The Ek's Files » Dave

The G5RV Returns

Dave — Mon, 05 Jul 2010 14:59:39 +0000

If you’ve read my past posts here about my antenna projects, you know that I live in a covenant-restricted neighborhood that supposedly doesn’t allow outdoor ham antennas (at least none visible from the street). Thankfully, there is no homeowners association or dues that support covenant enforcement, and none of my neighbors had thus far even mentioned the short vertical antenna I built and installed in my back yard.

Up until now, I hadn’t really given that antenna a good workout. But last weekend was Field Day, and this year I had to settle for working Field Day from the shack. Sadly, I was disappointed by my antenna’s performance. Although I managed to work 50 QSOs in four or five hours, I struggled to hear and contact other stations, even when running 100W. The noise level was very high, and signal levels were underwhelming. I worked only two SSB stations, the rest being CW contacts. It was time to rethink my antenna situation.

Up to now I’d ruled out a dipole or similar antenna because I had no trees to support one. I hadn’t really considered using the house itself (it’s a two-story) to support a dipole. The house is wood-frame construction with wood siding, so having an antenna wire running along the side of the house shouldn’t be too bad, I figured. I decided it was time to experiment.

One of my favorite antennas is a half-size G5RV (I suppose a full-size one would be my favorite if I’d ever had enough space for one). My main HF antenna at my previous QTH was a half-size G5RV in a vee configuration supported about 25 feet up at the center by an aspen tree. And when I take my ham station out to the field, my main antenna is usually a half-size G5RV constructed with twinlead and lightweight wire–the entire antenna fits into a gallon freezer bag.

I did a little measuring and came to the conclusion that I could get a G5RV up about 20 feet if I used the side of my house to support it. The feedline could run up the back corner of the house. One leg would run along the side of the house from the back to the front, and the other leg would run through the air toward the back corner of my property and be tied off at the privacy fence. But would it work?

It took about an hour of time to put up the ladder and add some small hooks in strategic places on my house (hoping my neighbors wouldn’t get too nosy about what I was up to), and I soon had rigged a system that would allow me to easily hoist my feedline and wire legs up the side of the house and lower them again. I got everything rigged up, hoisted up, and connected up, and I went into the house to fire up the radio. I didn’t know how the antenna would tune up in a less-than-ideal configuration, but I was pleasantly surprised by what I heard. This configuration beat the vertical hands-down! Noise levels were lower and the signal strength was much improved, and the antenna tuned sufficiently on every HF band except 30 meters.

My installation was far from stealthy, though. While the feedline and the leg on the side of the house were difficult to spot from the street, the leg running through the air in the back yard stuck out like a sore thumb–both the wire and the string supporting it were clearly visible. And since I wanted to save this antenna for portable work, I knew I’d have to rebuild it using a more stealthy approach. So I ran over to my favorite junque store and acquired some light-beige-colored 26-gauge stranded wire, and a stop at the sporting goods store yielded some nice invisible monofilament fishing line. I rebuilt the antenna using some extra twinlead I had laying around, hoisted everything back up, and tested again with the same happy result. And now the back leg of the antenna, while still visible, is much less noticeable. Hopefully, my neighbors won’t notice that any more than the vertical that I’ve since taken down.

Up to this point, hamming from this QTH has been a struggle. Hopefully this antenna will restore more of the fun. Tonight is the Adventure Radio Society’s monthly Spartan Sprint. I’ll let you know how the antenna performs.

Bluetooth Digital Setting Circles

Dave — Mon, 31 May 2010 17:09:25 +0000

Craig Combes has taken my Digital Setting Circles project and adapted it for bluetooth! I’ve added his project description to my Digital Setting Circles pages. You can see it here.

Thanks, Craig!

Soldering 101

Dave — Sun, 09 May 2010 02:42:55 +0000

For a surprising number of folks, my Digital Setting Circles project is their first introduction to electronics construction techniques–mainly, the art of soldering. If you’ve never seen it done correctly, soldering can be an intimidating prospect. Someone asked me the other day whether there were any YouTube videos of someone constructing my project (none that I know of). That got me thinking–there must be plenty of “how to solder” videos around. So I checked, and sure enough, YouTube has quite a few of them.

Here’s one for starters:

If you know of any other good soldering tutorials and resources, leave a comment below.

