Welcome back, readers! It’s been almost half a year since I last penned some radio notes for you to go over, and it’s been a busy year! We’re almost on the doorstep of the winter holidays, and I’m looking forward to a wonderful Christmas season this year. At KK4TSJ, we’re settled it at our new station and getting comfortable with HF and VHF operation.
I wrapped up the first version of the KK4TSJ HF/VHF base station on July 4th, 2014. I’ve got a Yaesu FT-897D with an integrated LDG AT-897Plus as the primary transceiver and a Tigertronics Signalink USB audio coupled sound card modem to integrate with Flrig/Fldig/Flmsg and other ham software. I’m still relatively inexperienced with digital radio modes, but I have had some success decoding CW and PSK31 on the 40 meter, 30 meter, and 20 meter bands so far. One day I’ll learn to copy CW by ear, but atleast I have a tool to fulfill that use case for me in the meantime.
The radio is solid, and it’s taken some work to get the station in a station that I’m getting more than static, and it has definitely been worth every hour of effort. Much more can be done, but I’m beginning to understand that maintaining a radio shack is like maintaining a vehicle and requires constant attention and maintenance and attention to detail. It is remarkable that I now have the capability of communicating with people worldwide thousands of miles away, and I never cease to be amazed by that fact!
I won the FT-897D on an eBay auction from a gentleman from California, and it came with many frequencies with calls from the San Francisco, Palo Alto, and Stanford areas. I saved a copy of the original channel programming with the memory clone mode in Chirp and began to program my Georgia frequencies. I have since found that the CAT (computer aided transceiver) support in hamlib (what Flrig et all make heavy use of) is lacking in a few areas, but it’s perfectly workable. The CAT SWR meter read out is very coarse, but there does appear to be some unpublished specifications of the Yaesu SWR meter reading message that aren’t fully implemented in hamlib that could be added. I haven’t had the spare time to code in support or understand hamlib well enough to add it, but I hope to change that circumstance over the coming holidays.
Well, the interior of the shack is only half the equation! Every ham worth his bacon knows that your radio doesn’t work without an antenna. From GoVerticalUSA, I picked up some four foot military surplus green aluminum mast sections from, a ground stake and plate, some vent mount mast clamps, guy rings, rope, and lots of coaxial feed line. This part was definitely the most difficult, and I had to erect the mast with only 10 of the 12 sections to be able to mount it stably with the HF antenna hanging off the side. The Wireman has some better ladder line standoffs, but I didn’t have the time to get an order out before I wanted to raise the mast, so I made some standoffs from 1/2″ schedule 40 PVC sections with u-bolts from the local hardware store to get it going quickly. I didn’t have a decent ferrite bead for the feed line, either, so I just coiled up a quick ugly balun.
I’m noticing that the compromise for the ugly balun narrows my bandwidth on the 70 centimeter band quite a bit to the point that the band edges trigger the transceiver’s high SWR power fold-back circuitry. I doubt that would happen with a basic 0.5″ diameter mix 43 ferrite bead in the same place. The lack of decent ladder line standoffs (or an HF antenna hung from a tree instead) tends to pull on the mast in the direction of the ladder line.
The VHF/UHF antenna on the top is a Comet GP-3, and it’s a 5/8 wave 2 meter antenna on top of a 1/4 wave 2 meter antenna. It works on UHF, but not very well, but I can get the MATPARC and W4QO UHF repeaters near me just fine. As for VHF, it is superb and I’ve been able to work simplex with Archie, KK4EQB, on 2 meters from Smyrna, GA to College Park, GA and able to hear each other almost like we’re on the same repeater. I am easily able to get into my closet local repeaters on the lowest power setting at almost full quieting. Ones further out need more power, but I’ve got a radius of almost 50 miles that I can easily operate.
The HF antenna is a G5RV/ZS6BKW multiband doublet fed with a 1:1 current balun on a no-brand toroid. After putting it up, I think the toroid is rated for power transformers and likely performs poorly, but it’s coming down next time I work on the setup. It gets me out and gets me heard, but it’s not what I’m going to use for a long term HF setup. I look at it as a stepping stone to get me on the air somehow, and I definitely learned a lot of lessons that are only learned from experience. My next HF setup will be a significant improvement over the present one!
Interior Feed Panel
On the interior of the house, I cut into the drywall with a keyhole saw and pulled out some minor amount of insulation to make space for cables and fittings. I picked up a 3 gang mud ring and a blank electrical face plate from the local hardware store. I drilled some holes out of the blank for bulkhead connectors and ground strap and routed some short RG-8x patch cables inside to the external bulkhead connectors. I know that some bulkhead connectors are long enough to go through the entire wall, but that’s not what I wanted to do.
