Radio novice Vance “KV4P” Vagell has designed a tool for the ham on the go, the kv4p HT — a pocket-size, open supply, $35 transceiver so as to add novice radio capabilities to any Android smartphone.
“kv4p HT is a homebrew VHF [Very High Frequency] radio that makes your telephone able to voice and textual content communication utterly off-grid with a minimum of a Technician class novice radio license,” Vagell explains of his creation. “The radio merely plugs into the USB C port in your Android smartphone and transforms it right into a fully-fledged handheld radio transceiver. It is sufficiently small to slot in your pocket and take anyplace, and because it has no inside battery it is the proper radio to place in a go-bag or your automotive’s glove compartment.”
The {hardware} itself is predicated round an Espressif ESP32-WROOM-32 improvement board linked to a low-cost DRA818V radio transceiver. There are not one of the components you’d anticipate to see on a cellular radio rig, with no buttons, no show, nor even a tuning dial: the whole lot is designed to be managed utilizing a companion app for Android smartphones and tablets, over a USB cable that additionally powers the radio.
Vagell launched an preliminary closed beta of the undertaking again in late September, earlier than opening it up extra broadly earlier this month. Every part he has developed is open supply, from the smartphone app to the provider PCB that takes the microcontroller and transceiver — although this latter design has been revised to enhance its filtering of harmonics, with assessments awaiting supply of an up to date prototype. “It is as much as you if you wish to look forward to this revision with higher filtering,” Vagell writes, “however I like to recommend it.”
These constructing a kv4p HT will discover a vary of spectacular features, together with the power to hold out APRS textual content messaging over a built-in 1,200-baud modem, 44kHz eight-bit audio with filters and squelch help, limitless reminiscences, a one-watt transmission energy, and accessibility options together with dwell closed captioning of voice conversations on supported telephones.
Extra info on the undertaking is offered on Vagell’s web site, with supply code and design recordsdata out there on GitHub below the reciprocal GNU Basic Public License 3.