On Tue, 9 Dec 2008 07:52:00 -0800 (PST), JIMMIE
wrote:

I dont have a problem with crimp on terminals just that where I work
someone has always borrowed the crimp tool just when I need it.

I know the problem. Tools are expensive. However, there are a
variety of cheap replacements that seem to work well for me:
http://802.11junk.com/jeffl/antennas/Misc/slides/crimpers.html
I have several sets of these that cover everything from RG-188 to
LMR-400 size coax. There's also one for LMR-600 but it was being
borrowed when I took the photo. (Yes, it came back eventually). I
think I paid about $35/ea for the tools in the photo. At that price,
spares are an option.

I
always have my trusty soldeing gun handy, no one wants to borrow it.

When I was working on the bench, I had my soldering iron bolted to a
large block of wood to discourage the borrowers. My biggest problem
was someone trading or outright stealing my Weller solder tips. I
kept my supply locked up and hidden.

For me one is as easy and works as well as the other.

I beg to differ. Many of my connector installs had to be done in the
field, usually at a mountain top repeater site or up on a tower. The
problem was that the wind would cool just about any soldering iron,
gun, or even a propane torch, sufficiently to cause problems. Same
with the USCG vessels, where the coax was snaked through the mast, and
the connector had to be crimped at the top in the field. The only
place where I would effectively solder a connector was inside a
building. I do recall one day on a tower, when I draped my jacket
over my head, and soldered some connector by flashlight, but I don't
recommend doing that.

The biggest
problem I have with the non crimp type is the shield is eventually
cut from the connector.

Agreed. I have the problem with my test cables. A good strain relief
is a big help at immobilizing the shield. Pomona jumper cables have
molded plastic strain relief's. I use clear shrink tube (so I can see
when things are starting to come apart). In general, it's nut much of
a problem as I have far more UG-88/u BNC plugs fall apart than the
crimped variety.

The ones at work that are disconnected weekly
for preventive maintenance have only lasted about 20 years before
needing the connectors replaced, BUMMER.

Weekly? 52 weeks per year times 20 years is over 1000 connector
cycles. That's quite a few. I suspect the ears on the BNC jacks will
also be worn. I'm not surprised that they're failing. I did some
Googling and found specs for UG-88/u connectors ranging from 500-1000
mating cycles. Methinks you're at the upper limit of the lifetime.

The crimp-on type are not
without their problems. I was doing an inspection after some equipment
installation and was able to pull the the ends off of 20 BNC
connectors. The inspection stopped at that point and the decision was
made to reaccomplish all of the connectors, about 200 of them. The
installer was not happy. The problem turned out to be a bad crimp
tool. Like the solder-ons if done properly they are both reliable
connections.

Bummer. At one employer, we had an Amp-o-lectric crimping machine.
Someone found that it was possible to mis-adjust the tool to produce
defective crimps and proceeded to explore the possibilities. I was
blessed with dozens of field failures and a recall because nobody had
thought to run a pull test on the crimped connections. Everyone
assumed the machine could do no wrong. However, that's the big
advantage of a crimped connection... it's consistent. I can't get
that kind of consistency from soldered connectors, especially those
done in the field.

Incidentally, I've seen more damage done by the razor blade coax
stripping tools, than by the crimping or soldering. One nick in a
solid center conductor and the center pin connection falls apart
inside the connector. I try to use a thermal wire stripper, but that
also takes some skill.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

In article .net,
SparkyGuy wrote:

Halfway down this page (it's a PDF doc):

http://www.cablesandconnectors.com/PIX/CC-040.pdf

the TNC and BNC connectors are advertised as "dual-crimp". What does this
mean? "Dual" as in center in crimp and outer shield ferrule crimp?
yes


As opposed to what? Single-crimp? That would be connectors that use the
center, solid conductor as the center pin
yes(solder or captivated

and then crimp the shield ferrule?
Or...? yes

Newly (did you guess?) into small coax connectors and trying to get the
terminology straight...
you did good

are you just trying to learn the terminology or do you really
need to make some connectors and seek the best/easiest? way to
do that??

if you did you got a bunch of good tips here from the others



Thanks.

i'll throw in a few other simular options to connectors

there are strip tools that can cleanly and safely strip the coax
they just spin around and do a great job i've seen cost between 50
to 100bucks depending on coax

also you can get a fixed center pin whereby you don't have to
solder or crimp, the captivated connectors the outer
sheild part gets a crimp only typically a bit of glue on the
inside heavy ga heat shrink shrink goes over all

they are rated very good soare are the center pins /outer shield
that gets crimped using the right tool of course

no matter what you use skills at doing the job and
inspection/testing of the work will always remain a constant

One nick in a
solid center conductor and the center pin connection falls apart
inside the connector.

