coax connectors: soldered vs. crimped?

assuming the connections between coax connector and antenna are properly weather proofed externally, does anyone have any info./ opinion on whether crimped connections are equal to soldered ones long term?
ive done both types of connection for 25+ years on residential 120/240 volt wiring with good results on both but im new to coax assembly methods. the coax in question is rg8u & lmr400.
any info. would be appreciated, mike.

I can't say which is 'better', but I do have a personal preference and opinion. That's not what you are asking though, so take this with as much 'salt' as you think advisable. I think the soldered connections are 'better' in general. More secure, at least the way I handle coax. I guess I've seen as many 'bad' connectors of both kinds as 'good' ones, which is merely a matter of how well they are applied. If I assemble a feed line that used PL-259s they will be soldered. If I buy a feed line with them already on it, there's no telling what they may be.
- 'Doc

WalterEKurtz said:

assuming the connections between coax connector and antenna are properly weather proofed externally, does anyone have any info./ opinion on whether crimped connections are equal to soldered ones long term?
ive done both types of connection for 25+ years on residential 120/240 volt wiring with good results on both but im new to coax assembly methods. the coax in question is rg8u & lmr400.
any info. would be appreciated, mike.

Click to expand...

In my opinion a job worth doing is worth doing well.solder them. ham radios are expensive to repair along with the parts in most cases.


K3CFC

It depends on the cable. LMR type cable has aluminum in the outer conductor, so you use crimp type connectors. Otherwise, done properly, it doesn't seem to matter. RF performance wise, you would be hard pressed to see a difference. I'm aware of 30 year old crimp connectors on cables, and even older solder types, and they'll all working just fine.

But I actually preferr the solder type connectors, especially at rempte mountain top sites. They're generally reusable, and if something goes bad, you can reuse the old connector. You can't always carry the right connector.

Solder.

The horror.... the horror... - Kurtz

As for connectors, I have seen more failures with solder type due to fractures but that's just my experience.

WalterEKurtz said:

assuming the connections between coax connector and antenna are properly weather proofed externally, does anyone have any info./ opinion on whether crimped connections are equal to soldered ones long term?
ive done both types of connection for 25+ years on residential 120/240 volt wiring with good results on both but im new to coax assembly methods. the coax in question is rg8u & lmr400.
any info. would be appreciated, mike.

Click to expand...

Crimp connectors is the 2 way industry has been the standard so to speak and also LMR type
coax does not lend itself well to soldering with the foam dielectric and you have to be both real
good to get it done fast and correctly to not distort the construction of the coax and ruin the
impeadance value once completed with that task. If your a newby to soldering then it would not
be wise to try it unless you have a lot of connectors and much LMR cable to try, try and try again
in order to practice. I have soldered many times with LMR type cable and never like to unless i
abolutely have to.

We use all crimp or clamp types, no solder types, in our professional cellular work. But, the types of connectors used have gold plated fingers on the spring finger center connections, and are typically expensive. And we alwasy ahvae the tooling and need to install alrge neumbers of connectors at each site. The only concern that I would have for general ham use with crimp types is if the cable ends are not done right (with a tool), then the spings fingers on the center conductor won't contact well, and the high power levels used in most ham transmitters can be come a problem on a poor center conductor connection. This really becomes an issue with mobile installations, where the vibrations will cause this to be even worse; the 2-way shops I know use solder connectors for this reason for all mobile installations. So for general ham use with the usual low connector counts made by individuals, and the lack of special tooling, I would recommend solder types.

Interesting discussion.
I've seen this before, and it seems like Amateur operators always prefer the solder on connectors. I often wondered if that was because it's cheaper than purchasing the proper crimping tools, and that the general low quantity of connections done makes it cost prohibitive to invest in the proper tools.

I've done a lot of both. I can't say that any one has failed more than the other. I've done a lot of solder on PL-259's and always disliked the procedure. When my quantity got high enough to warrant purchasing the correct tools, I've switched everything to crimp connectors. I do occasionally do the 3 piece connectors which often have the option of soldering the pin onto the center conductor, so I guess that confuses things. Anyway, once you learn to do crimp connections properly, it's really rare to have a failure. All the Heliax stuff we've done at work is clamp type with no solder. I've done a lot of LMR-400 and LMR-600 with the "EZ" version connectors, and have had very good experience with those.

I think the big question isn't which one is "better", but more "which one do you have the proper training and tools to do." That would seem to answer the question about why hams prefer the solder connectors and the LMR guys prefer the crimp/clamp connectors.

Modern aircraft wiring is all crimped - you may need a humungous hydraulic tool to put the lugs on power cables but they're still crimped. Crimping - if you get the right tools that have been checked recently - produces a 'cold-welded' joint. Even on those small coax cables that are used for the seat-back video displays.

majoco said:

Modern aircraft wiring is all crimped - you may need a humungous hydraulic tool to put the lugs on power cables but they're still crimped. Crimping - if you get the right tools that have been checked recently - produces a 'cold-welded' joint. Even on those small coax cables that are used for the seat-back video displays.

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Now that you bring that up, it reminds me that whenever I do wiring one of my own vehicles, I use crimp on connectors for any of the wiring for power/audio, etc. I always crimp the connector with the proper ratcheting crimp tool with the correct dies, follow up with solder and use heat shrink. In all my years I've never had one of them come apart. It's overkill, but peace of mind, so maybe I'm contradicting myself with using crimp coaxial connectors everywhere.

