Amateur Radio in Play in Aftermath of Nepal Earthquake

And yes - satellites / ISS are great too! Talking to a buddy - even next door - and knowing the signals are being directly repeated by a bird whizzing by overhead is still extremely cool :)

http://www.fix.net/~jparker/wilderness/nc40a.htm

The book takes you through the basic theory, backed up with experimentation while building the kit. You just need a a scope and function generator, and of course a soldering iron.

KD4HSO

The only downside to the Ensemble RxTx is the sound card requirement. I'm probably going to order something right away here, but if I could have a do-over, I'd probably go for a Peaberry: http://ae9rb.com/index.php?main_page=product_info&products_i.... They were out of stock when I ordered though.

73, VE5AJA

So the spec reads something like less than 10% error (usually low) at that freq. So a 10 Hz 10 KHz 10 MHz sine wave at 1 V p-p will display at 1 V p-p on a 20 meg scope. However shove in a 30 MHz 1 V p-p sine wave and (on an analog scope) you'll see a beautiful sine wave at, oh, who knows, maybe only 0.5 V p-p.

I do a lot more quant work with simple watt meters, at least for RF stuff.

A stereotypical example where qualitative accuracy matters not quant is you have a possibly 15 dB amp, and a -25 dB sampler on the input, and a -40 dB sampler at the output and you feed one into the X and one into the Y and shove a varying signal thru the amp and rather optimistically you'll get perfectly smooth lines on the triangle border. The numerical results are irrelevant, whats important is the amp isn't going into compression and what comes out is a perfect linear function of what goes in aka the line is perfectly straight. When you hit compression the end of the line will tilt over and no longer be straight, and thats bad. And your inline watt meter says that happens at 150 watts out or whatever, so I guess you can run cleanly at somewhat less than 150 watts.

Another example is a lot of "is this (four letter words) oscilator oscilating (which would be good) or is this amplifier oscilating (which would be bad)?" and things of that nature where quantative results simple don't matter, you just want to know if there's anything there at all.

Also you can peak up filters and LC networks in general without exact results just a "Turn the screw that way and the sine waves get bigger, turn the other way and output drops" mentality. If you're operating at a couple watts level, then cheap wattmeters will work. Not so much for low power level receiver work, then you use the scope to tune up.

Its a lot easier to use an analog scope at or beyond its limits than a digital scope, but it can be done with digital scopes if you really understand DSP undersampling theory and the sample and hold doesn't aggressively filter higher freqs etc. The reason why pros just dump money to not operate near or above limits while hobbyists can't is a long financial story, my employer can justify a $150K spectrum analyzer in the lab (aka a cheap one) but my wife has issues justifying more than a couple hundred bucks at home. But yeah I prefer the new hyper expensive digital equipment at work and analog at home for that financial reason.

Another fun thing to think about with cheap equipment is I own a 70s/80s era scope but the work I do would only have been cutting edge at a research lab in the 60s, and in the 60s all they had was 60s scopes, so I have it pretty good and could actually allocate my scope money elsewhere. If you want to do 10s (2010s...) work at home its going to be difficult to afford in the 2010s although in the 2030s it might be cheap.

I second that. you can get UV-5R for about $30 bucks. You can really learn a lot from a simple, small radio like that.

[0] http://www.arrl.org/licensing-education-training

[1] https://en.wikipedia.org/wiki/Amateur_radio

If you're not licensed, there are flashcard apps for your phone that will prepare to completely ace the test very quickly. The manual's a good reference for any questions you don't understand. I'd also recommend finding a local club or other operator just to get a demo of a basic radio contact and the protocol people follow for conversation. Some of it's mandated by governments, but a lot of it just convention.

There are also some nice apps. The free "Ham Radio Exam" apps for iOS by Roy Watson (one for Technician, one for General, and one for Extra) are quite good. I made extensive use of them.

Here, generally, is how I prepared for the tests.

TECHNICIAN. The electronics knowledge I already had from non-ham interests, plus what I remembered of ham rules and operating procedure from some studying I had done when I looked at getting licensed back in the '70s when I was a kid, covered most of the test. I took a few practice tests and passed them. I then read KB6NU's No-Nonsense Technician guide to fill in the gaps, and then drilled at hamstudy.org and hamexam.org until I was consistently getting 95+%.

GENERAL. I got the ARRL book for this. For Technician, I was fine with the no-nonsense guide, because all I was missing were things that you really just have to memorize. For General, I needed to actually learn some things. It took a week to go through the ARRL General book. I went through it in order. Then I drilled at hamstudy.org and hamexam.org until I was always passing practice tests by a comfortable margin. I found Roy Watson's apps during this and added them to the mix.

EXTRA. After finishing the ARRL General book, I still had a week until the exam, so on to the ARRL Extra book. I started with the chapter on antennas and feed lines, because that is one of the biggest areas on the Extra exam (8 questions) and my prior electronics knowledge did not cover this. I wanted to get that done early, so I could drill that section throughout the week. Then I basically did the book in order. Near the end of the week, it became clear my pace wasn't fast enough to actually finish the whole thing the way I was doing it.

The way I had been doing it was to read a section until I got to the point where it said to try specific questions. Then I'd try those questions, and if I got any wrong redo the section. To speed things up I changed this so that I'd quickly skim a section and decide if it was something I was already reasonably familiar with. If it was something new to me, I'd go back and do it the slow way. If it was something that I did already reasonably know, I'd skip straight to the questions. If I aced them, I'd move on.

While studying for Extra, I was doing practice General tests. Restroom break--take a test while sitting on the can. Commercial break while watching TV--take a test. Drive-through slow at Wendy's--take a test while waiting for them to take my order. I'd also toss in the occasional Technician practice test.

I finished the Extra book a day before the test. That last day, I took several Extra practice tests, and continued with the General and Tech practice tests to keep that material fresh.

It worked. I passed all three tests the next day (100% on each...not unexpected for Tech and General as I was generally acing them in practice, but a surprise on Extra, as I had never aced an Extra practice).

I highly recommend the ARRL books for General and Extra. Most of the other popular study aids I saw seemed to me to tilt too far toward just covering the test questions. The ARRL books flesh things out more, covering things not on the exam but related to things on the exam, so you come away with a better understanding. With the ARRL books, it did not feel like I was studying for the exam--it felt like I was learning interesting stuff that just happened to include what would be on the exam.