uSDX TriBand – 3 band SDR All Mode QRP Transceiver - designed by BARBAROS ASUROGLU 

Note: This project consists of several boards, three of which are mandatory - the main board, the board with the screen and buttons and the board with the amplifier and filters. There are two other boards that are not required, these are the front and back panel of the box for which the board is designed.

Also, the LCD pcb and the amplifier PCB have alternatives for different screens or for different amplifier transistors, respectively.

Different boards are published with different numbers.

All credit to BARBAROS ASUROGLU 

So what does uSDX TriBand design brings to the table:

– An Aluminum enclosure! Which protects all the electronics as it should be. So you can easily toss it into your backpack and you don’t have to worry about damage.

– Small enough to fit even in your jacket pocket and easy to travel with. It is 100 mm x 88 mm x 38 mm(3.9” x 3.5” x 1.5”)

– It is 3 band with separate PA board which means multiple PA boards can be switched to add multiples of 3 bands choices.

– Looks more like a classical pro TRX look with pcb front and back face plates to be bolted on aluminum enclosure.

– It has an ISP connector for ease of firmware upload.

– It has SDR I/Q output pin header on PCB which can be extended with a 3.5 mm jack cord to connect a PC soundcard audio line input to decode with various SDR software as any SDR dongle.

– It has a PTT OUT jack driven with a Solid State opto coupled relay capable of driving 500 mA relays for example an external RF Power Amplifier relay directly.

Apart from these my design philosophy didn’t change a bit which is KISS (Keep It Simple Stupid), easy to build just with a fine tip soldering iron and easy and simple to operate in the field:

– Schematic of uSDX is same as PCB V1.02 hence the 3 band lpfs and band switches.

– It is mostly through hole components. all IC’s are smd due to less real estate area on pcb but can be soldered easily with a fine tip soldering iron. If FST3253 can be soldered in V1.02 with a soldering iron then these ICs all have same pin pitch.

– It has the option of both Si5351 smd or SI5351 Module option. With the SI5351 module this rig can be soldered only with a fine tip soldering iron.

– Band switching has the same topology as my V1.02 pcb multiband module using two slide switches to switch between bands. uSDX firmware supports relay controlled automatic band switching but I avoided it on purpose to save space and for the sake of simplicity in configuration of choosing just 3 bands without all those relays etc.

– LPF design on uSDX TriBand is Manuel Klaerig, DL2MAN’s efficient serial resonance filter which can efficiently deliver 3.5 to 5 watts depending on band. Thank you Manuel for this great lpf design.

– uSDX Triband uses a COG (Chip On Glass) 2×16 LCD from New Haven Display which is relatively cheap, small and thin to keep the unit compact. I also designed a Standard 2×16 LCD display pcb as a classic display option. The only drawback of that approach is suggested aluminum enclosure is not an option anymore, it won’t fit.

As a summary uSDX Triband is an upgraded version of uSDX V1.02 pcb with a smaller display, multiband capability built in and stacked in an aluminum enclosure with bonus features on top of V1.02 PCB.

Sourcing Parts that are different than V1.02 PCB:

uSDX Triband uses most of the parts of V1.02 PCB design BOM. Here I will outline the parts that are specific to uSDX Triband and where to procure them.

Read the full story on the author site:

https://antrak.org.tr/blog/usdx-triband-sdr-all-mode-qrp-transceiver/

All credit to BARBAROS ASUROGLU