2017 Rover Rebuilt Complete

Its been awhile since I updated the blog. The Rover Rebuild is for the most part complete and works very well. For the June 2017 VHF Contest I barely put together a station for 50-1296 MHz, and the 2304 & 3456 MHz rack was the next build. The 2304 amplifier shown on the left was built from a “PyroJoe” 30W board from Ebay and a chunk of heatsink. The purple 3456 amplifier on the right was another Ebay purchase, this time a fully contained fully operational amplifier originally made for WiMAX. This amplifier has forward and reverse power detectors which is great since I don’t have a SWR meter for this band. If you saw the 902 & 1296 Rack pictures, you will see that I was not so careful this time routing wires and making things look neat.

This picture shows the antenna setup for the 222+ (August) distance contest. The 3.5G WiMAX parabolic antenna sits in the center of the setup with loopers on 902, 1296, and 2304. A small 5-element yagi on 222 and 11-element 432 yagi round out the bottom 6 bands for this event. The 5G and 10G setups are tripod mounted to the right of the vehicle. Since 5G and 10G contacts are somewhat rare, I had the luxury of sitting on my butt and simply use the rotor to point antennas. For several years I have manually pointed antennas. This method works ok on 6m and 2m, but becomes a real pain above 432 MHz. Having used the roof rack rotor in four contests now, I can definitely see how much easier it is to move through the bands. The entire roof rack system can be safely lifted and placed by one person by using the roof rack as a pivot point and placing a wooden 2×4 in the middle of the roof to prevent “additional” roof damage during installation. Perhaps someday I will add a rotor system for the hitch mounted 6m/2m antennas.

The pictures below show an example of how much neater the new rover setup looks compared to past setups. The two cables in the back of the console are for PTT switching and IF relay switching going to the rack in the rear of the vehicle. Additional connections are required for power, key extension, speaker connection, and FM antennas. The deep cycle batteries now sit in the rear of the vehicle and an inverter sits on the passengers floor area for powering the laptop and rotor controller.

The rack system has proved very useful and efficient. Its a little heavy (but possible) for one person, but quite easy to load in the vehicle with the help of my wife. The view from the rear shows the rack with the nearly bare 2304/3456 shelf, but provides a decent look at the power system. The 6V golf cart batteries are charged by the vehicle power system and the voltage booster keeps electronics happy at 13.4 – 13.8V at all times.

The system has been a pleasure to build and operate. I was finally able to reach the 100 multiplier goal I had set for myself in the September 2017 VHF contest and really enjoyed myself staying busy the whole contest. I hope that my blog posts motivate just one person to head into the garage and experience the Joy of Building !

 

VHF/UHF/Microwave contesting is all about experimenting, building, learning, and growing in a competitive environment. WINNING should be the consequence and not the goal. If you compete against yourself and use others ideas as inspiration, you will always stay motivated.

 

Rover Rebuild – Part 3-19″ Rack

One of the time consuming parts of assembling and tearing down the rover is getting everything into my car, hooking it up, connecting all the cables, and troubleshooting when I inevitably do something wrong. I start this process a couple of days before a contest and then try to take off at least a half a day before the contest to get the work done and pray that the weather is good. Other than my FM mobile radio, it’s not practical for me to leave things in my car, so what goes in must come out after the contest.

My design concept is to have a 19″ rack in the rear of the vehicle with all transverters, amplifiers, the IC-7000 body, power distribution, control components, and IF distribution. Then up front in the passengers seat I would have a box containing the IF radio, the faceplate of the IC-7000, rotor control, FM contest radios, and band switching. Between the two I would have an umbilical cord containing one IF cable, power cable, and control cable. Each end of the umbilical would have all the color coded connectors which would make it impossible to connect anything wrong. If all of this works out, the interior of the car could be built in an hour or less and testing would be minimal. Sounds good, but now to making it happen…

 The rack is a 19″ 12U molded plastic unit with rails in the front and the back. There is about 17.5″ between the front and back rails. In the picture I have set the 144, 222, and 432 amplifiers on some shelves along with the IC-7000 and a battery monitor. I dont expect the layout to look like this when done, but it gives an idea of what I am trying to do with it. The lower two shelves will contain the microwave equipment. One shelf will be 902 & 1296 while the other will contain 2304 & 3456. Somewhere in here I will need to fit the IF relay, a fuse block, and the 222 transverter.

