Dhiru's Notebook

WSJT-X 3.x has inbuilt support for band hopping!

This code generates a .wav file which emulates a fully-populated FT8 band!

Future radio receiver design ideas (from Ismo, Pete and other folks): Antenna ➔ (BPF) ➔ BFR93A based pre-amp from mcHF project ➔ MC1496 (Mixer) ➔ 455 kHz IF ➔ Ceramic filter SMD (HCI) ➔ 'IF amplifier' (20-40 dB gain?)

Shipping hardware internationally is a hard, labor intensive, and overall a frustrating process - especially more so these days.

Instead of punching islands or using commercial pads (islands) or making traditional pads myself, I simply make use of small pieces of single-sided PCBs to create the pads / islands easily for my boards.

For HF and amateur VHF bands our WiFi VFO works great.

Here is the FT8 WAV test file.

While running https://github.com/fhoedemakers/pico-infonesPlus, I found that my SNES gaming pad was not fully supported.

I recently spotted the Tokmas CI7N170SM TO-247 part on LCSC.

OCXO's are awesome - this is what I learned while trying to get WSPR working reliably on the 2m band.

The wspr_spread work is excellent.

Note: This HF LNA design is inspired by Charlie Morris ZL2CTM's prior work.

Notes to get Vivado 2025.1 running on Ubuntu 25.04 (plucky) Linux distribution.

Circuit: DDX-Commercial-7 Antenna: Small jumper cable attached Initial Results 10m: 36 dB on WSJT-X audio meter, on quiet and also with nearby beacon on !!!

Our WSPR beacon design works fine even on the 4m band (~70 MHz) .

The usage of ready-made coupled inductors in RF designs was pioneered by Jim Veatch in his award-winning RF amplifier designs.

Our 6m WSPR beacon design works fine now.

Here is a handy script that I often use to check the quality of the Zoom connection.

We make heavy use of Easy-Digital-Beacons-v1 for testing RF amplifiers.

I had bought two pairs of MOONDROP Aria 2 IEMs after auditioning them at a Headphone Connect event.

Tokmas CID9N65E3 rocks!

I recently found some FET gate drivers which are quite fast!

Recently, I was stuck trying to understand how Firebase gRPC calls worked and how I could generate, modify, and replay them.

This is an early design sketch of a 2m WSPR beacon.

Here is a quick script to verify that the certificate chain is valid and will work. % cat verify-cert-key.sh #!

Tangara is an excellent project!

This ~1W to ~5W WSPR beacon runs continuously on the 10m band.

This is an early design sketch of a 6m WSPR beacon.

Ismo (OH2FTG) recently introduced me to a bunch of Tokmas RF parts.

I have designed, built, and tested an all-HF WSPR beacon that produces 1W @ 5V and is rugged and cost-effective.

I found this 60W Electronic Load to be quite useful for testing small power adapters and supplies.

Tangara is an excellent project.

The Easy WSPR Encoder can be accessed here.

I have built what is probably the easiest, reasonably rugged, and most cost-effective 100mW WSPR (or FT8) beacon.

Notes to get RSP1 working on Linux and macOS using FOSS drivers (2025) Prerequisites Please use a mainstream Linux distribution like Ubuntu 24.04 LTS (or later) or the latest Raspberry Pi OS.

The Easy FT8 Encoder can be accessed here.

Bharath and I have written our thoughts on building an RF lab on a budget.

Some weeks back, we published our designs for building reproducible TX-BPF filters easily.

I was a bit late in realizing that Ubuntu has been going downhill for a while.

I am building an easy-to-use, cost-effective WSPR pHAT for Raspberry Pi Zero 2 W.

My homebrewed PA0FRI Active Antenna is working well from a very physically constrained location.

Sometimes we all need a bit of QRO - Life's too short for QRP sometimes.

Aim Finding 'Heartbleed' class of bugs with taint analysis.

This notebook (aka 'blog') is powered by free solar energy!