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Old 01-07-2015, 01:00 PM   #1
W9WLS
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Murphy’s Law as applied to RF Coax Connectors



Soldering RF connectors to coax cable can be frustrating. What many don’t know is Murphy is “helping.”



1. If you bring N connectors down from the shop for the job you will find you need at least N+1.

2. If using N type connectors you will drop the only center pin and never find it again.

3. If using RG-58 all your PL-259 adapters will be for RG-59.

4. And vice-versa.

5. You will find the solder is back in the shop after you bring the connectors down.

6. You will find the dykes are back in the shop after bringing down the solder.

7. The solder will readily cover the threads for the outer shell, but not adhere to the shield.

8. Once enough heat is applied to the center pin to melt solder you will find the center insulator has also melted and the pin is now at 45 degrees.

9. After one end is completed you will find you soldered the connector to the end of the roll of coax, not the piece you cut off.

10. Once the body to the connector is heated enough to take solder, the inside cable will have melted enough to cause a short.

11. If you solder one end and detect a short and remove the connector, the short will turn out to be at the other end.

12. If there are no shorts found the cable will be found to be open.

13. After completing the soldering on both ends you will discover you left off the outer shell.

14. If you remembered the outer shell it will be backwards.

15. After completing the connections you will find the length of the cable is exactly 1 foot short.


Gary – W5UUO
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Old 01-07-2015, 02:34 PM   #2
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Murphy's Law was slightly funny once long ago when it was fresh, new, and original.
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Old 01-07-2015, 05:55 PM   #3
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True, but every day it changes no matter what you seem to be working on. On the plus side I do get exercise trying to out wit Murphy.
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Old 01-07-2015, 06:21 PM   #4
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Which is why I buy my cables pre-made. I hate making cables. And apparently there are enough hams and even professional people that hate making cables that those willing to do it can make a living selling cables on the internet.

Among my many blessings in life, too many to name here, is the fact I have never had to solder up an N connector.
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Old 01-07-2015, 08:41 PM   #5
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A lot of times it is better to get the premade. By the time you get your coax, chase down the connector you thought you had, get all the tools out it is easier to just get out the credit card and order on line. Also saves burned fingers and holes in the pants.
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Old 01-08-2015, 09:47 AM   #6
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Not to mention having to do Time Domain Reflectometry to find out which end of the cable I shorted, so I can cut the connector off and do that end again. Before I had a device that would do TDR, I usually guessed wrong and had to redo both ends 'cuz the one I cut off first turned out to be the good end.
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Old 01-08-2015, 05:12 PM   #7
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Oh yeah, my big problem was cat 5 cables you can look at them all you want and still not cut off the right end.
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Old 01-10-2015, 06:18 AM   #8
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Here's another one from Gary !
Applies to Quads and almost anything else you can work on above ground level.

W5UUO’s Yagi Hanging Axioms





1. The day you pick to hang your Yagi antenna will be the hottest day of the summer.



2. No matter how careful you are at least one element will break off.



3. If you need “Y” bolts to hang the Yagi and bring “X” bolts where Y<X you will drop at least X-Y +1 bolts



4. Ditto for nuts and washers.



5. The sun will shine brightly exactly behind the item you are working on.



6. A critical tool will drop to the roof, slide off, miss the gutter, and hang 20 feet up in a tree.



7. If you brought a straight screwdriver you will need a Philips, if you brought both you’ll need a hex.



8. Each U bolt will run out of threads exactly 0.25 inches before it is tight. Ditto hose clamps.



9. The UPS man will come with a “your signature required” package just as you reach the top of the tower.



10. After getting the yagi mounted and the tower cranked back up you will find the SWR is 30:1 across all bands.



11. When you crank the tower back down the coax and rotor cable will get caught and cut in half.



12. After you spend 3 hours looking for the SWR problem at the Yagi, you will find it in the shack.



13. The cable pulley shaft at the top of the crank up tower will come loose and jam the tower half the way up.
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Old 01-10-2015, 03:45 PM   #9
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Up here the day you plan to work on the tower with helpers the night before you'll have an ice storm.
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Old 01-11-2015, 08:34 AM   #10
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A socket dropped while doing mechanical work on a car will roll to the geometric center of the vehicle.
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