I live in pa and there was a ham here that everyone called the bug man. he was the go to guy for cb repair. he didn't need a schematic and hours to repair cb's because did this all his life. he held a commercial license. he says crimp pl259's have their place and it is not in transmitters. now mind cell phones were not around at the time so we are talking about ham and cb. he held a class once a month for free and taught us the proper way to install pl259's. he said if you have a connection failure and don't know it it will take out the finals in your radio. so all i can say is do it right the first time and you will not have a problem.

K3CFC

I've built aircraft wiring harnesses and was prohibited from soldering any connector and these were cables that someone's life depended on. The key point here is you must have the proper crimper and it must be calibrated. If not there is no accountability and no guarantee the connection is reliable.

So for many hamsters a soldered connection might be better because the proper tools are not available.

prcguy

prcguy said:

I've built aircraft wiring harnesses and was prohibited from soldering any connector and these were cables that someone's life depended on. The key point here is you must have the proper crimper and it must be calibrated. If not there is no accountability and no guarantee the connection is reliable.

So for many hamsters a soldered connection might be better because the proper tools are not available.

prcguy

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Then again your not running legal limit rf through them either.

K3CFC

Keep in mind that there are no common crimp/clamp type coax connectors where you actually crimp the center pin onto the center conductor; they all use spring fingers to grp the center conductor. (At least that I know of....) So the wire crimp analogy with harnesses is not fully valid, IMO.

beachmark said:

Keep in mind that there are no common crimp/clamp type coax connectors where you actually crimp the center pin onto the center conductor; they all use spring fingers to grp the center conductor. (At least that I know of....) So the wire crimp analogy with harnesses is not fully valid, IMO.

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A number of the three piece crimp connectors have solder holes on the center conductors. Some others are crimp, but can be soldered also. But, you are correct, most of them use some sort of spring tension to make contact.

As for the argument about soldered connectors being better than crimp connectors, that argument leaves something to be desired. While the coax is soldered to the connector, the connector mating for the center conductor uses pressure to make contact, especially in the UHF type connectors that most hams use. I remember working in video in my earlier years, we had some monitors that used the UHF type connectors for baseband video. It was pretty common for the female connectors to have issues with the center pin sockets with the tabs migrating apart over time. Same thing happens with UHF connectors for RF if too many mating cycles are done.

So, while it's valid that soldering can make a good connection for coax to connectors, keep in mind that the connector to connector mating is NOT soldered.

prcguy said:

I've built aircraft wiring harnesses and was prohibited from soldering any connector and these were cables that someone's life depended on. The key point here is you must have the proper crimper and it must be calibrated. If not there is no accountability and no guarantee the connection is reliable.

So for many hamsters a soldered connection might be better because the proper tools are not available.

prcguy

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Right, I've heard that, and back when I was doing some fire alarm work, we were told that also. My understanding was that the solder could make things brittle. Crimp allows flexing, but if you flow solder down the wire, the flexing is gone and the result can be breakage.
I also know that the crimpers used in the aircraft industry are really high spec, and better than what a lot of the RF guys use.
I prefer to flow a bit of solder on them, but not too much. For things under the hood, it's really easy for vibration or corrosion over time to take it's toll. Leaving the wire a bit long and extending out past the crimp barrel allows a bit of solder to be applied. That, and the mechanical crimp work well together, but as you pointed out, that doesn't fly in the aircraft industry. As for the flexing, proper strain relief can prevent breakage, but not always.
As much as I dislike flying, I like to hear about the high spec stuff you guys do. Both my grandfathers work for Lockheed back in the 50's, 60's and 70's. One of them was airframe, the other was electrical systems. Some of the stuff he taught me has been very valuable.

The TNC connectors and RG-400 cable I was using in the aircraft harness would handle well in excess of legal limit in the HF band with the little crimp connector. If you crimped the connector using the right tool it should meet full specifications for power, VSWR and anything else.
prcguy

k3cfc said:

Then again your not running legal limit rf through them either.

K3CFC

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crimp

One disadvantage to solder is that it makes a connection that has higher acidity. THis is a disadvantage to anything that might occasionally get damp. In the marine industry connections on boats are crimped with special connectors. This suggests that crimped connectors hold up well in moist conditions and lots of vibration.

Moisture, dew, whatever works with the acidity to corrode the connection.

Bazel said:

One disadvantage to solder is that it makes a connection that has higher acidity. THis is a disadvantage to anything that might occasionally get damp. In the marine industry connections on boats are crimped with special connectors. This suggests that crimped connectors hold up well in moist conditions and lots of vibration.

Moisture, dew, whatever works with the acidity to corrode the connection.

Click to expand...

Absolutely. I run a very large PBX (10,000 lines +) here at work and a few years back we upgraded about 12 large DC power plants, including battery systems that weighed upwards of a ton and half, 1000 amp/hour 48v central office type gel cell system. We used a lot of 00 gauge copper cable for the battery installations, and that was all done with crimp lugs using expensive crimping tools. That is the generally accepted way to do these sorts of installs in central office environment. Soldering is not done. To prevent corrosion, the battery manufacturer includes a jar of a special grease that is put over all the connections. It works well and we get a lot of service out of these systems. There are certainly places where soldering isn't the best practice, and properly done crimp connections are the way to go.

The special crimp lugs for the marine environment usually have a adhesive lined heat shrinkable covering that seals out some of the moisture. Great connectors, but difficult to find in some areas unless you have a boat/marine supply store or order on line.