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.

Here’s one for starters:

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

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.

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.

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.

]]> http://eksfiles.net/2010/01/new-ride-new-radio/feed/ 0 http://eksfiles.net/2009/05/sena-bluetooth-adapters-with-digital-setting-circles/ http://eksfiles.net/2009/05/sena-bluetooth-adapters-with-digital-setting-circles/#comments Mon, 25 May 2009 15:07:31 +0000 Dave http://blog.eksfiles.net/?p=202 Eddie from Australia wrote me recently to tell me about his success using a serial-to-bluetooth adapter to connect his Digital Setting Circles board to his laptop (avoiding the serial cable which is an obvious tripping hazard, especially in the dark during an observing session). Eddie is using the SENA Parani-SD 200 serial-to-bluetooth adapter connected to the DSC board, and the SENA Parani UD100 USB-to-bluetooth adapter with his laptop.

Eddie wrote:

Dave,

I have finally managed to get the Bluetooth connection working with your interface and Cartes du Ciel. I will let you know what I had to do and the setup I’m running so that you can let other people know if you get asked the question.

Program: Cartes du Ciel
Serial Bluetooth adaptor: Sena Parani SD200
USB Bluethooth adaptor: Sena UD100

Information for the Bluetooth adaptors can be found on www.sena.com

You have to plug the SD200 into a computer with a serial port in order to set up the adaptor. The adaptor gets set to mode 3 with command response set to on. Using the Dip switches on the SD200 the Baud rate and flow control can be set to 9600 and off respectively, the other parameters are set at the factory and cannot be changed. When connecting the Bluetooth adaptors the UD100 will need to be forced to operate on one of the local com ports i.e. 1,2,3…. etc so that it can work with your interface.

Then I had to make up a null modem serial adaptor between your interface and the SD200 adaptor. Pins 2 and 3 have to be crossed over in the connector and 5 is straight through. Cartes du Ciel doesn’t like handshaking and therefore the remaining pins must be left off or the tracks on your PCB have to be cut.

Once all of this is done your interface works very well and the laptop can be setup remotely from the scope so that wires aren’t being tripped over or having to attach your computer to the scope itself.

I hope that this information will help you and any other Astro nuts out there setting up their interface with a Bluetooth connection.

Thanks, Eddie, for passing on that information.

I’ve heard of other users who’ve successfully used similar devices, especially those from AirCable. I don’t have any personal experience with any of these devices, but they’re an occasional topic of conversation in the Yahoo Groups’ PalmAstro group. I’d welcome any and all reports of other bluetooth adapters being used with my DSC system–just leave a comment below.

If you’ve used another enclosure and liked the results, leave a comment below and tell me about it.

Jimbo Harris actually adapted my decoder circuit to USB using a special cable from DLP Design. Jimbo was able to eliminate the MAX232 chip and the DB9F connector that way, but the net cost of the circuit was probably higher despite eliminating those parts. All the special cable really does is to make the USB port look like a serial port to the computer. There are plenty of commercial devices on the market that will do just that.

I’ve been told that USB-to-serial converters vary in terms of how well they work, which I find surprising. As far as serial interfaces go, the one in my decoder circuit’s about as simple as they come. It only runs at 9600 baud and only uses three serial lines (TX, RX, and GND) because it doesn’t use any hardware handshaking. There’s no twiddling of the lines at the hardware level. It really can’t get any simpler. It seems like, if a USB-to-serial converter works at all, it should work with my decoder circuit.

Are you using one of these USB-to-serial converters with my DSC circuit? Or perhaps with something else? If so, please leave a comment below and tell me about your experience. I’m going to experiment for myself here shortly–I ordered a $6 converter from Ebay (it’s hard to get cheaper than that, eh?) that I’ll try and post my results. And maybe I’ll consider doing a long-overdue update to my decoder circuit (but don’t hold your breath–it’s really hard to find the time for that kind of project these days).

