Topband: 1940 kHz intruder WWRU WKDM

Sat Jan 7 08:44:51 EST 2023

I had a similar situation on VHF. I operate on 222 MHz among other nose 
bleed bands, and was greeted by a very large chunk of RFI in the SSB/CW 
portion of 220. Others in northern New England were hearing it too. It 
was loudest at my QTH. I identified some of the programming as that of 
Channel 11 in Deerfield, NH. So I took to the road with DF gear and 
found the problem was coming from the Channel 9 TX in Goffstown, NH. 
(WMUR) A call to them brought a quick response. We had a meeting on site 
and I demonstrated the problem. They found a bad module in their solid 
state Larcan transmitter. It was causing the intermod. The problem was 
solved quickly and no government agency got involved.

As a side note, when analog TV was phased out, I ended up getting some 
of those same Larcan Hi VHF amplifiers from Channel 9. They make great 
222 amps!

73

Dave K1WHS

On 1/7/2023 12:52 AM, Don Kirk wrote:
> Hi Frank and gang,
>
> I might be able to help provide some additional insight/direction.  This is
> not necessarily a case of having to show harmful interference, as the AM
> Broadcasters are held to some very stringent spurious emission limits and
> the stations actually go through a periodic inspection to show compliance.
> 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 have dealt with a few AM broadcast station as well as TV station problems
> and the biggest hurdle is getting in contact with the chief engineer, but
> after getting in contact with the chief engineer the problem gets addressed
> but maybe not at the speed of light as many AM broadcast stations are in
> dire financial times and they often don't even have a full time chief
> engineer and the chief engineer most likely will not have the skill set to
> fix the problem and he will likely need to call in a RF consultant .  I
> would certainly avoid getting the FCC involved as a first step unless
> working directly with the station general manager and chief engineer fail.
> This normally does not need to be a confrontational situation as the chief
> engineer wants to make sure his station is in compliance.  In a recent AM
> broadcast station case I was involved with both the part time chief
> engineer and RF consultant were hams which made life easy.
>
> Just my opinion based on some past experience.
> Don (wd8dsb)
>
> On Fri, Jan 6, 2023 at 10:07 PM Frank W3LPL <donovanf at starpower.net> wrote:
>
>> Hello AJ,
>>
>> Topbanders have done an excellent job of precisely identifying the source
>> of the 1940 kHz intermod.
>>
>> I don't think its helpful for those of who are not being harmed to lodge
>> a complaint with the FCC. Its the responsibility of those being
>> harmed t file a complaint. Those being interfered with also have a knob
>> on their radios that allow them to avoid interference.
>>
>> American amateurs suffering harm can file a complaint to the FCC.
>>
>> Canadian amateurs can lodge a complaint to their regulatory authority,
>> that authority can then file a complaint to the U.S. government. It's
>> a routine process used often.
>>
>> 73
>> Frank
>> W3LPL
>>
>>
>> From: "A J" <iamfromcanadaalso at gmail.com>
>> To: "Frank W3LPL" <donovanf at starpower.net>
>> Sent: Saturday, January 7, 2023 1:39:11 AM
>> Subject: Re: 1940 kHz intruder WWRU WKMD
>>
>>
>>
>> Hi Frank
>>
>> How do we define harmful interference?
>>
>>
>>
>>
>> I know some of the guy's that talk on 1940 and at times it makes it
>> impossible for them to talk.
>>
>> One of the gents is located near Barrie Ontario (480 miles) and at times
>> he can not even hear others he is talking to. Others near Buffalo others in
>> north west Pennsylvania.
>>
>> About 380 miles to my location. I had a friend near North Bay Ontario