Can you say more about this? Or point to some web discussions / photos?

Thanks.

no matter what you use skills at doing the job and
inspection/testing of the work will always remain a constant

Your spacing makes for difficult parsing and comprehension.

SparkyGuy wrote:
One nick in a
solid center conductor and the center pin connection falls apart
inside the connector.

Can you say more about this? Or point to some web discussions / photos?

Thanks.


Any time you nick a solid copper wire it will be severely weakened and
will likely break.

Any time you nick a solid copper wire it will be severely weakened and
will likely break.

Dittos, can short internally too.

If it is anything important, the cable should be swept or at least checked
for return loss at a higher frequency. Just in case the parts were
mismatched out of the bag. Quality control can be a batch problem even in
the high end stuff. Good help is hard to find.

On Dec 10, 9:58*am, "JB" wrote:
Any time you nick a solid copper wire it will be severely weakened and
will likely break.

Dittos, can short internally too.

If it is anything important, the cable should be swept or at least checked
for return loss at a higher frequency. *Just in case the parts were
mismatched out of the bag. *Quality control can be a batch problem even in
the high end stuff. *Good help is hard to find.

I learned to make cables while assisting installation of a Doppler VOR
facility . We were sweeping the pre-made cables that came with the
system and finding a lot of them bad. We cut open a few of the bad
cables and founnd the center conductor was not in the center of the
cable. All of a couple of hundred cables had to be remade and cut for
proper phase. The other grunt worker Dust Craig and I became very
proficient at putting N connectors on RG-214 and using a vector
voltmeter.

Jimmie

On Wed, 10 Dec 2008 01:44:29 -0800, SparkyGuy
wrote:

One nick in a
solid center conductor and the center pin connection falls apart
inside the connector.

Can you say more about this? Or point to some web discussions / photos?
Thanks.

There's not much to say or show. The usual example is the common
RG-6/u cable TV coax, that uses the solid center wire as the center
pin of the F connector. By necessity, the center wire is rather
stiff. There's also no way to immobilize the center wire as there
would be no room for the mating jack. If the rotary razor blade wire
stripper or half asleep tech with the wire cutters manages to nick the
center wire, chances are good that moving the cable around will
eventually break the center wire at the nick.

Crimp type BNC plugs are also susceptible in the same area. The
difference is that the center pin is either crimped or soldered. The
center pin is also supported by the Teflon insulator. However, if the
coax is moved constantly, as is common with test cables, any nicks in
the center wire will eventually turn into a break. This one is
particularly insidious because it occurs inside the connector, where
both ends of the break are supported in place, resulting in an
intermittent, rather than a clean break.

Big fat center wires are not immune. They just have a different
problem. When one of the heavy stranded center wires from RG-8/u
style coax breaks at a nick, it's usually perfectly positioned to
short to ground. In the common PL-259 UHF connector, the coax end of
the break is not supported, resulting in a difficult to find, and
impossible to see, intermittent.

In my limited experience, the tools that cause the most problems are
the ones with the built in razor blades:
http://www.mytoolstore.com/ideal/ide08-07.html
http://www.mytoolstore.com/ideal/ide08-06.html#coax
http://www.mytoolstore.com/ideal/ide08-08.html
http://www.fab-corp.com/product.php?productid=1665&cat=281&page=1
http://www.hyperlinktech.com/item.aspx?id=879
(Note the huge variation in pricing)

As long as the blades are sharp they work just fine. However, when
the blades get dull, the user tends to bend the cable to assist in the
cutting, which sometimes results in a nicked center wire. Cleaning up
the stripping job with a pair of diagonal cutters also causes
problems. Stripping is also difficult with Teflon insulated wire and
non-wicking insulation (marine coax), where the dielectric materials
are bonded to the conductors. The best way to strip these materials
and to be sure not to nick the wires is with a thermal wire stripper.
http://www.teledyneinterconnect.com/products/wire_strippers/wirestrip.asp
I got lucky and ended up with pile of these from some aerospace
surplus outlet. Very handy. Just take care not to breath the fumes.

However, if you're working with LMR-400, LMR-600, or larger, the
blades of the thermal stripper cannot expand wide enough to fit the
coax cable. Therefore, I suggest getting the correct Times Microwave
EZ-Strip coax stripper for these cables:
http://www.hyperlinktech.com/item.aspx?id=881
http://www.hyperlinktech.com/item.aspx?id=882

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

A lot of this would seem to be trade secrets.