PL259 - how tight?


ab2tc
 

Hi all,

This is a continuation of a thread on he reflector that started with a totally different subject name that was terminated by Eric. I don't blame him.

But I would like to comment that in my opinion hand tightening of a PL259 onto a SO239 chassis connector is simply not enough, even if you wiggle it to make those teeth align. I always tighten them, not with a pair of regular pliers but with a wrench that I am used to calling a "pump-wrench" (maybe Canada jargon?). It allows the jaws to stay parallel while you adjust the gap by moving the pivot point back and forth. They are readily available at any hardware store. Using this tool the outer ring of the connector moves an appreciable amount without applying much torque and then stops hard. With this I never have any problem with bad coax connections.

BTW, I totally agree with Jim, K9YC, that SO239 connectors mounted with a single big nut makes the equipment junk! Fortunately none of my current equipment have them.

AB2TC - Knut


Ken K6MR
 

Here’s a silly question. 

 

All connectors that have torque specs have flats for a torque wrench.  PL259s have no such flats.

 

Doesn’t that mean that the designer(s) intended for the connector to be tightened by hand only?  The knurling on the shell is a clue to me that ‘hand tight’ is correct.  I once looked for a torque spec but didn’t find one.  Perhaps there is one out there.

 

And regarding the single hole mounting jack (which is actually an Amphenol 83-878 and similar):  The jack is supposed to be mounted in a ‘D’ shaped hole, not a round one.  If you punch the proper hole there is no problem with the jack spinning.

 

Ken K6MR

 


From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> on behalf of ab2tc <ab2tc@...>
Sent: Wednesday, May 1, 2019 3:40:22 PM
To: Elecraft-K3@groups.io
Subject: [Elecraft-K3] PL259 - how tight?
 
Hi all,

This is a continuation of a thread on he reflector that started with a totally different subject name that was terminated by Eric. I don't blame him.

But I would like to comment that in my opinion hand tightening of a PL259 onto a SO239 chassis connector is simply not enough, even if you wiggle it to make those teeth align. I always tighten them, not with a pair of regular pliers but with a wrench that I am used to calling a "pump-wrench" (maybe Canada jargon?). It allows the jaws to stay parallel while you adjust the gap by moving the pivot point back and forth. They are readily available at any hardware store. Using this tool the outer ring of the connector moves an appreciable amount without applying much torque and then stops hard. With this I never have any problem with bad coax connections.

BTW, I totally agree with Jim, K9YC, that SO239 connectors mounted with a single big nut makes the equipment junk! Fortunately none of my current equipment have them.

AB2TC - Knut


Steve Sacco <nn4x@...>
 

Actually, I've been installing some beautiful Messi and Paoloni connectors this week, and they have "nut" surfaces for tightening.  First time I've seen that.


73,
Steve
NN4X


Ken K6MR
 

Yes, but those are clamp connectors.  The flats are for tightening the connector onto the coax.  Same as a typical Heliax connector.  What I’m talking about is the shell on the UHF male connector.  I’ve never seen one with flats.

 

The other puzzling connector is type N.  Some have flats, some don’t.  When I worked at HP, all of our production line test cables had the flats and were torqued.  Without the flats it’s pretty difficult to tighten it to the correct torque.

 

Ken K6MR

 


From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> on behalf of Steve Sacco via Groups.Io <nn4x@...>
Sent: Thursday, May 2, 2019 9:31:35 AM
To: elecraft-k3@groups.io
Subject: Re: [Elecraft-K3] PL259 - how tight?
 
Actually, I've been installing some beautiful Messi and Paoloni connectors this week, and they have "nut" surfaces for tightening.  First time I've seen that.


73,
Steve
NN4X


ab2tc
 

Hi,

Very interesting video. That's a beauty of a connector! I notice that his cable has a double braid and he only folding back the outer layer. The actual connection between the shell and the outer conductor is a compression type connection. The tip is soldered as in a conventional PL259..

AB2TC - Knut


On Thu, May 2, 2019 at 12:31 PM, Steve Sacco wrote:
Actually, I've been installing some beautiful Messi and Paoloni connectors this week, and they have "nut" surfaces for tightening.  First time I've seen that.
 
 
73,
Steve
NN4X


Ben Loper <brloper@...>
 

I like to use a 6 foot length of pipe on the handle to give me some leverage. I have my wife sit on the radio while I put my full body weight on the pipe. That will lower your SWR about 3 points


John McCann
 

Oh yeah, that should do it!

