January 1, 2026
Glue guns & gigahertz
A Christmas Present to Myself – Vector Network Analyzer (2014)
Tiny Christmas lab toy sparks big fight over “real” vs budget gear
TLDR: A hobbyist unveiled a tiny VNWA signal tester that needed a hot-glue fix to stop “whistling,” sparking a festive lab-vs-budget debate. Some shared a VNA explainer for newbies, while others championed the cheaper NanoVNA with a built‑in screen—DIY ingenuity battles plug‑and‑play convenience.
A radio tinkerer treated himself to a tiny, USB-powered signal tester called the VNWA 3E, and the comments turned into a holiday showdown. This little box measures how a device reacts to radio waves—think: it checks what gets reflected back and what passes through—while classic lab machines are huge and pricey. Cue the community: one crowd is thrilled by clever hacks (overclocked chips! audio sampling!) and the hot-glue fix for a literal whistling inductor—yes, the gadget was singing carols until a drop of glue shut it up. Another crowd rolls in with the “read the manual” energy, dropping a primer from Tektronix to keep everyone honest.
Then the plot twist: the NanoVNA stans crash the party. “Same vibe, way cheaper, with a screen,” they say, turning the thread into budget warrior vs purist lab lore. Builders chime in with “thanks for the reference design,” hinting this post is a blueprint for DIY dreams. The spiciest debate? Whether clever shortcuts and glue-on-inductor fixes are brilliant or just… festive duct tape. The jokes wrote themselves: “Silent night? Not until you glue the whistler,” and “Santa prefers GHz over gifts.” The vibe: scrappy ingenuity vs slick convenience, and nobody’s backing down
Key Points
- •VNWA 3E is a compact, USB-powered VNA created by radio amateur Tom Baier (DG8SAQ).
- •Design uses overclocked AD9859 DDS chips and harmonics to extend frequency coverage up to ~1.3 GHz.
- •Dynamic range is about 50 dB above 500 MHz; output power is low (-17 dBm at 1 MHz, less at higher frequencies).
- •IF between 1 kHz and 12 kHz is sampled by an audio ADC; S11 and S21 can be measured simultaneously via an expansion board.
- •A whistling noise from a DC/DC converter was mitigated by gluing the inductor; the unit employs a MAX632 step-up converter.