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salmans (IS/IT--Management) (OP)
20 Jul 05 14:16
I am working on a project and am new to coax. I have a piece of RG-8 and a Philmore N Connector Female-RG-8/U connector (no.711), but dont have a clue as how to terminate the thing. Can someone please help. Thank you.

Do it right the first time, and there won't be a second time!

Helpful Member!  wires (TechnicalUser)
20 Jul 05 19:04
Hopefully instructions came with the connector.

The most important things you need to know are the size of the crimp die and the striping specifications.

The 711 is a solderless crimp type connector so the center pin crimps onto the center coax conductor. The size of the crimper is critical. Too small and it will just about cut the pin off and too large and the pin will be loose. Either of these problems will affect the performance (return loss at least) of the connector.

The strip guide will tell you how to prepare the cable. It could be either a 2 or 3 level strip. An example of a 2 level strip would be to strip down to the center conductor a length equivilent to the depth of the center pin cavity and strip the outer jacket off to where the braid turns back on the screw part.

With most N type connectors you only get one chance to get it right. The center pin usually locks into place when it is inserted properly.

You might want to consult with an engineer at a local 2-way  radio shop.
ISDNman (Vendor)
20 Jul 05 20:31
Wires is correct, this varies connector to connector, so you need to consult the connecotr manufacturer's data sheet.
salmans (IS/IT--Management) (OP)
21 Jul 05 9:38
Could you recommend an easy to install connector (N type connector) for RG-8? Thanks for the help!

Do it right the first time, and there won't be a second time!

wires (TechnicalUser)
21 Jul 05 10:26
I usually use RF parts from Times Microwave. Their LMR-240 cable is very close to RG-8. They have very good instructional materials on their site. www.timesmicrowave.com

I usually get my parts from Fleeman Anderson & Bird. They are fast and reasonably priced. www.fab-corp.com

If you only need to do this once it is not cost effective to buy the tooling to do it right. FAB can make up any type of cable with connectors that you need and ship to you.

On the other hand if you are handy with a soldering iron most crimp type center pins can be soldered on. Neatness counts because if you get solder on the outside of the center pin it might not fit/lock into the connector properly. The other tool/skill required is a 4-way caliper. Use the depth part to determine the strip pattern. Keep striping and fiddling until you get it right WITHOUT installing the center pin. Be careful not to nick the center conductor of the coax while stripping. This is not ideal but if you already have the parts and it is a one time deal it is worth a shot if you are handy and have the tools.

If you are embarking on a new skill then by all means get the proper tools and parts to do the job right. I really like working with LMR cable.


Best of Luck!!!
robertjo24 (MIS)
22 Jul 05 12:17
RF Industries makes a great crimp connector that is easy to install, will fit RG-8 and LMR-400, and is about half the cost of the Times Microwave connector.

RF Industries part number RFN-1006-3I.

Look up the connector on their web site for more detailed info   http://rfsearch.rfindustries.com/fshome.asp

salmans (IS/IT--Management) (OP)
22 Jul 05 15:48
This is a one time deal so I was trying to avoid purchasing a bunch of tools. Your inputs have been invaluable. Thank you all VERY much !!!

Do it right the first time, and there won't be a second time!

oldtimerbob (TechnicalUser)
25 Jul 05 17:11
RG8 is just the cable type and size.
You can get some neat 'twist on' connectors so you will not have to worry about a 'crimp' tool.
Most important will be your 'stripping' tool. Be sure to set it for the correct cable and test it with a spare piece of the RG8 so you can get the cable trimmed correctly.
You will want the ground braid portion to slip back towards the un cut end of the cable, so the connector will work correctly.
There are also some cheap 'testers' that will test the coax,end to end or you can use a multi-meter set for continuity.
Good luck !!
daronwilson (Vendor)
30 Jul 05 23:25
You never said what you were running on the RG8, so I'm not sure how much 'quality' you are after, maybe this is 10Base2 ethernet or something?

Good advice on crimping, I'm a frequent shopper at Fab Corp as well, and use the crimp tool and connectors for the majority of the coax needs.  However, you will find a big controversy between 'crimp' and 'compression' when it comes to quality, leakage, power handling ability, etc.

The compression style comes with a couple rubber parts and several metal pieces inside.  Basically the nut is tightened which compresses the ground braid between two metal surfaces via a rubber washer which maintains tension on them.  It is a good product, unfortunately RG/8 is made in different grades, qualities, and even physical sizes depending on the manufacturer, so your actual fit may vary.

There are fittings that screw onto the coax, but the only type I have seen like this require the center conductor to be soldered as well as the braid.  If they are similar to the hardware store "F" fittings for RG6 that just screw on, they are leaky and not very desirable.

One more 'gotcha', there is a 75 ohm "N" fitting available, and it will not work well mating to a 50 ohm connector.   They get used in video and broadcast work, just be sure what you get is designed for 50 ohms.


Daron J. Wilson, RCDD
Solving 'Real World' problems

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