Amateur Radio Exams Online

There are several websites that will allow you to take tests and gauge your readiness for the real thing, including:

Only the latter seems to have practice code tests, though. Since the code test is currently one of the biggest hurdles new hams have to face, I want to thank AA9PW for making this available. I used a practice test last night with my General class and it worked very nicely.

More Thoughts on Antennas

I recently corresponded briefly with a guy on the Elecraft mailing list about his difficulty in understanding antennas. As I’ve pointed out in the past, I’m no expert, but my purchase of an antenna analyzer has certainly helped, and I advised him to also buy one. He replied that he did have one, but…

I’m clueless whether those values of Z, L and/or C are good/bad when it comes to trying to maximize ERP.

This really bugs me because I KNOW the antenna is the most important element (“a dime in the antenna is worth a dollar in the transmitter”). Yet for me my antenna system is the least understood portion of my equipment.

If I could just find a ‘dummies guide’, something that just ‘boils it down’ in laymans terms to give me a foundation to start from I’m sure I could then progress to the more technical explanations.

My response was,

The short answer is that, for the most part, it doesn’t really matter. As long as an antenna’s SWR is less than 1.5:1 (and some would say 2:1), then it will radiate just fine. You know, there are many factors which contribute to an antenna’s effectiveness, and for most amateur installations, you’re not going to be able to optimize all of those factors.

How well an antenna matches the feedline and the transmitter is only one of those factors. Other things, such as the height above ground, location of nearby metal structures, etc. will all have an effect. Look at it this way — connecting a 50-ohm resistor to the transmitter output will give you a 1:1 SWR, but you’re not going to be radiating a lot of power with it.

To me, the big reason for trying to keep the SWR down is to reduce feedline losses when you’re using coax. Coax was designed for systems where the transmitter output impedance matches the feedline impedance and the feedline impedance matches the antenna input impedance. When there’s a mismatch, then the coax contributes greatly to the losses.

Another thing about coax, I think, is that the quality can vary quite a bit. I’m just getting into this, but I think it’s a good idea to actually measure how lossy a particular piece of cable is. I haven’t done this yet, but there are articles out there that describe how to do this.

You can, of course, avoid these losses by using open-wire feedline or ladder line. Because of the way they are constructed, they are not as lossy as coax, even when there’s a high SWR on the line. How cool, eh? The trick, however, is that you have to use an antenna tuner to make sure that the impedance at the transmitter input is 50 ohms. The reason for this is not because the antenna won’t radiate effectively, but rather so you don’t damage your transmitter.

The more I think about it, the more I think that coax is really the culprit here. Sure, it’s easy to work with–it’s flexible and you can run it just about anywhere. To get the best results, however, you have to use qualiy coax and use it with an antenna whose input impedance is close to the characteristic impedance of the coax. If your coax is less than optimal, or the SWR on the line is high, then you’ll get poor results.

I think this is one reason that the guys who have K1s and KX1s and use them with random wires and the internal antenna tuners seem to have such good results. The output power may only be 3-5 W, but nearly all of that power is going into the antenna. There’s no coax to suck up precious watts.

My next antenna project is going to be a loop antenna fed with 450 ohm ladder line. I’m going to string up as much wire as I can around the backyard and run the ladder line down to my antenna tuner. I should have enough space for a full wave on 40m and maybe even 80m. Should be fun.

I Learn Something New Every Week

One of the nice things about teaching the General class is that I actually learn a few things from time to time. For example, last Tuesday, we covered RF safety, a topic that was definitely not on the test when I took my General class test 30 odd years ago. In order to adequately explain the topic to my charges, I had to do some quick boning up of my own.

I found out some interesting things. For example, the resonant frequency of the typical human body is somewhere between 30 and 100 MHz. That’s why the maximum permissible exposure (MPE) for that frequency range is so much lower than the MPE at 1.8 MHz. It’s so low, in fact, that the FCC guidelines state that you must perform a routine RF safety evaluation if you are outputting more than 50 W on the 10m band. For comparison, note that you don’t have to do this evaluation if your output power is 100 W or less on 15m, 225 W on 20m, 425 W on 40m, and 500 W on 80m.

Not sure what’s required to comply with FCC Guidelines? Well, if not, you’ll want to pick up a copy of Evaluating Compliance with FCC Guidelines for Human Exposure to Radiofrequency Electromagnetic Fields, OET Bulletin 65. Supplement B of this publication deals with information for amateur radio stations and includes worksheets that step you through the process. You can get it by mailing the FCC or from the FCC website. It’s a pretty large PDF file, so you might not want to attemp it unless you have a broadband connection.

