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Solder quantity on PL-259 centre pin...

Discussion in 'Amateur Radio Antennas' started by TheBlaster, Jul 29, 2020.

  1. TheBlaster

    TheBlaster Active Member

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    Other than getting a good clean shiny solder joint between pin and coax core is there any specific quantity of solder that should be used ? (I of course always do a continuity test with a multi-meter afterwards) Back in the day someone said don't use more solder than you need to .. i.e. don't flow the solder so it overfills the pin tube.

    Is there some rule of the ideal... i.e. just solder the very tip of the copper core to the tip of the pin ?

    Ultimately my main concern is I just don't want lossy terminations. I have some "posh" coax and plugs coming, extremely low loss coax and plan to make 1 patch lead and a longer run of it so want to make the best of the soldering. Luckily I still have some lead solder which makes life easier.

    Or is it a case of it looks good and continuity tests, it is good !


     
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  2. Shadetree Mechanic

    Shadetree Mechanic 808 On The North Side of Dover

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    I would use as little as possible right on the end and not try to flow the whole pin. Maybe even point the pin downward slightly so the excess doesn't try to flow back to the insulator. If you have a stranded center conductor, it will try to wick the solder too. Of course if it could make it to the insulator, that means your center conductor is way too hot anyway. I would think a big iron to get the heat in and get the iron off quickly would be my goal. My crimp connectors for my 400 coax has the center pin that is soldered. The center conductor of the 400 does a good job of filling up the pin. I think if the solder was half way up the inside of the pin, I would call it good. Curious to see what others think about this.
    Chris
     
  3. Justme

    Justme Well-Known Member

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    Having tinned the center conductor and taking a small round file through the plug center pin i know they are clean.
    Using the large soldering iron i heat the center pin quick for a few seconds, add multicore solder and for 2 seconds let it flow, take away the soldering iron, and see the solder stirr nicely shining, check continuity with meter, done.
    You actually see the solder flow in the pin, making sure it solders both coax inner core and pin.
     
  4. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

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    If you like going thru a lot of connectors - well that is what you might wind up doing...

    So you know, the insulating Dielectric material used in the PL-259 and SO-239 is not exactly heat resistant.

    Older Bakelite materials handled the heat well but due to changes in MSDS and toxic material handling - they seem to have done away with this and subbed in other materials.

    You have to realize that not everyone is comfortable with any form of soldering let alone how much to use.

    So when you take on the task of "how much and where" remember many people "tin" their work before insertion - this way strands that would otherwise not have been part of the twisty you did, to stick it into and thru to the pin, are not frayed out and shorting out your work.

    Shield is another matter - but if you use too much solder it's like using too much heat. That melt has to dissipate it's thermal heat somehow - and it can "remelt" the centers' Dialectrical spacer and the PL-259's own separator.

    This is what I call Impedance bumps - because the perfect centering the PL239 would provide if it had used less heat - may not center well and even leave gaps to cause leaks later when your work is installed outside.

    When you're not sure - I also use a "barrel connector" after soldering - push the tip into its center - this helps pull heat from the tip and keeps the pin "Centered" so as the material reflows and hardens - it's not finding it's own center of gravity.
     
  5. Captain Kilowatt

    Captain Kilowatt Professional Amateur
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    Don't use cheap connectors. The GOOD connectors from Amphenol use Teflon as the insulator and it IS heat resistant. The cheaper shiny nickel plated connectors tend for the most part to use a cheap white plastic that looks like teflon but it is not heat resistant. Teflon dielectric connectors are quite plentiful and readily available but unfortunately so are the cheap plastic insulator types. Buy quality and don't worry.
     
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  6. TheBlaster

    TheBlaster Active Member

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    Yes, I have high end connectors and coax on its way.

