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Going Linear...
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Bruce Conti
If unable to shut off the noise source, I would consider going "ultralight unlimited class" by coupling an outdoor terminated broadband loop antenna to your ultralight radio for DXing from the comfort of indoors. The loop can be located at the quiet spot on your property with a noise-reduced lead-in to your radio shack and RF transformer coupled to the RF inputs of the radio (or alternatively with a few wraps of wire around the radio although that may also act as a in-house noise pick-up).
Terminated broadband loop antennas such as the Delta, Flag, and SuperLoop are easy to build, basically consisting of a single loop of wire with an in-line termination resistor and an RF transformer coupling to a lead-in. Example drawings are available at www.bamlog.com in the Antenna section. An internet search for "Delta antenna" etc. will find more info. These antennas produce a wide cardioid beam with a deep backside null. The null of the antenna can be aimed to further reduce noise while the terminating resistor can be adjusted to the desired deepness of the null. I don't have experience with coupling to an ultralight radio though. Perhaps others in the group will be able to provide more info if you decide to go that route. In terms of contests, the NRC contest over last season was a fun one. It was a series of sprints giving each participant the opportunity to compete in each segment while also offering a cumulative contest. -- Bruce Conti contiba@... www.bamlog.com |
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mike z
GM John- I also have noise on the low end of the BCB. I can track it to the utilities entrance on my house. From there, its pretty much radiated throughout the building. I've also found hot and cold spots in the yard, as you have. Over the years, as things have been added to the place, noises have popped up. Some with addition of computers, wireless router, solar panels/charger/invertor. Changing the style of fluorescent lamps in the radio shed was a bad move here.
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The metal roof made a negative impact on a non-augmented portable radio, but using a passive loop helps quite a bit. Odd thing, my crystal sets do not seem to be as hampered by the always present noise that's on the utilities. I use an approximately 250 long, tee fed antenna over who-knows how many feet of ground screen. One of the best all around listening spots for me is an upstairs storage area of the garage. 15 feet up, under a metal roof, on a SW facing gable end. There is nothing noise-wise to speak of. I'd be interested in what you find as the major source of noise. Mike AD1OS . --- In ultralightdx@..., John Cereghin <jcereghin@...> wrote:
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roberts50000
I would concentrate on trying to find the noise source if you
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are sure it is inside your house. That is far easier than trying to track down a noise source outdoors or somewhere down the road a mile or two. I would take a look at anything digital or anything that uses a switching power supply. Many of the older small wall-wart transformer power supplies are being replaced with small transformerless switching power supplies today that can throw out a lot of noise. Any appliance nowadays could be suspect, even a dishwasher, anything that has a digital clock or keypad could be throwing out noise. Don't forget battery chargers, light dimmers, fluorescent lights. TV sets, even when turned off could have some kind of live circuit inside just idling on low power. Use your ultralight radio to see if you can find where the noise increases and go from there. Don't overlook anything, even doorbell transformers have been known to create strong interference. 73 - Todd WD4NGG In a message dated 9/3/2012 9:23:40 P.M. Eastern Daylight Time,
jcereghin@... writes: Hi, all, Trying to get cranked up for the Fall season but severe line noise is really putting a crimp in my MW DXing. It's overpowering during the day, especially on the lower part of the band. It improves at night but I have to take a lawn chair and go to the far part of my yard to DX. The source of the noise is somewhere in my house but I have yet to localize it. |
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Adrian Flynn <ADRIANJAMESFLYNN@...>
Hi John, Try turning off different circuit breakers in your house until the noise disappears.
Then find out what is on that circuit and unplug them one at a time until the noise disappears. Don't forget lamp dimmers on wall switches!
If that doesn't stop it check when your house was built as if it has "KNOB & TUBE" wiring it might be warning you of a fire trying to start!!!
73 Adrian KF7DYU On Mon, Sep 3, 2012 at 9:23 PM, John Cereghin <jcereghin@...> wrote:
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John Cereghin <jcereghin@...>
Hi, all,
Trying to get cranked up for the Fall season but severe line noise is really putting a crimp in my MW DXing. It's overpowering during the day, especially on the lower part of the band. It improves at night but I have to take a lawn chair and go to the far part of my yard to DX. The source of the noise is somewhere in my house but I have yet to localize it. Yes, I am disgusted by this, as it even makes my FRG7 and DX150 about useless right now. So when you hit a brick wall, the best thing to do is to go back to basics. This season, I am going to try to focus on DXing on ULRs that have a linear (non-digital) readout, such as my SRF-59 (all 3 of them), R9011, this Radio Shack handheld I have (12-586), etc. Back to basics and the challeges it brings. I'll use my Select-a-Tenna and my Tecsun AN-200 passive loops, otherwise, I'll DX barefoot. If Allen Willie can haul in Europe on a SRF-59 barefoot, then I have to see what I can do! I'm not going to re-set my ULR log (currently at 856 stations) but I am setting up a seperate non-digital ULR log. I'm hoping that by "switching gears" that I can get some of the DX fire back. Even without the line noise, I'm having some trouble adding new stations right now. A good contest would help (hello IRCA and NRC!) to focus my attention. Barring that, I want to see what I can do on a "minimalist" scale. I might even put a crystal radio together, who knows. Alright, my first "non-digital" log is 660 WFAN New York, with the Georgia Tech-Virginia Tech football game on the SRF-59. :) -- John Cereghin WDX3IAO KB3LYP Smyrna, Delaware My radio page http://wdx3iao.wordpress.com Twitter- @Pilgrimway |
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