In the pictures above is the assembly of the 902 & 1296 shelf in various stages of construction. The two silver boxes are the SG-Lab transverters, the circuit boards on the right are the W6PQL sequencers, the blue component on the left is the 902-915 band pass filter and the components with the fans are the DEMI amplifiers. By putting all connectors (except antenna connectors) in the rear of the shelf, I should be able to remove a shelf and have all the basic components self contained to allow for testing and troubleshooting.

Both amplifiers have diode detectors (amplifier monitor outputs), so I ordered the DEMI LED power meter kits. If you are not familiar with the diode detectors, they are used as a gross power indication for UHF and microwave circuits. the DEMI power meter kit will show relative power levels as it corresponds to the voltage output from the amplifier. There is also a green LED above each antenna connector wired into the relay power. Between the green LED and the power meter, this will provide a good visual indication of what is going on. In the picture I have an FM signal into the transverter which drives the amplifier to full power and the red LEDs are full scale. On SSB, the bar will move relative to the microphone audio.

I am happy with the results so far. 902 is the only band complete at this point. 1296 needs a bit more wiring, but all components are mounted. In its current state, construction took about 16 hours for this shelf. I suspect it will take another couple of hours to finish and test 1296. Next up will be the 2304 & 3456 shelf. That one will probably take a bit longer since the 2304 amplifier needs to be built.

Rover Rebuild 2017 – Part 2

My wish list for the 2017 rover rebuild:

• Rotor for 432-3456 (minimum)
• Reduce setup time to 4 hours or less
• Reduce weight of push up mast (or eliminate altogether)
• Add more power to 1296, 2304, 3456, and 5760 MHz
• Stabilize DC voltage
• Improve human factors and operating “comfort”

After searching google images for pictures of rover vehicles, I sketched out several new designs that would address the wish list items. I decided to have two antenna stacks. One would be on the roof rack for 432 – 3.4G (and maybe 5/10 GHz) and the other would mount to the trailer hitch and carry 50, 144, and 222 antennas in some sort of telescoping mast configuration. At worst, I would use my existing fiberglass push up mast for 50, 144, and 222. However for this post I will just focus on the roof rack stack and a new equipment rack.

Some of the N6NB “Toolbox” designs used a Yaesu G-1000DXA rotor. Since it also had the same footprint as the G-800DXA which might be available to me used, I decided to build around these models. I sketched out a design that had a robust 1 foot cubed structure that would house the rotor and take a majority of the force imposed by the mast and antennas. Unlike the N6NB design, mine will have a 5 foot mast with an H-frame composed of 6 foot loop yagis and a long yagi on 432.

I ordered the G-1000DXA and the Yaesu thrust bearing. I also ordered a bunch of structural grade aluminum from http://www.onlinemetals.com. After a Saturday of cutting, drilling, and filing, I was able to get most of it put together. It will be awhile before I make up the rotor cable, so I will set this part aside for now. Part 3 will focus on the the 19″ equipment rack.

 

 

Rover Rebuild 2017 – Part 1 – History

Before I get into the 2017 rebuild, please bear with me while I explain the history and motivation behind it. My interest in VHF/UHF contesting was rekindled in January of 2014 when I used a dual band HT to make a few contacts in the contest. I setup a portable station in June of that year with limited success and then started roving in August. I have been learning more and growing my station along the way. I once thought I would never expand beyond 1296 MHz. Then I added 2304, but “promised” myself I would go no higher. Well, I have 10 bands now and it has been put together in piecemeal fashion. Since I never thought I would be a 10 band rover, I never really constructed the system to accommodate all of the equipment in any logical manner. My 2015 rover had everything in the passengers seat of the car (including the batteries and amplifiers on the floor). The antenna system was haphazard. 902 and 1296 were end mounted yagis that pointed in opposite directions and the 2304 loop yagi was mounted separately and could only be turned by moving the car. There was no rotor so everything needed to be turned by hand. Working a station from 432 – 2304 was a nightmare. But it worked and I was making contacts, so I was happy.