Tight as a tick in a summer campground...

John N7MZ


On 5/2/2019 6:31 AM, Ben Loper wrote:
I like to use a 6 foot length of pipe on the handle to give me some leverage. I have my wife sit on the radio while I put my full body weight on the pipe. That will lower your SWR about 3 points


ab2tc
 

Hi,

True, that's what they are showing in the video. But if you look carefully at the picture of the connector you see two "flats" used to tighten the clamp against the coax and one full hex nut just behind the knurled part of the sleeve. Unfortunately the video does not show how they intend to use that.

AB2TC - Knut


On Thu, May 2, 2019 at 01:22 PM, Ken K6MR wrote:

Yes, but those are clamp connectors.  The flats are for tightening the connector onto the coax.  Same as a typical Heliax connector.  What I’m talking about is the shell on the UHF male connector.  I’ve never seen one with flats.

 

The other puzzling connector is type N.  Some have flats, some don’t.  When I worked at HP, all of our production line test cables had the flats and were torqued.  Without the flats it’s pretty difficult to tighten it to the correct torque.

 

Ken K6MR

 


From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> on behalf of Steve Sacco via Groups.Io <nn4x@...>
Sent: Thursday, May 2, 2019 9:31:35 AM
To: elecraft-k3@groups.io
Subject: Re: [Elecraft-K3] PL259 - how tight?
 
Actually, I've been installing some beautiful Messi and Paoloni connectors this week, and they have "nut" surfaces for tightening.  First time I've seen that.
 
 
73,
Steve
NN4X


Richard Smith
 

I enjoy reading all the anecdotal accounts.  I wonder if someone actually measured the connection?  RAS

On May 2, 2019, at 12:57 PM, John McCann <gr8dxr@...> wrote:

Oh yeah, that should do it!

Tight as a tick in a summer campground...

John N7MZ


On 5/2/2019 6:31 AM, Ben Loper wrote:
I like to use a 6 foot length of pipe on the handle to give me some leverage. I have my wife sit on the radio while I put my full body weight on the pipe. That will lower your SWR about 3 points


ab2tc
 

Hi Richard,

Thanks four thoughtful question. Probably nobody has. Trouble is that a missing or bad return current connection (which this is all about) may not have a great effect on SWR or loss. That return current will in most cases find an alternative path, e.g through equipment bonding wires, third prong on AC wires, etc. So while you still may have what looks like a god connection to your antenna, it will have a huge effect on the leakage of RF to the shack, affecting both reception and possible RF interference with equipment in the shack. I have wrench tightened connections on all my my patch cords in the shack and I know I have an exceptionally "air-tight" shack. Witness, I can use my 2nd K3 to transmit a 100W carrier to a dummy load in the shack and it's just in the noise when listening to my main K3S connected to the (fairly distant) outdoor antenna. That path goes:

K3S - Directional coupler - LP100A - KAT500 - Alpha Delta switch - cable to antenna field.

The directional coupler makes me sniff the TX signal for a scope and a DSR used as a spectrum analyzer.. The Alpha Delta switch makes me choose whether the external antenna field get routed to the shack or somewhere else.

That's a lot of patch cords. I have made them all myself using Amphenol PL259s and LMR240 coax.

Now, back to the original question (which no responders have really touched upon). Is there any harm done in wrench tightening the connections? Humorous posts aside, my original post states that I use a fairly small wrench (12") and a very slight tug on the handle. The sleeve moves a noticeable amount and then comes to a dead stop. I do not tear down my connections ever, even if a thunderstorm is approaching, so the extra effort is no problem. If I get a warning of bad thunderstorms, at most I will switch the two Alpha Delta switches in the antenna path (one additional one outside) to ground. I have never had any electronics damage from thunderstorms (but we don't live in Tornado Alley either).

AB2TC - Knut


On Thu, May 2, 2019 at 02:30 PM, Richard Smith wrote:
I enjoy reading all the anecdotal accounts.  I wonder if someone actually measured the connection?  RAS

On May 2, 2019, at 12:57 PM, John McCann <gr8dxr@...> wrote:

Oh yeah, that should do it!

Tight as a tick in a summer campground...