Doin’ the Lindy

Dave — Tue, 16 Feb 2010 02:49:15 +0000

The parasitic Lindenblad, that is. I wrote in a previous post about how I was gathering the parts to build the parasitic Lindenblad antenna for 70 cm that appeared in an article in the February 2010 QST magazine. Since then, I’ve actually managed to build one of these beasts, and for what it’s worth, it even looks like the one in the picture in the article. My first trial with it on a good pass of AO-51 was less than impressive, though. For this trial, I used my Kenwood TH-F6A connected directly to the antenna with a three-foot section of RG-8X coax (to minimize the effect of feedline losses, which can be appreciable at 70 cm). There were moments when I had good copy on the satellite, but they were few and far between. I was a little disappointed, but I wasn’t ready to give up yet. Knowing that the antenna, being more-or-less omnidirectional, didn’t have much gain (especially compared the the handheld Arrow Antenna yagi I’d been using), I wondered if a preamp might be necessary.

I consulted with the smart guys on the AMSAT-BB mailing list, and the general consensus was that I would indeed need a preamp for best results. And then I read the last paragraph in the QST article:

On the downlinks, a low noise (1 dB NF) preamp mounted at the antenna was employed.

Duh. So, last week I ordered a 70 cm low-noise preamp kit from Down East Microwave. I’m looking forward to assembling it and trying it out as soon as it arrives. And while I’m waiting for it to arrive, I’ll be trying to repair my Samlex SEC-20 power supply. It went kaput last week. Luckily, Samlex tech support was kind enough to send me a schematic, parts list, and some troubleshooting info (let me know if you’d like a copy).

At any rate, I’ll update you on the Lindy and the preamp as soon as I have something to say.

As if “Parasitic Lindenblad” Isn’t Funny Enough

Dave — Sat, 30 Jan 2010 15:59:59 +0000

A few weeks ago I posted about a new Chinese ham radio satellite, and mentioned a couple of satellite antennas I was considering building. Just a few days later I found the latest QST magazine in my mailbox, complete with an article about (you guessed it) another ham radio satellite antenna project! This one, by AA2TX, describes an antenna he calls a parasitic Lindenblad (here’s a link to an AMSAT article). The antenna, for 70 cm, is right-hand-circularly polarized with an omnidirectional radiation pattern. This makes it well-suited to amateur satellite applications. I liked this design better than some of the others I was considering, so I decided to give it a whirl.

So last weekend I was at the local Ace Hardware store with a list of parts in my hand. This list included items like:

1/2″ x 1/2″ gray PVC insert connector
1/2″ x 1/2″ gray PVC insert-to-threaded adapter
12″ x 1/2″ threaded gray PVC riser
5″ x 1/2″ gray PVC ferrules for spacing rain gutter nails
1/8″ aluminum tubing
conductive grease

Some pretty obscure stuff, eh? I wasn’t having much luck finding the ferrules, so I enlisted one of the employees (an older guy) for some help. I showed him my list, and he squinted at it for a moment. Then he turned to me and asked, “Are you building an antenna?”

I laughed, “Yeah–how’d you know?” He chuckled and replied that another guy had been in the store recently with the same list. What are the odds of that? At any rate, he helped me round up the rest of the parts I needed, and construction begins today. I’ll post again with the results of the effort and my impressions of its performance.

New Ride, New Radio?

Dave — Sun, 10 Jan 2010 15:04:45 +0000

When shopping for a new car, a ham isn’t thinking about performance, color, or gas mileage. Instead, he’s asking himself, “Where can I put the ham radio?” It’s not that a ham will necessarily disqualify a car from consideration based on the ease with which a 2-meter rig can be installed. Rather, he looks at it more as an interesting engineering challenge–the more interesting, the better. After all, if it were easy, it wouldn’t be interesting, would it?

I certainly made things interesting for myself last week when I purchased a 2007 Pontiac G6 GT hardtop convertible. It’s quite a car–200-hp 3.5L V6 (not overwhelming, but adequate), power everything, heated leather seats, awesome Monsoon sound system with XM radio and a 6-CD changer–it’ll be nice and comfy for my half-hour-each-way daily commute.

Any mobile ham radio installation in a modern vehicle presents challenges, and this car has them in spades. Things are a little easier with today’s crop of rigs where the front panel separates from the rest of the radio (meaning a smaller box to find a place for around the dashboard), but there’s still the problem of locating the rest of the radio, routing cables, placing speakers, and slapping an antenna someplace.

