[Elecraft] P3 Loss of signal

[Brian Alsop]

Charlie,

Your information about BNC pin size diameter used to be true but not so 
anymore.

These days the BNC center pin size is the same for 50 and 75 ohms.
The quote below is from 2004 so this change took place a long time ago.
See:
http://forum.allaboutcircuits.com/newsgroups/viewtopic.php?p=157284

73 de Brian/K3KO
	
PostPosted: Wed Aug 11, 2004 11:25 pm    Post subject: Re: BNC centre 
pin size for 75 and 50 ohm sockets 	
"Fred" <Fred at nospam.com> schrieb im Newsbeitrag
news:4119d8e2$0$206$db0fefd9 at news.zen.co.uk...
Quote:
I have access to some 50 ohm BNC sockets. However it must mate to a 75
ohm
plug. Since we are talking about video frequencies here I'm not worried
about mismatches etc.

What are the dimensional differences between the 50 and 75 ohm sockets?

Can anyone point to dimensioned drawings of both types including pin size
etc?


Hello Fred,
I tried with Google: bnc 75 50 difference

The first hit.
http://www.levitonvoicedata.com/support/technotes/tech_note_detail.asp?tnID=175

Original text from this page follows.

--- begin ---

Difference between 50 Ohm and 75 Ohm BNC Connectors

What are the physical differences between 50 Ohm BNC connectors and 75 
Ohm BNC connectors?
There are a few physical differences. The 75 Ohm plug’s center pin has 
the same diameter in the rear as in the front mating interface area. 
Whereas, the 50 Ohm plug’s center pin has a thicker diameter in the rear 
area where it is crimped.

Both plugs have the same pin size in the mating area. Regarding the
dielectric on each, the 75 Ohm connector’s dielectric is made of Teflon
which has higher impedance properties than Delrin. The 50 Ohm connector’s
dielectric is made of Delrin.

Finally, the main physical difference is that the 75 Ohm plug does not 
have extended dielectric around its outer spring fingers.


On 11/20/2013 14:59, Charlie T, K3ICH wrote:
> When comparing similar size cables or connectors, the one with the
> smaller inner diameter will be the highest impedance.
>
> 73, Charlie k3ICH
>
>




-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2012.0.2247 / Virus Database: 3629/6351 - Release Date: 11/20/13