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eHam Forums => Antennas, Towers and more => Topic started by: KN6BJD on May 17, 2019, 09:44:48 PM



Title: Coax Questions (RG-8U)
Post by: KN6BJD on May 17, 2019, 09:44:48 PM
Does anyone make their own coax cables? 

I have some feedline runs that are difficult to estimate and I'm pretty good stripping coax and solderingso I'm wondering if it is practical to make my own cables? 

If so, where should I get the PL-259s and RG-8U from? 

What is the best method to protect exterior connections from the rain and humidity?  Heat-shrink?  Silicon sealer?

Also, is an ohmmeter sufficient for testing short pigtails to and from a switch box?


Title: RE: Coax Questions (RG-8U)
Post by: G4AON on May 18, 2019, 02:34:09 AM
Of course it’s practical to make your own cables. I personally prefer the compression fitting PL259 plugs, these are the more expensive ones that you fit in a similar way to N and BNC types. You can re-use them easily too. Don’t buy cheap coax, the economy versions skimp on braid. Good coax lasts years.

For weather proofing connectors, don’t rely on self amalgamating tape alone... sunlight damages it. Also don’t use hardware store silicon sealer anywhere near electrical connections, the acetic acid given off when curing corrodes metal.

When I worked in the mobile industry, the company handbook said to cover outdoor plugs/sockets firstly with PVC tape to cover any sharp edges, then with self amalgamating tape, then cover that with “Denso” tape. The latter is the non setting cloth tape covered in difficult to remove sticky stuff that resembles grease. It’s hard to clean off hands and clothes! Most riggers just used the S/A rubber tape, followed by “Denso”. For my home ham use, I prefer to use S/A tape covered with PVC tape... You can remove it all cleanly and the PVC protects the rubber tape from sunlight.

73 Dave


Title: RE: Coax Questions (RG-8U)
Post by: W9FIB on May 18, 2019, 03:39:50 AM
For the price most places charge for pre-made coax, I prefer to make my own.

Key is to use quality coax and quality connectors. You buy really cheap stuff like shows up on E-Bay, your going to have problems.

Also keep in mind that if you use crimp on connectors, you will need to have the tool to properly install them. And there is really nothing wrong with properly installed and soldered connectors. I have a few like that on an install I did in 1986. They are still fine.

And yes, don't skimp on the weather proofing.


Title: RE: Coax Questions (RG-8U)
Post by: N5CM on May 18, 2019, 06:18:53 AM
I usually make my own cable assemblies. 

There's a product known as Coax-Seal that I've used for weather-proofing connections, and it seems to work well.  It's on a roll like tape, and it's tacky.  You wind it around the connection, stretching it a bit as you wind.  You can press and mold the beginning and the end of the winding a bit like putty.  There are also products from Scotch Brand (the tape people) that serve the same purpose, but the specific product numbers escape me at this point. 

Some people will use electrical tape over the connector and wind the sealing material over the electrical tape.  I've read that this makes it easier to remove if need be.  Removing Coax-Seal from a connection is a bit messy.

If you are near a Ham Radio Outlet (or similar) store, that's where I'd go for coax and connectors.  For inside-the-shack jumpers for connections from radio to tuner or radio to SWR meter, or radio to amplifier, I would suggest using RG8X for that service.  It is more flexible than the larger-diameter cables and will not result in any deterioration of signal etc. for short runs between pieces of equipment.  You'll need to get some sleeves to attach to the PL-259s to use RG8X.  Should be the same sleeve used for RG59 coax.  Stores that sell coax and connections will be able to help you find the right components.

Yes, an ohm meter will work well for for verifying that your cable assembly is correct.

While you're at it, make up a few extra jumpers, and keep a few spare PL-259s in your parts box.

Good luck.

73, John N5CM



Title: RE: Coax Questions (RG-8U)
Post by: KN6BJD on May 18, 2019, 11:43:04 PM
I usually make my own cable assemblies. 

There's a product known as Coax-Seal that I've used for weather-proofing connections, and it seems to work well.  It's on a roll like tape, and it's tacky.  You wind it around the connection, stretching it a bit as you wind.  You can press and mold the beginning and the end of the winding a bit like putty.  There are also products from Scotch Brand (the tape people) that serve the same purpose, but the specific product numbers escape me at this point. 

Some people will use electrical tape over the connector and wind the sealing material over the electrical tape.  I've read that this makes it easier to remove if need be.  Removing Coax-Seal from a connection is a bit messy.

If you are near a Ham Radio Outlet (or similar) store, that's where I'd go for coax and connectors.  For inside-the-shack jumpers for connections from radio to tuner or radio to SWR meter, or radio to amplifier, I would suggest using RG8X for that service.  It is more flexible than the larger-diameter cables and will not result in any deterioration of signal etc. for short runs between pieces of equipment.  You'll need to get some sleeves to attach to the PL-259s to use RG8X.  Should be the same sleeve used for RG59 coax.  Stores that sell coax and connections will be able to help you find the right components.

Yes, an ohm meter will work well for for verifying that your cable assembly is correct.

While you're at it, make up a few extra jumpers, and keep a few spare PL-259s in your parts box.

Good luck.

73, John N5CM



Thank you.  I was at HRO today (Oakland, CA) and saw the coax seal stuff.  The main reason I'm asking is I don't know the length due to the routing and it is a major hassle to measure it out with rope or something else.  I was thinking of either making my own or buying a very long pre-made cable, cutting it to length after I get it routed to my shack and then terminating it at the appropriate point.  The other end can be used for a second feed line (if it long enough) or for other purposes.

I'm told from many people that RG8x is fine for short runs inside of the shack so that is a relief.