CT2GQV’s Homebrew Blog

Ricardo, CT2GQV, writes the blog, The “Speaky” HF SSB transceiver and other homebrew projects. I found this blog because Ricardo linked to one of my blog posts.

I like it a lot. Ricardo is a hard-core homebrewer, and has posts on a number of projects including:

  • 0-500 Khz converter to 4 Mhz
  • 100 w dummy load
  • Attenuator
  • Batery tester
  • BFO for hf-radio
  • Digital modes interface
  • HF SWR meter
  • Noise generator for filter aligment
  • PCB helping hand
  • RF Probe
  • S9 signal generator

…and much more.

I’m adding it to my links list. It’s certainly worth reading.

First, Check the PC Board

ATX80 board showing defectsBuilding is a lot of fun. You can build your own stuff, or take advantage of the work done by other hams and build projects from the ham mags like QST or CQ. One of the advantages of building projects from magazines is that frequently someone has already designed a PC board for it.

Even so, make sure you check that PC board before you start soldering parts. A recent purchase shows why.

The image at right is a scan I made of a PC board that I purchased to make a little 80m transmitter for transmitter hunting. Last night, I gave it a visual inspection before beginning construction, and I’m glad I did. For one thing, I noticed several spots that hadn’t been etched properly. These are marked with a “*” on the scan.

Those defects would have been easily corrected with an X-Acto knife, but when I flipped the board over to inspect the component side of the board, I found that none of the legends matched the holes in the board. Upon further inspection, I determined that the image used to print the component layout had been inadvertently rotated 180 degrees.

I e-mailed the vendor late last night, and this morning when I checked my e-mail, I’d already gotten a reply. The vendor apologized for the error, and said he’d get a new board out to me as soon as he could make a new batch. What great customer service!

Field Day Packets Available

From the ARRL website:

Attention All Amateurs…
ARRL Flag2010 Field Day Packets Now Available (Feb 2, 2010) — It’s that time of year again — time to start gearing up for ARRL Field Day, June 26-27, 2010! ARRL’s flagship operating event — always held the fourth full weekend in June — brings together new and experienced hams for 24 hours of operating fun. Field Day packets are now available for download and include the complete rules (including changes for 2010), as well as other reference items such as forms, ARRL Section abbreviation list, entry submission instructions, a Frequently Asked Questions section, guidelines for getting bonus points, instructions for GOTA stations, a kit to publicize your event with the local press and more.

Green Radio?

I’ve been living in Uganda since October 14, 2009, just over three months. I have visited Uganda on four previous occasions for three to six weeks each time. I remember well my first visit in the summer of 1999. That was the year we were preparing for Y2K, and there were a whole bunch of voices predicting the meltdown of civilization.

On that visit, I travelled across the countryside in an old Toyota LandCruiser. As we drove through village after village, I came to the conclusion that if the world were to meltdown because computers failed at midnight, December 31, 1999, it would have no effect whatsoever on Uganda.

Why? Because no one in the interior of the country was connected to an electrical grid! Most had never seen a television much less had the resources to own one. A few had radios.They simply lived too close to the land to be even remotely dependent on computers and the devices computers managed. They were, and are, a green society in that they make do, recycle, use what they have, improvise from resources at hand, and live off the land.

What, you ask, has any of that have to do with ham radio? Well, depending on your point of view, lots, or nothing at all. I just received the January 2010 issue of QST courtesy of a visitor from the States. American magazines are like gold here, and I am savoring each page. The cover calls this issue “the DIY issue,” and the articles largely live up to the billing. What impresses me, though, is how complicated ham radio can be, and in most cases, has become. Both the articles and the advertiserments describe many devices for connecting a radio to a computer, or operating a radio in conjunction with a computer, or operating over the Internet. Just about every company or person mentioned has a Web address. There’s also an article about working satellites, which I would like to do when I can. From another source, I just received an email notifying me of a QRP Net that will be meeting on Echolink!! QRP on Echolink just seems odd to me.

Ham radio is a technologically sophisticated hobby. It always has been. In the early days, savvy operators created components from what they hand. Today’s operators use and assemble more complex gear, but in principle do the same. There is one exception, however. Today, we rely on ready-made parts, manufactured components, and advanced engineering. Driven by time pressures and the compulsion to get on the air quickly, our economic status usually means we can buy what we need, plug it in, and go.

At the same time I browse QST, I have been reading “Calling CQ” by Clinton DeSoto. I found a link to the 1941 first edition in a PDF file one can download for free. Mr. DeSoto describes the early days of ham radio, and I am struck by the ability of ham radio operators to create working radios from almost nothing. Their ability to improvise and adapt is possibly directly tied to their times, their financial capacity, and the impossibility of buying parts or components given their circumstances. I will be the first to admit I cannot do what they did.

It was after I arrived in Uganda and began assembling my station that I began to have a new appreciation for the fine science of improvising and adapting. I had limited space to bring stuff and there are no simple or inexpensive means to acquire them. So one must do what one must. The whole country is run that way. Resources are limited and pricey. Don’t run out and buy it if one can make it or adapt something else to work. Even my ladder here is homebrewed. There are no ladders for sale in the entire district. You gotta make one if you want one. “Green” living is, in its simplest expression, living closely with what’s around you. It is Field Day every day here.