Now, don’t think for a moment that I’ve solved any of these problems yet. I’m still cogitatin’ on every one of these issues. Probably the first thing I started to think about was where to put the antenna. I normally favor a trunk lid mount. But watch this video of the roof retracting into the trunk:

(Is that cool, or what?) You can see that, at the very least, routing the antenna feedline needs to be well-thought-out. And when the top’s down, there’s very little room in the trunk, so it may not be possible to mount the radio body back there. On the plus side, there’s a fuse box in the trunk, so it might be possible to draw power from it for the radio if I can find a place to mount the radio back there.

Another challenge is getting the rig’s audio into the passenger compartment. On almost all mobile rigs, the speaker is contained in the radio box rather than the control head, so if the radio box isn’t mounted inside the passenger compartment, you’ll need to mount a speaker for the audio, or perhaps make use of an aux input to the car’s sound system. In my case, the Monsoon sound system doesn’t have a built-in aux jack, but I found a cool little add-on unit from PAC Audio that interfaces directly with my sound system to provide an iPod input as well as an aux input (or HD radio input). Installing this particular unit (at least in my car) requires removing dash panels and the radio, but the result is a seamless integration with the existing sound system. I’m seriously considering one of these just for the iPod interface. You can get this unit with the appropriate wiring harness for about $130 from several places on the web–much better than the $169 MSRP from the manufacturer. Other manufacturers make similar devices, such as Axxess Interface. Another option would be to use one of the FM transmitters on the market for playing the output of MP3 players on your car radio, but they don’t appear to work that well. And any solution that plays the rig’s audio through your car sound system makes it impossible to listen to the car stereo and monitor your rig’s audio at the same time.

So I’m nowhere near actually installing a rig in my new car at this point, and I’m not even sure whether I will install a rig. It’s a pretty sweet-looking car, and I don’t want to junk it up with a less-than-optimal installation job. If I can find a way to integrate a rig cleanly into the car (and be able to take it out again without leaving any residual effects), I may go ahead and do it. If I do, I’ll be sure to post about it here.

New Chinese Amateur Radio Satellite HO-68

Dave — Wed, 06 Jan 2010 12:51:34 +0000

On 15 Dec 2009, AMSAT China launched a new amateur radio satellite, now designated as Hope Oscar (HO) 68. This satellite not only has a V/U FM repeater but also a V/U linear transponder for SSB and CW as well as a packet BBS system. This one should be great fun to work. Here’s a Youtube video giving the details:

Now I really need to get crackin’ on that backyard satellite antenna–maybe W4RNL‘s turnstile antenna (from the Aug 2000 QST), or W6NBC‘s quadrifilar helix antenna (from the Oct 2009 QST). Or maybe it’s time to concoct that servo-driven crossed yagi for auto-tracking the satellite…

Dave’s Law of Cutlery Gifts

Dave — Fri, 25 Dec 2009 20:21:23 +0000

“Recipients of gifts with sharp edges will draw their own blood within an hour of unwrapping.”

Guess what I got for Christmas!

You’d think I’d be old enough to know better by now…

Microsoft Security Essentials is, well, Essential

Dave — Thu, 24 Dec 2009 16:44:40 +0000

I confess to a general loathing of antivirus software. For many years I ran Norton Antivirus on all my computers, gritting my teeth and forking over the subscription payment every year while wondering if it was worth it. And, over those years, Norton forced me to upgrade periodically or I wouldn’t continue to receive antivirus signature updates. Every upgrade was more bloated than the last and further degraded the performance of my computer. Norton and McAfee were in such a race for market share that their products were increasingly stuffed with “features” that I neither needed nor wanted. And never during this time did Norton ever report finding or protecting me from a virus. Was all this virus business just a bunch of hooey?

A couple of years ago I reached the breaking point with Norton, and I replaced it with the free version of AVG. AVG’s performance and footprint were definitely an improvement over Norton’s, and I wouldn’t have to pay for antivirus signatures. Of course, AVG has more “full-featured” versions that you pay for, but I was happy with just some basic virus protection. And, frankly, most of the advanced “features” in security products like AVG, Norton, or McAfee are based more on Fear, Uncertainty, and Doubt (FUD) than actual need or usefulness.

Even AVG had its drawbacks, though. It definitely made my PC start slower, and it nagged me every so often to either upgrade my free version or buy one of the “not free” versions. I resigned myself to these shortcomings in the name of getting something for free. That is, until I read about Microsoft Security Essentials.

