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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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20m-EFHW for 40-30-20-17-15-12-10m

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 40m EFHW resonates at 40-20-15-10m, but it’s 20 meters long, I think it’s too long for SOTA activations. I opt to a 20m EFHW which is about 10 meters. It resonates at 20m and 10m, to get 12-15-17m, I simply cut the wire and tune each band, form a linked wire EFHW. For 30m, I add ~10uH inductance at 17m joint; for 40m, I add ~20uH at 12m joint. I have tuned all bands(40-10m) below SWR 1.3:1 and the antenna performed well in the field. The wire is from Ethernet cable twisted pair and the whole antenna weighs 1.5oz For reference: 10m: 4.61m (15' 1-1/2") (not necessary, just in case) 12m: 5.15m (16' 10-3/4") 15m: 6.04m (19' 9-5/8") 17m: 7.22m (23' 8-1/8") 20m: 9.51m (31' 2-3/8) 30m: Add 10.7uH at 17m joint 40m: Add 20.3uH at 12m joint The 49:1 transformer has 2T for primary and 14T for secondary. Use 2m (6') coax, no tuner required for CW only operations.
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