We all accumulate junk boxes and use what’s in them. Even though we use microprocessors and internet connections and computers, hams are really “green” at heart. Creativity is, by definition, the art of making something new or using something old in a new way. I hope we all have gear at our disposal that does not require an internet or computer connection to work. The scare about Y2K came about because of our dependency on systems stored or managed somewhere else. While there is no fear these days of a Y2K-like meltdown, I am still concerned about an over-reliance on systems outside our control. The emphasis these days on emergency radio procedures should speak to us hams about the need to be ready, whatever the situation, to get on the air and communicate regardless of the challenges we face. And if you want to practice, I have a spare room here in Masaka.

Media Hit: WeatherBrains

Weather and ham radio have a lot in common, most notably SkyWarn. This week, episode 210 of WeatherBrains, “a weekly audio show delivered by the Internet that unites weather geeks worldwide” has a pretty long segment on amateur radio.

Starting at about 7:45 of this episode and lasting past the 40:00 minute mark, the amateur radio segment includes guests Allen Pitts, W1AGP, the PR Manager for the ARRL, and Rob Macedo, KD1CY, SKYWARN Coordinator for the National Weather Service in Taunton, MA. James Spann, WO4W, is the show’s host. They talk about all kinds of things including emergency communications in Haiti, SkyWarn, and the Civilian Weather Observer Project.

Help Say No to This Proposed Rule

Usually, I don’t pay much attention to Notices of Proposed Rule Making (NPRMs) by the FCC. But this one—WT Docket 09-209—has got my attenion. The proposed rules would clarify certain rules regarding vanity callsigns and revise the rules applicable to club stations.

It’s the latter that I’m concerned about. The revision would add the following wording to 97.5(b)(2):

After [date reserved], no additional club station license grant will be made to a club whose trustee already holds a club station license grant for that club.

In other words, clubs will only be allowed to hold a single club call sign, unless the club already has more than one, even if there are good reasons to hold more than one club call sign. Our club, for example, has four club call signs:

  • W8PGW is our long-held club call sign.
  • WC8RC is the call sign we use at our club station at the Washtenaw County Red Cross.
  • WA2HOM is the call sign we use at the Ann Arbor Hands-On Museum.
  • W8CWN is another call sign that we use occasionally at the Hands-On Museum. This was the call sign of Dr. Richard Crane, one of the founders of the Hands-On Museum, and we requested it to honor Dr. Crane.

None of these callsigns were obtained for frivolous reasons and they all serve a purpose. Should this rule be enacted, however, clubs who have similar operations would be unable to get more than a single club call sign. This sounds like a solution looking for a problem to me.

I urge you to contact the FCC and ask them to strike this from the NPRM. You can make comments in the following ways: via the Federal eRulemaking Portal or via the FCC website. Comments must be submitted by March 26, 2010; reply comments are due no later than April 12, 2010.

Operating Notes: 1/25/10 – 1/31/10

This week, I made some notable QSOs:

  1. K0HL RigMonday night, I contacted K0HL, operating CW mobile from his truck in ND (see right). On his QRZ.Com page, he lists his occupation as clockmaker. I need to e-mail and ask him how he became a clockmaker. I’ve always had an interest in clockmaking.
  2. Tuesday night, I had a QSO with YS1ZC. He’s my first contact with El Salvador.
  3. On Thursday night, I stayed up late. When I got home from bowling, my wife informed me that her parents’ power went out and that we might have to go get them, if their power didn’t come back on soon. Just after midnight, I called CQ on 80m, with my crummy 25W and random-wire antenna, and lo and behold, I got a call from DJ0KC, who heard me while getting ready for work. He’s my first European on 80m, and only my second DX contact. I’m amazed when I make any contact on 80m, much less a DX contact.
  4. Thursday night, I worked HA3NU. He is the first DX station that I’ve worked with the same suffix as mine.
  5. On Saturday, down at the museum, we worked one of the stations in the REF French DX Contest on 20m. Later that evening at home, I heard a couple of French stations on 40m and worked them. That got me caught up in the swing of things, and overall, I made ten contacts, including one in Guadeloupe and three in Martinique. I also made one on 80m—F5KIN—who, as you’ll note, has a callsign that spells a word (kin).

Soldering Difficult Connections

Almost three years ago, I blogged about splicing my 40m dipole back together. The problem was that the wire had corroded, and I just couldn’t solder it properly. This episode came to mind when I read the following e-mail by Chuck, W5USJ, to the qrp-l.org mailing list:

Not a new thing and came up recently — problems soldering oxidized wire like coax shield and connections that are bright nickel plated and so on.

I used to have the old type rosin flux used for soldering copper plumbing. It worked really well for difficult surfaces (used sparingly). But that’s no longer available in favor of fluxes that will work with lead-free solders.

