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Re: [RFI] mystery noise

To: Larry Benko <xxw0qe@comcast.net>
Subject: Re: [RFI] mystery noise
From: Pete Smith <n4zr@contesting.com>
Reply-to: n4zr@contesting.com
Date: Thu, 13 Jan 2011 06:33:02 -0500
List-post: <rfi@contesting.com">mailto:rfi@contesting.com>
I'm sure you guys are probably right about the switcher.  I should have 
mentioned that the active antenna is perhaps 100 feet from my shack, and 
that I have a 10-turn coax choke on the feedline right at the output of 
the antenna.  I measured a 1-turn choke on the same big toroid, and it 
is around 30 ohms at 1.8 MHz, so if I'm not mistaken I have about 3000 
ohms of common mode choke.  It's not the QS1R wall-wart, because I've 
had it for a year, and this noise is new.

This, plus the fact that this noise was not present earlier, suggests 
that the noise source may be my back-door neighbors, who live in a 
trailer maybe 30 feet from the active antenna.  I'm going to try moving 
the active antenna away from both them and my house and see if the noise 
goes away or diminishes.

Thanks to everyone who responded.

73, Pete N4ZR

The World Contest Station Database, updated daily at www.conteststations.com
The Reverse Beacon Network at http://reversebeacon.net, blog at 
spots at telnet.reversebeacon.net, port 7000

On 1/12/2011 5:37 PM, Larry Benko wrote:
> Pete,
> I agree with what Jim said but I would like to add another comment.  
> Any source that is Q5 at one location and unable to be heard at 
> another location 200' away is DEFINITELY close to the Q5 location.  It 
> would be humorous and slightly embarrassing if the power supply that 
> runs your QS1R was the noise source.  My vote is for a small wall wart 
> type power supply.
> 73,
> Larry, W0QE
> On 1/12/2011 12:50 PM, Pete Smith wrote:
>> I have a small active vertical for my QS1R receiver, mounted on my
>> garage roof.  Using the QS1R's panadaptor display, I can see that I have
>> recurrent broad, strong noise sources every 54 KHz. When listened to on
>> CW with a wide (10 KHz) filter they sound like a rough CW signal, and
>> the waterfall shows definite pulsations.  I first noticed these on 160,
>> and searching with the QS1R they appear to be pretty much gone by 5
>> MHz.  I can provide a recording to anyone who wants one.
>> Does the description or the periodicity suggest a source that I can look
>> for?  It must be close, because my Beverage-on-Ground a couple of
>> hundred feet away shows no trace.  The antenna is near the fence with my
>> neighbors, so it would be helpful to know more or less wehat I'm looking
>> for before I go over there.
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