Copasetic Flow

Or, how I learned to miss hard resetting RFI. Up until about a week and a half ago, Project TouCans and the Flying Rockmite before it had never blown a final amplifier transistor. Our good fortune with transistors was caused in large part not by any particular genius in the construction or handling of the radio, but almost entirely to radio frequency interference. When too much RF energy was reflected back into the radio on key down, the Rockmite's picokeyer would reset chirping out an only slightly irritated 73 in Morse code. Hence, we couldn't use the rig, hence we changed the antenna or repaired the rig, or turned down the bias voltage on the Tuna Topper final until we could use the rig without resetting that little keyer. Then! Then we did something that was both cool and, (we'd later find out), somewhat daunting. We removed the last of the wires that attached Project TouCans to the Earth and our RFI just went away. Which has been great for signal quality, and as it tu...

 Discussing ham radios embedded in antennas in the comments of the previous post this morning inspired me to look through some POTA videos and make a new one. Here's a Google Earth tour of the path from the Organ Mountains to Stanford, straight through Baylor Pass. And... Here's Baylor Pass up close.

  Squigily audio in our homebrew ham radio rig? Capacitors! This extends the capacitor post from last week. This week, while adjusting the Tuna Topper amplifier bias after a run-in we had with an unexpected rain shower, I put capacitors across the dit and day switches on the keyer. The dit capacitor was particularly useful because with the amplifier bias set above a certain level, the keyer chip would immediately reboot when the dit key was pushed. I'm assuming RFI transients were punching through to the little processor, befuddling it in the process. Today, the kid—Diaze—and I changed the battery from a D cell pack to a LiFePO4 battery. The extra bit of punch provided by the nicer battery meant we had to turn down the bias on the TunaTopper's onboard pot just another quarter turn or so. The resulting keying sidetone over the headphones was less than esthetically pleasing though. When Diaze sat down to key out a CQ, the buzzing and squiggly sounds were too much for her. A rec...

 I've alluded to Project TouCans over the last several posts, but I've yet to introduce it. Today is the day! Project TouCans is the new, very compact, packaging of the RockMite  20 with an attached TunaTopper amplifier suspended in a halfwave dipole antenna. Here's the design drawing Diaze and I made In short, both components are suspended from the top of a pineapple can. The tuna-sized can the Tuna Topper shipped in is flipped over and used as a rain cover and antenna mounting structure. The antenna is mounted to the red and black banana plug binding posts at the top of the assembly. You saw a picture of the latest incarnation of TouCans in yesterdays post. Here's the original—and more colorful—project in its first incarnation The Ethernet port is the same one used by the Rockmite in the Flying Rockmite—for that matter, the radio is also the same one used in the most recent flying Rockmite. The first coil of Ethernet cable is attached to the pineapple can using elect...

 The ionosphere at 5 AM in San Francisco wasn't set up to support long range communications, but I did get a pretty picture of the rig as Venus was rising behind it. The radio/amp pair reached across the Bay to both the Berkeley stations— W6BB and NU6XB — and nowhere else. References: The Ionosphere this morning Project TouCans RBN

 OK, so this isn't so much one I learned, as one I remembered, and then empirically proved. Did you know that human thumbs are capacitative—as in they act like capacitors? Yup! They are! The project TouCans Rockmite/ TunaTopper stack suffers from the same issue the Flying Rockmite often did. Sometimes, the RFI from the antenna gets to be too much, and the memory keyer decides to stop keying out its memory. I noticed that when using the keyer with Project TouCans, if I put my thumb across the leads to the 'dah' keyer switch, the issue went away and the memory keyer ditted and dahed along to completion. I had brought a small capacitor out to the radio site to try placing across the headphone leads to solve an AM pickup problem inherent with having 25 foot long headphone wires. The same issue on a far lesser scale had been solved by Mark— N6MTS —as part of his work on the Open Headset Interconnect Standard, OHIS . The cap hadn't down the job for the Flying Rockmite or Pr...

 I've been doing a lot of amplifier testing over the last week with the Tuna Topper as part of what has become Project TouCans. It's led to many more QSOs—meaning, more than one per week—from the house. I maybe haven't remembered to log them all, and so I wasn't too surprised when I saw that  N2AKJ had logged a Parks on the Air, ( POTA ), contact with me last Thursday when they activated K-2114 Nissequogue River State Park . Still, since I didn't remember the QSO, I wanted to make sure I was at least on the air. And.... There's an app for that! Using the RBN network data automatically accumulated by rm-rbn-history about QSOs and RBN spots from my callsign—KD0FNR— served through datasette , I was able to determine if I'd been on the air when the QSO was logged. Spoiler alert: I was. Understanding the SQL formatting to get the information was a bit tricky, so I'm documenting the SQL statement here so I can go back to it later. select rowid, id, tx_lng,...