On the exterior of the house, I mounted a DIY fabricated aluminum grounding plate on the exterior fascia of my basement wall. It’s 1/8″ thick aluminum plating that I cut down with a metal cutting blade on the table saw. Lacking an angle grinder, I smoothed the cutting edge down as much as I could with coarse grit sandpaper and block as well as some metal files on hand. I drilled out the holes with the drill press and a step drill bit. If you intend to drill into metal plating in this manner, support it with a wood block to prevent the bit from bending and creasing the plate.
As for performance, all of this has been completely worth the effort! I have a much better VHF installation, and I’ve got HF capabilities. I’m not satisfied with the HF quality, but it’s functional and is much like my prior VHF setup was before this one. However, I cannot complain too much! I have been able to hit the West coast, up and down the East coast, and Europe. I’ve received Africa, Asian, South America, and it’s incredibly interesting to practice receiving HF on single sideband as well as AM. The setup does seem to pick up some local HF stations, but seems better at DX and skip in a North-South pattern. The next setup will have an East-West pattern from the start of the plan! NC4FB has a much better write up on this particular antenna than my efforts will do, and you can find that at http://www.nc4fb.org/wordpress/zs6bkw-multi-band-antenna/ to see an analysis of the theory, dimensions, construction, and SWR plots of various bands through this antenna.
Well, this post has taken almost 6 months in the writing just the same as the station took almost 6 months in the making. It’s been fun and I’ve got more projects in the pipeline, so stay tuned for more updates!
YIS ES 73 DE KK4TSJ
June 7th, 2014 is the day of the Atlanta Hamfest! Put on by the Atlanta Radio Club and the Kennehoochee Amateur Radio Club at Jim Miller Park in Marietta, GA. Adults are $6 at the gate, kids 17 and under are free. Talk-in frequency at 146.820(-) PL 146.2Hz via the W4DOC repeater. Please bring any junk electronics you want to have recycled, too!
Anderson Powerpoles are the gold standard in amateur radio DC power distribution, and they provide connectors stable to 15A, 20A, 30A, 45A, and more current ratings. Grab some red/black low gauge zip cord wire, a crimper, and go. I like to throw in a little bit of heatshrink and other things, so here goes.
You need a tool. Some are better than others. It all depends on how many crimps you need. I don’t need a lot very often, so I got an inexpensive crimper. See those interlocking half-moon grooves and the pair of circular grooves in the mouth of the pliers? Those are the powerpole crimpers. They also work pretty well on other types of crimp type terminals. You put the seam of the crimp terminal over the protruding half-moon, and the back into the recessed one, and press down. Then you close it off in the circular grooves. Let’s move on.
These terminals are great, but they don’t work worth a flip if you don’t have a heavyweight current distribution bus. You can go commercial and get the heavy duty RigRunners and MFJ buses, but those cost money. They’re good, but I had everything on hand I needed to fabricate a bus. I crimped the 30A terminals onto 12 AWG solid core copper wire, and cut down some perfboard to size enough to fit inside the smallest Radio Shack projecct box I could find. I had to drill out the holes that corresponded to the wires, and then I pushed the whole thing flush and wrapped it with a rubber band.
Well, that’s great, but it’s not a circuit. I added positive and negative rails in the form of another 12 AWG wire that I wraped the other leads around and soldered a bead around the joint. I knew I needed to make a cut out of the top of the project box to accommodate the headers.
After some drilling and cutting and sanding, I had a decent opening for the headers. A lot of hot glue was used to make sure there was a sizeable amount of insulation was around the buses and to secure the circuit board. Onward to more crimping!
I needed a spade terminal adapter for my power supply. I was very tired of just screwing down the bare wire, and wanted this to be the input to the bus. I guessed well on the dimensions, and it fit perfectly on the first try.
A trip down to Ham Radio Outlet to get the Powerpole adapters also had me picking up a few other things. After cutting up a 6 pin Molex connector I picked up for a rig, I found a quick target for some more crimping. I pulled the fuse caddy and radio power plug out and got to work.
Overall, everything works out. I’m ashamed to admit how much glue I went through, but it went towards a good cause. I completely ran through my supply of Powerpole connectors, and there’s always bound to be something I could pick up from the radio store again, hihi!
Well, it’s getting late. 73 DE KK4TSJ.
I got the bug to get some weekend projects going in the workshop, and this is the first of those. I decided that I needed a 1:1 current balun for an upcoming ZS6BKW/G5RV ladder line fed doublet antenna, but it’s pretty important to make use of a 1:1 current balun to choke off the RF of the coax shield. I also want something that will handle a full 100W safely without risk of sparking, overheating, or breaking down in some way.
I started with a 4″ x 4″ project box made by Hammond Manufacturing and a green 3″ diameter toroidal ferrite core made by Amico. Not sure they’re the best, but it’s not a huge deal at HF frequencies. It’ll likely have enough inductance to form a LC filter with the antenna as the capacitor (that’s what antennas are electrically to an AC signal) squelching off UHF and probably higher VHF frequencies from the feedline system. I doubt it’ll affect 6M operation, but I lack the test equipment to know that for sure.