    I cannot wait to be blasting your S- meters with my 0.15 - 0.2dB reduction in losses.:ROFLMAO:
     
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  7. Justme

    Justme Well-Known Member

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    Save 0.1 dB here, 0.15 dB there, and before you know it you gain an S point....:sneaky:
     
  8. sp5it

    sp5it Master of puppets

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    Only when you use crap connectors. Quality ones use PTFE as insulator, you can heat is as long you want.
    Soldering: I use as much solder as needed. That's all.
    I still use bunch of connectors I bought early in 90's. Soldered/deslodered many times. Still as good as new.
    Mike
     
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  9. bob85

    bob85 Supporting Member

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    one common error I see people make is using too much solder on the pin so they creates a blob at the tip fatter than the pin sometimes with solder on the outside of the pin,

    the blob spreads the contacts in the socket & makes poor connections over time,
    also makes properly soldered plugs a loose fit or not contact at all,

    pins should have no solder on the outside or bulbous globes of solder at the tip,
    a wipe with solvent to clean any flux residue is all that should be needed to leave a clean factory plated surface,

    solder is a poor contact surface so keep it where it belongs, inside the pin,

    trim the pre tinned wire to the correct length & solder, not the other way around,

    solder clip & file/sand is a bodgers way of doing it but common & does work,

    Another tip to make life easier is use 63/37 tin/lead eutectic solder,

    eutectic melts at a little lower single temperature than 60/40, it lacks the pasty phase as it cools that causes shittty dull/grainy solder joints if you don't keep it perfectly still as it cools or you dither with the iron.
     
  10. Tokin

    Tokin 42Zero Tampa

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    Back in the day someone said don't use more solder than you need to .. i.e. don't flow the solder so it overfills the pin tube.
    (y)(y)(y)
     
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  11. Tokin

    Tokin 42Zero Tampa

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    I can tell you from experience that the insulating material in heliax hard line melts like wax when hit with high heat. I scrapped a couple thousand feet of 2" and 1 1/2" a few years ago. If I'm not mistaken there is a brand new 500' spool of 7/8 hard line out in the trailer.
    I tip my fitting forward and use a drop of kesters. I'll warm the fitting then load the tip of my iron with solder and use the hot solder to help heat the fitting then smooth it out with my iron. I run my iron at 480°f for this job.
     
  12. Alexis Mercado

    Alexis Mercado Active Member

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    By experience, just use enough solder to fill half the pin. This is to assure hot solder don’t reach coax dielectric.
     
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  13. TheBlaster

    TheBlaster Active Member

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    Thanks I will bear all of this in mind, I am pretty ok at soldering so should be ok, I just won't over do the solder and take my time. Do them right, worth spending a bit of time on as they might be in service for some decades if I am lucky.
     
  14. bob85

    bob85 Supporting Member

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    The trick with not melting insulation while soldering the braid is use the right iron & use it fast,

    little pre preparation turns a pita job into a simple task,

    file the holes & tin them,
    pre tin the braid
    trim braid clean & even so that it reaches almost up to the insulator in the plug,

    then get a proper sized iron 100/120w with a fat high mass tip, weller sp120 does a good job,

    a few seconds is all it should take to fully wett the pre tinned holes & away with the iron asap,
    let it cool before doing the next hole,

    IF IT TAKES ANY LONGER THAN A FEW SECONDS PER HOLE YOU HAVE THE WRONG IRON FOR THE JOB,

    some of the soldered holes i see are not wetted to the plug body, its just blobs & flux residue plugging the holes through using farty little hakkos & the like.

    folded back braid screwed in part way is a commonly used & poor way of doing it,

    pl259's don't have a 50ohm surge impedance even when installed correctly,
    half ass braid jobs make the impedance bumps worse & leaves the inside of the coax exposed to atmosphere/moisture,

    ever cut a plug off to find the coax braid is all black & green for a distance down the line & your chopping lumps off hoping theres enough good stuff left to reach.
     
  15. TheBlaster

    TheBlaster Active Member

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    I made my new cable and patch lead yesterday without any dramas. The most tricky aspect is making sure you remove the right amount of outer black sheath, so your inner conductor does not fall short of the end of the pin.. I ended up with one slightly short by 2-3mm so had to heat the pin slightly away from the very end so I could see with my eye that solder flowed on the 2.7mm copper centre core and bonding it to the pin further down the pin.

    1 out of the 4 connectors had this issue but it all checks out on the multi meter and shows very low resistance and the joint is shiny and looks normal.

    I am liking these gold plated tip compression type PL-259's they feel industrial and professional. Super solid and strong.The cable is very stiff, significantly more stiff than my 213-UBX it has a 2.7mm thick solid copper core so will need careful winding/packing/storage up each time.
     
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