If you have been working with Arduino boards, you may already know about this great little board. The Arduino Pro Mini is about 1.7″ X 0.7″ in size. It has the normal 14 Digital I/O lines and several analog inputs as well. The one thing you need to know is that you must have a Pro Mini Programming Cable for this board. These cables convert USB to Serial I/O and provide a 6-pin header that connects to the Pro Mini when you are downloading or debugging.
Spark Fun is the designer of the Pro Min. There are also some “knock-offs” out there that are even less costly. if you look around, you can find these Pro Mini Arduino boards for under $ 5.00. These are great for an embedded project. I am using one to design a USB interface for my DX Doubler 2-Radio Controller box. It almost fits inside a D-sub connector backshell. I am using a small Ethernet port box to house mine. It makes for a nice small platform for various Micro Controller projects.
There are a few things to be careful of with this board. There are 3.3V and 5V boards, so you need the right voltage on your Programming Cable. The programming cable is also not cheap, but you only need one and they have a genuine FTDI chip, so they are reliable and very flexible using the FTDI driver and configuration software. Beware of cheap FTDI imitations. If you buy one, there is no guarantee that your FTDI driver software will work. There are also different pin-outs and different clock speed version available.
Pro Mini boards come with headers for the programming cable and the I/O pins. Some sell them already installed, others make you solder them in if you want them. They are easy to install, so this is no big deal. My one minor complaint is that this board has no mounting holes. That makes it a challenge to put into a chassis, but the board is so lightweight that you can use a cable tie or some double-sided tape to put in wherever you want to mount it.
I mentioned varying pinouts. If you are just using the Pro Mini on the bench, the only issue is that you may need to reverse the programming Cable on some versions. If you are planning to put an Arduino Pro Mini on a circuit board, you need to be careful to use the correct pinout for the devices you buy. I am currently using PCB123 to layout a PC Board and plan to build a footprint that will be compatible with both pinout versions I have seen. This will let me keep my costs down by purchasing whatever version is the cheapest when I am ordering.
The pro Mini is a great little board. Buy a few and have some fun. You might be surprised at what you can do with them.
I just saw on the ARRL LOTW Web Page that they have processed my application for the ARRL Triple Play Award. I do enjoy Contesting but otherwise I do not spend much time chasing awards. The Triple Play Award, if you don’t know, is for confirmed contacts with all 50 States on CW, Phone, and Digital modes. I like to bug other Hams to get on the Air and make some contacts. This shows I am at least making an effort to use the Bands and try the various modes. I will be glad to have this award hanging on my Wall. Congratulations to the other 1,747 Hams who have received the Triple Play award.
The 2nd prototype of the DXDUSB Interface has been completed. I ran it hard through the recent NAQP CW contest, and it did very well. Now it is just a matter of finalizing the software (of course software is never really “final”). Here is a look at the 2nd prototype
Next i will be designing a custom printed circuit board for the interface. This has been a fun project so far. The final product will allow me to use my DX Doubler SO2R controller box with a USB interface, without spending a fortune. This will make it possible to use the great DXD controller with any computer. I may use it with a laptop when I go on my annual VA QSO Party mobile trek in March. Full details of the DXDUSB project will continue to be posted to the SO2R page on this site.
After a weekend-long CW contest at my Home, I jumped into my Ford F-150 to head out, and it was acting very strange. It seemed like the automatic transmission was dead or dying. I knew it was a little touchy going into 2nd gear at times, but it had been working just fine when I parked it for the weekend. I thought my week was ruined and I would have to call for a tow of my truck for an expensive transmission repair.
As I headed out of the driveway, shifting was still awkward. Then I noticed that as it changed gears, the dash display still said I was in 3rd gear. Once I saw that I knew something was fishy. So I went back to the house. I went through a couple power on-off cycles and things started to change. The dash display went nuts briefly, but then it started to come back to normal.
Seeing this change in behavior made me finally realize what had happened. I had parked the truck with its HF rig and screwdriver antenna right under one of my wire antennas, a ZS6BKW. The tip of the truck’s HF whip was directly under the antenna and only about 20 feet away. My guess is that there was RF coupling between the Home antenna and the wiring in the truck. As a result of the RF, some computer memory in the truck got corrupted. Eventually the vehicle must have loaded some historical or factory settings. After that, all was well again.
So now, when I park near the Home HF antennas, I remove the whip from the truck. I plan to do some more RFI mitigation soon, but for now this seems to have solved the problem.
