[Elecraft] Elecraft Noise RFI
Phil, I would suggest that you eliminate sources within your home as noise sources before you search elsewhere. There are hundreds of potential noise sources in homes. Just a few examples would be: CFL and LED lights, low voltage lighting systems, electric blankets, air conditioner and heating systems and fans, electronic igniters in stoves, ovens, and boilers, most power supplies, plasma TV's, internet routers, doorbell transformers starting to go bad, battery chargers. You get the idea..nearly anything electronic, even devices that are turned off. So it would probably be easiest to turn off circuit breakers one at a time, or perhaps just turn off the main breaker and run a radio on battery power. I am sure others will offer many suggestions also. If your house is OK, you might drive around the neighborhood with your AM BC band radio tuned to a blank spot near the top of the dial and possibly you will get a real general idea of the extent of the problem. However at low frequencies like the BC band, noise/rfi can be propagated long distances (like 1000's of yards) over power lines, so the use of a directional antenna on something like an AM aircraft band portable, or possibly even a 6 or 2 meter AM, CW, or SSB receiver would be much better for localizing the "noise". There has been much written on the internet and ham publications on locating and fixing "noise". Good Luck, Rick KL7CW __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
[Elecraft] kx1 20 meter oscillation
Stan, Before you conclude you have an oscillation on 20 meters, please make sure you are actually correctly sampling the actual output of the kx1 from the BNC antenna jack and not picking up stray signals radiated from the interior of the kx1, especially if its cover is removed. Sometimes the kx1 waveform as viewed on a oscilloscope or spectrum analyzer looks much better if correctly sampled. Put the cover on the kx1 and ground the case. Run it into a dummy load through a coax cable and a T connector. One way to sample the actual signal is to put a piece of insulated wire into the t connector (no direct electrical connection) and run this short wire and a ground to a variable or fixed pad and adjust the coupling and pad to provide a reasonable signal into your monitor receiver (say something less than about S9 + 20 db. I have also coupled a small signal to an outdoor antenna through a T connector, insulated wire & dummy load, then hooked my receiver to another outdoor coax fed antenna.even if it is not a 20 meter antenna, possibly through a pad and/or receiver attenuator, and have had a good (reasonable level) signal to monitor. There are also RF sample circuits and special pads (possibly around 100dB ?) which provide the attenuation to safely and correctly sample the transmitter RF, which are probably not necessary unless you want to set up an actual means of measuring levels. Please be very careful not to couple too much signal into your K3. Probably you will need only a small amount of capacitive coupling into the T connector and can use a considerable amount of padding (try 20 to 40dB or more). Signal levels into a receiver of > +10 dBm could potentially damage a receiver. Rick KL7CW KX1 # 798Palmer Alaska __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
Re: [Elecraft] kx1 antenna
From: Rick & Carolyn Dwight [mailto:kl...@mtaonline.net] Sent: Saturday, May 05, 2012 10:32 AM To: 'elecraft@mailman.qth.net' Subject: kx1 antenna Mike, I have used a kx1 portable for many years in many locations with approximately a 25 ft wire, more or less vertical and one or two counterpoise wires approximately 17 ft. If the "counterpoise" wire(s) are laying directly on the ground nearly 100% of the time the rig tunes < 2:1 on 40 meters and typically lower on 20 and 30 meters. If the counterpoise wires are elevated (even laying on bushes) the rig may not tune on 40 meters. It is usually OK if you sit at a table and drape the counterpoise wires down to the ground. I have found it very useful to always carry approximately a 6 or 8 foot wire with a medium size car battery charger clip on one end. Often clipping onto a metal picnic table, guard rail, car body, chain link fence, or whatever is all I need for a workable ground/counterpoise. Or in your example, just try lengthening one of the radials with the clipped on wire, or for 40 meters only try lengthening the 24 ft radiator with the clip lead. There is a good chance that the rig will then tune on 40 meters. It is possible but not likely that something is wrong with the antenna tuner, you can step through the L and C combinations manually as outlined in the manual. The 25 ft wire and 17 ft counterpoise/radial is not proposed as a high performance antenna, but as a very workable, light weight antenna which is easy to set up and will yield many happy QSO's ..some well over a thousand miles on all 3 bands. This is my usual travel and backpacking antenna, however, if I am operating in a contest and can set up a more elaborate antenna, it may be worth the effort. It is probable that this very simple antenna "counterpoise" combo will actually work better than many of the compact, expensive, cute, loaded antennas that you see advertised). For 40 meters a longer radiator(closer to 33 ft) and a more extensive counterpoise or radial system will perform better, but radiators much longer than approximately 26 or 27 feet will not tune on 20 meters. If your radials are laying on the ground, a larger number of radials are more important than radials longer than about 17 ft. If your counterpoise is elevated above ground, for example on a deck, one or two resonant (quarter wave) radials will be probably be better, although I have found rather unlikely combinations that actually worked just fine. Rick KL7CW KX1 # 798 __ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