Project TouCans is well underway! I'll have more details soon. The key difference between TouCans and the Flying Rockmite is that it includes a Tuna Topper amplifier. The amplifier/radio combo chews through the 8 AA batteries more quickly than the Rockmite alone did. Consequently, Diaze—the 12 year old here—and I switched over to D cell batteries. Our keyer, however, is located on a AA battery case. Today, the design for the TouCans keyer became obvious when I looked at the Rockmite's current keyer next to the new battery pack: The two D cell battery packs will be glued together back-to-back. As you can see, the battery pack manufacture graciously included an indentation in the top of the battery packs that holds the on/off switch snugly—even more so after a drop of superglue is applied. The keyer video game switches will be attached in the same way they were on the AA battery pack in roughly the same location at the front of the D cell battery packs. The Ethernet breakout boar...

I'm starting to be handy enough with Datasette that I can quickly get answers to my questions! This morning, the question is whether or not the Tuna Topper amplifier combined with the Rockmite is giving better propagation results than the we get with the Rockmite running alone. Since we have a database of all the QSOs and RBN spots of the Rockmite, this is exactly the kind of question Datasette can answer. Here are the commands to run datasette to get an sqlite database from the Rockmite's RBN and QSO data table . I'm listing the commands here because I've been to lazy to simply write a script, and thus far I haven't been able to get the whole assmeblelage to work on Windows, meaning I'm working on a github codespace. Codespaces are super-cool, but also—at least for me... so far—completely unable to keep command history around between launches python -m pip install csvs-to-sqlite python -m pip install pandas==1.5.0  csvs-to-sqlite -dt timestamp rm_rnb_history...

A bit more about shielding the Tuna Topper amplifier with a can of Progresso soup. I tried a shielding experiment here at the home station today, and had great results. There was in fact no reductcion in output power. It's unclear to me if there's a reduction in general noise yet. There are roofers next door, and their propane heaters are laying down a nice, even, low-level ground floor. Here's a detail picture of the shielding: The soup can is opened on one end, the soup has of course been removed, and the can cleaned. The open end i placed over the exposed Tuna Topper circuit board. I thought there would be issues with the RF in and out wires being sandwiched between the two cans, but there are not, (at least for this installation.) I made a contact with AE7CG with the shielding in place. Here's the QSO map: You can see the signal was reaching out fairly far, but no further than Utah. This is an afternoon thing here in San Francisco that I haven't entirely figure...

Just before heading to a POTA yesterday, I taped an empty can of Progresso Soup over the top of the Tuna Topper. In my typically lazy fashion, I left the radio's new nose on when I arrived at the POTA site. I could hear a few AM stations in the background, but nothing that was screaming loud. I also hear a few CW stations. Out of curiosity I removed the soup can and... So much AM screaming!!! Curious if the can was also causing signal to not make it out, (was it simply forming a capacitor between the RF in and out leads?) I checked the RBN results. The radio was five feet off the ground next to a highway, and reached two stations:  nearby W6BB and KO7SS, each with 10 dB.

The 12 year-old and I got a chance this last weekend to test out the Rockmite complete with Tuna Topper amplifier on a POTA activation. The results were outstanding! We were making a QSO per minute for most of the activation. Something we've never done before. On top of  that, the prototyped packaging of the combo of devices solved a few problems we've always had when we suspended the Rockmite from the antenna. Here's a look at the how the pair were packaged together: The first, biggest advantage, is that we moved the BNC coax connector out of the equation. As you can see, it is now the input to the Tuna Topper. That means that it is not supporting the antenna. That means  that there are no longer any torques on the BNC connector in the case. This fixes an issue that inspired so many washi tape fixes . The second advantage is that there is now access to the power leads outside of the Rockmite. This frees us up to send power in on a different path than the Ethernet cable ins...

The twelve year-old, Daize, and I flew the Flying Rockmite with the Tuna Topper II+ amplifier installed for the first two times ever this weekend! The results were outstanding! And! The kid made her first QSO ever on Sunday! She and I wrapped up amplifier construction late in the week. From there, we were able to do some basic testing on the back balcony of the house where we learned that the LED was soldered in upside down, and that our multimeter was reading rather wonkily because it's battery was (already!?) going dead, and maybe also a heavy dose of RFI (radio frequency interference.) I'll be writing up way more about the initial tests, the ideas they spawned for the radio/amp packaging you'll see below, and other things soonish. Anyway, after our one brief day to test the amplifier, the kid and I were scheduled to hop on a plane to New Mexico where we would camp just below Manzano Peak and eat  breakfast each morning in Mountainair, (Yum!). We took the Rockmite and...

The 12 year-old unschooling kid here has been soldering since she was eight. She'll be taking her ham exam soon. (She's also contributing to the development of the ham practice exam app she's using. That's how we've been working on programming.) So, with all this ham radio work going on, it only made sense to ask if she'd like to help build an amp that will hopefully help the Rockmite get a little further out. So far things are working out great! She soldered the first third or so including most (all?) of the resistors last night. I got up this morning and soldered in most of the capacitors and the Zener diode. We'll be up and running in no time! Anyways: There are also ideas for suspending the Rockmite and the Tuna Topper in the antenna: There might even bee a second can of tuna for the batteries!

