Tokmas CID9N65E3 rocks! It is CRAZY how efficient this GaN FET is in TO-252 (DPAK) package. It generates 5W @ 28 MHz with 13.8V at drain without even warming up! Datasheet excerpt: The full datasheet is available here. Here is the 3D render for a PCB I made for testing this part: The PCB design is available @ https://github.com/kholia/HF-PA-v10/tree/master/GSD-Hacks-v4-SMD (non-commerical use only).
I had bought two pairs of MOONDROP Aria 2 IEMs after auditioning them at a Headphone Connect event. After a few months of usage, one of the Aria 2 earphones lost audio in the left earpiece. We got it 'serviced' under warranty from https://www.headphonezone.in. After an year of almost no usage, the other pair of Aria 2 IEMs lost audio in one of the earpieces too! I have never seen this poor quality, reliability and longevity before! ...
I recently found two FET gate drivers which are quite fast! Wuxi Maxinmicro MX1025D BD2311NVX-LBE2 ROHM Semiconductor They are perfect for driving the fast Tokmas GAN FETs that we recently discussed on this site.
Recently, I was stuck in figuring how the Firebase gRPC calls worked and how I could generate, modify, and replay them. Trapping and modifying the existing gRPC traffic was not working too well. Finally, I took a step back and spent some time on learning how to build and debug simple Firebase applications. This approach helped me tremendously and I was able to make further progress with my original task in almost no time. ...
I am posting an early design sketch of a 2m WSPR beacon. Here are the key points: 25 MHz HCI 0.5ppm TCXO powering the Si5351 module instead of the 26 MHz TCXO. If this fails, we can use a 10 MHz OCXO instead (a bit out of spec but works fine). Tokmas CID10N65F GaN FET might work @ 144 MHz as the 'final'. If not, use Mitsubishi RD15HVF1-501 MOSFET as backup. ...
Here is a quick script to verify that the certificate chain is valid and will work. % cat verify-cert-key.sh #!/usr/bin/env bash certFile="${1}" keyFile="${2}" caFile="${3}" certPubKey="$(openssl x509 -noout -pubkey -in "${certFile}")" keyPubKey="$(openssl pkey -pubout -in "${keyFile}")" if [[ "${certPubKey}" == "${keyPubKey}" ]] then echo "PASS: key and cert match" else echo "FAIL: key and cert DO NOT match" fi openssl verify -CAfile "${3}" "${1}"
Tangara is a pretty awesome project! It recently inspired us to build a similar FOSS DAP product but at a much lower cost of <= 40 USD. Our initial tech stack: RP2350-Zero, PCM5102A 32-bit 384kHz DAC, Burr-Brown OPA1662 (specified for 3.3v) as the unity gain buffer and headphone driver, no explicit DC-DC converters anywhere, microSD card, everything will be a module if possible We quickly got this prototype working on a breadboard and discovered some limitations: ...
I am posting an early design sketch of a 6m WSPR beacon. Here are the key points: 25 MHz HCI 0.5ppm TCXO powering the Si5351 module instead of the 26 MHz TCXO. If this fails, we can use a 10 MHz OCXO instead (a bit out of spec but works fine). Tokmas CID10N65F GaN FET should work @ 50 MHz TI UCC27614 or Onsemi NCP81074 gate driver Results: To be built and tested soon! ...
This ~1W to ~5W WSPR beacon runs continuously on the 10m band. It handles extreme environmental temperatures pretty well (it is 42°C plus here). Our article on this beacon's design and operation will appear in the May/June 2025 issue of the QEX magazine soon. References: http://www.carnut.info/WSPR_Tx/WSPR_Tx.htm QEX May-June 2025 TOC QEX May-June 2025 Perspectives ...
Ismo (OH2FTG) recently introduced me to a bunch of Tokmas RF parts. Out of these, the Tokmas CID10N65F GaN FET stood out. It seems to have a lot of potential (for HF + 6m) at a very low price point. This RF MOSFET part can be purchased from LCSC. It seems Tokmas CID10N65F has the potential to completely replace the RD16HHF1 part from Mitsubishi Electric! Datasheet excerpt: The full datasheet is available here. ...