In 2016 I decided to make several changes. I purchased an IF radio (FT-817) for use with all the transverters, freeing up my IC-7000 to operate on its native 3 bands. I added 3456, started bringing my portable 10GHz system with me and mounted all new microwave antennas on an H-frame so that everything could point in the same direction. I still used the manual “armstrong” method of rotation, which was getting a bit tiring as I ran back and forth peaking on signals to line up microwave contacts. I added wood shelving and downsized the top-heavy rack in the passengers seat moving batteries, amplifiers, and some transverters to the back of the vehicle. I swapped the very large 1296 base station radio with a much smaller transverter and upgraded the 2304 transverter as well.  I noticed that my score was starting to rise quite nicely with all the new bands. Along with my score, my anxiety was rising while my energy seemed to be plummeting by the end of a contest. The antenna structure was becoming too heavy for me to deploy multiple times a day and was pushing well beyond the design limits of the fiberglass mast.

While I have been able to take off of work the day before and the day after a contest for setup and tear down, I can imagine a day might come when I can’t or won’t want to. I promised myself that after the January 2017 contest, I would tear everything down and start over, no matter how long it took to rebuild. Knowing what was to come I was able to maintain my sanity during the January 2017 contest. Every square inch of shelving was now full and things were getting quite annoying. To change bands, I had to switch the IF frequency, rotate the PTT switch, rotate the RF switch, get out of the car to move the antenna, get back in see if the signal improved. To move to 3456 I had to move into the back seat, swap the IF cable, and power cord for the transverter and wait for it to warm up. Never again…

You are welcome to follow along as I go through a whole new design and attempt to build the rover from scratch… The right way (if there is such a thing)

 

 

10 GHz Station Progress

Everything is all wired up and has been powered up. All the right voltage in all the right places! Now just need an on the air test to make sure it does what it is supposed to do.

As an enhancement, I would like to have a pipe mount added to the back of the box. It could be used as a mast mount, or add a short piece of PVC mast for a liaison antenna while tripod mounted. Always something else to do!

Mobile PSK31 on VHF/UHF

I have a fairly small vehicle as far as rovers go. Its a Ford Edge which is more like a car than it is a SUV. The so called “cross-over” style. I know folks have done more with less, but I keep trying to cram more in. Over the past week I worked on adding a laptop capable of digital modes such as PSK31 (and eventually WSJT). I have used PSK31 extensively on 20m, but only a handful of occasions on VHF. My normal software is Ham Radio Deluxe (HRD) installed on a desktop PC. While not overly expensive, the software does have a pricetag. However I know there are many free alternatives, so I decided to give FlDigi a try along with FlRig. FlRig works as an interface for rig control. This allows FlDigi to know what frequency the radio is on. It also allows me to save configurations for the radio, like microphone gain, power, volume, frequency, etc.

My interface between the radio and the PC is a RigBlaster Advantage. It is powered by the USB port of the computer, which proves helpful in a mobile configuration. In the picture, you can see it just sitting in a radio bracket at an angle unmounted. The connection to the radio is made through several cables. One controls the radio, another connects to the rear microphone port on the radio, and a third brings audio back from the the radio auxiliary port to the RigBlaster. All of this can be home made, but the simplicity of the commercial product was worth it to me.

Once the RigBlaster was selected as the soundcard on the PC, everything worked well. My first contact was with WB2GFZ and we had a good QSO on 6m.

 

Building a Lightweight 10 GHz Portable Station – Design/Procurement Phase

The 2014 Microwave Update Conference in Rochester , NY sparked an interest in 10 GHz operation. I have very limited experience on this band, but in high school I built a pair of gunnplexer based radios using a couple of FM broadcast receivers. That was fun, but they were of limited use with homebrew horn antennas and the few contacts made were line of sight, where I could literally see the other guy I  was working at a distance of maybe 0.5 km. So the thought of contacting someone I did not know at distances of over 100km seemed intriguing. I sat on the thought for a couple of months.

In a separate line of thinking, I started to consider VHF/UHF portable operation again. I made an attempt at “portable” QRP operation in June of 2014, my first major VHF contest attempt. While the setup was certainly QRP and it was not located at a permanent station, it barely met the definition of portable. It took a separate U-Haul open trailer to carry everything and no less than 90 minutes to set everything up. I have learned a lot since then and now recognize that location is one of the most important factors to be considered. What if I could carry an entire VHF/UHF station literally on my back and hike to whatever location I wanted to operate? What if I could setup in 15 minutes or less? Given my start with over 100 pounds of gear, I would have to start my design from scratch.

