Hello Marshall
I always solder my center pins on both the crimps and the clamp type. The
crimp connectors I use from RF Connection are from RF Industries I believe.
They seem to work very well, and in over about 2 years of use and about 500-750
crimps or more, I am very satisfied with the results. The metal crimp ferrule
is thick, and it takes some muscle to crank it down...a very positive feeling
for me. I always check new stuff to look for problems before going with it. The
crimp choice was a biggie. In the past I had heard horror stories about them,
so never tried them. I had seen a few failures in my travels with older crimp
connectors. I cannot tell you how many bad clamp connector failures I have
seen. Almost all are due to improper assembly with poor braid combing as the
culprit. The center pin gets recessed, and the connector body becomes loose and
can be rotated by hand. If left as is, they can short out. I have ben guilty of
that in the past. Now I always use a metal brush t
o comb out the braid with any clamp connector I use.
I secured a few crimp samples and tested them before I went with them. I
use an HP 6 GHz vector analyzer to test them. They were great. When I use them,
I make sure the connector center pin is concentric before I apply the outer
body to make sure the pin is centered. You must do that with the clamp type as
well. I have also been testing the LMR cable knockoffs, and so far I am still
using LMR cable. The Vp variation between rolls is pretty good, and the VSWR
is fine up to the lower microwaves. VSWR is very important at the higher bands,
as it translates to terrible losses if it is not correct. Making good coax is
not easy, or they would all be good, right?.
In summary, I would not shy away from crimp connectors. Just make sure you
go with a quality brand and use a coax stripper made for the job. Do not cut
with a knife, or you will do it wrong and nick the braid, or get the dimension
wrong. Same with coax: Go with a reputable manufacturer. Even then, you should
test all your work.
Dave K1WHS
----- Original Message -----
From: Marshall Williams
To: Nate Duehr
Cc: k1whs@metrocast.net ; Jack
Sent: Thursday, December 04, 2008 5:14 AM
Subject: Re: [VHFcontesting] Type N crimpers?
Hello all....I have been using the Type N crimp connectors for a very long
time as well. I have been getting mine from a vendor on eBay. This guy has
been most helpful and has given very good service. However, there is one issue
that I have found with his(all??) connectors: If I try to crimp on the center
pin, it either does not make a really good connection OR it cracks the center
pin because it is very brittle brass. I have to solder each and every center
pin to be damn sure that it is right. Because of the heat on the center foam
insulation, it is fairly common that the center pin is now not exactly in the
center when you put on the outside shell. I have to be sure to check this with
every connector and "adjust" the center pin / center conductor until things are
exactly centered. This can be a pain sometimes. I want to mention that I am
using CommScope's LMR-400 clone(their part number 3227, I think) which has a
#10 solid Cu center conductor rather than the Cu p
lated Al that Times Microwave uses. That means that you have to use more heat
to get a good solder flow.
Mike Staal, K6MYC, said that he crimps all his center pins and has never had
any failures. An Internet friend of mine also crimps all of his and does not
have the problem that I have had with cracking / breaking the brittle gold
center pins. Has anyone else had this problem?? Do I need to start buying my
connectors from a better source?? Even with the solder issue, these connectors
are magnificently better than the much maligned and hated PL259's.
73 Marshall K5QE
www.k5qe.com
Nate Duehr wrote:
David Olean wrote:
Hello Jack,
I had been using clamp type N male connectors for many years, but recently
switched to crimp type N s for LMR-400. I have tested them, and actually
think they are better than the clamp type when used along with a manual wire
stripper. It makes a better cut, and is more uniform with no loosening of
raid as the connector gets flexed . The clamp type are touchy to assemble,
as the braid must be carefully combed out and formed over the internal metal
ring, or the connector works loose over time. Few people are that careful
when assembling those connectors. I get the crimp connectors from RF
Connection in Maryland. Joel also sells a hand coax stripper for LMR-400.
The crimp tool I use is a RF Industries RFA 4005-020 with replaceable jaw
inserts for different cable types. The latest version of this tool is pretty
good. Older versions were not as strong. I broke the first one, but the
latest one has been re designed and looks very rugged for the price. I am
sure there are better ones, but this RFI one is good enuf. The Crimp
connectors stay tight and have excellent RF properties.
I do not use the readily available "ham" solder type N connectors that
resemble UHF connectors in their construction/assembly. I found that
soldering them alters the VSWR and phase. They work, but I chose not to use
them for those reasons. For lower freqs they are probably fine. The RF
Connection LMR-400 crimp connectors have a very nice heavy ring ferrule that
crimps very positively. I have seen others that are much thinner and not as
rugged.
Dave K1WHS
Wow, Dave sounds like he's been through exactly the same path I have.
Same tools and all.
The only difference is that if I can, I like using "well-known brand
name" crimp connectors... any of the well-known RF manufacturers. I'll
have to try out the RF Connection's ones. They're probably fine.
Definitely agreed on those "fake" N connectors that solder on. I put a
couple on a test cable, took the cable outside, spun it around my head
an launched the connector I'd spent an hour putting on, into the
neighbor's yard. Just to make sure I hadn't done it wrong, I consulted
with others, put another set on, and did the same thing. They suck.
Plus... when it only takes MAYBE 10 minutes to put the crimp-on
connectors on (if you're SLOW and METHODICAL about it), and they never
have problems like that... why bother with the other stuff anymore?
Times have changed.
(I'll still solder on RF connectors for some applications, but that's
mostly because I still have them in the junk box! Not because I enjoy
it anymore...)
This article on eHam by Mike K6AER has some nice photos and prices, and
isn't too old. He has written a couple of nice articles on the high
quality of crimp-style connectors for a number of uses these days, and
probably has more detailed ones available if you contact him than this
one that Google found on eHam:
<http://www.eham.net/articles/19257>
You might contact him -- I think he also did some RF connectivity
testing later on. Not sure.
He's given his "using crimp on connectors" presentation at just about
every ham club in the Denver Metro area for a couple of years running,
now. (He also does a decent tower climbing/safety talk, trying to drag
hams into the 20th Century by explaining the benefits of full fall
arrest climbing harnesses and modern gear...)
Nate WY0X
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