Operating notes: vacation, building a copper-pipe J-pole

Last weekend, I went “up north,” as we say here in Michigan. What that means is that we drive up to northern lower Michigan and spend a couple of days on a lake. Normally, I’d take my KX-1, throw an antenna  up in the trees, and operate QRP.

This year, however, I opted not to take my stuff. Instead, I chose to work on my upcoming book, The No-Nonsense Guide to Amateur Radio. I made some good progress on the book, which will be a combination of Ham Radio for Dummies, AC6V’s DXing 101, and the ARRL Operating Manual, with my twist on things.

A Petoskey stone, the state stone of Michigan, is a fossil colonial coral. These  corals lived in warm shallow seas that covered Michigan  during Devonian time, some 350 million years ago.

A Petoskey stone, the state stone of Michigan, is a fossil colonial coral. These corals lived in warm shallow seas that covered Michigan during Devonian time, some 350 million years ago.

When I wasn’t working on the book, I was in no particular order:

  • looking for Petoskey stones, the state stone of Michigan, on the beaches of Grand Traverse Bay,
  • organizing the more than 300 books I had on my Kindle,
  • playing different board games and card games with my sisters and their kids,
  • cooking and eating and eating and eating.

I had a blast, except on Saturday. Saturday was cold and blustery, and the high winds at night forced the people running the Elk Rapids Harbor Days festival to cancel the fireworks show. I was also looking forward to a BBQ chicken dinner by the Elk Rapids Rotary Club, but by the time I got there at 5:30 pm, they’d run out of chicken. I had to settle for a Lions Club bratwurst instead.

Building a copper-pipe J-pole
A couple weeks ago, I was talking to one of my recent students, Prem, KD8SRV, and we got to talking about how to increase the range of his HT. I don’t remember exactly the entire course of the discussion, but he decided to build a copper-pipe J-pole. He purchased all of the materials for the antenna and came over to my house yesterday to build it.

We used the instructions on the website of the Colorado Douglas and Elbert County ARES group.

Cutting the pipe proved to be the first challenge. Prem had previously tried to cut the pipe with a Dremel tool, but as you can imagine, the cut was uneven and not all that easy to make. I have a pipe cutter, which made a better cut, but it wasn’t a very expensive tool, and it proved to not be very sharp, but with a little elbow grease, Prem was able to make all the necessary cuts.

Next, was soldering the pipes together. Prem had purchase a propane torch, flux, and solder. This was his first attempt at soldering copper pipe, and let’s just say that the first solder joint was perhaps a little marginal. He improved as he went along though.

Finally, we had to decided how to attach the coax to the pipes. The plans showed drilling a hole in the stub and mounting a BNC connector there. I didn’t like that arrangement, so I attached some wires to an SO-239, and we soldered those to the pipes with my 100W soldering iron.

That worked OK, but we still need to find a better solution. One that holds the SO-239 more securely. I just Googled a bit and found a better mounting scheme on the “Zombie Squad” website of all places. If you’re reading this, Prem, take a look at how they did it.

After connecting the wires, we propped up the antenna in my basement and connected the antenna to my 2m rig. The SWR was just under 2.0:1 on 144.63 MHZ and about 1.5:1 on 146.36 MHz. That’s not too bad, and should be better once the antenna is outside and in the clear.

This was an interesting project. I’ve made many 450-ohm ladder line J-poles, but this was my first copper-pipe antenna. It takes practice to solder the pipes correctly, especially with  lead-free solder.

From the trade magazines: spectrum sharing, active filters, real capacitors

Passive components aren’t really so passive (Part 1): Capacitors. Transistors and ICs are considered active components because they change signals using energy from the power supply. Capacitors, resistors, inductors, connectors, and even the printed-circuit board (PCB) are called passive because they don’t seem to consume power. But these apparently passive components can, and do, change the signal in unexpected ways because they all contain parasitic portions. So, many supposedly passive components, like the capacitor shown below, aren’t so passive.

The model above shows that a capacitor adds more than just capacitance when you use it in a circuit.

Peaceful coexistence on the radio spectrum. How two engineers (shown at right) tried to get the military to share some spectrum with their small company.

