[Elecraft] RFI issues

Tue Feb 18 19:47:30 EST 2020

One of the first things to try is to operate the station receiver from a 
battery, disconnect everything including the external ground,  but the 
antenna.  Then drop the mains breaker to the property.  If the noise 
changes, then some or part of it is on your property.  If the noise does 
not change then it is most likely not on your property.  Don't forget 
about any UPS that you may have on the property.   It must be turned off 
as well.  Our fiber internet service has a battery back-up at the 
demarcation. You may need to unplug that unit as well.

If it is not on your property, I suggest a portable AM radio tuned to 
1700 or such if there is not local station on the frequency.  Most of 
those radios have a rod antenna that is bi-directional.  Use it as a 
null device as the null will be much more pronounced than trying to peak 
the noise.   Headphones or earbuds will help.    You'll need a local / 
sub division map. Mark the axis of the radio on the map,   then move 
over 100 to 300 yards to the side and do the same.  Usually 3 or 4 sites 
will have the lines intersect.    You can then move to that location.  
Worst case, should you have 2 or more noise sources which are then a 
real challenge to chase.

If it is on your property, then drop every individual breaker, bring the 
mains back on and observe.  Then add one breaker and observe.  Add the 
next breaker and observe.   Finally you will find the 2 or 3 that 
contributes greatly to the noise.  Then you can check the devices on 
each one.   Don't forget about the doorbell transformer.  Those go bad, 
make noise, yet the doorbell will still work.

Once the location is known, then contact the property owner or the local 
utility.  You may have to be persistent with the local utility, move up 
the chain of command,  but diplomacy along every step goes a long way to 
getting something done.

It is also worthwhile to note the day and the times the observations 
were made.  It could be related to something only furing the day or only 
at night or maybe on each Wednesday and Friday  etc.

I doubt it is anything from the TV stations.

73

Bob, K4TAX

On 2/18/2020 4:45 PM, Michael Walker wrote:
> HI Andreas
>
> Sorry to hear about your noise.
>
> I doubt your noise is related to digital TV as that is a long way away in
> the frequency world.  It is pretty common to assume that it is not on your
> own property.  I saw one guy who said the same thing and then found out a
> year later it was his new dryer that was noisy even when they were not
> using it.
>
> I would not be surprised that most of your HF noise is within your own
> property unless you did some significant research by  holding an AM radio
> near each and every power cube or charger for phones, etc.  There are not
> too many that are quiet.
>
> I use my KX2 to find most of my HF noise issues and I must have tossed out
> 15 bad chargers.  The ones I could not just toss away, I had to add Mix 31
> chokes to.
>
> When you moved into your new house did you replace all the light bulbs with
> LED bulbs?  They can be noisy.
>
> If you haven't taken the time to do an indepth study on your own house, you
> should.  You might be surprised.  I would plan an all day exercise when
> everyone is out of the house.
>
> Mike va3mw
>
>
> On Tue, Feb 18, 2020 at 2:25 PM Dave Cole <dave at nk7z.net> wrote:
>
>> Hi,
>>
>> I might suspect something else...
>>
>> Have you done a power off test of your home yet?
>>
>> 73, and thanks,
>> Dave (NK7Z)
>> https://www.nk7z.net
>> ARRL Volunteer Examiner
>> ARRL Technical Specialist
>> ARRL Asst. Director, NW Division, Technical Resources
>>
>> On 2/18/20 8:29 AM, Andreas Wachter via Elecraft wrote:
>>> I live about 1.6 miles from some tall antenna towers broadcasting
>> digital TV (KBCB) at 208 kW ERP on channel 19 (500 - 506 MHz) and on FM
>> (KWPZ-FM) at 63 kW ERP on 106.5MHz - according to FCC info on KBCB and
>> KWPZ-FM. Ever since I moved to this QTH a few months ago, I am unable to
>> use my K3: solid S9+ noise on all bands using a makeshift dipole strung up
>> on some trees outside my house. I’ve tried to locate the source of the RFI
>> within my home but so far have been unable to locate any RFI emanating from
>> within my home. Could it be that the TV/FM stations antenna towers, which
>> are within direct line of sight from my house, might be responsible for the
>> RFI?
>>> 73, Andreas
>>>
>>> K6AKW
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