Cool Calculators Save Time

Online calculators are nothing new, but Calculatoredge takes the concept to a new level. On this site, you’ll find more than 200 different calculators in 12 different categories including mechanical engineering, electrical engineering, electronic engineering, physics, and more.

Most all of them are interesting and educational; some of them could even prove to be useful. For example, the “line of sight” calculator determines how far you can communicate by line of sight given two antenna heights. It doesn’t take into account effects such as multi-path propagation, but it will give you a figure that you can use as a rule of thumb when figuring out a simplex link.

Another one I found interesting is the “wire parameter” calculator. Input the wire gauge and it will tell you the wire diameter and the current-carrying capacity of the wire. Crank in the length, and it will also tell you the resistance of that length of wire.

There are lots more. Check it out.

Radio Architectures

Recently, RF DesignLine published an article on RF front ends. Now, they’ve come out with a series of follow-up articles on radio architecture. All are excerpts from the book, RF Circuit Design, 2e by Christopher Bowick.:

Virtual Ham Radio?

EchoLink is one of those topics that is sure to start an argument whenever someone brings it up at a ham gathering. I started one myself recently, when I proposed that we allow EchoLink contacts for our club’s Worked All Washtenaw award. Some guys maintained that EchoLink contacts shouldn’t be allowed because it allows for computer to computer communication, and in that mode, EchoLink contacts are not “radio” contacts. While I see their point, I felt that they should be allowed because this is just a fun award.

Now, these guys have even more “virtual ham radio” operations to complain about: QSONet and HamSphere. Both of these services claim to simulate the ham radio experience with a computer program.

CQ100QSONet, which bills itself as “virtual ionosphere for amateur radio,” has been around for at least a year. To get on QSONet, you download software that simulates an HF transceiver. (The software only runs on computers running Windows operating systems.)

Once you start the program, you select the mode that you want to operate (including CW!) and the “frequency” on which you want to operate. Then, you log into the QSONet network. The company claims that, “it works with dialup, DSL and cable internet connections. There is no need to configure router ports. The network consists of an array of internet servers which provide streaming voip audio between stations. After installing transceiver software, QsoNet stations are connected to a central server by a single, outbound TCP connection.”

To use QSONet, you must be a licensed radio amateur, even though, as they say on their website, “There is no RF. Everything is done over the internet.” It also costs to use QSONet. After a 90-day free trial period, you must pay a $32 subscription fee.

A new service that I just heard about is HamSphere. Created by Kelly Lindman, the founder of DXTuners, this service seems to be a bit more sophisticated than QSONet.

For example, the HamSphere websites notes that “skip, fading, QRM, QRN, multipath phase effects, etc. are all factors and rules in this simulation. The system follows the ionospheric laws of radio wave deflection.” You can also choose different power levels and antenna types. The user interface isn’t as slick as the QSONet interface (see below), but perhaps that’s a good thing.

HamSphere display

One big difference between HamSphere and QSONet is that anyone can use HamSphere, licensed or not. Another difference is that the software will run on Macs and Linux boxes as well as Windows computers. And, finally, there’s no free trial period, after which you have to pay. Instead, HamSphere is allowing users to run the basic version for free and trying to make money by selling optional features.

Like EchoLink, I think these virtual ham radio services might be appealing to hams who live in antenna-restricted communities or others who for whatever reason are not able to set up their own station. BUT, they are certainly not a substitute for the real thing. I just can’t see how making contacts with QSONet or HamSphere would be as satisfying as making on-the-air contacts.

Thumbs Up for FCC Customer Service

I don’t know about you, but I’m favorably impressed with the Federal Communications Commission customer service. For one thing, they process new license applications with an alacrity we could only dream of back in the good, old days. Folks that pass the Tech test generally have to wait less than a week before their callsigns appear on the FCC’s online database.

Another thing I’m impressed with is the Univeral Licensing System (ULS). This online database is easy to search, and if you want or need to download the information, it’s very easy to do so. You can search by zip code, and then have the database generate a delimited text file that you can then import into a spreadsheet or database program of your own.

I recently did this, generating a mailing list of all licensed amateurs living in zip codes starting with “481.” (There is, by the way, 4222 licensed amateurs living in those zip codes, which make up most of Southeastern Michigan.)

When I first tried this, I didn’t think that I got all the data that I’d requested, so I e-mailed tech support. Within 24 hours, I got back an e-mail explaining where I went wrong. On top of that, I just got a phone call from someone representing the FCC asking about my experience using tech support.