Signal-chain basics #43: Active filters. While low-frequency filters can be designed with inductors and capacitors, they often require physically large and often expensive inductors. This is where active filters, which combine an operational amplifier (op amp) with some resistors and capacitors, become attractive. Active filters can provide an LCR-like performance at low frequencies

I love to hear from readers

Today’s e-mail brought good news from two readers.

Chris, AG6TJ, wrote, “Hi, Dan. Sorry I forgot to let you know, I passed my Extra on the first try! I read it [the No-Nonsense Extra Class License Study Guide] twice, and in between took online practice tests. It was a 50/50 chance I was going to pass, but did only missing six! The nice thing I like about your study material is that it just isn’t memorizing the answers—I actually learned  from it as well.

Diann, KK6BSQ, said, “Became an Extra Class this am about 11:00. Thanks to your great study guide!”

I love to hear that from my readers.

Tip of the Day: Collect tech books from the 1970s

1974-arrl-handbookTodays tip is from Kenneth Finnegan. Thanks, Kenneth!

Collect as much technical literature from the 1970s as possible, including ARRL Handbooks, magazines, etc. This was the decade when transistors and basic ICs were affordable, but monolithic ASICs for every problem didn’t exist yet. I’ve found literature from this era to be the most educational for discrete electronics design and understanding how contemporary one-chip-solutions work.

Why you should upgrade to General Class

While getting a Tech license is no small feat, one of the first things you should do as a Technician is to start studying for the General Class license. Oh, I can hear the complaints and excuses already. “I’m never going to get on HF, so why should I get my General?” “I only care about emcomm and public-service communications, so why should I bother?” “I just don’t have the time right now to study for the General Class exam.”

Well, if you ask me, all of that is just hooey. If you don’t upgrade to General (and steadfastly refuse to learn code), then it’s a certainty that you’ll never operate on the HF bands. It’s a self-fulfilling prophecy. Why deny yourself that capability before you even try it?

Similarly, saying that all you intend to do with your ham radio license is to participate with your local CERT or SkyWarn group is fine and dandy, but public-service and emergency communications do take place on HF as well as on VHF/UHF. Why limit your usefulness as an emergency communicator by not having HF privileges?

And, if you don’t have time now, when will you have time? It’s a matter of priorities, and while the material on the General Class exam is more difficult than the material on the Tech exam, it shouldn’t take you all that much more time to study for the General Class test than it did for the Technician Class test. Not only that, waiting is only going to make it that much harder to start studying again when you do decide to do it.

Here are three great resources to help you upgrade to General Class.

Here are three great resources to help you upgrade to General Class.

Resources
One excuse that you can’t make is that there aren’t any resource available. There are more than you could ever use. My favorite, of course, is The No-Nonsense General Class License Study Guide. It’s my favorite because I wrote it! A PDF version is available for free from my website. E-book versions are available for $7.99 from Amazon or Barnes&Noble.

Another resource is the ARRL General Class License Manual. When you buy this book, you also get practice exam software. This Windows software allows you to take randomly-generated practice exams using questions from the actual examination question pool.

Also popular is the General Class Manual by Gordon West, WB6NOA. “Gordo,” as he is known in the ham world, has been around a long time and does a great job explaining the answers and highlighting keywords. This study is also available as an audio book.

There are many more resources out there. To find them, simply Google “amateur radio general class license study guide.”

There really is no excuse not to upgrade. Once you do, you’ll be more knowledgeable about our great hobby, be a more effective communicator, and have a lot more fun with amateur radio.

From my inbox: 43 years of 73 magazine, SP DX contest, useless answer

I found these three items in my inbox this past week…Dan

73-apr-67-cover43 years of 73 on-line
Wayne Green has now released all back issues of 73 to the public domain. Although the last issue was published more than ten years ago, there’s still lots of good stuff to be found in them. You can download individual issues by going to archive.org. Indexes can be found on these web pages…

The first lists the contents of each issue. The second has direct links to the to the issues at archive.org.

The cover shown at right, a takeoff on MAD Magazine, is one of my favorite covers. Take a closer look at the soldering job Al Freddy is about to attempt. Click on the image to get a larger version if you can’t quite make it out.

Wayne Green actually published the first article that I ever wrote, “Assembling Robots with a TRS-80.” I was 23 or 24 at the time. It was published in Byte, arguably the first widely-read magazine for computer hobbyists. The article was a short one on how to program in assembly language on the TRS-80. It displayed a robot-like thing on the screen using the blocky graphics available on the TRS-80.

