Aluminum Tubing Length Question

insomnia2002 · 10-01-2002

Most everything I do is in metric so I was curious about how exact my conversion needed to be.

1.22" equals 30.988mm. To be sure that I was able to cut each one the exact same length would it mess things up if I cut the tubing segments at 31mm? (that equates to 1.220472440944882" if my conversion software is correct).

Insomnia

lincomatic · 10-02-2002

at .039% error is not going to kill you. the imprecision of several other factors will far outweigh this error. of course, i don't even know what you're building, but i'm assuming it's some sort of antenna

insomnia2002 · 10-02-2002

Doh! I appears I've gotten a bit ahead of myself. I'm just throwing together a standard pringles cantenna from Rob Flickenger's design.

renderman · 10-02-2002

I tried building my first cantenna to his specs. After hunting around for the size parts he specifies, it worked OK, but was pretty flimsy.

My next attempt was with 1/4" all-thread instead of that flimsy 1/8" stuff he used. I used the appropriate 1/4" ID washers and 1/4" nuts and nylon acorn nuts.

I put 1 nut on each side of each washer and used those to hold it in place instead of the tubing. It was alot nicer because you had some fine control to get the spacing between washers just right. When everything was in place I just locked the nuts in place with some nail polish.

Tests showed besides being sturdier and mildly adjustable, I got a couple db more with the edited design, rather than the original.

The distance between the washers still has to be about 1.22", but being a little off won't kill you. Besides, fiddling is fun.

Render

10-01-2002	#1 (permalink)
insomnia2002 Registered Member Join Date: Sep 2002 Posts: 7	Aluminum Tubing Length Question Most everything I do is in metric so I was curious about how exact my conversion needed to be. 1.22" equals 30.988mm. To be sure that I was able to cut each one the exact same length would it mess things up if I cut the tubing segments at 31mm? (that equates to 1.220472440944882" if my conversion software is correct). Insomnia

10-02-2002	#2 (permalink)
lincomatic Squaaawk! WiFi! WiFi! Join Date: Apr 2002 Location: Tinsel Town Posts: 1,682	at .039% error is not going to kill you. the imprecision of several other factors will far outweigh this error. of course, i don't even know what you're building, but i'm assuming it's some sort of antenna __________________ ~lincomatic

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10-02-2002	#3 (permalink)
insomnia2002 Registered Member Join Date: Sep 2002 Posts: 7	Doh! I appears I've gotten a bit ahead of myself. I'm just throwing together a standard pringles cantenna from Rob Flickenger's design.

10-02-2002	#4 (permalink)
renderman Drunken Stumbler Join Date: Jun 2002 Location: Anywhere but Utah Posts: 1,862	I tried building my first cantenna to his specs. After hunting around for the size parts he specifies, it worked OK, but was pretty flimsy. My next attempt was with 1/4" all-thread instead of that flimsy 1/8" stuff he used. I used the appropriate 1/4" ID washers and 1/4" nuts and nylon acorn nuts. I put 1 nut on each side of each washer and used those to hold it in place instead of the tubing. It was alot nicer because you had some fine control to get the spacing between washers just right. When everything was in place I just locked the nuts in place with some nail polish. Tests showed besides being sturdier and mildly adjustable, I got a couple db more with the edited design, rather than the original. The distance between the washers still has to be about 1.22", but being a little off won't kill you. Besides, fiddling is fun. Render