I then wrapped about 14 turns of 12 AWG zipline around the toroid and zip tied the ends in place. I had a number of SO-239 panel mount sockets laying around, and I soldering the red lead to the center conductor. I crimped and soldered a ring terminal to the black lead (it is the grounded shield…), and screwed that down with the socket to some holes I drilled in the project box. I then crimped on ring terminals to both leads on the other end of the zip core wires, and then secured them with some #10 bolts, nuts, and washers I also had laying around the shack. The KK4TSJ shack can be somewhat messy at times, but there is a system to the chaos.
After a lot of hot glue, the front panel, and some electrical tape, here’s the finished product. I haven’t quite figured out mount to the mast system, but it’ll need to be mounted at a standoff to keep the mast from interacting with the ladder line up to the center insulator. The Atlanta Hamfest is next weekend, June 7th, so I’m looking to pick up the rest of the supplies to complete the larger antenna mast project.
73 for now, DE KK4TSJ
KK4TSJ here, and it’s been a while since I’ve last posted. I’ve been pretty busy in my personal life, but I wanted to take a moment to post some photographs of my temporary mobile rig. My Jeep has over 150,000 miles, so I’m not particularly excited thinking about doing a permanent mobile install. I opted to go with an inexpensive cell phone holder that works well with my handy talkies, a speaker microphone, and magmount antennas.
I started with an inexpensive MFJ-1724B dual band 2M/440 quarter wave mag mount. Comes with about 15 feet of RG-58 feedline terminating in a PL-259 connector. With this configuration, the rig was useful for short range repeater contacts, but dropped out a little closer to the sites than I would like. It’s still light years better than the rubber duck, and even a capactively coupled counterpoise is better than none at all.
That did well for a while, but I wanted to treat myself a little for passing my general class exam. Right after the exam session from the North Fulton Amateur Radio League, I went straight to Ham Radio Outlet to get a new mobile antenna. Again, I didn’t want to do anything permanent considering the age of my Jeep, so I went with an MFJ-1729 five eighths wave mag mount. I did a straight replacement of the older one, and I noticed an immediate improvement over the quarter wave. I’m really happy with it, and it comes just under the performance of the outdoor antenna mounted at the home QTH.
Overall, the total cost of the mobile kit is just under $150 for the radio, mobile mount, speaker mic, antenna, and mobile DC power supply. Not bad for a modest start, and it’s given me a number of ideas for a permanent installation of a true mobile rig in the Jeeps eventual successor.
Part 1 of the freeze had me stuck in traffic for 12 hours, but Atlanta was better prepared for part 2. I noticed something odd with the flag on the front porch on Wednesday, so I called the missus out to take a photo. Our trusty stars and stripes no longer required a stiff breeze to keep it up at an angle!
So far, I haven’t had any luck making contact with the astronauts up in the ISS. I’m certain a better transceiver or a directional antenna would do the trick, but I’ve had none yet with simple quarter wave verticals yet. I’ve read some reports of other hams having success with that configuration, but none yet at this station.
Essentially, there’s 4 problems to tackle when making contact with an orbiting satellite:
1. You need to achieve line of sight with a moving object that is often eclipsed by the Earth. This will likely require steering a directional antenna system, and forces short contact windows. This typically requires satellite orbit prediction software and advance planning for good timing. I’ve attempted contact unsuccessfully a few times with the aid of those applications, but no dice.
2. While in process of contact, frequency shifts must be employed to counteract Doppler shifting of the orbital body’s signal through the procession of the contact. It’s only for about 10 KHz overall, and can easily be overcome by programming in the proper contact frequencies into the transceiver memory.
3. Distances at the leading and trailing edges of the time window have the craft at extremely long distances in comparison to overhead distances. Higher power transmitters, more sensitive receivers, or higher gain antennas will need to be employed for extended orbital contacts. I believe this is where the majority of my difficulties lie.
4. Astronauts are humans. They get busy, tired, need rest, and aren’t always available for radio contacts. I know they’ve got a lot of work to do up there, and it may simply be possible that my transmissions would have made it and they were not available to return contact. I don’t want to flatter myself here since I’m pretty sure my transceiver and antenna system were too weak to make it the distance.
I’m only interested in attempting voice operation in ITU region 2 since I live in North America, and I’m not equipped to operate packet radio presently. I programmed the following three FM voice channels into my list for my attempts:
- ISS 1: 145.805 MHz offset -1.32 MHz
- ISS 2: 145.800 MHz offset -1.31 MHz
- ISS 3: 145.795 MHz offset -1.30 MHz
There appears to be conflicting information available about which frequencies to use for contacts and how to compensate for the Doppler effect, and I suspect a fine grained VFO knob is the best answer for that. This is what I’ve attempted with no luck, so perhaps someone out there has some advice. I think I’ve got the research down properly, but the results haven’t been forthcoming.
Let’s wrap this up with some sources I’ve used for my research notes:
73 DE KK4TSJ QRT