 

SP DX Contest actually wants my log
A month ago, I made a few contacts in the SP DX Contest. It was only 20 contacts or so, and I had meant to submit the log, but I soon forgot about it. Well, this morning, I go this e-mail:

The first review of logs received for the SP DX Contest 2013 shows that your callsign KB6NU apears in many logs. However you propably have not submitted your log.

The SP DX Contest took place during the first weekend of April (2013.04.06-07). This year we are celebrating 80th Anniversary of the SP DX Contest as it was organized for the first time in 1933. We would like to make the log checking process as accurate as possible. It will also be a honour for us to list your callsing in the final results.

We would kindly ask to send your log to the SP DX Contest Committee, even if you made only a few contacts, even if perhaps you are a causal contester.

Well, how can I refuse? I’ll have to do this as soon as I can get down to the museum again.

 

Useless answer department
I’ve been doing writeups for the product pages on AmateurRadioSupplies.Com. (Yes, that’s a plug for them, but they’re paying me to do these writeups, and they’re even advertising here on KB6NU.Com.) For the past week, I’ve been working on coax descriptions.

In doing this, one question that came up is why does marine grade coax have a white jacket? I e-mailed a question to Marinco tech support, and got the following answer, “It’s hard to say but I think it is to distinguish it  as marine grade vs. house cable.”

Seriously? That’s all there is to it? Does anyone know the real answer?

From the trade magazines, impedance matching, EMI basics, open-source hardware

elelctronic-design-logoBack to Basics: Impedance Matching. electronic design editor (and amateur radio operator) Louis Frenzel is the author of this short e-book on impedance matching. Note: this e-book was intended for engineers and does use a fair amount of math, but nothing you can’t figure out if you work at it.

EMI Basics. This article  comes from the book Signal Integrity Issues and Printed Circuit Board Design by Douglas Brooks. I like the discussion of how twisted pair wire helps prevent radiation.

Interview With SparkFun’s Director Of Engineering. Peter Dokter is director of engineering for SparkFun, one of the major suppliers of open source hardware. SparkFun designs and sells things useful and interesting to the aspiring electronics tinkerer, including microcontroller boards, Bluetooth, GPS, Wi-Fi, LCD displays, e-textiles components, robots and robotic parts, motors, motor drivers, buttons and switches, tools, and books.

From my Twitter feed: software-defined scanner, TAPR in Seattle, the art of electronics

n0rc
How to get started using the #rtlsdr as a scanner for as little as $19http://t.co/VK3qKdpMJS #sdr #hamr

This looks like fun…..Dan

 

HamBeat1
Seattle Will Host the 32nd Digital Communications Conference:http://t.co/0xGJUpjw1C #hamradio #hamr

I should have gone last year, when it was a lot closer……Dan

 

o0ToTOm0o
The Art of Electronics – Horowitz & Hillhttp://t.co/4p2rYYfcvV

A classic! Get it. It’s free……Dan

From my Twitter feed: kits, cool transmitter, new CW book

MW0IAN
Tim Walford G3PCJ does a nice bunch of radio kits and accessories http://t.co/ZgIdxUc2aj

 

This brings new meaning to “having a cool one.”

kc5fm
“A new “Cool Transmitter” from W5IG.”http://t.co/vtxAwfsWar #ARRL #hamradio

 

The ARRL stole my idea! (just kidding)

ke9v
NEW book from the @ARRL – Morse Code Operating for Amateur Radio ~ Don’t Just Learn Morse Code, Master It!http://t.co/kzlgAQJSUN #hamr

 

From my Twitter feed: old book, HAMcurmudgeon, mountain topper radio

ke9v
Really? Everything? I somehow doubt it.http://t.co/3CKO04H3pO

Screen shot 2013-03-30 at Sat, Mar 30 - 10.06AM 1

What Jeff is referring to is the book above, All About RADIO and Television. I love books like this and tweeted Jeff about that. Being the great guy that he is, he actually bought the book and sent it to me. THANKS, Jeff! If I see you at Dayton this year, I owe you a beer….Dan

HAMcurmudgeon
U might be a HAM if when U tell your wife that 20 meters is dead she sighs & asks, “How much will that cost to fix?” #hamradio

W2MDW
First blog post in a while. My MTR arrives!http://t.co/ABZCKSU9oH