Now back to 10 GHz. My design goal is to be able to make a 10 GHz station that can be tripod mounted with an integrated liaison system, mast mounted for rover or fixed station use, and portable enough to be carried on a short hike. If built with flexible features, the station could be transformed in one format for QRP portable operation, another setup for rover operation, and a third setup for 10 GHz contests and experimentation.

WIth these goals in mind, I started system design and purchasing of components. Those delivered so far are shown in the picture above. I have the Kuhne Electronic 200 mW transverter, a 2W power amplifier, and a coax switch. I have acquired an FT-817 QRP HF-70cm radio and an open frame backpack. The biggest challenge so far has been a lighweight antenna. The Procom 48cm model seems perfect weighing in at under 3 pounds, but it has been difficult to purchase.  A company in Germany seems willing to ship to the US, so I will see how it works out. In the meantime I have a NEMA 4 rated aluminum enclosure on backorder. It has a similar foot print to the cardboard box, but will be a bit taller. The empty space will be reserved for a future 10 MHZ GPS disciplined oscillator. I quickly went overbudget with the addition of the FT-817, so the oscillator will have to wait.

I hope to begin assembly at the end of March and have the tripod version of the system operational in April. In parallel, I will try to design a mount for the backpack and assemble a QRP system that I might consider using in June. Although these are my plans, in this hobby nothing ever happens exactly as planned. I will post some updates as I make progress.

73,

Jarred – KF2MR

A January to Remember – 2015 January VHF Contest

So I got stuck in a ditch 40 minutes before the contest. Digging out and trying to have N2QIP/R pull me out (with jumper cables?) didn’t work (go figure). This left me frustrated, N2QIP/R behind schedule and the jumper cables completely shredded. So as I waited for the tow truck (the only one in 40 miles) to pull me out, I was still able to get the first QSOs in the log starting at 1900 on FM. I had a 20 minute gap in the log as the tow truck got me out and I put up the antennas. I was soaking wet and cold, but at least the contacts were rolling in. I must have been having a good time because I didn’t notice the ice storm at first. By the time I was ready to leave, there was about 1/8 inch of ice on the west side of my vehicle, my antennas, coax, and … my mast. A push up mast does not come down when covered in ice (strange huh). How much worse could this day get!? After taking the hammer to the mast for about 15 minutes, I thought about that question as I headed down the very steep snow and now ice covered road. But I guess a higher power felt my day was bad enough and let me get off this hill without further incident. This all occurred on the “warmer” of the two days with Sunday dropping into the teens. I still finished the four grids I planned to activate and had a great time doing it. Will I do it again? You bet!

FM activity was booming this January. 146.550 was the busiest frequency in the area. At times it seemed impossible to get a word in, trying the patience of others trying to use the frequency. I also found activity on 146.58 and 446.1 when trying to find alternate frequencies to use. Although I did not track contacts by mode, I know for sure that well over half of all of my QSOs were made on FM, including all of my 33cm and all but one of my 23cm contacts. I even heard people calling CQ on 223.5 and 446.0 and having others respond, which is somewhat rare to hear. It was great to hear a canadian rover work a 15 minute pileup on 146.55 and then run many of the stations through 223.5 and 446.0 from FN14 and later in FN04. These two grids helped many of the FM crowd rack up some late gains in their scores if they stuck around.

Results

   Band   QSOs    Points  Unique Callsigns    Grids

• 50        54           54            34                             7
• 144      80           80            48                            12
• 222      36          72             17                              8
• 432      51          102           28                              7
• 902      11          44              3                               4
• 1296    11          44              4                               4
• Activated                                                              4

396             x                              46 = 18,216

 

Multi-Band CW Beacon with HackRF One

The Microwave Update conference in Rochester was a great time. I admit that some of the formal topics were a bit too much for a newbie to grasp, but the conversations in the hallway and hospitality room were worth the price of admission. I was introduced to Clayton Smith by Ryan Tucker. Ryan was aware of what I was trying to do with the HackRF and knew that Clayton would be able to help. Clayton had developed a GNU Radio Companion file that contained transmitters for pretty much all the modes. By extracting out the CW transmitter and only including blocks that were absolutely necessary I was able to make the flow graph shown below:

