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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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Old 01-11-2015, 06:00 PM   #11
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Of course in my case it would be not where near where I could reach it no matter where it rolled.
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Old 01-12-2015, 10:43 AM   #12
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Back when they first started calling it Murphy's Law.. I was in college,, Some of my professors (3 of them) shared an office (Science Dept.) These were my favorite teachers of course (Science major). They had a Murphy's Law Calendar.

This was the 2-months on a page type so we got to see the same graphic for two months.

Picture this: Company picnic, Reviewing stand, VIP's a-plenty on it, all draped in bunting, Big sign COMPANY SAFETY PICNIC ONE YEAR WITHOUT A LOST TIME ACCIDENT.

In the background is the plant,, The plant has a smokestack, at the top of the stack was a bag house... Wait a second, WAS!!!!, Yup, Was, it has fallen off,, The dotted line showing its path has it bouncing off the roof of the plant to its present location about half way from the plant to the reviewing stand.. Continuing the path.. That stand is about to get flattened.

I guess the next safety picnic will have to be in 366 days cause today,, They are going to have a loss time accident.
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Old 01-12-2015, 01:45 PM   #13
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Quote:
Originally Posted by wa8yxm View Post
Back when they first started calling it Murphy's Law.. I was in college
I guess that means you were in college in 1951 or earlier, because it's been called Murphy's Law at least that long, and possibly a lot longer.

Let's see, if you started college at age 18 in 1951, you're 82 now, right?

Of course, as humor the idea was stale and trite at least as early as 1880; but it's possible (by no means certain) that it was first called Murphy's law in 1951 at the latest. That is to say, certainly by 1951 by hard evidence, and possibly earlier.
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Old 01-14-2015, 11:26 AM   #14
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And folks two things you need to know about Murphy...
First it's Mrs. Murphy

Second, She was an optimist

(You are surprised that Murphy is a Mrs? you should not be, after all the discovery was immortalized in song... What song: Who Threw The Overhauls in Mrs. Murphy's Chowder)
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Old 01-15-2015, 09:42 AM   #15
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Quote:
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I guess that means you were in college in 1951 or earlier, because it's been called Murphy's Law at least that long, and possibly a lot longer.

Let's see, if you started college at age 18 in 1951, you're 82 now, right?
1968 and you will still be off on my age.

In the 60s I heard it called Finagal's law, And to this day Sod's Law (Google Sodslaw.exe, you can download it, it is a DOS program).

First time I heard it called Murphy's was in that office.

However as I noted elsewhere, Much older, since Mrs. Murphy discovered it.

Oh, you do know who threw the overhalls in her Chowder don't you?

(HINT: When they were ladeled out she fainted dead away, NOBODY ANSWERED, because... She had fainted dead away and thus could not till she recovered from the faint).
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Old 01-15-2015, 12:24 PM   #16
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Quote:
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Oh, you do know who threw the overhalls in her Chowder don't you?
I think it was my old friend Jeanne Cook. I accused her of it in 1976 or so. She looked surprised, and I explained that anyone who threw overalls (jeans) into a cooking pot must be a Jeanne Cook. She was at most slightly amused, but it was still funnier than Murphy's Law ever had been, even when fresh and new.
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Old 01-16-2015, 11:03 AM   #17
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Carl.. That is a good one.. and yes, I agree with you
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