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Re: [TowerTalk] How far does RFI travel?

To: towertalk@contesting.com
Subject: Re: [TowerTalk] How far does RFI travel?
From: Dave Thompson <thompson@mindspring.com>
Reply-to: Dave Thompson <thompson@mindspring.com>
Date: Mon, 9 May 2016 09:02:31 -0400 (GMT-04:00)
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
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@windstream.net>
>Sent: May 9, 2016 8:31 AM
>To: towertalk@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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