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Raspberry Pi Projects

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This page will be where I post about the Raspberry Pi projects I have created or are working on.

Years ago I learned C++ extensively (my Computer Science degree). I started looking into Raspberry Pis in 2019 and started learning the Python programming language.

I’ve written a lot of home security programs, home automation and also stream my favorite local repeater.

I’ll write more here about the projects soon.

Mobile Installation in Ram Truck

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Built only from parts found at your local hardware store. No modifications to vehicle for mounting.

Initially I built this as a single mount for my BTech GMRS-50×1 mobile radio. I have a bench seat in my Dodge Ram but very little room elsewhere to mount the radio. Years ago you could drill into the dash when they were metal…not so easy anymore.

I bought two L-shape brackets and two straight brackets with assorted hex bolts. I also included four rubber feet with the intent of sliding the bracket under the center front seat.

It started out wide but I had to make it more narrow due to restrictions under the seat. The holes already drilled made this easy.

As you can see the BTech GMRS-50×1 radio fit quite well on the bracket and with the rubber feet, it slipped great under the seat. For added security I left the bottom metal strap long and zip-tied the two side holes to the seat mount points.

Later on, I got my ham license and wanted to add my Yaesu FT-2980. That radio is larger so I decided to flip the BTech GMRS-50×1 GMRS one to the top and put the Yaesu on the bottom.

I already had wires through the plastic firewall knockout and I didn’t want to disturb them so I found it easier to drill a second small hole in the same knockout. I removed the connector (the pic was actually to make sure I put it back on with the correct polarity…I triple checked!).

I mounted the BTech GMRS-50×1 radio on top and fitted the Yaesu FT-2980 bracket on the bottom side. Because the bracket wasn’t originally designed for this alignment, I had to add some spacers, etc. but it did fit exactly in the space between the seat and extended cup holders. The angles changed a little as well, but it wasn’t bad.

All in all, the entire bracket seems quite secure and does not vibrate or move when on the road!

(Oh and if you are wondering why I have green and red labels on equipment it is for the family. That way they know NOT to pick up ham equipment but they can use GMRS as covered by the WREY366 license).

Original Dry-Run Assembly
Needed a narrower fit under seat
BTech GMRS-50×1 Mounted
Pin removal from connector
Plastic knockout in Dodge Ram Firewall
Positive post directly between battery and under-hood fuse box
Flipped the GMRS radio to the top position
Needed spacers/washers because the top side was not built originally to mount a bracket
Finished Product!

2 Meter Quick J-Pole Antenna

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Being stuck at home during the COVID-19 outbreak I wanted to explore building a J-Pole antenna for the 2 meter band. I spend most of my “ham time” on the 2 meter repeaters in my area jumping on the local traffic nets.

The Virginia QSO party was starting that weekend so I built this as quickly as possible.

I had built one J-Pole before for GMRS frequencies (Call sign: WREY366) tuned around 465 MHz.

The design I chose came from the Oroville Amateur Radio Society in California website. Their posted J-Pole antenna design is shown to the right. I did need to adjust the connection points as expected. Mine have a bit more distance than the ideal specifications. The analysis is posted below.

As a quick test to see if my VSWR was on track, I held it together with duct tape! It was kind of just for fun but it actually worked surprisingly well. (I use a cheap radio for these tests).

Next was the soldering. I expected the VSWR to change because of, well, adding soldier and the end caps. Minor adjustment was needed at the hose clamps, but it wasn’t far off to start.

Next came the fun part. I used a kid’s bow and arrow set here to send fishing line up over the highest trees. I tied the ends to paracord and pulled that up, anchoring the first end to the ground.

Over the area I wanted the antenna to be fixed, I tied a loop in the cord to hang the antenna by fishing line as a separator to keep water off. Two additional ropes are added to prevent swinging and orient the “J” stub as desired for the repeaters I want to reach. The far end of the suspension rope is tied off with lots of excess so I can lower it as needed. I used split ferrite beads on the RF cable looped as a choke.

This is obviously a temporary construct but it seems to work exceedingly well. If I were to leave this up long term I would redo this with cable as the rope will decay in the weather (but I’d have to make sure it was far from the radiating element field as needed–maybe add rope only over the antenna section?). Also the antenna is not water-proofed. So far the rain it’s taken on doesn’t seem to interfere too much. The wind is more of a problem if it spins and moves around. Again, it hasn’t been too bad even in high (30 MPH) winds.

This was a quick project using what I had around the house. Paired with my Yaesu FT-2980 (pulled from the truck), I have been getting great range! I can now join nets and other 2 meter discussions from the convenience of my living room using my mobile radio.

SWR minimum at 146.800. Not too bad!
Lower end near 144.400 MHz still decent at SWR of 1.17. Curve looks dramatic because of scale.
Smith chart showing impedance of 49.0 ohms at 146.800 MHz. Pretty darn close to 50 ohms!
TX to WA4TSC repeater on uplink of 147.9 MHz. SWR of 1.04 double checked by a second meter
Courtesy Oroville Amateur radio Society
Quick test before soldering (it actually worked pretty well with duct tape!)
Time to solder it all together
Final connector bound with 14 AWG copper wire
Fun games: getting a rope in the air
RF Choke using split ferrite beads
Hanging about 40 feet above ground level and at 1,415 feet above sea level
Mobile radio on inverter in living room