Going through this material really got me thinking about my own installation here. I’ve been thinking about a tower, but now I’ve pretty much decided against it. One reason is the lay of the land here. My house is situated on a hill, and my neighbors to the rear are uphill of me. A beam on a 50-foot tower would probably beam right into their house when pointed in that direction. Couple that with the difficulty in erecting one in the first place, and I think that I’ll just forget about it for now. It may just be time to move to a better antenna site…..errrrr, new house anyway.

What’s Going on With 30m?

For the last week, there’s been three or four big pileups on 30m every evening. (It may be the same on other bands, but I pretty much stick to 30m lately). The pileups are so big and spread out that between them and the weird QRM on the band, there’s practically no room for “normal” QSOs.

Why the pileups? Well, there are two high-profile DXpeditions on the air these days. The first is the 3B9C DXpedition to Rodrigues Island. Rodrigues Island is about 400 miles east of Mauritius in the middle of the Indian Ocean. The operators are very good and they’re ripping them off one after the other. The website notes that they’ve already made more than 50,000 contacts.

The other is the HK0GU DXpedition to San Andres and Providencia Islands in the Caribbean. This is a somewhat lower profile operation, as there’s only one operator – Gerd. He’s spending four weeks on Providencia to celebrate his 25th wedding anniversary. His operation might be lower profile, but he still creates some good pileups.

I complain about the pileups, but the upside, of course, is that band conditions have been very good. If band conditions weren’t so good, then there would be fewer stations in the pileups (at least fewer stations that I can hear). There’s also a lot of DX stations on. Mostly, they’re trying to work the DXpeditions, but I’ve worked several, who I conjecture got tired of the pileups and just started looking around for other contacts.

I was, in fact, going to rant about the pileups, but Wednesday night, I was just hanging around the shack, and decided to tune around the band. I copied 3B9C, and even though there was a good-sized pileup, they were putting in a pretty good signal, so I decided to give them a call. I got them on the third or fourth try!

A little later, I was tuning around again, and happened on HK0GU calling CQ. He copied me on my first call. I just happened to be in the right place at the right time. As soon as he sent 73, there was again a big pileup.

At any rate, I guess I can’t complain too much about the pileups.

It’s cute, but not for everyday use

You may have noticed that many CW geeks have a big collection of CW sending implements, including straight keys, bugs, and paddles. I’ve felt like a piker because up till now all I had was a straight key and the Bencher BY-1 paddle.

Well, all that’s changed now. I now am the proud owner of a AZ ScQRPions/W5JH Paddle. This paddle was designed by Jerry Haigwood and is sold by the AZ SQRPions club. It comes in kit form and only costs $25.

It’s quite a cute, little paddle. The base measures only 2-in. square, but because it’s almost entirely brass, it’s heavy enough that it stays put as long as you don’t beat on it too much.

How can it cost only $25? Well, it is a kit, for one thing. You not only have to assemble it, you have to finish the brass pieces. This means buying four different grades of sandpaper and sanding down the six brass pieces four separate times. This took me about two hours total to do. Once you’ve sanded down the pieces, you then have to polish and/or apply lacquer to them. It’s a lot of work, but if you take your time and do it right, you’ll have something that you can really be proud of.

After the sanding and polishing, you assemble the paddle. The included instructions are very good, and the paddle went together without a hitch. One thing I’m not real crazy about is the way the paddle arms connect to the common connection. To make this connect, you much solder a small silver wire to each arm and then route the wire through a hole in the base to a lug on the bottom of the base. It seems as though the wire could easily fatigue and break as it moves every time you move the arm, but the arm doesn’t move that much, so I guess it’s not too bad.

Another thing that I don’t like about the paddle is that it doesn’t sit up that high off the desk. The center of each finger piece is only about 3/4-in. off the desk. Maybe I’m just used to using the Bencher, though, whose finger pieces are about twice as high.

I’ve been using it a little tonight, and I must admit that the action is pretty smooth. It has a nice feel to it as long as you’re not too ham-handed. It can’t be too bad–tonight while using it on 30m, I worked both the HK0GU DXpedition to San Andres Island and the 3B9C DXpedition to Rodrigues Island.

Will I use it every day? Probably not. It is, though, a nice piece to add to my collection.

