On Sun, 19 Oct 2025 11:07:29 +0200, Jeroen Belleman
<
jeroen@nospam.please> wrote:
On 10/18/25 20:46, Jeff Liebermann wrote:
On 18 Oct 2025 11:27:23 -0700, peter@easthope.ca wrote:
P.s.
In article <10d0hek$1v0m2$1@dont-email.me>, peter@easthope.ca wrote:
https://en.wikipedia.org/wiki/List_of_RF_connector_types
Aliexpress has several listings mentioning Q9.
Eg. https://www.aliexpress.com/item/1005008750664154.html
All I've found about Q9 is marketing related. Any enlightenment about Q9? >>>
Thx, ... P.
"What is the Difference Between BNC Connector and Q9 Connector?"
<https://www.renhotecrf.com/rf-connector-cable/what-is-the-difference-between-bnc-connector-and-q9-connector.html>
"The BNC connector is based on the imperial system and has specific
dimensions measured in inches. (...) The Q9 connector, on the other
hand, follows the metric system and conforms to national standards. It
has slightly different dimensions compared to the BNC connector. The
core of the Q9 connector is thicker and closer to the edge of the
connector."
I'd never heard of Q9 connectors, despite having been an intensive
user of all sorts of coax and connectors for over 40 years. I gather
Q9 is near enough to BNC to mate with it, but not enough to be
reliable? If that is so, that's yet another connector perversion.
Grrr!
Jeroen Belleman
Don't panic. The connectors are almost identical. If the connector
looks like something that should be used on test equipment (machined,
brass, nickel/tin plated, or silver plated) it's probably BNC. If the connector is looks like something found on low end consumer
electronics (die cast zinc and chrome plated), it's probably a Q9.
Those are my general guidelines.
As I understand it, Q9 is common in China: <
https://www.kabasi-connector.com/news/the-difference-between-q9-head-and-bnc-head-46317674.html>
So far, I have not run into a product where the connector is specified
as Q9 only. I also haven't run into any compatibility issues with
potentially mixed connectors, such as my various TDR's (time domain reflectometer) that use both types depending on vendors. However, I
have dealt with mechanical compatibility problems between 50 ohm and
75 ohm BNC connectors.
I suppose the connector type might make a difference at the maximum
frequency (4GHz) where a BNC connector might be found: <
https://www.everythingrf.com/tech-resources/connectors>
Notice that the Q9 connector is not listed. Also note that nobody
offers BNC to Q9 adapters. For 4GHz and up, a TNC connector would
probably be more appropriate.
Also, I didn't have any luck finding specifications and dimensions for
the Q9 connector. The Q9 connector also does not appear on the
Wikipedia BNC page:
<
https://en.wikipedia.org/wiki/BNC_connector>
To preserve what remains of my sanity, I'll pass on diving down that
rabbit hole. However, for those seeking enlightenment, start here: <
https://landandmaritimeapps.dla.mil/programs/milspec/ListDocs.aspx?BasicDoc=MIL-PRF-39012>
--
Jeff Liebermann
jeffl@cruzio.com
PO Box 272
http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272 AE6KS 831-336-2558
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