[TowerTalk] How far does RFI travel?

[Patrick Greenlee]

Yes, aquariums! The metallic contact type aquarium thermostats can make 
significant noise bursts when making and breaking the heater current. Of 
course the make or break generated noise burst will coincide with your 
attempt to "pull out" the rare CW  DX call sign.

Patrick        NJ5G


On 5/9/2016 8:02 AM, Dave Thompson wrote:
> Power line noise can radiate over a long distance.  Even underground can radiate but usually this type of noise stops around 9 MHz.  Touch on lights
> and bad wall warts especially the flat switching types can cause terrible RFI  but it seldom goes beyond a block from your location.
>
> Other things to look for are door bell transformers, all sorts of motors especially fish tanks motors. Appliances but these only generate noise when in use.  I assume that there is no commercial stuff nearby.
>
> I suggest you get one of the RFI books sold by ARRL or HRO as these are very good.
>
> Dave K4JRB
>
> -----Original Message-----
>> From: Patrick Greenlee <patrick_g at windstream.net>
>> Sent: May 9, 2016 8:31 AM
>> To: towertalk at contesting.com
>> Subject: Re: [TowerTalk] How far does RFI travel?
>>
>> Of course there is no magic distance beyond which RFI hits a "Gardall
>> Shield." Distance attenuates and at some point the level will go
>> significantly below your natural noise floor (world wide lightning
>> discharges etc.) Another answer is, "It depends."  If you have some pot
>> growers using industrial lighting instead of residential lighting then
>> be prepared for lots of noise.  Fairly recently there was a big flap
>> over commercial/industrial lighting being sold at the big box stores
>> being put into residential use. The RFI emissions of the residential
>> grade lighting are much lower than the industrial which cause
>> significant RFI problems.
>>
>> Patrick        NJ5G
>>
>>
>> On 5/9/2016 2:21 AM, Ray Benny wrote:
>>>    body {height: 100%; color:#000000; font-size:12pt; font-family:arial, helvetica, sans-serif;}This may seem a strange question to ask and there maybe many answers, so I will try to be specific as to what I am looking for.
>>> A new subdivision is being built about 1/4 mile away, east and north east, towards EU. The homes are custom build on 1 acre parcels. What I am trying to find out: can I expect my noise level to go up as more homes are built?
>>> I spend a lot of time on 160m. I have a RX 4SQ and 2 wire beverage, and I do hear a number of small RFI noises in a number of directions from nearby homes in my rural area. Most of the time they do not cause any long term problems. My thought is that when new housing comes in, new and more electronic gadgets will be inside that can generate more RFI.
>>> I have done some RFI tracking, mostly electric fences and leaking/defective power line hardware, but these sources are usually very distinctive and usually easy to fine. Finding wall wart, LED, etc RFI is harder to find, especially on someone else's property. Another way to ask my questions: "Does this type of RFI noise typically radiate more than several hundred feet"?
>>> Any thoughts or experiences are welcome.
>>> Tnx & 73,
>>> Ray, N6VR
>>> Chino Valley, AZ
>>>
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