I recently completed testing of the first prototype of the USB interface for DX Doubler using N1MM+ software. This was a rough prototype, so it isn’t pretty but it does seem to work fine. It currently handles RX and TX Focus, and STEREO for listening to both radios at once. There is an FTDI chip-based USB –> Serial converter that allows the interface to fully support PTT and CW keying on the single Serial port that is configured. I just need to add the BAND Data support. The interface uses the Open Two Radio Switching Protocol (OTRSP) that is used by several other SO2R Control boxes. This protocol, created by K1XM who generously shared it with the Ham Community, is supported by N1MM+ and several other Contesting Software Applications.
I used a cut-up LPT cable to connect the DX Doubler box to my interface. The interface uses and Arduino Board. In the photo, the Arduino is still tethered to the PC for power and uploading of Code. But there is no LPT and only the USB interface is now configured in N1MM+. I used an Intronix Logic Analyzer to scan all the data lines before connecting to a rig. Here is a shot of the Logic Analyzer screen.
Remaining work is making a 2nd prototype on a perfboard and testing with both radios.
I was recently reminded that I can use my 80 meter Dipole antenna to get on 160 meters. I have heard that in the past, but thought it would be shaky, narrow-bandwidth, RFI problems, etc. Well I recently acquired a MFJ-927 remote antenna tuner so I thought I would give it a try. There was a contest the following weekend and I thought 160m would be good to try in the late evening.
The suggestion made to me (by K7SV) was to tie the two ends of the dipole together. That becomes the center conductor on my Tuner Antenna connector. I drove a ground rod near the remote tuner, and used that as the ground at the antenna connector.
This tuner uses 12 volts DC which is supplied through the coax using a Bias Tee. To Tune the antenna, I applied a low-power carrier using the AM Mode on my Icom-7600. This worked quite well. SWR was between 1.4:1 and about 1.9:1 across the CW portion of the Band. Since the tuner was at the end of my ladder-line feeder, it took care of the mismatch there, minimizing losses in my coax. I also had zero RFI problems, probably because the last 50′ of feedline to the shack was the coax.
Since this was a CW contest, I did not need a big signal to make contacts. I think I worked about 25 states in just a few hours. I plan to give it another run in the upcoming Stew Perry 160 meter contest this weekend.
On the day Before Christmas I was told of the passing of Jim, KG4YLZ. Jim was one of those people you just enjoyed seeing and talking with. He never had anything bad to say about anyone, and he always seemed genuinely interested in what you were up to in the Hobby.
Jim was an active CW OP. I remember him talking of the fun he had in the CW Fox Hunts. He introduced me to the Palm Mini Paddle for CW, which I found so unique that I had to get one for my Mobile/portable operating.
Just wanted to pass along my final 73. Rest in peace Jim. We will all miss you.
I have been using the DX Doubler (DXD) by Top Ten devices as my central Station controller. This box is widely known as an SO2R box for Contesters using two radios, but it is a great solution for anyone with two radios who wants to use a single Mike, Headset, Keyer, etc. Instead of buying a radio with two receivers, I bought a second complete radio and this box. Total cost was probably not much more and if one radio dies, I am still on the air.
In case you haven’t noticed, most PCs no longer come with an installed connector for a Parallel (LPT) interface. For those of us using the DXD, I see there is a Universal USB-to-LPT converter available and I have heard this will work with the DXD box. Last time I looked, these were over $100.
I am investigating a dedicated interface for N1MM+ software and the DXD box, using a small Arduino computer with USB to connect in place of the LPT interface. This approach provides more control over the DXD box, perhaps allowing me to add some customization to the features. The USB interface will include lines for CW Keying and PTT. If anyone has already done this, please let me know. If not, and you are interested in what I am doing, let me know that as well.
I attended a Meeting and Food Fest at the NR4M “Goat Farm” today. This is the location of an incredible Multi-Multi Ham Station like nothing I have ever seen before. It is one of the Flagship Stations of the Potomac Valley Radio Club PVRC, which I joined last November. There was a great bunch of Hams there, great weather, lots of food, and drinks. Hard to beat that.
There were a couple SO2R Demonstrations provided. This was very interesting to me, as I have an SO2R station and have been trying to learn how to utilize it to advantage in Contests. One of the presenters started by saying “when you first start using SO2R it will REDUCE your scores”. That was certainly true for me. I think I am at the point where it is helping me, but I still have a long way to go to really benefit.
The presentations were eye-openers. Serious Contesters devote a great deal of effort to shaving seconds off of each QSO. In a contest where you might have 500 – 1000 QSOs (even more in some cases), the seconds add up. Bottom-line, if you want to be competitive in Ham Radio Contests, you have to be obsessed with those wasted seconds.