*. 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.
YD1OSC (ex YD6DEK)
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.
After a long rest, its get back
One feature on HBRAA3 Antenna analyzer is a filter response plotter.
Its worked based on
*. Si5351 as freq synthesizer
*. AD8307 logarithmic amplifier
by generate some range of frequency , send it to input port of a filter, then let AD8307 amplify the output port, then read the value (25mV /dB) by using micro controller ADC, we can draw the response on LCD. This feature very help for analyze crystal ladder filter, BPF and LPF of any transceiver.
an example 10MHz ladder filter plot response (non scale)
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.
Finally I found the biggest problem with HBR10HF carrier leakage and make this item cannot running well on bigger power. I missed to make sure the BFO level from the si5351 signal generator. There’s a mistake on Si5351 capacitor output coupling on RTC03 board. The board used 100nF capacitor instead used of 100pF. Its make BFO level to big for modulator/demodulator. This cause the carrier going to xtal filter then to mixer even no modulation inject on transmitting stage (see attached picture below the wrong capacitor). You can remove the smd one and replace with non smd cap
After replace the capacitor with 100pF. I adjust the carrier balance trimpot (see attached picture below).
Voila all unwanted carrier leakage was gone. Then I adjust the power gain trimpot, yes this make the power out getting bigger. Then I replace the IRF510 with IRF530.. this changes make awesome power out, but be careful the heat sink, fuse and output transformer. How ever I tested 3 minute continue transmit test everything seem okay. I could made a contact around 1000 km on 40m band in the morning.
So the step is
*. replace 100nf with 100pf on RTC03 board
*. adjust the carrier balance trimpot
*. adjust the power gain trimpot
Power out tested using 50 Ohm dummy load and CW key, take note cw mode in HBR10HF is inject 700Hz tone into modulator.
we got 34 W power out on 10m
After two years our first iambic keyer launched https://diankurniawan.wordpress.com/2015/01/28/iambic-keyer/, its time to launch new generation iambic keyer with build in morse decoder. This iambic keyer used AVR Attiny13 as iambic control as previous version and ATMega8 for morse decoder works with LM567 tone decoder. Its actually an old design but I have no much time to build the prototype, a lot of mechanic works, cnc process, laser cutting and etc. Some improvement from firmware, additional side tone speaker.
This keyer will also have memory keyer store in ATMega8 EEPROM
*. AVR ATMega8 morse decoder and 16×2 LCD panel
*. 4 memory and function button
*. AVR ATTiny13 iambic generator
*. LM567 tone decoder
*. Acrylic with laser cutting paddle with bearing
*. Aluminum enclosure
*. Lithium battery with internal charger (optional)
we hope this will be available on December 2017
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.