In message , Spike
writes
On 19/08/2017 09:32, Ian Jackson wrote:

Sheffield & District Wireless Society

///////////////////////////////////////////
Foundation Course Material in PDF Format

Posted: 18 Aug 2017 04:04 AM PDT

http://sheffieldwireless.org/2017/08...aterial-in-pdf
-format/

PDF File versions for the Foundation Course

Please may I offer one correction:

In 'Antennas & Feeders', the information about BNC connectors, you
are warned "Take care not to mix incompatible 50 and 75 Ohm versions
which have different inner pin sizes".

This is NOT totally correct. While the profile of the pins are
slightly different (the 50 ohm usually has a somewhat stubbier
point), the diameters are the same. The difference in characteristic
impedance is achieved by the amount of PTFE dielectric.

As a result, you CAN physically mate 50 and 75 ohm BNC connectors
(both sexes).

This is far too technical for a 'training scheme' that produces Fulls
who have to ask the question "USB/LSB? I'm confused!".

Don't worry - I can also confirm that both impedances of BNC connectors
are totally compatible with both USB and LSB.



--
Ian