Microvaxen bits etc.

From: Russ Blakeman <rhblake_at_bigfoot.com>
Date: Sun Nov 1 13:54:46 1998

William Donzelli wrote:

> > BNC is a UHF constant impedence connector. They work very well at
> > several GHz! They just don't like high RF power (voltage).
>
> They are not that great, compared to later connectors. The F (a quality
> one) will do a better job in the UHF region.

The F still won't hold that much wattage due to the fact you're using the bare
single conductor of the cable itself to make the connection. The coax used for
most F connections also has low wattage capacities. It's great for low wattage,
high frequency like satellite apps though. All test equip uses BNC for the ease
of removal, high stability, strength and wattage ratings. The missiles I worked
on in the USAF (air launched nukes) all ran in the Ghz ranges and were connected
by either threaded UHF style connectors and BNC.

> > When BNC started to be used for Eithernet, Ts were expensive and got cheap
> > due to volume. F connectors are common to cable industry and if they
> > needed Ts they would be cheap too.
>
> Actually, BNC Ts were quite common back then. They were used in radar test
> sets quite a bit. OK, being military, they were still expensive...

All MILSPEC items are more expensive due to the fact they are generally custom
built and nonstandard. When it comes to commonly available items, the MILSPEC
items are generally built to a higher rating or different than the common ones
in durability. There's noting like having a cheap Taiwanese cable when you're
out in the middle of nowhere doing an alignment on a radar unit in the elements.
Many of the diehard ham radio people I know refuse to use the generic junk
available and will wait up to a year to find surplus at dealers and government
auctions. I'm not that fussy with ethernet since we aren't talking about a lot
of energy in watts or frequency so the common BNC's work for that. The cables I
use for my scopes are surplus MILSPEC though.

I had an Artisoft setup known as "Simply Lantastic" that was ethernet/thinnet
and came with it's own NE2000 cards, but instead of tees, BNC's and terminators,
they used 1/8" phone plugs and two earphone jacks. The earphone jacks switched
the terminators in or out as needed so it was auto-magic when the cable was
removed. Bad thing was the plugs were prone to being pulled out slightly and not
making a good connection, and therefore a nightmare (at first) to figure out for
troubleshooting.
Received on Sun Nov 01 1998 - 13:54:46 GMT