The gang and I were out camping for five weeks this summer. I'm finally getting a chance to take the time to write, and to look at old pictures, so you'll be hearing more about all of this, but a post on the GQRP group this morning asked about using radios without enclosures, driving me to this particular topical niche of our camping trip first.  The GQRP poster mused about using either a plastic enclosure for a radio, or no enclosure at all. The 12 year-old here, Daize, and I had discussed mounting a radio on its battery a few times at the start of this year. As it happened, we had an extra Rockmite 20 laying around, so right before we went out for our camping trip, we moved the radio out of its case and onto its battery, this was mostly done to reduce voltage drop between the battery and the radio since the Rockmite is typically mounted at the antenna feedpoint when we're out and about. Here's the rockmite about to be launched with the antenna: and here it is up with...

Got the following data back from my rbn_telnet.py program this afternoon. It's not what the script was created for, but it's wound up being a nice use model: b'DX de VE6JY-#:   14057.5  KD0FNR         CW     5 dB  20 WPM  CQ      2254Z\r\n' b'DX de VE7CC-#:   14057.5  KD0FNR         CW     3 dB  21 WPM  CQ      2254Z\r\n' b'DX de W6BB-#:    14058.1  KD0FNR         CW     2 dB  21 WPM  CQ      2255Z\r\n' b'DX de VE6JY-#:   14058.1  KD0FNR         CW    10 dB  21 WPM  CQ      2255Z\r\n' Note that the same station, VE6JY has the rockmite coming in first at 5 dB on 14057.5 kHz at 2245Z and then at 10 dB one minute later on 14058.1. I had suspected there might be battery issues with...

I'm not sure what to make of this yet, but I'm seeing different signal strengths received at the same receiving stations based on the output frequency of the Rockmite which only works on two different freuqencies: 14057.5 kHz and 14058.1 kHz. Here's the data I collected this morning: I wondered if this was simply variations in the atmostphere, but notice that in the case of reception by ND7K, there's a difference of 10 dB in the two transmitted frequencies with only a two minute difference between the measurement times. I saw even clearer results watching the waterfall display of the Utah SDR : Notice the nice, well-defined line at 14057.5, and then a few seconds later, the fuzzy, weaker line at 14058.1: first second I don't think it's an issu with the radio since sometimes the stronger recpetion was on 14057.5 and others it was on 14058.1. I'm not sure what's causing the differences. I'm looking forward to finding out.

The 20 m Rockmite had a QRPp QSO with  SM5CAK in Sweden  last night! Might I add that the two stations involved were 5,360 miles away from each other, and that the little Rockmite, even with the cool power modification has an output of 3/4 of a Watt? It's all true. You may have noticed that in my many, many ham radio posts, virtually none of them discuss QSOs (QSO is ham radio abbreviation—a Q code— for a two way contact) made from the house. That's  because I don't, in fact, make a lot of QSOs from the house. There's generally a lot of noise in town, and while the antenna placment is apparently pretty good, things just don't pan out very often. That's the first reason last night's Swedish QSO was so legitimately strange. About 9:45 PM Pacific Standard Time, (that'd be 04:45 the next morning, GMT, Greenwich Mean Time; yes, again with the ham radio phraseology), I heard SM5CAK calling CQ DX (DX means they were calling for a foreign country with respect to...

 The (newly) three quarter watt Rockmite ham radio reached Hungary from Great Basin National Park a few days ago! Maui relayed the receive side from Hungary. A few days ago, a POTA outing from Great Basin National Park ( K-0032 ) had kind of petered out. I listened for the RockMite on the Maui software defined radio , SDR, because—for whatever reason—I can usually find the 20 meter output of the RockMite there during the day whether I'm operating from San Francisco or Great Basin. Sure enough, there was the station: But, this time, I heard another station as I listened. And! They were calling me! A bit more listening revealed that it was HA9RE . I answered back on the RockMite, where I could not hear HA9RE, and was immediately rewareded with his answer which I could only hear on the Maui SDR. Here a few more vidoes that detail the contact, the first ever software defined radio relayed contact with the Rockmite! From the IRL point of view: From the SDR point of view: ...

 A fairly gentle hike led to a QSO with Japan at 3/4 watts, and a brand new SOTA ham radio activation. Summit:  W7N/WP-147  8340 Getting there Welp, there's no public transit avilaable to this particular summit, so the gang and I drove.  If you're not from the area, and you're able to, plug in the cooridnates of the peak and let Google plot a route for you. You'll also want to download the offline Google maps for the area; there's plenty of phone signal at the summit, but there are places on the drive in where there’s none at all. Google Maps led us through several forks in the gravel/dirt road to a location just to the south of the summit.  If you stop where we did, you may notice a set of tire tracks that lead most of the way up to the mountain’s central ridge. They make for a nice easy start to the hike. When the tire tracks peter out, you can navigate the rest of the way up on a variety of game trails. My path deposited me on a picturesque saddle in the ridg...