50 vs 75 ohm N-connectors

[w2bvh]

I just picked up some fine looking heavily built male N connectors at a
hamfest. Before I mount one onto the antenna end of a cable and send it
up 18 feet over my roof I'd like to make sure it's a 50 ohm "N".

Does someone know how to tell a 50 ohm from a 75 ohm "N"?

Thanks in advance for your help.

73,
Lenny W2BVH
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[KB5DXY]

w2bvh wrote:
>
> Does someone know how to tell a 50 ohm from a 75 ohm "N"?
>
>
The impedance is a characteristic of the coax cable, not the connector.
What does matter is what coax cable(s) the N connectors are designed
for, such as RG8, RG58, RG214, etc. Take a look at
http://www.smelectronics.us/typencableconnectors.htm. This might help
you match your connectors to their appropriate cables.

73
Larry
KB5DXY
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Jim Price-3]

Not so.  There is a very real physical difference between 50-ohm and 75-ohm
type N connectors.  The 50-ohm male pins are bigger than the 75-ohm pins and
will damage a 75-ohm female connector.  Likewise if a 75-ohm male is mated
with a 50-ohm female there will not be good electrical contact.

73,
Jim - N4ST

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Larry
Sent: Saturday, October 14, 2006 23:56
To: w2bvh
Cc: [hidden email]
Subject: Re: [Elecraft] 50 vs 75 ohm N-connectors

w2bvh wrote:
>
> Does someone know how to tell a 50 ohm from a 75 ohm "N"?
>
>
The impedance is a characteristic of the coax cable, not the connector.
What does matter is what coax cable(s) the N connectors are designed for,
such as RG8, RG58, RG214, etc. Take a look at
http://www.smelectronics.us/typencableconnectors.htm. This might help you
match your connectors to their appropriate cables.

73
Larry
KB5DXY
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[k6mr]

Not sure you have anything to do the measurement, but the center pin of a 50
ohm type n male connector should be 0.0640 inches in diameter (this is the
last part of the pin before it tapers to a blunted point).  A 75 ohm pin
will be 0.0353 inches.  It's easy to tell if you have one of each, but
unless you've seen them before it may not be obvious.  

If you can remove the center pin and have a known 50 ohm female jack, insert
the pin into the center conductor of the jack.  If it goes in easily and
seems loose, the pin is a 75 ohm.  The pin should require a small amount of
force to spread the fingers of the jack.  As was mentioned before, don't try
this with a 75 ohm jack since you will ruin the jack if you push a 50 ohm
pin into it.  No problem with a  50 ohm jack since it is too big for the
smaller 75 ohm pin.

Ken  K6MR



-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of w2bvh
Sent: Saturday, October 14, 2006 8:28 PM
To: [hidden email]
Subject: [Elecraft] 50 vs 75 ohm N-connectors

I just picked up some fine looking heavily built male N connectors at a
hamfest. Before I mount one onto the antenna end of a cable and send it up
18 feet over my roof I'd like to make sure it's a 50 ohm "N".

Does someone know how to tell a 50 ohm from a 75 ohm "N"?

Thanks in advance for your help.

73,
Lenny W2BVH
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[w2bvh]

On Ken Kopp, K0PP's advice (nice call by the way), I checked for some
markings. With bright light and a magnifier I find it's an Andrew 42W
connector, of which there is little info on the internet. Except that
it's for use with hardline, 1/2" I believe.

But with some more poking around on the net I found the following:
http://www.amphenolrf.com/products/CatalogPages/typen_catalog.pdf

Page 2 of the pdf shows the length and diameter of the center pin! So
tomorrow I'll go mike mine up and from that i'll know what impedance
connector I have!

Thanks for the background info.

I think maybe I can adapt it for use with RG-213 / LMR400 / 9913F  if it
is a 50 ohm job.

73,
Lenny W2BVH
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com