Okay, he’s a high school teacher, so fortune might be a bit of a stretch. Nevertheless, he’s earning his own paycheck, paying his own bills, and putting his own food on the table. One of his parting gifts from me was the title to my 1994 Ford Escort. He’d been driving it around at college for the past four years anyway, so I certainly wasn’t going to miss it, and it had been a good car.

Of course, one of the first things to eat out of his initial paychecks was–you guessed it–car repairs. His front brakes needed to be done, and he needed new tires.

He’s teaching in a little town in western Kansas, about four hours’ drive from me, so he’s been a frequent weekend visitor, and one weekend he decided he’d get the brakes, tires, and an oil change done at the shop I’ve been using for years here in Colorado Springs. A few hours and about $475 later, we went to pick up the car at the shop. The guy at the front desk was kind enough to point out that the clutch was in need of replacement (my son confirmed that) and gave us a $711 estimate for that work.

Well, I got to thinking about the clutch, and whether it made sense for him to drive a car with a bad clutch back to Kansas. Finally I offered to let him take my ’97 Pontiac Sunfire for the week and I’d get the car back into the shop for a clutch replacement. So that’s what we did. I drove his car back to the shop on my way to work Monday morning (and learned that his clutch was indeed in bad shape), rode my bike the rest of the way to work, and then picked up the car again on my way home that evening.

The good news was that the clutch replacement was successful.

The bad news was that the speedometer no longer worked, and the “check engine” warning light was now on.

I dropped it back off at the shop on Wednesday morning for them to fix the speedometer. I figured they’d forgotten to hook up a sensor or something, and that would be why the “check engine” light was lit, too. They called me later that morning to tell me that the speedometer cable was broken.

“Since the car’s got 120,000 miles on it, the cable might have broken on its own,” the guy told me. “But my mechanic might have broken it during the clutch replacement, so we’ll go ahead and take care of it for you. The problem is that we can’t get a new cable until Friday, and since the dash is completely disassembled right now, we’d like to just keep the car until then.”

I gave them the okay for that. Being short a car would require a little car juggling for everyone in the family to get where they needed to be, but I could manage that.

When Friday came, the shop called to tell me that the car was ready. I picked it up after work and drove it home.

The good news was that the speedometer worked again.

The bad news was that the “check engine” light was still on. Rats!

Out of curiosity, while the car was in the shop I’d been rummaging around on the web to see if the speedometer not working could be the reason for the “check engine” light being on. I didn’t find anything definitive. What I did find was that it was easy to read the trouble codes from the computer on this particular car. The only equipment needed was a jumper wire and an eyeball. Being an older car, it uses OBD-I codes, and by connecting two test terminals with a jumper, I could read the codes as they were flashed on the “check engine” light. Cool–especially since I knew the shop would charge me at least fifty bucks to read the codes for me.

I wanted to wait until my son returned before trying to read the codes, so on Saturday morning I decided to give the engine a once-over to see if there were any obvious reasons why the idiot light was still on. One thing I noticed immediately was that the oil was about a quart low, and it was also dirty. Knowing that my son had paid for an oil change the previous weekend, it was pretty clear to me that he hadn’t gotten one. When he arrived, we took the car back over to the shop and pointed out their error. They were suitably embarrassed and took care of the oil change for us.

So, let’s recap:

1) Shop is paid for tires, brakes, and oil change.

2) Car returns to shop for clutch replacement.

3) Shop breaks speedometer cable while replacing clutch.

4) “Check engine” light is on after clutch replacement.

5) Shop fixes speedometer. “Check engine” light is still on.

6) Shop does the oil change they failed to do the first time.

Now, to their credit, the shop never gave us any flack about fixing the speedometer cable or doing the oil change. That’s one of the reasons why I’ve taken my cars there for so many years–they’ve been honest and taken care of mistakes when they’ve happened. But my patience was wearing thin, and we still had the “check engine” issue.