So how does this work? The Vector Source contains a pattern of 1’s and 0’s that match the pattern of the international morse code for the letters being sent. Dits are represented by a single 1 and a Dah is represented by three 1’s in series. Spaces between the dits and dahs of a character use a single 0 and spaces between characters use three 0’s. So the letter V is represented by “1,0,1,0,1,0,1,1,1” and the first two letters of my callsign are represented by “1,1,1,0,1,0,1,1,1,0,0,0,1,0,1,0,1,1,1,0,1”. Since a series of 1’s and 0’s can be processed so fast that its not audible, each piece of data is repeated 5000 times. The speed of the morse code can be changed by adjusting the repeat interpolation value. This is multiplied by a cosine wave to provide something resembling an analog signal and then “upconverted” to the sample rate compatible with the hardware. When executed, the GUI chooser provides the following options:

So far, testing on 6m and 2m has turned out just fine. Close range testing produces a subtle carrier at all times followed by the full scale carrier when the HackRF is “Keyed”. However when 100′ away from the transmitter, the low level carrier is not noticeable. Next steps will be some mobile testing of range on different antennas.

Others familiar with SDRs might comment on my lack of filtering. While Clayton had filtering in his flow graph, I don’t know how it works. My overall philosophy has been to use the simplest flow graphs possible. So I deleted many features I cannot yet explain, and everything still works. As I learn more I am sure I will eventually figure out filtering. Until then, I have something that works just fine for my simple experiments and testing.

Transmitting on HackRF One 6m – 1296 FM

Last week, I was able to get HackRF One receiving using SDR Sharp software. This week my goal was to start transmitting. I wanted to get through the tutorials on GreatScottGadgets.com, but one of the first challenges was getting a Linux operating system up and running. This was easier said than done. The Pentoo derivative of Linux downloaded just fine, but I could not get it to load the .iso image on the USB drive, no matter how it was formatted. I went to Target, bought a stack of DVDs and another USB disk. The new USB disk worked just fine and I was off using Pentoo. Or so I thought. With so little knowledge of Linux, I wasn’t able to get GNU Radio Companion installed. But with the new knowledge of setting up a bootable USB, I downloaded the .iso file from the GNU Radio Companion website, which included a different Linux OS (Ubuntu). http://gnuradio.org/redmine/projects/gnuradio/wiki/GNURadioLiveDVD (Warning: All work done under the USB boot will be lost when your computer reboots. Save your files to the hard drive to avoid losing work. I speak from experience)

One of the great things about open source concepts is the willingness of the community to post their solutions. With that in mind, I searched for examples of transmitter flow diagrams made in GNU Radio Companion. After completing the “homework” of creating the FM broadcast receiver, I thought I was ready to move on to transmitting. I copied examples I saw on the internet, but they did not work. The HackRF One would transmit on frequency, but the audio was not understandable. I guess completing one tutorial did not make me an SDR expert 😉  After completing more lessons and doing more reading, I recognized that I probably had sample rate mismatches in my flow graph.  My point here is to share the FM transmitter flow graph, not get into theory. However there is a vast amount of theory behind sample rates.

In the above flow graph, the Wav source produces a morse code file “KF2MR Test” which repeats a couple of times, provides the option of changing the amplitude, then goes through the Narrow Band FM Modulator. The signal is then resampled to a rate compatible with the hardware. The FFT Sink produces a visual display of the FM signal as shown below. A slider is linked to the audio gain (Multiply Const) block and a frequency selection interface is linked to the Osmocom sink (HackRF driver). One block that is disabled is the Audio Source, which will use the laptops microphone. This is usually where the audio gain comes in handy. When the flow graph is executed, the following user interface is shown.

After working for nearly 4 hours to create this transmitter and losing all of my work (See USB Boot Warning above), I decided to install Ubuntu and GNU Radio with HackRF libraries. This process was very challenging and I was very surprised when it all worked. Re-Creating the transmitter was much quicker this time and I was able to simplify the flow graph to remove some blocks that did not do anything useful. But having to do all of this again is why the post is coming out on Monday instead of the weekend.

I started with the Narrow Band FM Transmitter to learn the software, but one of my goals is to use the HackRF as a temporary beacon for testing. However the NBFM will provide a simpler demonstration (than my intended CW transmitter) at the upcoming Rochester VHF Group meeting. If you are interested, please plan on attending October 10th meeting of the Rochester VHF Group. You can find more information on www.rvhfg.org.