John N7MZ

 

On 5/2/2019 6:31 AM, Ben Loper wrote:
I like to use a 6 foot length of pipe on the handle to give me some leverage. I have my wife sit on the radio while I put my full body weight on the pipe. That will lower your SWR about 3 points


southdaleus
 

Jezzus, I never thought in my my 59 years haming that tightning a PL259 could be so complicated….For me I use both methods, hand tighten and water pumps, small version.  I don’t know what the torque raiting is and don’t care…I snug them up and once in a blue moon loosen then retighten…

Cheers
Dale, K9VUJ



On 02, May 2019, at 12:57, John McCann <gr8dxr@...> wrote:

Oh yeah, that should do it!

Tight as a tick in a summer campground...

John N7MZ


On 5/2/2019 6:31 AM, Ben Loper wrote:
I like to use a 6 foot length of pipe on the handle to give me some leverage. I have my wife sit on the radio while I put my full body weight on the pipe. That will lower your SWR about 3 points


Mel Farrer, K6KBE
 

Kurt,

The focus of your question is in general terms, How tight should it be?.  Well, there are very few torque specifications since the connectors are from so many source that are not consistent in the manufacturing.  Here is what I know, steel products usually have a torque spec.  Brass and copper do also, BUT,  both of these relax after the first torque down.  WHAT, yep as I proved many times to electricians installing VERY large buss bar to cable with allen screws.  Tighten them down to spec.  Come back tomorrow and I can torque them by hand.  Then reset the proper tightness spec.  I find this true with any shell connector with threads.  Tighten them down snug wait a day and you can tighten them more..........

Mel, K6KBE

On Thursday, May 2, 2019, 2:32:15 PM CDT, ab2tc <ab2tc@...> wrote:


Hi Richard,

Thanks four thoughtful question. Probably nobody has. Trouble is that a missing or bad return current connection (which this is all about) may not have a great effect on SWR or loss. That return current will in most cases find an alternative path, e.g through equipment bonding wires, third prong on AC wires, etc. So while you still may have what looks like a god connection to your antenna, it will have a huge effect on the leakage of RF to the shack, affecting both reception and possible RF interference with equipment in the shack. I have wrench tightened connections on all my my patch cords in the shack and I know I have an exceptionally "air-tight" shack. Witness, I can use my 2nd K3 to transmit a 100W carrier to a dummy load in the shack and it's just in the noise when listening to my main K3S connected to the (fairly distant) outdoor antenna. That path goes:

K3S - Directional coupler - LP100A - KAT500 - Alpha Delta switch - cable to antenna field.

The directional coupler makes me sniff the TX signal for a scope and a DSR used as a spectrum analyzer.. The Alpha Delta switch makes me choose whether the external antenna field get routed to the shack or somewhere else.

That's a lot of patch cords. I have made them all myself using Amphenol PL259s and LMR240 coax.

Now, back to the original question (which no responders have really touched upon). Is there any harm done in wrench tightening the connections? Humorous posts aside, my original post states that I use a fairly small wrench (12") and a very slight tug on the handle. The sleeve moves a noticeable amount and then comes to a dead stop. I do not tear down my connections ever, even if a thunderstorm is approaching, so the extra effort is no problem. If I get a warning of bad thunderstorms, at most I will switch the two Alpha Delta switches in the antenna path (one additional one outside) to ground. I have never had any electronics damage from thunderstorms (but we don't live in Tornado Alley either).

AB2TC - Knut

On Thu, May 2, 2019 at 02:30 PM, Richard Smith wrote:
I enjoy reading all the anecdotal accounts.  I wonder if someone actually measured the connection?  RAS

On May 2, 2019, at 12:57 PM, John McCann <gr8dxr@...> wrote:

Oh yeah, that should do it!

Tight as a tick in a summer campground...

John N7MZ

 

On 5/2/2019 6:31 AM, Ben Loper wrote:
I like to use a 6 foot length of pipe on the handle to give me some leverage. I have my wife sit on the radio while I put my full body weight on the pipe. That will lower your SWR about 3 points


Jim - N4ST
 

I just use the German spec: Gootentight.


___________
73,
Jim – N4ST


From: Elecraft-K3@groups.io <Elecraft-K3@groups.io> On Behalf Of dalej via Groups.Io
Sent: Thursday, May 2, 2019 15:54
To: Elecraft-K3@groups.io
Subject: Re: [Elecraft-K3] PL259 - how tight?

