Any one who has EVER coiled wire, coaxial cables, audio cables or even a hank of rope knows UNCOILING it has at one time or another created a “rats nest” of tangled mess that will increase your blood pressure, makes you exceedingly cranky and often has caused Tourettes-like symptoms. Fighting an unruly coil of coax or audio cable wastes a lot of time when setting-up a gig, a Field Day site or even coiling a power chord at home! Having spent years working in television studios, control rooms, and other audio gigs on a daily basis, I learned early on from the engineers that there is ONE way to coil cabling… W2AEW shows that in his video! (P.S. Engineers can be especially grouchy if you don’t coil correctly and THEY get to untangle YOUR improperly coiled rats-nest from a previous gig tear-down as they work on an important production. Time is money.)
This is another cool video by W2AEW. He does the best job of explaining theory I have found. His videos are excellent and his schematics and formula explanations are easy to understand. I have exchanged messages with him and he encourages us to follow his blog and learn. Also check out his website below!
This video shows how to zero-beat the WWV signal as a tool to adjust the frequency reference of an old frequency counter. It demonstrates the concept of zero-beat’ing a test signal against the WWV carrier. Since the WWV carrier is likely more accurate than any other frequency reference that most hobbiests and hams have in their labs, this is a useful technique. It can be used to check or adjust the 10MHz reference in the counter, if it has one, or can be used to very precisely set the output frequency of a signal generator which can then be used as a test signal for the frequency counter.
Similar techniques can be used to adjust the frequency accuracy of a ham radio’s reference. Several years ago, I wrote up a procedure that I put on my website. If can be found here:
This video shows how to measure the value of unknown capacitors and inductors using your oscilloscope and a simple pulse generator. There are many ways to do this, but this video focuses on just two basic techniques. The video was inspired by this blog post on scopejunction.com:
The techniques are very simple, and are a good example of basic principles of RC and LC circuits. Another bonus is that it shows another use for the fast-edge pulse generator that was shown in a video I posted several days earlier on making your own basic TDR:
The capacitors are measured by simply measuring the RC time constant, and the inductors are measured by making a simple LC tank circuit and measuring the resonant frequency.
This video shows one way to use a scope and function generator to measure the length of a piece of coax transmission line as well as estimate its impedance. It uses a “poor man’s TDR” type of measurement by launching a pulse into the coax and measuring how long it takes to return after being reflected by the open circuit end. This same technique can be used to determine the distance to a fault (open or short). A simple method for determining the impedance of the line is also shown.
This video touches briefly on transmission line and reflection theory, but is definitely not intended to dive deep into these topics. There are literally books written about this topic – so that won’t be covered here.
This tutorial discusses some general rules of thumb that make it easy to understand and analyze the operation of most opamp circuits. It presents some ideal properties of opamps, and discusses how negative feedback generally causes the input voltage difference to be equal to zero (input voltages are made equal by the action of negative feedback). In other words, the output will do whatever it can to make the input voltages equal. Applying this simple fact makes it easy to analyze most opamp circuits.
Another SUPERB W2AEW video! I love PSK31 and this is a GREAT video explaining how to have a clean and crisp signal showing up in everyone’s waterfall.
W2AEW does a FANTASTIC job of explaining all sorts of nifty concepts in Ham Radio. I follow his videos on YouTube and spend many evenings learning from this fine gent! I also have some of his books as reference material.
I am gonna HAVE a scope some day!