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Coax stripping

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John Ackerman

Joined: 19 Jun 2006
Posts: 130
Location: Prescott, AZ

Posted: Thu Jan 24, 2008 7:02 pm Post subject: Coax stripping

Can someone help a newbie with coax stripping?



I'm hoping I'm just too tentative (fussy), but I have a traffic  

system that is exceptionally sensitive to coax antenna length. There  

are 4 antennae and they all have to have RG400 length of 16 feet  and  

all four need to be matched in length. Two of them are routed more or  

less irreversibly, so one error in final assembly could be a  

disaster, or at least quite expensive.



My 3-blade  coax stripper (H-tools, Taiwan) is adjustable for depth  

of cut but not for length of insulator exposed. It cuts RG-400 like a  

charm with very little adjustment or learning required. However...

First issue: The cutter leaves 0.32" of braid exposed. That  

corresponds nicely with the connector manufacturer's specs.   

Pasternack Enterprises model PE4450  right angle male TNC spec is  

0.300" and PE4044  straight male TNC requires 0.325". Good! The  

cutter leaves 0.16" of insulation exposed. The Pasternack spec is  

0.100". Not so good?  There is no way to adjust that length.  Could  

it be that the exposed length of insulator is not terribly critical,  

because Googling coax strippers doesn't show any units that specify  

the lengths that they cut, or any that allow adjustment of the  

exposed insulator length, although some, including mine, seem to be  

adjustable for length of exposed braid?

Second issue: Fit of the center conductor into the pin. There's no  

spec on this, but It seems that 6 or so individual strands need to be  

clipped to let the conductor slide into the pin. Is this common? Am I  

missing something about fitting the conductor into the pin? Also, the  

spec for the exposed center conductor length is 0.100" (PE4044) or  

0.125 (PE4450), but it appears that the pin will accept at least  

0.180". Hmmm...

Any help from the experts in this group is greatly appreciated.

John Ackerman 40458

trying to get as much done as possible before installing cabin lid.

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Tim Olson

Joined: 25 Jan 2007
Posts: 2872

Posted: Thu Jan 24, 2008 7:53 pm Post subject: Coax stripping

The best advice I can think of is to buy a couple of sacrificial

connectors and crimp some scrap and see what you think.  I used some

TNC connectors by Cambridge, I think, and for me, the stripper worked

great and everything went together pretty much with just the right

lengths.  The connectors and pins were made for RG-400, and every

strand fit in the pin just fine.   Perhaps the connectors you're

using aren't perfect, but I'm not sure at all.  But, doing some

tests might be a good idea.



Tim Olson - RV-10 N104CD - Flying

do not archive

John Ackerman wrote:

 	  Quote: 	
		   

 

 Can someone help a newbie with coax stripping?

 

 I'm hoping I'm just too tentative (fussy), but I have a traffic system 

 that is exceptionally sensitive to coax antenna length. There are 4 

 antennae and they all have to have RG400 length of 16 feet  and all four 

 need to be matched in length. Two of them are routed more or less 

 irreversibly, so one error in final assembly could be a disaster, or at 

 least quite expensive.

 

 My 3-blade  coax stripper (H-tools, Taiwan) is adjustable for depth of 

 cut but not for length of insulator exposed. It cuts RG-400 like a charm 

 with very little adjustment or learning required. However...

 First issue: The cutter leaves 0.32" of braid exposed. That corresponds 

 nicely with the connector manufacturer's specs.  Pasternack Enterprises 

 model PE4450  right angle male TNC spec is 0.300" and PE4044  straight 

 male TNC requires 0.325". Good! The cutter leaves 0.16" of insulation 

 exposed. The Pasternack spec is 0.100". Not so good?  There is no way to 

 adjust that length.  Could it be that the exposed length of insulator is 

 not terribly critical, because Googling coax strippers doesn't show any 

 units that specify the lengths that they cut, or any that allow 

 adjustment of the exposed insulator length, although some, including 

 mine, seem to be adjustable for length of exposed braid?

 Second issue: Fit of the center conductor into the pin. There's no spec 

 on this, but It seems that 6 or so individual strands need to be clipped 

 to let the conductor slide into the pin. Is this common? Am I missing 

 something about fitting the conductor into the pin? Also, the spec for 

 the exposed center conductor length is 0.100" (PE4044) or 0.125 

 (PE4450), but it appears that the pin will accept at least 0.180". Hmmm...

 Any help from the experts in this group is greatly appreciated.

 John Ackerman 40458

 trying to get as much done as possible before installing cabin lid.

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ricksked(at)embarqmail.co
Guest

Posted: Thu Jan 24, 2008 9:27 pm Post subject: Coax stripping

John,



Your in the ballpark, there should be just a smidge...(a thousandths or two) showing between the pin bottom flange and the top of the nylon inner insulator. If it is too short the pin will not engage the inner portion of the connector, you will almost hear and feel it click into place as you slide it into the connector. As Tim says sacrafice a piece of coax and a connector and see. Most BNC/TNC connectors come with a detailed measurement of inner conductor, inner insulator and outer insulator measurments. On my stripper, I measured each blade and adjusted them to the given measurements. Mine has a hex screw for each to adjust. It has worked like a charm since the inital setup.



