kv4p HT homebrew VHF radio Android phone into ham radio transceiver PCB v1.7 SA818-V SA818S radio module

kv4p HT

Thank you KV4P for his great contribution to this project.

Turn your Android phone into a modern ham radio transceiver

Free open source software & hardware.

1.Product Description:What is it?

kv4p HT is a homebrew VHF radio that makes your phone capable of voice and text communication completely off-grid with at least a Technician class amateur radio license.

The radio simply plugs into the USB C port on your Android smartphone and transforms it into a fully-fledged handheld radio transceiver. It's completely open source (GPL3): the Android app, ESP32 firmware, PCB designs, and 3D printer files.

It's small enough to fit in your pocket and take anywhere, and since it has no internal battery it's the perfect radio to put in a go-bag or your car's glove compartment.

2.Features:

-100% ham radio, always completely off-grid
-Crystal-clear 44kHz 8-bit ADC/DAC audio, with filters and squelch

-Texting with notifications just like SMS — radio-based APRS messaging (not just location) with built-in 1200 baud modem

-Scan through unlimited memories and groups

-No battery means nothing to charge except your phone

-1 watt transmit can go miles yet sips your phone's battery

-Accessibility options: live closed captions (on supported phones), turn off animations, sticky PTT with haptic feedback

3.Firmware Version:

Dec 14, 2024: Android app update v1.4.0, ESP32 firmware v3

-Add new mic gain option to settings
-Add new settings to control rx and tx sampling rates
-Add setting to change bandwidth, narrow or wide

4.Test results:

KV4P: I've tested harmonic filtering with a TinySA spectrum analyzer to ensure it meets FCC part 97 spurious emissions requirements (which for VHF must be at least -40dBc for 2nd harmonic and below 10uW).

PCB v1.7
v1.7 of the PCB is -52.7dBc for the 2nd harmonic, and below 4uW of harmonic power, fully FCC part 97 compliant (tested with 56dB of attenuation):

-This Picture is from kv4p.com

5.Package list:

1.Kits with case

- kv4p HT Module*1

- ES32 Module*1

- Short Micro USB to USB C Cable*1

- Adapter Micro USB to USB C*1

- SMA Female*1

-Dual Band VHF UHF 136-174MHz 400-470MHz Ham Radio Antenna*1

-3D Print Case(PETG-CF)*1

2.Assembled with case
The difference from a kit is that it assembles modules. As shown in the following picture：

- kv4p HT Module*1

- ES32 Module*1

- Short Micro USB to USB C Cable*1

- Adapter Micro USB to USB C*1

- SMA Female*1

-Dual Band VHF UHF 136-174MHz 400-470MHz Ham Radio Antenna*1

-3D Print Case(PETG-CF)*1

Note:

For every KV4P HT product sold, we will donate a certain amount to the Hope Animal Rescue project mentioned by the founder of KV4P. We will strictly count the order amount and make donations.

-This Picture is from kv4p.com