When the Platform Walks Away: Shopify enables easy scams!

Disclaimer: This post reflects my personal experience with a merchant operating on Shopify. It is not an allegation that Shopify intentionally supports fraudulent merchants. Rather, it is a critique of the incentives and customer experience I encountered. Recently I purchased from a merchant running on Shopify. The store looked legitimate, accepted payment without issue, and presented itself professionally. Unfortunately, that was where the positive experience ended. The merchant failed to deliver what was promised. Attempts to resolve the matter directly went nowhere, so I tried contacting Shopify expecting that a platform of its scale would at least investigate. ...

June 28, 2026 · 3 min · 613 words · Dhiru Kholia

Generating 1W RF from 5V

The constraints 5V (~500mA) power from phone 1W RF output required Very compact with less "moving" parts 14 MHz capable The design We purposefully utilize "high Rds" EPC GaN parts with very low Qgs. Simulation Results Power consumption: Around 300mA @ 5V. pout: AVG(v(out)*i(r3))=1.0606 FROM 5e-05 TO 0.0001 pin: AVG(-5*i(v3))=1.38209 FROM 5e-05 TO 0.0001 isupply: AVG(-i(v3))=0.276418 FROM 5e-05 TO 0.0001 eff: pout/pin*100=76.7393 Cost Cost: < 500 INR. ...

June 27, 2026 · 4 min · 798 words · Dhiru Kholia

Connecting Across Distance: From Ethernet to Fiber

The old hack Sometime around 2015-2016, I had to connect two rooms that were separated by a balcony. The simple answer was obvious: run an Ethernet cable through the balcony and plug it into the router on the other side. It worked. It was cheap, fast enough, and did not need any special equipment. For a while, it felt like the sort of practical fix that makes home networking fun. ...

June 23, 2026 · 4 min · 852 words · Dhiru Kholia

Baby-QRO FT8 Amplifier 2026

Related work Baby QRO Switching RF amplifier for HF Digitally Adjustable RF PA Supply A new generation of the Baby-QRO switching amplifier targets 25W to 50W of RF output for FT8 and other FSK modes. While it can do 100W, it becomes more of a thermal engineering project then ;) It is designed to operate with a Bare DDX-Commercial transceiver board and has an inbuilt T/R switch. Design 3D render: ...

June 20, 2026 · 1 min · 179 words · Dhiru Kholia

Digitally Adjustable RF PA Supply

Related work Baby QRO Switching RF amplifier for HF A new generation of the Baby-QRO switching amplifier targets 25W to 50W of RF output for FT8 and other FSK modes. Goal The Baby-QRO amplifier already has a very useful RF power control knob: the PA drain voltage. A bench supply works for experiments, but it is not the right answer for a digital beacon or transmitter stack. We want the MCU controller to set the PA voltage, and therefore the RF output power, in software. ...

June 20, 2026 · 3 min · 600 words · Dhiru Kholia

DDX-UNO: The HF Radio You Actually Carry

Photographers often say: The best camera is the one you have with you. DDX-UNO ("Digital Pixie") applies the same philosophy to amateur radio. The best HF transceiver isn't necessarily the most powerful one. It's the one you remembered to bring. Most HF stations remain at home. Portable radios often require batteries, coax cables, antenna tuners, protective cases, and a backpack full of accessories. The result is that many operators leave their radios behind. ...

May 26, 2026 · 5 min · 937 words · Dhiru Kholia

Local AI Coding on Ubuntu 26.04

Running your own AI coding assistant locally using ROCm, LLaMA C++, and Nanocoder. Why Local AI Coding? Cloud AI coding assistants are convenient, but local models offer: Better privacy Lower long-term cost Offline development Faster iteration for small/medium models Full control over models and tooling With modern AMD GPUs and ROCm support improving rapidly, Ubuntu 26.04 makes it surprisingly easy to run local coding models. In this guide, we'll set up: ...

May 16, 2026 · 3 min · 548 words · Dhiru Kholia

After-Sales Support Is the Real Product

I recently bought a ceiling fan from Kuhl which came with "free installation". The experience was simple: Wait 4 days Nobody comes No installation No accountability Ultimately I returned the fan - it took around 15 minutes over a phone call with Amazon's customer care to initiate the return process. This time could have been better spent on something else… Now yes - I can install a ceiling fan myself. ...

May 13, 2026 · 2 min · 225 words · Dhiru Kholia

Minimal Kernels, Reduced Attack Surface, and Why Linux Optimization Still Matters

"While minimal kernels cannot prevent every vulnerability, reducing attack surface by removing unnecessary kernel features, drivers, and services can proactively mitigate many classes of security issues and reduce exploitability." For a long time, Linux optimization work was seen mostly as a performance exercise. Faster boot times. Smaller images. Lower RAM usage. Better cache behavior. But over the years, something interesting became increasingly obvious: Optimization and security are often deeply related. ...

May 10, 2026 · 5 min · 875 words · Dhiru Kholia

Pocket Chaos: Coding (and Decoding) on the R36S

Intro There's something slightly absurd about turning a tiny retro handheld into both an app development platform and a weak-signal radio decoder. The R36S - cheap, hackable, and rough around the edges - wasn't built for any of this. That's exactly why it works. The Constraint Advantage Modern development hides inefficiency. The R36S exposes it. With limited CPU, RAM, and screen space, you're forced to: Write tighter code Design simpler interfaces Think in constraints, not abstractions That same constraint-driven thinking applies perfectly to signal processing tasks like FT8. ...

May 5, 2026 · 9 min · 1809 words · Dhiru Kholia