>that has been sitting as close as two feet from my K2 with no >problems that I noticed.
Proximity to the radio is meaningless. The following comments apply to virtually ALL Ethernet devices, including your computers. What matters are: 1) The antennas connected to the Ethernet device -- their length, and their proximity to YOUR antennas (but NOT to your radio). 2) The design of the device with respect to SHIELDING of its own internal wiring 3) The design of the device with respect to the internal generation of RF trash 4) The design of the device with respect to keeping whatever trash it produces off the antennas connected to it. 5) The directivity of the ham antennas and the Ethernet antennas. Ah, you say, you don't connect antennas to it, only Ethernet cables and a power supply lead. And if it's a router, the Cable TV coax or DSL connection. But even though we don't call them antennas, they ARE antennas, and they will radiate whatever RF trash they carry just like any other antenna. I have yet to find a piece of Ethernet gear that doesn't put out trash on the ham bands. Some are worse than others, and Linksys has been viewed as really bad. But when I switched to Netgear switches to get rid of noise, I noticed no difference! MOST of the noise in the equipment I've tested comes out of the box as a COMMON MODE signal, and is radiated by those cables as if they were a long wire antenna. The good news is that the noise can be greatly reduced by winding some turns of both the Ethernet cables and the power supply cables around the RIGHT ferrite toroids. Once you do that, you're left with what comes out of the box due to poor shielding. And, of course, whatever is radiated by your neighbors systems that are close enough to your radio antennas to be loud enough to hear. [You can identify 10BaseT Ethernet as the source by listening around 10,106 kHz, 10,120 kHz, 14,030 kHz, 21,052 kHz for strong carriers with some subtle modulation. While we buy 100BaseT gear, it carries both 10BaseT and 100BaseT traffic, and most routers and modems talk 10BaseT. These carriers are not based on a clock with a tight frequency tolerance, so every system is running on a slightly different frequency. That's why, for example, you will hear carriers between about 14,029 and 14,030.5 kHz.] I just moved from a city lot in Chicago (neighbors 15 ft from my house in every direction) to a rural area in CA (one neighbor 250 ft, another 350 ft, others at least double that). In Chicago, my ham antennas were all within 20 ft of Ethernet cables. Here in CA, the closest ones are at least three times that distance. In Chicago, I could get my own trash down to a bit above the noise level, but I still heard my neighbors loud and clear. Here in CA, I don't hear anything from these Ethernet systems, even though my noise level on the ham bands is way down too! There is a detailed tutorial on ferrites on my website, along with presentations I've done to a couple of ham clubs. All can be downloaded as pdf files. No cost, no cookies. http://audiosystemsgroup.com/publish BTW -- shielded Ethernet cable doesn't help -- for the shield to do anything, it would need to be connected at both ends, and you would be hard put with these boxes to find a connection that meant anything. 73, Jim Brown K9YC _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
