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Wednesday, March 27, 2024

KD0FNR's Amazing San Francisco TouCans Rig -- A Rockmite and a Tuna Topper in a Pineapple Can Mounted on the Dipole in a Shopping Bag

Click on the image for a better look

This post has a definite San Francisco vibe. 

Hamilton KD0FNR appeared on the SolderSmoke blog way back in 2011.  Perhaps he should join forces with N6ASD who lives quite close to him in SF, and seems to share radio interests.  Also in their area is the esteemed Bay Areas blogger and homebrewer Dave AA7EE ; Dave recently sounded the CBLA alarm, alerting us to the presence of an intruder on 3579 kHz.  In the process, Dave mentioned the Pt. Reyes Web SDR, the presence of which came as welcome news to Hamilton. Finally, Dave and Hamilton mention the KPH Web SDR, which brings to mind Dick Dillman W6AWO who has been on the SolderSmoke blog several times 

Hamilton and his kids have their rig (a Rockmite and a Tuna Topper in a Dole Pineapple can) mounted at the feedpoint of their dipole (in the red shopping bag above).   They link to it via WiFi and Bluetooth. FB.  Thomas Witherspoon has a nice presentation (by KD0FNR) of the TouCans project on his blog: https://qrper.com/2023/12/field-radio-kit-gallery-kd0fnrs-rockmite-20-and-tuna-topper/ 

Hamilton KD0FNR writes: 

At the moment, the kids whose dad I am, better known as the gang—12, 10, and 8 year-old Diaze, Mota, and Tawnse.. all internet aliases—are big into 20 meters QRP CW with Project TouCans, a Rockmite coupled to a Tuna Topper. The radio and the amp that popped us out of QRPp to plain-old QRP are both housed in a Dole Pineapple can with a tuna can as a cover and antenna mount. The whole rig is still very much mounted in our half-wave dipole! 

Project TouCans consists of a Rockmite feeding a 5 Watt Tuna Topper, all of which is housed in our dipole antenna. The Rockmite has a single crystal bandpass filter on it's rx input. That makes it a pretty wide reciever which is fine, but it's particularly sensitive to its tx frequencies, 14075.5 and 14058 kHz AND—for some reason I have yet to understand—10459 kHz. By watching the SDRs that now—thanks Dave—envelope us here at our home QTH in San Francisco, we can see the frequencies of incoming signals. That information keeps me from responding to 14059 kHz signals in vain.

And now, the headphone repeater: TouCans is completely wireless with respect to the ground. That means there's no power line, no feedline, no keyer lines and no headphone line. Keyer controls are handled via wifi to a Raspberry Pi Pico-W on the rig while audio is brought back to my headphones via Bluetooth. Power is provided by a USB-C battery pack that lives in the rig which is mounted above us in the antenna. (Yes, all of this is becuase I thought feedlines matches and baluns were too mystical and hard to understand years ago. Yes, this has probably all been more work than a balun. Yes, I am still totally enamored of my original design decision. :) ) Anyway, the bluetooth range is about 50 feet and the wifi range is shorter than that. The short of it is—pun not intended—that I can't quite use the rig while I'm in my office. But, I can send CQ to the rig every half minute or so via a memory keyer, then turn on the SDR in my office, and then sprint a bit closer to the rig when someone calls back. (It helps that houses in SF are a bit tiny.) So, SDRs are kinda an integral part of our QTH setup and it's awesome to learn about a new—to us—one! Thanks again!


  1. This is really quite magnificent! I have heard of hams who have the rig at the center of the dipole, and run DC lines to the shack for power, audio, and keying. That approach eliminates all feedline losses. This completely wireless approach though is geeky/nerdy in the very best sense.

    The crowning achievement though, is the upside-down shopping bag. Hanging in mid-air, it could almost be an artistic statement in itself, part of a project involving everyday objects presented in out-of-context situations. Reminds me of a table, chair, and standing lamp I once saw hanging from a tree in Berkeley. There was a surreal aspect to these objects suspended in mid-air.

    Yes, a definite San Francisco vibe to it Bill. Great job Hamilton, and thanks for letting your family's freak flag fly for all to see!

    73 for now,


  2. No HOA will claim it's an antenna there is nothing connected to this flagline. Next disguise is a Tibetan prayer flagline ;-)

  3. Hi Dave!
    TouCans had a phase where the keyer wires and power lines were carried up to the rig via an Ethernet cable, for us though, it caused a little bit of RFI. With the wireless setup, that's gone . It's been really nice.

    I'm with you on the shopping bag! The kids and I started out using Donettes bags for rain amd fog shields. Then, we graduated to donut store bags, (they're waxed), and ground coffee bags, (plastic lined), from local coffee shops. TouCans wireless was a little bit bigger with the battery compartment and the Pico-W on the side, so the fortune cookie company bag made sense. On this first version, I cut one of the handles so I wouldn't inadvertanly snag part of the rig on it, but! It's occurred to me that the rain cover can also work as the carrying case for the radio if I leave both handles in place. There's always a new phase of development with this rig :)
    72 de Hamilton KDOFNR

  4. Hamilton - I can hear you calling CQ on 14057.3 right now. I assume you are using project toucans? As expected, you are not very loud, as we are too close to each other. You are under the noise level, but perfectly Q5. I called you back several times, but you are not copying me. Aaah well. Maybe another time!

    73 for now,
    Dave AA7EE


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