Foundations of Amateur Radio Random bits of wire ... One topic that is longer than all other topics combined is that of antennas. Designing, planning, sourcing, building, tuning, using, you name it, all of this is regular fare in the day of a radio amateur. I've discussed the topic here regularly and no doubt I'll revisit that when the mood or necessity takes me. One topic that is rarely discussed is that of failure. About six months ago I moved house. I've been rebuilding my shack, doing all manner of fancy shuffling of gear and yesterday I finally got to the point of getting some HF activity happening. During that process I went through boxes and boxes of stuff, with coax, connectors, wire, nuts, bolts, heat shrink and all the other necessities of being a member of an experimental hobby like ours. One box contained wire. You know the adage, only two types of wire required in our hobby, cheap wire or free wire with a preference for free. This box was stuffed with wire. Bits with connectors, bits wound around spools, bits in zip-loc bags with labels, bits of random length - lots of bits of random length. There was even an abortive attempt at labelling dipoles for various bands on the outside of a couple of zip-loc bags, but no idea if the bit of wire in the bag was actually ever tested and resonant on whatever band was on the label, so who knows, they might have just been cut long waiting for another day and another set of experiments and measurements. I needed around 50 meters of hook-up wire for my HF antenna experiment and it occurred to me when I was hunting through my box that I couldn't look at a spool and tell you how much wire there was. I did a dodgy measurement of one bit, put it on the kitchen scales and determined that another spool was heavier, so it was likely longer, but without bringing in my calculator, doing extra measurements and doing some head scratching there was no way that I was going to get to the point of knowing how much actual wire was on that spool. In the end I made do with the dodgy piece, soldered some joins, that's a whole other adventure, involving a gas-powered soldering iron and a flame, the flame won, as well as several other breaks and fixes. While I was in the process of putting up my new antenna experiment it occurred to me that part of the process of experimentation, even of shack maintenance should be the documentation stage. I have bits of terminated coax, some of it 20 meters long, some longer, some shorter. How much longer, and how much shorter you ask? No idea. But wouldn't it be great if I could put my hands on a piece of kit that I needed that was the length that I expected and not 10 meters over length, or 1 meter short. In my audio kit, I have started labelling patch leads with their functions, using key-ring tags. I don't expect that to work for plain wire, but it should be a good solution for coax. I could use cable tie labels, but past experience with those leaves the text fading on the label. I've experimented with a printed label with clear heat shrink, but for reasons best known to chemists, the clear heat shrink becomes yellow in short order leaving the label unreadable. I've heard of people using electrical tape with colour coding, perhaps one ring for every 5 meters of length, but they seem to come undone in the dust when you go camping. One thing I do know is that this is a recurring problem for me. This is the first time I've actually stopped to talk about it and perhaps it means that I'll get a little closer to a solution. I'd love to hear what you do to deal with this and how you keep track of the countless different lengths of wire, coax and rope that's lying around your shack. I'm Onno VK6FLAB To listen to the podcast, visit the website: http://podcasts.itmaze.com.au/foundations/ and scroll to the bottom for the latest episode. You can also use your podcast tool of choice and search for my callsign, VK6FLAB. All podcast transcipts are collated and edited in an annual volume which you can find by searching for my callsign on your local Amazon store, or visit my author page: http://amazon.com/author/owh. Foundations of Amateur Radio Volume 7 is out now - with chapters on digital modes, coax connector loss, waterfalls, station performance and more. Feel free to get in touch directly via email: onno@itmaze.com.au, or follow on twitter: @VK6FLAB (http://twitter.com/vk6flab/) If you'd like to join a weekly net for new and returning amateurs, check out the details at http://ftroop.vk6.net, the net runs every week on Saturday, from 00:00 to 01:00 UTC on Echolink, IRLP, AllStar Link and 2m FM via various repeaters.
For me coax is easy, my reach from hand to hand outstretched is six feet, pretty much a meter. So when I coil up coax I wind up a loop from hand to hand, each loop represents 6 feet or really close to a meter. When I search the coax archives for a length I need I just count the loops in the coil of coax and multiply by 6. Works well for rope too. Has worked now for 20 years!
3,28084 feet or 3' 3,37" in a meter. We should not have to do this. South Africa went metric in 1961, but as all my father's tools were imperial we did conversions for a long time after. I still have his foot/pounds torque wrench, and fold out wooden rules. Since becoming a Ham I find myself converting again. It's time for the whole world to go metric or was the second world war not long enough ago? There are well priced cable marking printers with labels that weather the outdoors. You can get brightly coloured self adhesive tape from 3M that can be written on with a permanent marker which also weathers quite well.
Ok, I messed up on the meter thing. I was just trying to convey a method for measuring a length of stored coax or rope without having to string it out and actually measure it. 6 feet is close enough for guesstimating. I am sure glad I said 6 feet. Thanks for the correction guys.
It won't help you on the spool but most coax has markings on it every 2' or so. Look at the two ends and do the subtraction and you will be accurate to within +/- 12". I agree with the basic need to label what something is because after we sleep a few nights, we forget why we cut that piece a certain way, soldered something a certain way or my favorite, finding that something was broken and placed in the box to be worked on only to be drug out and to become the source of frustration 6 months later.
