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I was thinking about making a coaxial colinear for 2.4Ghz, has anyone had any experience in this? I think I may run into size issues i.e it will have to be millimeter perfect.I'm not really to worried about vswr because of the mW's involved but obviously a way of measuring vswr without costing a small fortune would be helpful.

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I've built a couple. Cutting the coax is the hardest part. I had a partial spool of lmr-400 that was too short to use for anything else so I cut pieces too long, then used a razor blade to cut the coax part the correct size then trimmed the center conductor. If you make the elements a half inch too long they are easier to work with, and you can roll them on a flat desk to make the cuts. You have to be careful for the starting cut, but after that the blade will ride in the cut. Being as the whole thing is home made, a little off here and there isn't going to make a huge difference, especially if it's "tuned" for the center of the band. I'm pretty sure most of the destructions you will find on the internet are made this way.

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When cutting the coax cable for this sort of antenna and you aren't as adept as some at the cutting then try making a jig (a few blocks of wood glued and cut in a way that lets you put a piece of cable in and make the cuts in the correct place and to the correct depth). You will have to turn the cable in the jig 5 or 6 times for where you are just trimming bits back or your jig will be very complex.

Once you have a jig sorted you can push out a the individual lengths of coax cut and trimmed quite quickly and know that the quality will be pretty consistent from piece to piece.

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Thanks Jason I was thinking along the lines of a jig myself. I will also be making one for 70cm so the chances are it'll be out of RG58 but then my mind wandered and with 16 half wave elements , and two quarters , a 2.4Ghz antenna would only be just over 1m long and whilst yagis and biquads have a nice bit of gain , they are also very directional....

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