Project TouCans Digital noise issue fixed-ish

The intermittent noise issues in Wireless TouCans are fixed! Sort of. After a variety of fixes that involved resoldering the audio jack and taping the audio cables in various locations, I finally arrived at a solution yesterday. The solution came in two parts and is still a little bit rough.

First, I replaced the rig's headphone jack with a headphone plug. It doesn't make a lot of sense for the rig to have a headphone jack, except for debug purposes—on rare occasions I plug in headphones while the rig is being worked on. It does make sense for it to have an audio micro-stereo plug since that's the format the Bluetooth audio transmitters expect.

You can see the original version of the audio out plug and patch cable in the picture of an early TouCans version below.

Notice the headphone jack to the left of the Bluetooth transmitter under the rain shield. That's the bit that's been removed. Now, the audio wires from the rig that were attached to the jack are soldered to a plug that plugs directly into the transmitter. That has helped by removing a few flaky connections.

The second change also had great affects for very little work. I moved the audio output wires so that they were not draped over the rigs power wires. This significantly reduced the noise heard in the headphones!

The Brand of Bluetooth Transmitter Matters... For Now

Due to a battery outage last night on the ML300 model of the 1Mii transmitter pictured above, I also tried our Aluratek transmitter and learned a few things. First, it's noise performance is better. Second, when it's battery is fully charged, it produces RFI that causes the Rockmite keyer to reboot on the first character it sends... Not good. Finally, it's range is not as wide as the 1Mii

For now, we're sticking with the 1Mii. It doesn't reboot the Rockmite's keyer and has a larger range. I wish it had better noise performance.

Next Steps

The next step will be to route the audio wires out of the can through a notch opposite to the current notch for the power wires. That will take the audio as far from the RFI causing power lines as possible.

UPDATE

I was able to try routing the audio connector out the other side of TouCans this morning. I also moved the ground wire for the audio so that it was plugged directly into the USB-C power supply. That helped with the noise issue. Taping the Bluetooth transmitter to TouCans so that it couldn't move quite as much resolved the rest of the noise issue! I now just hear white noise static for noise, you know, like you'd hear with a normal radio. Here's a look at the Bluetooth transmitter's current position with respect to the rig.

You can see it next to the cut off bag handle of the rain cover. You can see the arrangement even better in this video. There's a post coming soon about the new rain cover as well :)

There is still an RFI issue. With the keyer set at 20 wpm, the Rockmite will reboot after "cq de" The simple fix was to turn the keyer speed down to 18 wpm where the problem disappeared. I'll need to debug this further in the future.

The rig is proved out. I just had a QSO with W7SUB near Portland, Oregon!

Cool Math Tricks: Deriving the Divergence, (Del or Nabla) into New (Cylindrical) Coordinate Systems

Now available as a Kindle ebook for 99 cents ! Get a spiffy ebook, and fund more physics The following is a pretty lengthy procedure, but converting the divergence, (nabla, del) operator between coordinate systems comes up pretty often. While there are tables for converting between common coordinate systems , there seem to be fewer explanations of the procedure for deriving the conversion, so here goes! What do we actually want? To convert the Cartesian nabla to the nabla for another coordinate system, say… cylindrical coordinates. What we’ll need: 1. The Cartesian Nabla: 2. A set of equations relating the Cartesian coordinates to cylindrical coordinates: 3. A set of equations relating the Cartesian basis vectors to the basis vectors of the new coordinate system: How to do it: Use the chain rule for differentiation to convert the derivatives with respect to the Cartesian variables to derivatives with respect to the cylindrical variables. The chain ...

The Alcubierre Warp Drive Tophat Function and Open Science with Sage

I transferred yesterday's Mathematica file with the Alcubierre warp drive[2] line element and space curvature calculations to the +Sage Mathematical Software System today, (the files been added to the public repository [3]). If you haven't used Sage before, it's a Python based software package that's similar in functionality to Mathematica. Oh, and it' free. I also worked a little more on understanding the theory, but frankly, I made far more progress with the software than the theory. What follows will be a little more of the Alcubierre theory, plus, a cool Sage interactive demo of one of the Alcubierre functions[1], as well as a bit about my first experience with using Sage. Theory The theory is fun, but it's moving slowly. Here's the chalk board from this morning's discussion Alcubierre setup the derivation using something called the 3+1 formalism which means we consider space to be flat, (in this case), slices that are labelled ...

How Many Files Can You Add to a GPT Project? An Interview with GPT-5 on Limits, Context Engineering Tips, and Chats

Setting the scene: I’m tinkering with Project TouCans, knee-deep in radio logs, SQLite dumps, and Cesium code. Naturally, I’m wondering if shoving all this into one GPT Project is a recipe for brilliance… or for disaster. So I turn to Vril — you know, after Brainy from the Legion of Super-Heroes , because what else do you call your AI sidekick who always has the answers? Time to ask him straight up. [ As an aside, yes, GPT-5 has decided to sometimes call me Vail. I'm not sure why to be honest. Also, I asked Vril, er GPT-5, to write up our interview for me. Apparently, me asking it to 'Bro' up a few stories, just for fun, has convinced Vril that I use 'Like,' more than I actually might. ] Me (Vail): So Vril, how many files can I throw into a GPT Project before it just starts choking? Like, is there some magic number where the context window taps out and everything falls apart? GPT-5 (Vril): Great question. There’s no single hard file limit. What matters is ...

Copasetic Flow

Search This Blog