Hardline splicing

[Rob_Walker]

That was a good article in the newsletter regarding hardline splicing.  Thanks Tom.

I didn't get my Yagi up this past summer so my 1/2" Heliax sits in two pieces.  I have an Andrews connector specifically for splicing hardline, and I also have a collection of "N" connectors with bulkhead connectors for joining them.

I was particularly interested in the newsletter article using copper tubing.  I'm curious what one would use for a dielectric after the centre conductor was joined but before the 1/2" copper tubing was installed on the outside jacket?

What I like about this method is it would minimize the weak spot where the hardline might want to kink.  Open to suggestions.

73 Rob

[Tom VA3TS]

A dielectric such as RTV silicone or something similar. It would need to survive the heating due to soldering, but there is a high temp RTV that is red in colour for such applications. Another option is nothing at all. I used a copper foil tape to make a join on a piece of rg58...in my vehicle for the roof antennaa...still in use after 12 years...73

[Rob_Walker]

I contacted Karl, the author of the article, and we got a bit of a dialog going on.  If you go to the Groups IO forums where the repeater builders hang out, there are mixed opinions on the dielectric.

My inquiries said foam dielectric is 2 to 3 times better than air, but it didn't say say at what frequency.  Karl uses air and has had no problems.  I think the sure-fire test would be to connect a VNA and see if you get a bump down the line.  My guess is you would get less of a  performance or return loss issue with the copper tubing verses all the Andrews N connectors and couplers.  Either way, the return loss would be so insignificant in my short run (<200') , it would not make a difference

I hope to keep you posted

By the way, 1/8" OD refrigerant copper tubing will take care or the centre conductor.

Cheers

73 Rob