Considering recent Ethernet debate and previous inquiry about 1-wire
serial port network, I'd like to add that I have been using simple
RS-232 single wire local area network for quite some time.
It is made by just an 1N4148 diode with anode to TXD and cathode to RXD!
Now use shielded cable to connect all computers RXD's and GND together.
Software driver is simple CSMA protocol already used by ICOM radios.
Regarding GAS debate, let me emphasize that USA hams are not even aware
how clean is their HF radio environment so nobody cares about RX performance.
Beverages are the only real investment made while the TX bandpass filters are
practically enforced on M/M stations.
Just an historical EU example:
In 70's we had KW and 2 el. quad on 40m at YU1BCD and the only way to dig
out most of the signals on our superb Collins 75S3 RX was to put 7 MHz
crystal filter between receiver and antenna together with attenuators.
More recently we are working on improvements of FT-1000 RX's.
73 de Mario, S56A, S57MM, N1YU, ex YU3EA, YU1PCF.