2

I found several guidelines for building a passive ethernet hub, mostly quoting this. The guide specifies which diodes to use, but I cannot find them anywhere. What are the parameters I should search for to find a suitable replacement?

Adam Trhon
  • 143
  • 5
  • Assuming that this idea does work (?) then probably something like a 1N914 or 1N4148 would be a likely contender. – brhans Jan 23 '15 at 14:24
  • @brhans I assume it would work, they discuss it at http://electronics.stackexchange.com/questions/10864/building-a-passive-ethernet-hub-with-anti-parallel-diodes?rq=1 and don't complain. – Adam Trhon Jan 23 '15 at 14:40
  • the diodes he's chosesn are massively over-specified for the task 10-base-2 is only 20 MHz and those are 1GHz parts. ordinary signal diodes like 1N914 or 1N4148 should work just fine. it'd probably even work with resistors instead of the diodes, somewhere 22 to 47 ohm feels about right. – Jasen Слава Україні Jan 24 '15 at 12:49
  • @Jasen Why did you turn your answer into a comment? I won't be able to accept it... – Adam Trhon Jan 24 '15 at 12:56
  • it's all speculation on my part I haven't built it these ordinary diodes might be unsuitable in some way (too much capacitance?), build it and if it works you post an answer. – Jasen Слава Україні Jan 24 '15 at 14:55
  • My guess is that @Jasen is probably right and any signal diode will work fine. OTOH resistors may not since we need to prevent the signal from reaching the transmitting computer or it will detect a collision. Resistors will only attenuate the signal while 2 hops of diodes should cut it off completely. – jpc Jan 25 '15 at 14:43
  • I found what looks like a substitute part. – Jasen Слава Україні Jan 26 '15 at 01:09

1 Answers1

2

The diodes he's chosesn are massively over-specified for the task 10-base-2 is only 20 MHz and those are 1GHz parts. ordinary signal diodes like 1N914 or 1N4148 should work just fine.

it'd probably even work with resistors instead of the diodes, somewhere 22 to 47 ohm feels about right.

Else BA479 is avalable from mouser.com for less than a dollar each seems to meet all the important performance figures of the BA243 diode

Jasen Слава Україні
  • 31,874
  • 1
  • 31
  • 65