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Registered Member #96
Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4059
Re. Al soldering.
A "ghetto" hack is to use indium which is pricey but for the hassle factor it can't be beaten. Use no clean flux and sandpaper to prepare the joint, then use indium to make the connection.
Please note, I strongly advise to use a different soldering iron to do this as indium significantly weakens Sn/Pb or SnAgCu joints if it contaminates the bit. This can be a pain to fix and wastes a lot of solder before it clears!
I used this method to solder wires to some phosphate cells and it worked fine with no bad joints. If anyone would like some indium please PM me.
Re. coax, I've used satellite cable for this before, because it works perfectly at over 1 GHz, there will be some losses but the better shielding more than makes up for them.
Some people also salvage the screened cable from a broken VCR but this isn't as good and usually results in significant losses. I've also salvaged a cable from a broken laptop's WiFi as this also has the small connector at one end which saves a lot of pain and makes it user replaceable.
I would also use heatshrink around the cable pair as this adds structural strength and reduces the chances of cable damage which can result from handling.
Registered Member #2004
Joined: Sat Feb 28 2009, 11:43PM
Location:
Posts: 39
Hey guys, I guess I should have mentioned it before, but I am NOT trying to make a massive length of cable here; the "balun" cable is only a couple inches long at most (pictured below) I'm not sure how much effect the inconsistencies in my cable will have on the overall performance, because when you look at the normal coax balun in most designs, it's practically folded in half! There's no way the cable's conductor spacing and geometry will stay the same with that kind of abuse, yet most people get it to work fine.
Anyway, thanks for the links. I'll try crunching some numbers later.
Edit: hmm... I think I just lucked out majorly here. The dielectric layer from the coax cable I have just happens to fit perfectly in my copper tubing. I think this means I can just replace the cable's outer wire braid with the tubing and use the already-known Vfactor of the cable. I'll test this out and hopefully be able to post results within the next week or so.
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Calculating "velocity factor" (wifi antennas)
