HF Signals

Work the world on 40 meters ($59 USD)

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When was the last time you used a radio you had built? The BITX40 board is a two board, 40 meter SSB transceiver module kit with digital control! Inside an evening, you can be on-air with this digital SSB transceiver, chatting with the local gang or chasing DX. Plug in the earphones, the included electret mic, tuning and volume controls and you are on air! Included are high quality connectors, all the needed sockets and jacks, tuning and volume controls, mounting hardware, etc.


The Raduino The new BITX40's Raduino is an Arduino Nano powered, small, hackable board based on the rock steady Si5351 synthesizer with a clean 16x2 frequency display, free and open source code, 6 analog ports, three oscillators and six digital lines.

Receiver The listen to the very clean, crisp and quite receiver. The front-end has a triple tuned circuit that cuts out-of-band signals. The diode ring mixer front-end makes this a crisp receiver that doesn't overload easily. The all analog signal path to your ear provides outstanding signal clarity that is to be heard to be believed.

Transmitter 7 watts of low distortion SSB provides you with enough juice to have thousands of contacts on 40 meters, daily rag chew and occasional DX chasing. Any common 2 ampere 12 linear volts supply will provide enough juice for this transceiver. Or you could simply run it from a battery!


The BITX40 will inspire you to experiment. Modify it, mount it, tweak it, change it.

Raduino is a standard Arduino Nano that makes it easy to write code in simple C language to work on more modes, bands, utlilities. RIT, dual VFOs, more bands, CW/RTTY are just some code away! who will be the first to the Raduino keyer?

The main board uses all analog large sized SMD components that are laid out on an easy to understand manner on a double sided board with broad tracks. This can be your main module around which you can start experimenting. There are jump-points from where you can add more modules like the DDS, more bands, better audio amplifier, etc. Imagination is your limit. You can separately increase the power amplifier's supply voltage to 25 volts to be more than 20 watts of power : You will have to add a better heat sink. The mods are on the way!

The boards can be installed inside any box that you like. Make your own station rigs, man-packs, SOTA rigs, trail radio or mount it in a cigar box and leave it on your bedside table. Watch the instructions video.

Box Contents

We have tried to include connector/hardware you might possibly need to build a full radio. However, we also had to balance the shipping weight to keep the overall cost down. You will have to supply your own box, power supply and earphones/headphones/speaker.

* Note : A speaker is not included in the kit as earphones/headphones/speakers are easily available locally. No cabinet is included to save on the postage cost. Almost any box maybe used.


The BITX boards are hand assembled by a collective of women. Each of the toroids is hand wound. This provides these women with livelihood. The assembled boards are then DC checked a final RF check is performed to check the receiver's sensitivity as well as transmitter's output before being shipped. Each board is individually numbered.

About Us

HF Signals is founded by Ashhar Farhan, VU2ESE as a part of Paradigm E-commerce Pvt. Ltd to encourage people all over the world to get more active in amateur radio, analog electronics and self-learning. Building and modifying radios is a great education. Lack of access to elmers and and radio builders' community, absence of test equipment : all impede the spread of homebrewing. With the BITX40, we hope to recover that ground and encourage more and more people to get on air, modify, experiment, build and learn. So, go head, make that mod you wanted to.