From Newsgroup: sci.electronics.repair

In article <c44bbk91qdflto66450i3ia5m16crta4j4@4ax.com>, legg <legg@nospam.magma.ca> wrote:

You sure it's BNC?

No. There are many coaxial connectors. https://en.wikipedia.org/wiki/List_of_RF_connector_types
My knowledge is minimal and some statements here are speculative.
Corrections welcome.

I've posted a photo of four connectors. https://easthope.ca/CoaxialConnectors.jpg
The photo isn't high resolution but suffices to show salient features.

Left to right in the photo.

(1) BNC to Lemo adapter with a Lemo patch cable connected. Connects
to the Owon HDS2202S oscilloscope BNC connector.

(2) BNC to RCA with patch cable connected. Connects to the scope.

(3) BNC on the Hantek HT-25 automotive ignition pickup. Connects to
the scope.

(4) ?? on a patch cable marked ITT WIRE & CABLE DIV. RG-59/u COAXIAL
CABLE. The protrusion of the white insulator prevents connection to
the scope.

There is a similar HT connector that won't fit BNC hardware.

(4) appears to be an instance. I don't see it in the Wikipedia list
and don't have a name for it.

Now fairly certain I can connect the Owon well enough to see
significant automotive ignition problems.

Thanks, ... P.


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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.

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On 04 Sep 2025 08:07:38 -0700, peter@easthope.ca wrote:

In article <nphbbk9k2q4u562nt7kenbb7dmrmcsv68d@4ax.com>, Jeff Liebermann <jeffl@cruzio.com> wrote:

Do you really want 2.5 meters of coax cable stored in the engine
compartment?

Ignition connection to firewall will take at least a meter. Surplus length >is easily coiled and zip tied out of the way.

You could punch a round hole in the rubber plug, but it's easier and
neater to cut and "X" in the rubber. If you change your mind later,
an "X" is easier to reseal than a hole.

Good idea. Might do that. Thanks.

Or, just remove the existing rubber plug and replace it with an
aftermarket grommet:
<https://www.amazon.com/Electrical-Retractable-Protecting-Assortment-Automotive/dp/B09CDHLLPG>
Notice the "X". You can cut these grommets from the center to the
edge of the grommet which only requires a hole the diameter of the
coax cable instead of the larger BNC connector diameter.

In this instance the grommet is oval with diameeter at one end bigger
than the other. Unfortunately a round grommet won't work. Don't
recall another opening in the firewall but will check again.

This should be easy. Measure the circumference of the oval hole. I
suggest using a piece of copper wire. Grommets are specified by the
equivalent diameter of the round hole that it will fit. Divide the
measured oval hole circumference by 3.14 to obtain the diameter. Look
for a grommet with the same diameter. If it's made from fairly
flexible, the grommet should deform to the desired oval shape.

If the grommet size is too large for commodity grommets, try using a
continuous grommet strip: <https://www.google.com/search?udm=2&q=continuous%20grommet%20strip>
To make it water resistant, you might need to add a plastic or PVC
cut-out which is slightly smaller than the oval hole.

Also see "grommet edging" <https://www.iqsdirectory.com/articles/rubber-molding/grommet-edging.html>
--
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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From Newsgroup: sci.electronics.repair

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."
--
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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From Newsgroup: sci.electronics.repair

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
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From Newsgroup: sci.electronics.repair

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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