Tweaking BritX based Hambuilder exciter (carrier leakage #1)

For older version of britx based (BITX) Hambuilder transceiver some buyer reported carrier leakage during transmit, its also affect the microphone gain setting. Please find the attached document for missing part and revision.

Hambuilder team


Tweaking BritX based Hambuilder exciter internal speaker and headphone jack

First version of HBR4HF or HBR10HF are used hybrid microphone with loudspeaker. Basic idea using this is to reduce complexity and cost. also considering it as portable radio. How ever there’s a requirement to operate with external audio amplifier or external speaker for better audio receiving. The newest HBR4HF already have internal loudspeaker, and the newest HBR10HF already have audio jack also.


Hambuilder team

HBR10HF and HBR4HF front panel face lift

HBR10HF facelift :

*. Additional phone jack
*. Additional key jack
*. Additional pc audio in and pc audio out
*. 5cm Aluminum rotary knob for freq dial

HBR4HF facelift :

*. 2.0 inch TFT display replacing 16×2 char LCD
*, Additional phone jack
*. Additional key jack (back side)
*. 5cm Aluminum rotary knob for freq dial

Hambuilder team

Hambuilder SSDR100 prototype

This is the next Hambuilder transceiver (SSDR-100)
*. 3.2 inch TFT display
*. STM32F407 as display control and waterfall processing
*. ATMega8 (21st order FIR LPF processing)
*. Weaver SSB modulation and demodulation method using 2 x ADC MCP8201 and 2x DAC TDA1543
*. Embed CW decoder/Encoder using ATMega8
*. Bluetooth Access for setting, remote access and firmware upgrading
*. Android remote access Apps
*. 18 button access for band and control
*. 1 rotary main dial
*. 3 rotary for RIT/XIT, Bandwith Control and WPM
*. PC audio interface for digital mode
*. 80-100 Watt power out

Hambuilder Team


Hambuilder Antenna Tuner prototype

This prototype inspired by MFJ-928 or KAT100 or ATU from OM K2ZAR Automatic Antenna Tuner from internet. On diagram below show the basic concept but I considered not to use Z sensor and frequency counter to make it simple for now and may be will adopt later.




HBRATU control board


HBRATU main board




Hambuilder Team

CW adapter for HBR4HF and BritX

This design using Atmel ATTiny13 microcontroller with 1KB flash, this flash is more than enough to handle the duty to generate 700Hz tone and handle PTT delay. ¬†Actually using 555 is also possible to build the interface but using microcontroller give alot of option and possible “future feature”

*. ATTiny13
*. Digitally 700Hz tone generator
*. adjustable PTT off delay time

*update 03.09.2017 (prototype image)

Hambuilder Team