QSLs from Stations Whose Calls Spell Words

I just finished processing the latest batch of QSL cards from the FISTS QSL Bureau. In this last batch, there were two cards from stations whose calls spelled words. That kind of amused me, so I thought I’d plow through the pile of cards I have here to see how many other QSLs I had from stations whose calls spelled words. Here’s what I found:

  • AA1OF
  • KA2NAB
  • W4MOW
  • KB3JAR
  • KA1OX
  • KA3RED

I’m kind of surprised I don’t have more.

Update 3/22/04: In browsing NM4C’s Vanity HQ, a site that keeps track of the availability of vanity callsigns, I note that K3ZEN is now available. Maybe with that call, I could discover the true meaning of ham radio.

Update 12/6/04: I just got a card from Joe, KI6ON. He suggests that, if I get enough cards, I could form sentences with them. Great idea, Joe!

Squeaks and Squawks

While browsing the eHam forums this afternoon I came upon an item with links to websites that have recordings of the sounds of various digial modes. These pages are great if you’re thinking about getting on digital and want to try copying some signals before jumping into it all the way. There are four of them:

The latter has quite an extensive set of recordings of digital modes used by the railroads, law enforcement agencies, and other utility radio users.

Now, I Want to Work Satellites

Tuesday evening, Tom Bray WB8COX graciously volunteered (without too too much arm-twisting on my part) to give our club a talk on operating the satellites. Tom has been working them for quite some time, and he put together a very informative talk, including some sample audio. (I plan to post his slides as soon as he sends them to me.)

Of course, now I want to work the satellites. I probably won’t, of course. I just don’t have the time to do everything, but it’s a cool thing to think about, anyway.

Two Finds

The Friends of the Ann Arbor District Library hold a sale every Saturday and Sunday (except during the summer). According to their web page, the Friends resell more than 100,000 books a year. I used to go nearly every weekend, until my bookcases couldn’t hold any more books. I still go there from time to time, but I’m much more selective now as to what I buy.

I just got back from the library. I donated a bunch of old software and culled a few books from my collection. Feeling as though I now had some space for more books I did a walk-through to see if there were any gems. I actually found two:

  1. The Radio Amateur’s Handbook, 1954 edition. In 1954, the Handbook costs $3. Possibly the most interesting thing about this edition is the catalog section. It’s 180 pages long and includes ads from well-known names, such as National, Hallicrafters, and E.F. Johnson (of Viking and Matchbox fame). What’s perhaps more interesting, though, are the ads from companies long out of business, such as Lampkin Laboratoies and the Multi-Products Co., the latter of which apparently made the PMR-6A receiver and AF-67 transmitter near here in Hazel Park, MI.
       Many of the advertisers made both assembled receivers, transmitters, or test equipment, as well as components. James Millien, for example, advertised oscilloscopes, a grid-dip meter, and a linear amplifier, as well as panel dials, tube socket, and variable “condensers.”
  2. Elements of Radio, Third Edition, Marcus and Marcus. I’ve owned several copies of this book, which according to a source on the Internet, was first written as a World War II training manual. After the war, Prentice Hall published four different editions of the book for use in high schools. Of all the books I’ve read on radio and electronics, this one is the most well-written. I never really understood how capacitors were supposed to work until I read the appropriate chapter in Elements of Radio.
       If you ever find a copy–and it’s not too expensive–buy it. If you don’t need it, you can always pass it on to some beginner who is having a hard time with the theory. That’s what I’ve done with most of mine.

Finding this 1954 edition of the Handbook has gotten me thinking that maybe I want to try to collect as many of them as I can. Several years ago, I bought a 1965 edition at the Friends’ book sale, so now I have two of the 80 different editions that the ARRL has put out over the years. Got any you want to sell cheap?

Don’t Be Shy

Yesterday, I called CQ on 30m, and a station came back to me. He was sending kind of slowly, but that’s OK. I’m happy to work guys just getting their feet wet.

Unfortunately, this guy stumbled a bit sending my call the first time, tried it again and made another mistake, then disappeared altogether. I called QRZ? to get him to try again, but he was gone, apparently too nervous or embarassed to try it again. I understand the emotion; I’ve done that myself in the past. But, I’m still sorry that I didn’t get to meet the guy.

My advice for new operators is to stick with it no matter how many mistakes you make. In my book, you get points for trying, and if other ops give you a hard time, then to heck with them.

If you’re a new op or a slow op, don’t be shy. If you hear me calling CQ, call me back no matter how slowly you send or how many errors you think you’ll make. You can only practice so much on your own, and at some point, you just have to jump in and start making contacts. I hope one of those is with me.