Jezzus, I never thought in my my 59 years haming that tightning a PL259 could be so complicated….For me I use both methods, hand tighten and water pumps, small version. I don’t know what the torque raiting is and don’t care…I snug them up and once in a blue moon loosen then retighten…

Cheers
Dale, K9VUJ



On 02, May 2019, at 12:57, John McCann <mailto:gr8dxr@frontier.com> wrote:

Oh yeah, that should do it!
Tight as a tick in a summer campground...
John N7MZ

On 5/2/2019 6:31 AM, Ben Loper wrote:
I like to use a 6 foot length of pipe on the handle to give me some leverage. I have my wife sit on the radio while I put my full body weight on the pipe. That will lower your SWR about 3 points

_._,_._,_


Ben Loper <brloper@...>
 

I would not use a wrench to tighten PL-239 or N connectors for two reasons, one person’s snug is not another person’s snug so over tightening is a possibility and you can also scratch up the knurling.  N and SMA connectors do have torque specifications and you can find them on the data sheets, Im not sure about 239.  With N connectors they are hand tightened and then safety wired in aircraft or applications where vibration is a possibility.  SMA connectors are torqued with a small torque wrench and the torque can vary depending on the application, but there is an upper limit.  You can reach those limits with your fingers with an N connector.  The SMA connectors are typically put on once and meant to stay there.  That’s been my experience.  My concern is that you damage the connector or the radio without any added value.  Hand tighten will fully mate the connector and the ¼ inch of additional thread contact you gain by tightening with a wrench is not of any added value.  With an N connector, you could also damage the water seal.


Timothy Haueter
 

Ben,

I liked your first response to all this ‘nonsense’.  I was a QC/QA inspector and auditor that worked in the trades have worked as an engineer.  I just don’t get some of the thoughts I see on the reflectors.  Good to see you are still doing ham radio.

Been a while, 73.
Tim Haueter, W6NS


On May 3, 2019, at 15:46, Ben Loper <brloper@...> wrote:

I would not use a wrench to tighten PL-239 or N connectors for two reasons, one person’s snug is not another person’s snug so over tightening is a possibility and you can also scratch up the knurling.  N and SMA connectors do have torque specifications and you can find them on the data sheets, Im not sure about 239.  With N connectors they are hand tightened and then safety wired in aircraft or applications where vibration is a possibility.  SMA connectors are torqued with a small torque wrench and the torque can vary depending on the application, but there is an upper limit.  You can reach those limits with your fingers with an N connector.  The SMA connectors are typically put on once and meant to stay there.  That’s been my experience.  My concern is that you damage the connector or the radio without any added value.  Hand tighten will fully mate the connector and the ¼ inch of additional thread contact you gain by tightening with a wrench is not of any added value.  With an N connector, you could also damage the water seal.


W9BIK
 

Since we're talking about RF connectors, does anyone know why the C-Type connectors never caught on in ham radio applications. We used them in the military and they were great. Quarter turn snap lock, so no over-torque issues, and they are waterproof. Seems like they would be nice for ham radio. 


redarlington <rdarlington@...>
 

We use them extensively over at the W5PDO club station here in Los Alamos.  Mostly because we got them surplus from LASL (before they turned into LANL).  Lots of random length patch cords with them at each end, or one C and one PL259 on the other.   They're used where we need to quick disconnect our antennas at the patch panels before they go into the K3 and Jupiter rigs.  We never leave them connected since we have a lot of lightning in this area.


Why didn't they catch on?  No idea.  Why won't they?   They're $45 a pop to go onto the end of a cable.

-Bob N3XKB


On Sat, May 4, 2019 at 10:44 PM w9bik <w9bik@...> wrote:
Since we're talking about RF connectors, does anyone know why the C-Type connectors never caught on in ham radio applications. We used them in the military and they were great. Quarter turn snap lock, so no over-torque issues, and they are waterproof. Seems like they would be nice for ham radio. 


HB
 

They are expensive to manufacture. We use them at work. Most hams are cheap and they’re not many Chinese knockoffs I’m aware of. 

We pay upwards of $35/ea in quantity. 

Hank
K4HYJ

On May 4, 2019, at 11:55 PM, w9bik <w9bik@...> wrote:

Since we're talking about RF connectors, does anyone know why the C-Type connectors never caught on in ham radio applications. We used them in the military and they were great. Quarter turn snap lock, so no over-torque issues, and they are waterproof. Seems like they would be nice for ham radio.