The moral of the story is that while we can perhaps question their recent rule-making, we certainly can’t complain about how they are administering the licensing system.

Check Your Controls!

On the IC-746PRO mailing list, a fellow posted:

I was having problems using packet last night on my 746PRO, and after determining the issue, felt that others in this group may be interested in this little pearl of wisdom.

I was attempting to connect to a telpac node from my KAM+, but could not establish a link. I was getting signal back from the telpac node, but no connection. I checked all the usual suspects (d-mode, xmit power, frequency, etc) to no avail. At first I thought my KAM+ had failed, but it worked OK with a different radio.

Then I noticed the small ‘nr’ icon on the front panel indicating that I still had noise reduction engaged from when I was down on 20 meters. After turning off NR, packet worked like a charm.

So if folks are having trouble with not being able to establish a
packet connection, check to make sure that noise reduction is off.

I did something similar while operating PSK31 a couple of weeks ago. I heard someone calling CQ, and called him, but noticed that when he came back to me, he was about 50 or 60 Hz off from where he was calling previously. I clicked on his signal, copied his transmission, sent my first transmission, and when he came back again, I noticed that again he was off about 50 or 60 Hz.

Then, it hit me. He wasn’t off, I was. I had forgotten to turn off receiver incremental tuning before switching to PSK. I was the one sending off frequency, not him.

So, the moral of the story is to make sure to change all of the settings when changing modes.

Free Electronics Classes on the Web

About a month ago, the 2008 version of my General Class license course got started. We’re using the ARRL General Class License Manual as the text, but it’s really not the best text for those that might be having trouble understanding some of the basic concepts.

Concidentally, a thread just got started on the Flying Pigs QRP mailing list discussing electronics tutorials on the Web. A couple of good ones have already been mentioned:

  • Electonic Circuit Theory (Univ. of Texas – Austin). This tutorial is interesting because it uses a mechanical analogy, not a hydraulic analogy to illustrate the concepts of voltage, current, and resistance. It also uses a Flash animation to illustrate this.
  • Socratic Electronics. This site purports to use the Socratic Method to teach electronics. It notes,

    Central to the Socratic Electronics project is a large collection of questions and answers, intended as student assignments. By requiring students to research answers to these questions, then present their findings in class, students learn how to locate information, problem-solve, collaborate, and clearly articulate their thoughts while learning the basic subject matter.

    That sounds like an interesting concept that I’ll have to look into for future classes.

What’s In an RF Front End?

This online article is an excerpt from Chapter 8 from a new edition of the book, RF Circuit Design, 2e by Christopher Bowick. The main idea is:

The RF front end is generally defined as everything between the antenna and the digital baseband system. For a receiver, this “between” area includes all the filters, low-noise amplifiers (LNAs), and down-conversion mixer(s) needed to process the modulated signals received at the antenna into signals suitable for input into the baseband analog-to-digital converter (ADC). For this reason, the RF front end is often called the analog-to-digital or RF-to-baseband portion of a receiver.

Of course, this is for most modern radios, including digital cell phones. Lots of older ham gear is strictly analog. For these radios, the front end is all the circuitry up to, and including, the IF stage.

This Changes Everything?

On the Elecraft mailing list, there’s been a discussion of a new program called CW Skimmer, which the website describes as a “multi-channel CW decoder and analyzer.”

Its features include:

  • a very sensitive CW decoding algorithm based on the methods of Bayesian statistics;
  • simulatneous decoding of ALL cw signals in the receiver passband – up to 700 signals can be decoded in parallel on a 3-GHz P4 if a wideband receiver is used;
  • a fast waterfall display, with a resolution sufficient for reading Morse Code dots and dashes visually;
  • the callsigns are extracted from the decoded messages, and the traces on the waterfall are labeled with stations’ callsigns;
  • a DSP processor with a noise blanker, AGC, and a sharp, variable-bandwidth CW filter;
  • an I/Q Recorder and player.

Most of the folks taking part in the discussion bemoaned the loss of yet another skill, mostly referring to contests and DX pileups, I guess. One guy even went so far as to say, “This changes everything.”

It might change contesting a bit, but I can’t get too excited about it. If it does really give someone an advantage in a contest, then everyone will soon have it, so at that point it’s not an advantage. And in a DX pileup, anything is fair, if you ask me.

All in all, I rather like it. The ability to scan 10 kHz of spectrum for signals is very cool, if you ask me, and the CW decoding seems to work really well. What do you think?