While we were waiting for the oil change to be done for real this time, my son and I went over to the auto parts store and picked up a Haynes manual for his car. The information on the web about reading codes and what they meant was a little sketchy, and the manual was much more complete. When we got his car back, we gave it a whirl and tried reading the codes. It took a couple of tries before we really understood what we were seeing, but eventually we got a single code:

172: Lack of Heated Oxygen Sensor (HO2S-1) switches, indicates lean (Bank # 1)

Unfortunately, the manual didn’t really give us much of an idea about what to do about this particular condition. Neither did a web search, although I did find some information on the web that suggested replacing the PCV valve and inspecting the hose that feeds it. We ended up replacing the valve and those (for less than $10), but that didn’t take care of the problem.

The weekend was over before we figured out how to fix this problem, but the car was running fine so my son drove it back to Kansas. I continued to search for useful information on the web, and I gradually came to the conclusion that it would probably make sense to replace the O2 sensor. My son was coming back in a couple of weeks and he told me he’d like to get it fixed, so when he arrived we went out and bought a new sensor ($45!) and prepared to install it.

Job one was to figure out exactly where this sensor was. The Haynes manual wasn’t clear on this, but we’d gone to the library to pick up a Chilton manual for the car, too, and it showed that the sensor was located on the front of the engine. So, I prepared to remove the sensor (it wasn’t going to be easy because there wasn’t a lot of room for a wrench). First, I needed to disconnect the cable from the sensor.

You know what happened next.

I found that the sensor was already disconnected. Doh! and Yessss!!!

That was obviously the reason why the “check engine” light had been coming on. And it meant that we wouldn’t need to replace the sensor. My son returned it the next day, and the guys at the parts store laughed when he told them the story.

After a few minutes of searching, we figured out how to reconnect the sensor, and that was the end of the “check engine” light being illuminated.

I’m at a loss to explain why the sensor was disconnected. It doesn’t seem like the kind of thing that would need to be done during a clutch replacement, but I could be wrong. Or, maybe the mechanic did it on purpose so that I’d have to bring the car back in for more work. I just don’t know.

What I do know, though, is that I had fun working on my son’s car. I had long ago stopped doing my own car repairs when I got rid of my old ’70 Ford Torino. Cars had just gotten too complicated, I thought, and I wasn’t really saving any money by doing my own oil changes. But I discovered that I missed puttering around with cars, and I also discovered that with the right information, even modern cars are accessible to the weekend mechanic. And now it’s easy to recycle things like used motor oil because many of the auto parts stores will do it for free.

Finding a reputable auto shop and getting repairs done right seems to be a real crap shoot these days. I’m pretty sure that my relationship with this particular shop is over, and since I have a nice big garage and plenty of tools, I think I’ll be doing more of my own car work from now on.

The KTS1 uses 10-32 thumbscrews to attach to the K1 (the stock K1 has the holes for the screws already in place). I decided to use a strap of aluminum and a couple of thumbscrews to make my own stand.

I found suitable thumbscrews (actually, knobs) and a 1″ wide strap of 1/16″ aluminum at Lowe’s for a total of about $10. I cut and bent the aluminum to make a U-shaped handle that can swivel around the back of the K1 (acting as a handle), and then I added an extra piece of aluminum on the bottom that swivels out to stabilize the stand:

I fastened the swivel piece to the rest of the stand using a pop rivet, but any number of methods could have been used. I also used a thin nylon washer between the two aluminum pieces, and between the stand and the K1, to minimize scratching the metal. The only other things that I did were to use a metal snips and a file to round the ends of the aluminum, and to give it a couple of coats of Krylon satin black spray paint. No one who knows me would confuse me with a master craftsman, so if I can build it, so can you.

If I were to build another one, I’d consider using heavier aluminum. The one I built will wobble slightly due to the thinness of the aluminum, but it’s a very minor issue. Overall, it seems plenty stable, and it’s extremely lightweight.