Rick,
yes the power being underground does help alot with conducted rfi from
switching power supplies, and this seems to help more if you do not share the
same transformer secondary with a neighbor. if you share the secondary with a
neighbor who does have a noisy switching power supply, or any thing else
electronic that will be conducted back into the secondary system, it will be
conducted into your home wiring, it has happen to me.
also, if a neighbor that is not sharing the same secondary, but is next door,
you could hear the rfi just from being radiated from their house wiring or any
wiring originating from their home. the idea of cutting the power to your house
is where i would start. cut each 15 or 20 amp breaker to see if the rfi will
cease, if not cut all breakers, and look for a home type UPS system, they cause
all kinds of rfi. Cell phone chargers, battery chargers, tv sets, vcrs, dvd
players, any thing electronic these days, which most of the time is made in
china who has no regards to engineering best practice to rfi.
richard
wb4byq
________________________________________
From: rfi-bounces@contesting.com [rfi-bounces@contesting.com] On Behalf Of
donovanf@starpower.net [donovanf@starpower.net]
Sent: Wednesday, January 26, 2011 11:37 AM
To: rfi@contesting.com
Subject: Re: [RFI] Old RFI back and a new one help please
Rick,
Before you invest time searching for the RFI outside your home, you should be
certain that its not originating from inside your own home. You don't have to
introduce a new device for RFI to originate from your home, RFI can be caused
by many chenges that can heppen to your existing devices and infrastructure.
Shut off all of the breakers except the breaker feeding your radio, and don't
forget to turn off all UPSs too. If the RFI is still there, then you know
you're ready to look outside your home.
73
Frank
W3LPL
---- Original message ----
>Date: Wed, 26 Jan 2011 09:05:59 -0800 (PST)
>From: Rick Scott <w7psk@yahoo.com>
>Subject: Re: [RFI] Old RFI back and a new one help please
>To: "Battles,Richard" <Battles.Richard@lee.k12.al.us>, "rfi@contesting.com"
><rfi@contesting.com>
>
>Well I have not added a power supply here.
>
>All our lines are underground until the top of the hill. Would that make a
>difference>
>
>
>
>
>----- Original Message ----
>> From: "Battles,Richard" <Battles.Richard@lee.k12.al.us>
>> To: "rfi@contesting.com" <rfi@contesting.com>
>> Sent: Wed, January 26, 2011 8:34:01 AM
>> Subject: Re: [RFI] Old RFI back and a new one help please
>>
>> Scott, this sounds like a switching power supply in you home, or near you
>> from
>>a neighbor. switching power supplies sound like a buzzsaw. the rfi from
>>the
>> supply will be conducted into the house wiring, then into the power lines
>> from
>>the power company. the rfi will not go past the transformer, on the pole,
>>but
>>will flow
>> into the ground system of the power system.
>>
>> a common mode choke will most likely fix the problem.
>>
>> richard
>> wb4byq
>>
>> ________________________________________
>> From: rfi-bounces@contesting.com [rfi-bounces@contesting.com] On Behalf Of
>>Rick Scott [w7psk@yahoo.com]
>> Sent: Wednesday, January 26, 2011 10:00 AM
>> To: rfi@contesting.com
>> Subject: [RFI] Old RFI back and a new one help please
>>
>> The noise I talked about a while ago is back. It was a blissful 2 weeks
>>without
>> it.
>> But last night It showed up again. This bites. Ive got the ARRL sending me
>>a
>> helpful
>> gent soon. He isn't available right now due to family issues but I'm sure
>> he
>> can help.
>>
>> Ive got a new one that showed up too that's really strong. Hopefully some
>>have
>> heard it.
>>
>>
>> Its a buzzsaw sound that lasts for 1 second and cycles every 6 seconds. So
>> every 6 seconds
>> I get 1 second of extremely strong buzzsaw.
>>
>>
>>
>>
>> Whee I love city living.
>>
>> Scotty W7PSK
>>
>>
>>
>> _______________________________________________
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>>
>
>
>
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