[TenTec] Coax Connectors

[Dr. Gerald N. Johnson]

On Sat, 2008-05-31 at 10:19 -1000, Ken Brown wrote:
> >
> > Wonder what you think of the TNC, seem to be used a lot in the labs, together with BNC and N.
> >
> >
> >   
> BNC, TNC and N connectors are identical on the inside. That is, the 
> center "hot lead" pin and the outer shield fingers are the same 
> dimensions. You can plug a N male connector into a BNC female connector 
> and make a proper connection, though there is nothing to hold it in 
> place. The only difference between the three types is the outer "hold it 
> together" mechanisms, and in the case of N that also serves as a weather 
> seal. Beware however that there are 50 ohm and 75 versions of all of 
> them, and they should not be connected to one another. Damage to the 
> center conductor female part will result. There may be other impedance 
> versions too. The non 50 ohm versions are much more common in BNC and 
> TNC than they are in N.

While the N male will mate with the BNC and TNC female, there is some
impedance mismatch because the BNC and TNC connections are filled with
dielectric, while the N connection interface is filled with air.
> 
> Also there is MHV which looks very much like a BNC, yet has the 
> dielectric extending out further in front on the male connector. Don't 
> try to plug a MHV male into a BNC female. You will not get the bayonet 
> turned and latched. MHV is typically used for low current, high voltage 
> supply to photomultiplier tubes and vacuum gauges.
> 
> I like to use N connectors for cables with transmit power on them and 
> BNC for receive only connections. This results in quality constant 
> impedance connections for both, and an easy way to avoid getting them 
> mixed up.

Works well.
> 
> DE N6KB
> 
73, Jerry, K0CQ