On 12/09/2008 at 08:55 Ken wrote:
>Hi Scot.
>Does the noise sound like 50Hz?, if so you probably have an 'earth loop'
>somewhere, always worth checking for earth loops.
>
>73.
>Ken M0KHW
Or 60Hz?
John F5VLF
>----- Original Message -----
>From: "Scott Tilley" <[email protected]>
>To: <[email protected]>
>Sent: Friday, September 12, 2008 3:16 AM
>Subject: Re: LF: Re: AC Noise on RX...
>
>
>> Hi Guys
>>
>> Thanks for the responses.
>>
>> This one has me still scratching my head.
>>
>> All of the LF bands are affected. I have tried my RF isolation
>> transformer that worked rather well back in the city. I have not tried
>> the AC mains iso xfmr yet. Yes my iso is wound like yours. No computer
>> yet.
>>
>> To answer others questions about a local noise source. Can't be as I
>can
>> shut off all the breakers in the house save the one feeding the radio
>and
>> nothing else and the noise is still there. Doesn't matter which PSU of
>> the many I have I use and the noise is still there. Switch to the
>battery
>> and turn on everything and bang the noise is gone.
>>
>> The noise is only there AFTER I connect the antenna. So it has something
>> to do with the mains AC, coax run and the antenna...
>>
>> 73 Scott
>> VE7TIL
>>
>> PS - The day we get the band back on 2200m is the day I'm back on the
>> air... This time with a 70' high big honking flat top about 500m from
>the
>> ocean...
>>
>>
>> [email protected] wrote:
>>>
>>> Scott
>>>
>>> Welcome back! Agree with previous comments on checking the power supply
>>> first. What frequency range is affected?
>>>
>>> Is the isolation transformer an ac mains isolation transformer or an
>rf
>>> isolation transformer? Even if you're using an ac mains isolation
>>> transformer an rf isolation transformer on the lead will probably be
>>> required. For this transformer I've found that a conventional wound
>>> ferrite transformer with the primary and secondary separated on the
>core
>>> work best. Bifilar wound transformers are not the way to go here. If
>you
>>> have a computer connected to your receiver a 600 - 600 ohm isolation
>>> transformer in that connection can also improve noise pickup.
>>>
>>> Any hope of transmitting again?
>>>
>>> Jay W1VD WD2XNS WE2XGR
>>>
>>> ----- Original Message ----- From: "Scott Tilley" <[email protected]>
>>> To: <[email protected]>
>>> Sent: Thursday, September 11, 2008 12:10 AM
>>> Subject: LF: AC Noise on RX...
>>>
>>>
>>>> Hi All
>>>>
>>>> Been awhile since I've posted to the reflector. I'm pleased to
>announce
>>>> I have escaped the noisy clutches of the City and bought myself a nice
>>>> piece of land up the coast in a very quiet spot.
>>>>
>>>> Presently I'm only using my passive RX loop which has a single turn
>>>> 'sense' loop for coupling into the main multi turn loop... When the
>RX
>>>> is connected to an AC power power supply I get terrible AC growlers;
>>>> however, put the RX on a battery and bang not a peep of nasty AC noise.
>>>>
>>>> I presume this is due to some coupling between the AC mains and the RX
>>>> system and my isolation transformer doesn't seem to help so I wonder
>if
>>>> someone could set me straight on what is going on here so I can solve
>>>> the problem.
>>>>
>>>> Thanks for any support!
>>>>
>>>> 73 Scott
>>>> VE7TIL
>>>>
>>>
>>>
>>>
>>
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