Picked up a tip from an old FAA inspector about coax cable prep

I was helping a guy troubleshoot a glideslope antenna issue last Tuesday and this older inspector walks up and watches for a minute. He pulled me aside and said my coax cable ends looked clean but I was stripping too much of the dielectric back. Apparently you only need like 1/8 inch exposed past the connector shoulder, anything more and you get signal reflection issues at higher frequencies. I've been doing it the same way for 6 years and never even thought about it. He showed me his method using just a razor blade and a piece of heat shrink as a depth stop. Tried it on a couple cables yesterday and my VSWR readings dropped by almost 0.2 on the 1090 MHz band. Anyone else run into old school tips that totally changed how you do basic stuff?

3 comments

3 Comments

abbycraig29d ago

Ngl I strip more than that on purpose for easier soldering and never had an issue.

hugo64529d ago

Oh man, you know what, I used to be super careful about stripping as little as possible because I thought shorter exposed wire meant less chance of shorts. But then I kept getting cold joints on thicker wires and finally tried stripping a bit more like you said. It made a huge difference, especially with stranded wire where I could actually see the solder flow properly. I was wrong about the short risk too, as long as you're not leaving bare wire sticking out past the joint it's totally fine.

drew79126d ago

Funny you mention that @hugo645 because I was the same way for years. Always figured less stripping meant less chance of something going wrong later. Took an old timer showing me that exact trick with the heat shrink depth stop to finally get it through my head. Now I check every prep with that 1/8 inch rule and my VSWR numbers don't lie. It's wild how such a small change can make a practical difference on the bench.