Rick S.



---

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John Ackerman

Joined: 19 Jun 2006
Posts: 130
Location: Prescott, AZ

Posted: Fri Jan 25, 2008 7:38 am Post subject: Coax stripping

Hi Rick!

Thanks for the post.

Where do you find a stripper that adjust for length (as opposed to  

depth) of cut? I'd have to move the blade  1/16". That's a lot!

I've made test connectors with some spare stuff BNCs that _look_ OK  

to my unpractised eye, but the dimensions might  (probably would) be  

different and the  right angle TNCs are not cheap.

I'm gonna pursue this with the connector vendor.

Best

John



On Jan 24, 2008, at 10:22 PM, Rick Sked wrote:



[quote] 



 John,



 Your in the ballpark, there should be just a smidge...(a  

 thousandths or two) showing between the pin bottom flange and the  

 top of the nylon inner insulator. If it is too short the pin will  

 not engage the inner portion of the connector, you will almost hear  

 and feel it click into place as you slide it into the connector. As  

 Tim says sacrafice a piece of coax and a connector and see. Most  

 BNC/TNC connectors come with a detailed measurement of inner  

 conductor, inner insulator and outer insulator measurments. On my  

 stripper, I measured each blade and adjusted them to the given  

 measurements. Mine has a hex screw for each to adjust. It has  

 worked like a charm since the inital setup.



 Rick S.



 ---

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John Ackerman

Joined: 19 Jun 2006
Posts: 130
Location: Prescott, AZ

Posted: Sat Jan 26, 2008 10:02 am Post subject: Coax stripping

Outcome:



  I worked with Pasternack, and found that the stripped lengths that  

my stripper (and most others, I'd wager) gives are well off optimum,  

but OK. They will give a  reliable connection, but are not what the  

data sheets specify. It seems you have to have worked with this stuff  

to know what you can get away with.



The center conductor insertion issue is strictly a matter of  

developing good technique. It is very easy to bend or displace one or  

more strands of the center conductor of RG400. That makes it very  

hard to slide the pin over it, so considerable care is required not  

to damage the bundle of strands . Although bent stands can be combed  

back, and the bundle can be made round by twisting slightly (it tends  

to flatten if {when?} you clip it to length), these remedies are hard  

to do and often don't work.



Thanks to Rick and Tim for their quick and accurate replies.



John Ackerman 40458

trying to get as much done as possible before installing cabin lid.

On Jan 24, 2008, at 8:17 PM, John Ackerman wrote:



 	  Quote: 	
		   



 Oops - 2 antennae, four cables (two per antenna)

> Can someone help a newbie with coax stripping?

>

> I'm hoping I'm just too tentative (fussy), but I have a traffic  

> system that is exceptionally sensitive to coax antenna length.  

> There are 4 antennae and they all have to have RG400 length of 16  

> feet  and all four need to be matched in length. Two of them are  

> routed more or less irreversibly, so one error in final assembly  

> could be a disaster, or at least quite expensive.

>

> My 3-blade  coax stripper (H-tools, Taiwan) is adjustable for  

> depth of cut but not for length of insulator exposed. It cuts  

> RG-400 like a charm with very little adjustment or learning  

> required. However...

> First issue: The cutter leaves 0.32" of braid exposed. That  

> corresponds nicely with the connector manufacturer's specs.   

> Pasternack Enterprises model PE4450  right angle male TNC spec is  

> 0.300" and PE4044  straight male TNC requires 0.325". Good! The  

> cutter leaves 0.16" of insulation exposed. The Pasternack spec is  

> 0.100". Not so good?  There is no way to adjust that length.   

> Could it be that the exposed length of insulator is not terribly  

> critical, because Googling coax strippers doesn't show any units  

> that specify the lengths that they cut, or any that allow  

> adjustment of the exposed insulator length, although some,  

> including mine, seem to be adjustable for length of exposed braid?

> Second issue: Fit of the center conductor into the pin. There's no  

> spec on this, but It seems that 6 or so individual strands need to  

> be clipped to let the conductor slide into the pin. Is this  

> common? Am I missing something about fitting the conductor into  

> the pin? Also, the spec for the exposed center conductor length is  

> 0.100" (PE4044) or 0.125 (PE4450), but it appears that the pin  

> will accept at least 0.180". Hmmm...

> Any help from the experts in this group is greatly appreciated.

> John Ackerman 40458

>

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ricksked(at)embarqmail.co
Guest

Posted: Sat Jan 26, 2008 2:46 pm Post subject: Coax stripping

John,



Sorry for not getting back BACK to you. My strippers are the same ones Dan Checkoway posted on his site, here's the link  http://www.rvproject.com/20041005.html  



The blade depth is adjustable by hex head screw, the blades can be relocated to different slots depending on the strip you want. Mine came preset for RG-400 and has worked flawlessly from day one. Just for giggles I went out and checked the measurement's and they were right there for what the package on the BNC/TNC connectors called for.These were fairly expensive connectors in comparison to others I had priced, like $12 each for Ampehnol.



Hung the prop today....now the neighbors think it's an airboat instead of a sail boat  



Rick S.

40185

---

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