[Elecraft] Re: Ether Nets and Interferrence, redux

[Geert Jan de Groot]

> After returning from a rather long hiatus from ham radio, I discovered an
> obscene amount of interference on the ham bands.  I later learned that it
> was largely the result of 6 Ethernet'ed computers in the house with cat 5
> wiring running all over, and 3 runs going through the ham shack.

In addition to what has been written already (make note of comments on
noisy wall warts and other power supplies!), I should note that classic
10 Mbit ethernet uses 5 MHz machester encoding.
This means that one only sees spikes every 5 Mhz (with sidebands, alas).

100BASE-TX, because of it's encoding, is a lot wider and hence a lot
noisier.

If you don't need 100 Mbit speed to talk to that 2 Mbit ADSL modem,
then you may want to consider setting up a 10 mbit network.

Does the trick every time in ad-hoc setups like with JOTA.

Don't throw out the 'old' 10 mbit hubs, and when you do,
give them to a fellow ham fore safe-keeping.

73,

Geert Jan PE1HZG