For as helpful as computer systems are within the trendy ham shack, additionally they are usually a robust supply of undesirable radio frequency interference. Widespread knowledge says making use of just a few ferrite beads to issues like Ethernet cables will assist, however does that actually work?
It certainly seems to, for probably the most half at the very least, in response to experiments done by [Ham Radio DX]. With a selected curiosity in decreasing the noise flooring for operations within the 2-meter band, his take a look at setup consisted of a NanoVNA and a easy chunk of wire standing in for the twisted-pair conductors inside an Ethernet cable. The NanoVNA was set to comb throughout your complete HF band and up into the VHF; numerous types of ferrite have been then added to the conductor and the frequency response noticed. Merely clamping a single ferrite on the wire helped a bit of, with marginal enchancment seen by including one or two extra ferrites. A way more dramatic enchancment was seen by looping the conductor again by the ferrite for a further flip, with diminishing returns at greater frequencies as extra turns have been added. One of the best efficiency appeared to come back from two ferrites with two turns every, which gave 17 dB of suppression throughout the examined bandwidth.
The query then turns into: How do the ferrites have an effect on Ethernet efficiency? [Ham Radio DX] tested that too, and it appears like excellent news there. Utilizing a 30-meter-long Cat 5 cable and testing file switch velocity with iPerf, he discovered no measurable impact on throughput it doesn’t matter what ferrites he added to the cable. In actual fact, some ferrites really appeared to spice up the file switch velocity barely.
Ferrite beads for RFI suppression are nothing new, after all, nevertheless it’s good to see a real-world take a look at that tells you each how and the place to use them. The truth that you gained’t be borking your connection is good to know, too. Then once more, perhaps it’s not your Ethernet that’s inflicting the issue, during which case perhaps you’ll want a little help from a thunderstorm to trace down the problem.
