Subject: Re: How to check for a 50 or 75 ohm connector
Summary: What do you think of these ping times eh?
Reply-To: You can't see me, and I pass right through planets...
X-Newsreader: Forte Agent 1.91/32.564
Date: Sun, 22 Dec 2002 20:42:48 GMT
NNTP-Posting-Date: Sun, 22 Dec 2002 15:42:48 EST
On Sun, 22 Dec 2002 19:01:09 +0000, Don Pearce
>On Sun, 22 Dec 2002 17:56:18 GMT, DarkMatter
>> The cable is the SOLE determining factor.
>> Try again. Review your data, and make information for yourself out
>>of it. Unless disseminated properly, it is mere data. It is not
>>INFORMATION until it gets examined, and absorbed properly.
>I won't argue this any further - go and look here at the 50 and 75 ohm
>pdf files. You will see the difference in the connector (mating) side
>of the connectors. Look inside the connector at the design of the
>insulation (or lack of insulation in the case of 75 ohms).
Look, Chucko, here is a quote directly from the Amphenol page that
has the entire history of the connector in question. It clearly
states that 50 and 75 ohm BNCs can be plugged into each other.
In other words, they can be mated against their stated impedance
without destructive damage to either. That makes them physically the
same. The electrical nuances of each type are determined by factors
surrounding the cable side AND the insulative section of the center
pin pass through, and plating differences. Materials, not shape.
Here is the quote from the Amphenol page:
"Developed in the late 1940?s as a miniature version of the Type C
connector, BNC stands for Bayonet Neill Concelman and is named after
Amphenol engineer Carl Concelman. The BNC product line is a miniature
quick connect/disconnect RF connector. It features two bayonet lugs on
the female connector; mating is achieved with only a quarter turn of
the coupling nut. BNC?s are ideally suited for cable termination for
miniature to subminiature coaxial cable (RG-58, 59, to RG-179, RG-316,
Amphenol 50 O BNC connectors are miniature, lightweight units designed
to operate up to 11 GHz and typically yield low reflection through 4
GHz. Designed to accommodate a large variety of RG and industry
standard cables, BNC connectors are available in crimp/crimp,
clamp/solder, SURETWIST?, and field serviceable termination styles. A
full line of printed circuit board receptacles, bulkhead receptacles,
resistor terminations, and other accessories complement the product
A variety of our 50 O BNC connectors are recognized under the
Component program of Underwriter?s Laboratories, Inc. These connectors
are ideal for use with medical equipment and test instrumentation
where safety cannot be compromised.
Amphenol also offers a full line of 75 O BNC connectors to meet the
needs for higher performance impedance-matched cable interconnections.
These connectors can be used in a variety of applications where true
75 O performance is needed to insure low signal distortion. Designed
for the most popular 75 O cables used in broadcast and CATV
applications as well as for plenum and other cables, these connectors
feature crimp-crimp cable affixment for quick and reliable
Two distinct types of 75 O BNCs are available, and both mate with each
other and with 50 O BNCs. Type 1 is designated 75 O BNC-T1 and
provides constant 75 O performance with low VSWR DC ? 4 GHz. Type 2 is
designated 75 O BNC-T2 and is usable with low reflection DC - 1 GHz.
For applications above 1 GHz, Type 1 is recommended.
Part numbers that are listed with the appropriate M39012 number are
military grade connectors produced in accordance with and actively
qualified to the military specification MIL-C-39012. Connectors not
listed with the M39012 number constitute the industrial grade product
offering. These connectors provide comparable performance and
generally feature nickel-plated brass bodies, Teflon insulators, and
either gold or silver-plated center contacts. Amphenol?s commercial
grade connector offering carries the part number designation ?RFX? for
easy recognition. These low-cost connectors typically utilize die cast
and molded components. While performance will not be equal to the
industrial or military grade products, these connectors are ideal for
use on a variety of commercial applications.
Reverse Polarity BNCs are also available. Reverse polarity is a keying
system accomplished with a reverse interface, and ensures that reverse
polarity interface connectors do not mate with standard interface
connectors. Amphenol accomplishes this by inserting female contacts
into plugs and male contacts into jacks. Other manufacturers may use
reverse threading to accomplish reverse polarity keying."
End quote. Nuff said.