Check-ins: K0WLY (Carl), K07BUX (Jody, Eagle Mountain), KN0JI (Noji), KK7RW (Wade), AJ7KY (Kyle), KM7CSR (Mike), N7BEB (Bruce), KC7XC (Stan) checked in.
Bench Reports:
- Carl (K0WLY): Built and 3D-printed a SolidWorks-designed case for his CW Keyer (CWK), though his SolidWorks Maker subscription lapsed mid-project and he had to renew it ($50/year). Also updated the CW Keyer firmware so it can load and play back files at adjustable speed for practice, and is working on adding over-the-air/cable firmware updates so users don't have to compile and flash manually. Separately, diagnosed and is repairing a failed receive channel on his mobile radio, discovering the board has unpopulated protection component footprints the manufacturer left off.
- Jody (K07BUX): Testing a new 29.5-foot vertical antenna — wire run through the center of a Jackite 10m mast, suspended with a 3D-printed top block, fed with a 9:1 unun and four 18-foot counterpoises. Reported good results in the first 24 hours, including an FT8 contact into Lithuania despite otherwise poor band conditions.
- N7BEB (Bruce): No major builds, but has a QMX+ kit and started inventorying parts/winding toroids in preparation; may attend a planned group kit-build session (Carl is targeting September or October).
Ideation / Main Discussion — Signal Direction-Finding:
KN0JI raised an idea for building affordable hardware/software to triangulate interference, stuck mics, or problem transmissions, citing two recent real-world incidents in Salt Lake County — a group using ham frequencies as improvised walkie-talkies for hours, and a station stuck on cross-band repeat — that took hours or days to track down. He wants a low-cost (under ~$100) solution accessible to average operators. The group discussed several approaches:
- KrakenRF/KrakenSDR — purpose-built RF direction-finding hardware (~$750/node), considered too pricey for the goal.
- Doppler direction-finding nodes — cheaper, needs at least 3 coordinated nodes; can network nodes over IP to auto-triangulate a source, accurate to within feet using phase/timing differences.
- Classic maritime radio direction finders (RDF) — a member with boating experience described using pre-GPS RDF units with three coordinated stations for triangulation; noted used units show up on eBay/Facebook Marketplace for roughly $25–$100.
- DIY loop antenna with a NanoVNA — a small tuned loop with a trimmer capacitor gives a directional null useful for tracking signals from multiple locations.
- Time-of-flight/TDOA multi-antenna systems — a member described using this method professionally (locating buses in a bus yard), noting it requires three antennas and fast enough microcontrollers to measure timing differences.
- Distributed/crowdsourced network — KC7XC suggested fixed LoRa/Meshtastic-style nodes around the valley each carrying an RDF/Doppler sensor. Carl said he's already been exploring a low-cost, crowdsourced solution (aiming for ~$5–10 per participant, using existing radios plus a dongle) and hinted at revealing more details in a future net.
Magic Smoke Award: No damage/failures reported, though Carl shared a near-miss: low-temperature desoldering solder wire he'd ordered arrived from Amazon melted into a blob (likely from heat in transit) and had to be reordered.
Closing: Net closed at 7:41 PM local time. Carl reminded everyone to send write-ups, links, or photos to k0wly.ham@gmail.com for the blog (uvarcmakernet.blogspot.com) and pointed people to the UVARC Slack's MakerNet channel for ongoing discussion.
No comments:
Post a Comment