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SOTA Trip Report: W6/NS-140 Andrews Peak — 5/19/2026

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  I had studied W6/NS-140 Andrews Peak last year and thought it was doable for me as a backpacker, so I planned a 5-day trip from Hetch Hetchy. I started on May 17 and arrived at Hetch Hetchy around 10am. The weather was perfect. I passed the dam, then the roaring Wapama Falls, and continued ascending toward Tiltill Valley. Tiltill Meadow was flooded around ankle deep, and that made my boots wet for the whole trip. The campsite was very nice. On the second day, I kept moving toward Jack Main Canyon. The flooded meadow was not easy to navigate. Right before I decided to give up, I found the trail again. Beyond Tiltill Valley, the trails were less maintained, but with help from Google Maps and Earthmate, I was able to stay found the whole trip. I walked slowly to avoid triggering altitude sickness, and it worked. I only met one hiker during the whole day. I stopped around 6pm and camped next to a small creek. The third day was my activation attempt day. I hiked about one mile to the ...
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Train a mini LLM on FT8 messages to Explore What’s Under the Hood of AI

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Back on Nov. 18, 2025, I asked ChatGPT: “Can I build a tiny LLM from scratch?” “Maybe one trained only on FT8 messages?” I didn’t know where the journey would lead. Turns out I wandered straight into an amusement park . Here’s the toy — no further explanation needed. https://github.com/wcheng95/MiniLLM
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Operating truSDX like a mountain topper

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  Replacing encoder with three buttons will dramatically reduce truSDX's packing size(from 54mm to 33mm) The hardware modification was done on a classic band truSDX. The software modification was done on uSDX. It's pretty straightforward. https://youtu.be/McM1w-0wEL4 https://github.com/wcheng95/usdx
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Portable SOTA/POTA Station Breakdown

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After about 10 months of refinement, my portable SOTA/POTA station has reached a good balance between functionality and weight. It supports CW, FT8, and SSB. The setup weighs just over 1 pound when a tree is available for supporting an antenna; otherwise, it weighs a little over 2 pounds. QMX-HB + 40m       225g Battery(14500x3)        73g EFHW(40-10m)           58g Coax(2m)                  45g Lightening 2 USB-C 21g Paddle,Mic,Cable      23g Earbud                    14g Log+Pen                    24g -------------------------------                                   483g HRD 20ft mast        452g Two short ropes         14g ---------------...
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W6/NS-187 Smith Peak SOTA Activation on May 26, 2025

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 If you’re fit enough to hike 10+ miles in Yosemite, you’ll enjoy this SOTA summit. The trail is well-maintained for the first 5 miles. The last 1.7 miles are slightly overgrown, but the brush is mostly below knee level. Wearing long pants will keep you comfortable. The trail can be a bit confusing in a few spots, so it's a good idea to have it mapped out on your favorite app (I recommend CalTopo). I started feeling nauseous above 6,000 feet. I just slowed my pace to around 1 mph, took frequent breaks, and sipped water every 10 minutes. After spending about 30 minutes at the summit, I felt fully recovered. Altitude sickness is real, so plan your trip conservatively and listen to your body. There aren’t any trees tall enough to support an antenna, but I brought my own mast and set it up next to a large rock that also served as a windbreak. The summit offers an unforgettable panoramic view. Setup sota station QMX with truSDX as backup The camera cannot capture the magnitude of th...
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If you chased me during weekends, this is the setting

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 If you chased me during weekends, this is the setting: QMX with linked 20m-EFHW, supported by HRD LD6 mast
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If I chased you during weekdays, this is the setting

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 If I chased you during weekdays, this is the setting: KH1 whip with K6ARK designed coil for 40/30m
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