new -- it's been
around since the 1920s. When I lived in Chicago, I used the ICE model
BCB, which is pretty decent. It's rated for 100W. When the ICE
owner/engineer died a few years ago, the company was taken over by one
of the employees under a different name.

WX0B (Array Solutions) was a distributor for ICE, and is selling AM
broadcast filters built by W3NQN. One model is designed for receive
only, so would be used at the RX antenna patch point with a K3. It is a
VERY sophisticated filter, designed for VERY sharp cutoff so it can
eliminate stations at the very top of the AM band just below 160M. It
sells for $225. Another is rated for 150W, with a less sharp cutoff (but
still a VERY good filter), and sells for $189. W3NQN filters are pretty
much the Rolls Royce of filters.

Array Solutions also builds their own RX only filter for $56. The
cutoff is not nearly as sharp nor as deep as the W3NQN filters, but
would likely be sufficient if your interference is below about 1300 kHz.

http://www.arraysolutions.com/Products/BCB%20RF%20Filters.htm

73, Jim K9YC
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Jack Smith-6

Re: Broadcast band interference

I also have several receive only filters that are suitable for AM
broadcast suppression. Two high pass filters and a band-reject filter.
More details on those at
http://www.cliftonlaboratories.com/z10020_am_medium_wave_band_reject_filter.htm

http://www.cliftonlaboratories.com/z10022a_high_pass_filter.htm
http://www.cliftonlaboratories.com/z10023a_elliptic_high_pass_filter.htm

The Z10023A is an elliptic filter and provides 45 dB attenuation at 1700
KHz and 1.5 dB at 1800 KHz.

Prices on all of these are in the $70-80 dollar range.

Jack K8ZOA

On 1/14/2013 3:10 PM, Jim Brown wrote:

> On 1/14/2013 11:05 AM, Al Lorona wrote:
>> There are at least two other ways of knocking down interference from
>> nearby AM
>> broadcast stations. Each requires the choice of a particular type of
>> antenna.
>
> The BEST way to kill AM broadcast interference coupled via the antenna
> is with a high pass filter. This concept is far from new -- it's been
> around since the 1920s. When I lived in Chicago, I used the ICE model
> BCB, which is pretty decent. It's rated for 100W. When the ICE
> owner/engineer died a few years ago, the company was taken over by one
> of the employees under a different name.
>
> WX0B (Array Solutions) was a distributor for ICE, and is selling AM
> broadcast filters built by W3NQN. One model is designed for receive
> only, so would be used at the RX antenna patch point with a K3. It is
> a VERY sophisticated filter, designed for VERY sharp cutoff so it can
> eliminate stations at the very top of the AM band just below 160M. It
> sells for $225. Another is rated for 150W, with a less sharp cutoff
> (but still a VERY good filter), and sells for $189. W3NQN filters are
> pretty much the Rolls Royce of filters.
>
> Array Solutions also builds their own RX only filter for $56. The
> cutoff is not nearly as sharp nor as deep as the W3NQN filters, but
> would likely be sufficient if your interference is below about 1300 kHz.
>
> http://www.arraysolutions.com/Products/BCB%20RF%20Filters.htm
>
> 73, Jim K9YC
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

David Cutter

Re: Broadcast band interference

It would be very nice if these could be fitted inside the K3, or modify the
existing K3 receive filters to provide similar results.

David
G3UNA

----- Original Message -----
From: "Jack Smith" <[hidden email]>
To: <[hidden email]>
Sent: Monday, January 14, 2013 8:20 PM
Subject: Re: [Elecraft] Broadcast band interference

>I also have several receive only filters that are suitable for AM broadcast
>suppression. Two high pass filters and a band-reject filter. More details
>on those at
>http://www.cliftonlaboratories.com/z10020_am_medium_wave_band_reject_filter.htm
> http://www.cliftonlaboratories.com/z10022a_high_pass_filter.htm
> http://www.cliftonlaboratories.com/z10023a_elliptic_high_pass_filter.htm
>
> The Z10023A is an elliptic filter and provides 45 dB attenuation at 1700
> KHz and 1.5 dB at 1800 KHz.
>
> Prices on all of these are in the $70-80 dollar range.
>
> Jack K8ZOA
>