I too suffer from some severe local noise, of several varieties, which comes and goes depending on time of day, day of week etc. So I picked up a DX Engineering NCC-1 here and am happy with it. It's well made and the control knobs are *big* and very smooth, a pleasure to operate.
It integrates nicely with the K3, inserted between the K3 antenna OUT and antenna IN jacks. I have a horizontal trap dipole which I use as the RX antenna on the K3 when I need to fight noise. A vertical doublet antenna or inverted L is used as the transmit antenna, but I also use these as the noise sense antennas when the NCC-1 is in-line. To do this, the horizontal antenna goes to antenna port A on the NCC-1 (receive antenna input), K3 antenna OUT (from the transmit antenna) goes to antenna port B on the NCC-1 (noise antenna input) and the output of the NCC-1 goes to the K3 antenna IN. Now I have 3 choices: If I then select the RX antenna on the K3, the NCC-1 is inserted and I use the horizontal antenna for receive. If I don't select the RX antenna on the K3, the NCC-1 is bypassed, and the transmit antenna is used for receive. If I select the RX antenna on the K3, but turn the NCC-1 OFF, then I receive on the horizontal antenna, but the signal passes straight through the NCC-1 from antenna port A to the output without modification (for some local noise that's all that's needed). K3 KEY OUT goes to NCC-1 T/R CTRL to put it in bypass mode when the K3 is keyed. Cancellation of local noise seems to work well with this setup, using a full size vertical as the noise sense antenna, and the horizontal antenna as the receive antenna. The NCC-1 can provide a very deep null on the horizontal antenna for vertically polarized noise which is "heard" better on the vertical. The trick is to correctly balance the levels of the two antenna inputs on the NCC-1. The balance and phase controls are very precise and repeatable, and the phase control has great range. Having the P3 to look at helps in identifying the noise and finding what can be a rather sharp null. So far, the noise canceller has proven helpful in dealing with many (but not all) local noise problems and I'm glad I have it when I need it. Of course no two stations are identical. An alternate setup might involve a separate noise antenna (usually vertical) on NCC-1 antenna port B, with K3 antenna OUT going to NCC-1 antenna port A. In this case the K3 transmit antenna is used for receive at all times, but the NCC-1 is bypassed if the RX antenna is not selected on the K3. Another might involve dedicated noise and receive antennas, with the NCC-1 output connected to the K3 antenna IN. The NCC-1 is designed to work with the various active antennas offered by DX Engineering, one of which might make a good noise sense antenna. Bob NW8L >Guys >I am being hammered by what I believe are switching power supplys from >the local hospital >although it could be from a neighbor as it doesnt show any directivity on >my rcv loop >are there any suggestions on a good noise canceler ?? I have a anc >product which isnt always >effective and wondered if the DX eng. unit may be better,, I believe it >will rotate / control the phase 360 # >it is a lot more expensive >anybody have any expierence with any of the noise cancelers ?? >Bob K3DJC ______________________________________________________________ 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