>> listen when I was trying to figure out where it was coming from or what
>> stations it was he is 500 miles away and it is heard there.
>>
>>
>> I hear it before ~1hr sundown and hear it about 45 minutes after sun rise.
>>
>>
>> Other times I have heard it mid morning.( signal level from S3 to S9+10
>> with ~12 db attn)
>>
>>
>> Is it possible it is re-radiating from some other structure?
>>
>>
>>
>>
>> Cheers AJ___ VE3HJ
>>
>>
>> On 1/6/23 19:40, Frank W3LPL wrote:
>>
>>
>>
>> Hi AJ
>>
>> In my opinion, the next step is to determine if this intruder is causing
>> harmful interference,
>>
>> Several of us can hear it weakly and intermittently hundreds of miles
>> away,
>> but so far no one has claimed that its harmful.
>>
>> 73
>> Frank
>> W3LPL
>>
>>
>> From: "A J" [ mailto:iamfromcanadaalso at gmail.com | <
>> iamfromcanadaalso at gmail.com> ]
>> To: "Frank W3LPL" [ mailto:donovanf at starpower.net | <
>> donovanf at starpower.net> ]
>> Sent: Saturday, January 7, 2023 12:27:47 AM
>> Subject: Re: Topband: Spur as it reappeared
>>
>>
>>
>> Hi Frank
>>
>> So what is the next step?
>>
>> What do we do?
>>
>>
>>
>>
>> AJ___ VE3HJ
>> On 1/6/23 18:44, Frank W3LPL wrote:
>>
>> BQ_BEGIN
>>
>> Hi George,
>>
>> Faulty day/night switches may well be the cause!  You may have seen
>> in my previous email that both stations switch patterns from day to night.
>>
>> This is the first time I've ever hears of two AM stations with two
>> antenna arrays sharing the same small site
>>
>> 73
>> Frank
>> W3LPL
>>
>>
>> ----- Original Message -----
>> From: "George Hirst" [ mailto:geohirst at yahoo.com | <geohirst at yahoo.com> ]
>> To: "Rick Stealey" [ mailto:rickstealey at gmail.com | <rickstealey at gmail.com>
>> ] Cc: [ mailto:wd8dsb at aol.com | wd8dsb at aol.com ] , "donovanf" [ mailto:
>> donovanf at starpower.net | <donovanf at starpower.net> ] Sent: Friday, January
>> 6, 2023 11:39:10 PM
>> Subject: Re: Spur as it reappeared
>>
>> I am “talking through my hat” here. The fact that it seems to suddenly get
>> much stronger right about your (New Jersey) sunset make me wonder if it is
>> related to the AM broadcast station(s) changing their antenna pattern(s).
>> (I haven’t done the research to know if these stations are ones that are
>> required by the FCC to change their patterns at night to “protect” more
>> senior stations who share the sane frequency.) Perhaps there is some
>> corrosion on the RF switches employed in that function that introduces
>> nonlinearities. Those nonlinearities result in mixing products (ie. 1940
>> kHz) which are then radiated. ????
>>
>> George - WF4U
>>
>> BQ_BEGIN
>>
>> On Jan 6, 2023, at 4:14 PM, Rick Stealey [ mailto:rickstealey at gmail.com |
>> <rickstealey at gmail.com> ] wrote:
>>
>>
>> Note the waterfall.  The timestamp on the right is accurate.  The
>> horizontal line is a lightning burst.  But notice the ugly signal that came
>> up on 1940 before the carrier.  Anyone have any idea what is happening
>> there?
>>
>> <image.png>
>>
>>
>>
>> _________________
>> Searchable Archives: [ http://www.contesting.com/_topband |
>> http://www.contesting.com/_topband ] - Topband Reflector
>>
>> BQ_END
>>
>> --
>> Knowledge is Power and Power is Knowledge.___AJ___1967
>>                                                    Tell me and I will
>> forget. Teach me and I may learn. Involve me and I shall understand.
>> ___AJ___
>>
>>
>> BQ_END
>>
>> --
>> Knowledge is Power and Power is Knowledge.___AJ___1967
>>                                                    Tell me and I will
>> forget. Teach me and I may learn. Involve me and I shall understand.
>> ___AJ___
>>
>> _________________
>> Searchable Archives: http://www.contesting.com/_topband - Topband
>> Reflector
>>
> _________________
> Searchable Archives: http://www.contesting.com/_topband - Topband Reflector