What I found that works really well is something called NoKorode Regular Paste Flux made by Rectorseal. It’s designed for lead-free solder but seems to work well on just about any metal. On the label there is this note: “Non-aggressive paste flux. Works on copper, galvanized iron, lead, tinned steel and other metals.”

One particular problem I have is with the shield on RG-174, the silver plated stuff anyway. With regular solder, even with high heat the solder wouldn’t stick well and often the insulation melted to the point of damage.

I had prepared some 174 with a short pigtail of twisted shield.

With the NoKorode, I applied a really thin coating on the shield. Then when I applied the solder it completely wicked into the shield almost instantly with complete coverage. As the name suggests, it does not seem to be corrosive in any way.

On some RCA connectors with what looks like nickel plating, I lightly dipped the end of my solder into the paste. Then tinned the area around the holes for the connections. That worked great too when I attached the wires; it was much easier to make a proper connection. No where near as much time was needed to heat the joint to get the solder to stick to the bright nickel surface.

It doesn’t take much to do the job with this flux and used sparingly should be fine for soldering other than electronics circuits. I’m going to try it with some of the bright metal finish on connectors like PL-259s. The 1.7oz container that I bought should last a very long time.

Sounds like I need to go get some of this stuff. If you go to the Rectorseal website, you’ll find that they make a whole bunch of different fluxes for use in different situations.

UPDATE
I just got this update from W5USJ:

Got some replies asking where to find the flux I used. One mentioned a few times was ACE hardware. My source is a local hardware, plumbing supply, lumber yard, welding supply, mini-Walmart affiliated with no national chain. It’s located in the county seat city of Emory, population 1100, Rains County, population 11,000. Sort of a rural location you might say…8^)

Also, I’d expect some plumbing supply stores would handle the NoKorode brand. Oatey has a similar product and a much bigger name in the brand stores. But the NoKorode seemed like a better idea to me. So I haven’t tried the Oatey brand.

The Ham That Has Everything?

These two photos were e-mailed to me with the subject line, “The Ham That Has Everything.”


ham that has everything 1

ham that has everything 2

My comment is that I bet this ham doesn’t have a wife or girlfriend!

The Ultimate Stealth Antenna?

From the 2010-01-26 issue of NIST Tech Beat:

Engineered Metamaterials Enable Remarkably Small Antennas

NIST Z Antenna
This Z antenna tested at the National Institute of Standards and Technology is smaller than a standard antenna with comparable properties. Its high efficiency is derived from the “Z element” inside the square that acts as a metamaterial, greatly boosting the signal sent over the air. The square is 30 millimeters on a side. Credit: C. Holloway/NIST

In an advance that might interest Q-Branch, the gadget makers for James Bond, the National Institute of Standards and Technology (NIST) and partners from industry and academia have designed and tested experimental antennas that are highly efficient and yet a fraction of the size of standard antenna systems with comparable properties. The novel antennas may be useful in ever-shrinking and proliferating wireless systems such as emergency communications devices, micro-sensors and portable ground-penetrating radars to search for tunnels, caverns and other geophysical features.

NIST engineers are working with scientists from the University of Arizona (Tucson) and Boeing Research & Technology (Seattle, Wash.) to design antennas incorporating metamaterials—materials engineered with novel, often microscopic, structures to produce unusual properties. The new antennas radiate as much as 95 percent of an input radio signal and yet defy normal design parameters. Standard antennas need to be at least half the size of the signal wavelength to operate efficiently; at 300 MHz, for instance, an antenna would need to be half a meter long. The experimental antennas are as small as one-fiftieth of a wavelength and could shrink further.

In their latest prototype device,* the research team used a metal wire antenna printed on a small square of copper measuring less than 65 millimeters on a side. The antenna is wired to a signal source. Mounted on the back of the square is a “Z element” that acts as a metamaterial—a Z-shaped strip of copper with an inductor (a device that stores energy magnetically) in the center (see photo).

“The purpose of an antenna is to launch energy into free space,” explains NIST engineer Christopher Holloway, “But the problem with antennas that are very small compared to the wavelength is that most of the signal just gets reflected back to the source. The metamaterial makes the antenna behave as if it were much larger than it really is, because the antenna structure stores energy and re-radiates it.” Conventional antenna designs, Holloway says, achieve a similar effect by adding bulky “matching network” components to boost efficiency, but the metamaterial system can be made much smaller. Even more intriguing, Holloway says, “these metamaterials are much more ‘frequency agile.’ It’s possible we could tune them to work at any frequency we want, on the fly,” to a degree not possible with conventional designs.

The Z antennas were designed at the University of Arizona and fabricated and partially measured at Boeing Research & Technology. The power efficiency measurements were carried out at NIST laboratories in Boulder, Colo. The ongoing research is sponsored by the Defense Advanced Research Projects Agency.

* R.W. Ziolkowski, P. Jin, J.A. Nielsen, M.H. Tanielian and C.L. Holloway. Design and experimental verification of Z antennas at UHF frequencies. IEEE Antennas Wireless Propag. Lett., 2009 vol. 8, pp. 1329-1332.