🚀 go-pugleaf

In sci.electronics, dhina@dxcern.cern.ch (Mourad Dhina) writes:

> Hello,
> i am trying to realize a circuit i found in an electronics magazine.
> one of the components it uses is a semi-rigid coax cable of
> 25 ohms impedance. this is the first time i hear of this (i only
> knew 50, 75 and 93 ohms cables, which are standard). anybody
> knows where to find this?
> Mourad

You used to be able to buy 25 ohm semi-rigid coax from Precision 
Tube in Pennsylvania, but I am not sure they still make it.
Most people just use two 50 ohm lines in parallel.

If you don't mind flexible coax, here's a trick I used.  I ordered
"Braid-shielded teflon-insulated wire" from Alpha wire.  By 
choosing #18 wire, and a very thin insulation (I think is was 
something like 10 mils thick), I ended up with 16 ohm "coax" which
worked quite well to at least 100 MHz.  If you ordered the
#20 or #22 gauge version (which they also make), you should be 
able to get up to 25 ohms.  Anyway, they're all standard catalog
items.

Rick Karlquist
rkarlqu@scd.hp.com