HBR10HF new board design with ADE-1 as RF mixer

Specification :
*. BRITX Based
*. Front End RF gain using 2SC2570
*. Front End RF attenuator
*. TX RF attenuator
*. ADE-1 main mixer (detachable)
*. Detachable ladder filter
*. CW generator/Key PTT delay on board
*. AGC on board
*. Band Pass Filter on board

By replacing main mixer with ADE-1 we can get very good carrier suppression, increase sensitivity, and we can get more TX power on almost band. We also added crystal ladder filter adapter, so it can be upgrade next.  You can replace the crystal with your mechanical filter (please take note the impedance matcing), or you can make variable BW filter by using varicap diode.

We decided to use separate RF amplifier board with LPF on it. We hope we can increase the power out, but still using the low cost MOSFET.

Dian Kurniawan


HBR10HF intermittent blank or gray/white LCD on start problem solving

Hambuilder HBR10HF using RTC03 as controller with 3.2 (320×480) TFT LCD. This item worked very nice, good color,  viewing angle, speed (using 16 bit parallel data). But the main problem is the availability is a night mare. I using this TFT since early 2016 when I started to build the RTC03.  Until now, this TFT already have 3 difference controller in market, with 3 difference firmware and specification and the worst is, seller from China that I bought this TFT did not know and did not help what kind controller or even give me any datasheet. I must find out by my self how to make this LCD works.

its look same but they have difference

when you look at their back side its HX8357C, V2.0 and blank, its all false
The HX8357C using ILI9481, the V2.0 using HX8357D and the blank one using HX8357C.
They need difference firmware and have difference command, and what I want to tell here is they have difference habit and speed. The blank one do not need hardware reset, but the other one intermittent required. This habit make your RTC03 sometime show the white or gray or even blank display on start.

How to solved this problem? actually is very easy (this bug already solved on our production line), please check the image below. We just need to added R-C reset delay. please see the picture below

and implemended like this on your RTC03, I choose R 10K and C 100nF.

Then if you get your RTC03 with intermittent gray or white screen on start you can applied this solution.

Best Regards
Hambuilder team

HBR4HF (RTC01C + BritX tranceiver) tunning

Similar condition with HBR10HF some buyer report carrier leakage on HBR4HF, same proble with his brother HBR10HF, BFO level is too big injected to modulator. Here’s the solution :

*. Replace BFO coupling from RTC01C with 100pf value
*. Tunning the preamp trimpot
*. Tunning the carrier balance
*. Adjust gate bias voltage (Vgate) into 3V






How ever please take note, power of the transceiver considering many thing not just increasing the final stage value. We must consider also the cabling, switch relay, PCB track and etc. HBR4HF and HBR10HF not designed to produce big power.

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


HBRADD1 for HBR4HF, CW Encoder-Decoder and Digital Mode set-line

HBR4HF memang menggunakan desain klasik dengan fitur yang umum saja. Beberapa rekan mempertanyakan mengenai absen nya mode CW dalam desain HBR4HF. Hal tersebut sebetulnya sudah masuk kedalam road map pengembangan yang sebetulnya sudah sangat lama di desain. HBR4HF memang dibuat sederhana sebagai pintu masuk kedunia HF dengan pertimbangan harga dan memang faktanya untuk amatir lokal rasanya masih sangat terbatas penggunaan mode selain SSB.

HBRADD1 adalah road map setline dari HBR4HF, mengapa dibuat terpisah, kembali ke alasan harga serta tidak semua amatir menggunakan CW, HBRADD1 juga memungkinkan di kembangkan dengan fitur GPS (APRS) bila nantinya mau dikembangkan untuk radio matirim yang murah. Pada BRHADD1 ini juga telah dilengkapi interface ke sound card PC bila rekan-rekan ingin bereksperimen menggunakan digital mode via PC sound card. Pada HBRADD1 ini juga di tambahkan 5 watt audio amplifer dengan loudspeaker yang besar melengkapi loudspeaker yang ada pada HBR4HF.

Spesifikasi :
*. ATMega8 as main controller for CW decoder and display
*. NE567 as tone decoder
*. ATTiny13 Iambic keyer and PTT control with buzzer tone
*. 16×2 character LCD for TX and RX CW encoder/decoder
*. 3-5 watt audio amplifer
*. 1 x 3.5 mm audio jack for Iambic keying input
*. 1 x 3.5 mm audio jack for sound card interface input
*. 1 x 3.5 mm audio jack for sound card interface output
*. 2 x 600 ohm audio transformer sound card in and out audio
*. 5 watt speaker
*. Dimension 200(w) x 60 (h) x 100 (deep) mm



Hambuilder Team

RTC03 + BritX (All Band SSB) + Wide BPF/LPF + RF-PA20(4xIRF510), Its almost complete now

I got many request from friend to listed full set of transceiver module on ebay. Its already pushing me hard to realize it as soon as possible. Really hard to worked with my “pneumonia” problem since last year, I didn’t smoke but its happen to me because the air conditioner bacteria. I have a full day jobs as a SAP consultant. Yes, It mean lot to do but I tried to build it as soon as possible, and this post is the progress.

Nothing new design of this BritX, its just some variance of famous BITX, I just added and replace some component exist on local, plus an audio band pass filter to make better audio in receiving. Everything is generic design but, my big job is to make all module work together in all band, its not easy, at least for me. After some PCB design, prototype testing, testing and again testing. Its worked now.

The transmit test result with 13.8v supply with dummy load after lowpass filter:
1. 160m 16.3Watt
2. 80m  17.7Watt
3. 40m  25Watt
4. 30m  20Watt
5. 20m 24Watt
6. 17m  22Watt
7. 15m 19.3Watt
8 10m 8.3Watt

Yes power out is getting low on the 10m band but its common for IRF510 mosfet. Using RD16HHF or RD70HHF will be a better with flat RF output on all band. For my friend thats already bought my RTC03 on eBay, please be patient this complete set will be list there soon.


All Band BPF/LPF

All Band BPF/LPF

Dian Kurniawan

RTC03 Enclosure

Enclosure ini adalah jawaban atas beberapa request melalui email yang masuk mengenai enclosure, namun sebenarnya ini memang sudah menjadi bagian roadmap jalapindai/homebrewprtner/Hambuilder akhirnya enclosure RTC03 mulai diproduksi.

Enclosure ini memiliki ukuran 95 x 200 x 200 mm ukuran cukup minimalis. Enclosure ini terlah menyediakan

  • 1 x 4 pin CB connector untuk mic dan PTT
  • 2 x potensiometer untuk volume dan mic gain
  • 1 x toggle on off power switch
  • 1 x Antenna connector
  • 1 x 2 pin CB connector untuk power supply
  • 1 x fuse holder utk pengaman
  • 1 x aluminum heatsink

Kombinasi RTC03 dan endclosure menyebabkan homebrewer benar-benar fokus ke exciter, PA, filter dsb.


if you want to buy this enclosure please visit the link below

RTC03 Aluminum Enclosure on Ebay