One should always view a new product with a certain degree of skepticism, but Ars Technica and others gave MSE some pretty good reviews (and, unsurprisingly, other antivirus vendors poopooed it). So I gave it a whirl.

MSE is easy to install and configure, and it does what I want and only what I want. Its footprint is minimal, I don’t notice it hampering performance (even on my old PC), and its updates occur completely in the background. Once in a while it reminds me to run a scan (I don’t run scheduled scans), but other than that, its little icon sits in the system tray and it does its thing.

MSE continues to receive accolades, and I continue to be happy with it three months after I installed it. I’ve installed it on all the PCs in my household, too. I cannot understand why anyone would buy a product like Norton or McAfee these days when there are so many free alternatives available. Don’t believe the hype from these companies that “you get what you pay for.” With the free products (at least MSE, anyway) you get what you need, and you don’t get all the other worthless “features” that Norton and McAfee would like you to think you can’t live without.

All Dressed Up and No Place to Go

Dave — Sun, 20 Dec 2009 20:36:59 +0000

I enjoy writing software when I get the opportunity. I used to do a fair amount of Windows programming for fun, and I still do some for work, but it seems to me that the days of writing code for standalone PCs are numbered. And I think that the number of consumer-oriented packages being written for Windows for the commercial market is dwindling. Have you looked on the shelves for software at computer and electronics stores lately? Except for games, the selection’s pretty slim–mainly operating systems, office suites, and malware protection.

That’s not to say that you can’t still find PC software for almost any application, but you have to look online. Much of it can be had for free, even. In fact, it’s pretty rare these days that I’ll pay for software, because I can almost always find something that’s free that’ll fill the bill. Maybe that’s the reason there’s so little of it on the store shelves.

But (news flash!) applications are definitely drifting away from the standalone platform and towards the web, for a variety of reasons. First, on the web you can profit from advertising revenues while keeping the service itself free for users. Second, so many applications have been enhanced by allowing users to interact with each other–difficult to do with software that has to be installed on a PC. Third, if your service is valuable enough, you can charge subscription fees–much easier to do when you control distribution via the web. Finally, the web is cross-platform–you don’t have to develop separate PC and Mac versions.

Especially with widespread availability of broadband, consumers are embracing the web for all manner of tasks, even to the point of doing word processing and money management online now. It’s clear to me that the future of computer programming lies in embracing web technologies. And I want to get on board.

When I took the plunge to buy my own domain name and web hosting, it took me a while to realize that not only would I now have a place to park my own HTML pages, but I could also install a myriad of ready-made web applications if they used HTML, PHP, Javascript, and MySQL. So now I use WordPress for the site you’re looking at, Roundcube for my own webmail, and Joomla for hosting a personal start page.

So, I keep thinking that it would be entertaining to see what I could write in the way of an honest-to-goodness web application. And over the past year or two, I’ve collected several books on PHP, MySQL, Javascript, and HTML. I’m actually quite the book collector–I’ve purchased many books that I still really haven’t cracked open, but I digress. In particular, I have Head First PHP and MySQL as well as Web Database Applications with PHP and MySQL. They’re both decent books. Head First PHP and MySQL is a hands-on introduction that’s very readable and entertaining, but doesn’t get you in too deep (the Head First books are all like that–I have several and I like them very much). The other book gets into a lot more detail and probably would be too much to swallow for a newcomer to the topic. But I figure that with these two books in hand, I should soon be off and running with PHP and MySQL programming fun.

The one place that both these books fell short was in helping the reader get a suitable development environment configured, meaning installing the Apache web server, PHP, and the MySQL database server on a PC and getting them all to work together. (It’s worth mentioning that it would have been possible for me to just write code and then run it on my real web server, but more desirable is to create a development environment on my own PC so I don’t have to mess with FTP’ing code to my server each time I make a change that needs to be tested.) Even for someone with some experience, like me, this turned out to be a frustrating task. Apache isn’t so hard to get going, but for some reason PHP would never install correctly using the Windows installer that’s available.

Finally, I went in search of a tutorial for getting the environment set up, and I found this one. Apparently, the Windows installer for PHP doesn’t work very well, and there are some nonintuitive steps that must be performed manually. Finally–my development environment was up and running.

Now I just need an idea for an interesting application to code. Sure, the books have examples, and I’ll probably work through some of them, but the real fun is in creating something cool and useful. So I’m sitting here, waiting for inspiration to strike me, all dressed up and no place to go. I guess I’ll go work through the sample code.