Choosing Digirig Model

The USB port in the back of the transceiver usually means that the radio is equipped with an internal digital modes interface and you don’t need Digirig. All that required is a USB cable directly from the transceiver to the computer. This is the case with popular models such as ICOM IC-705, ICOM IC-7100, ICOM IC-7200, ICOM IC-7300, ICOM IC-7600, ICOM IC-7610, ICOM IC-9700, Yaesu FT-991A, Yaesu FT-710, Yaesu FTDX10, Yaesu FTDX3000, Xiegu X6100, Xiegu X6200 etc.

The notable exception to this list is Yaesu FT-891 which uses USB port for internal USB-to-serial bridge (CAT control), but does not have an onboard sound interface; see next recommendation. Other situations where you would would bypass the internal interface is when it has failed (serial port, sound card or both) or you need better soundcard performance than offered by the internal codec (e.g. for VaraFM wide).

This one is easy: pick Digirig DR-891. This model is specifically designed for your radio, utilizing maximum interfacing capabilities. There never was and likely never will be a better option. With the fallback PTT methods this also includes support of the apps on the mobile platforms as long as your phone or tablet can accept a USB connection.

The mobile platforms, especially iOS and to smaller extend Android, are quite restrictive when it comes to the access to the custom hardware. Because of that the support for some PTT and CAT control methods may be difficult to implement. On the other hand the sound cards are the standard accessories and don’t require any special accommodations.

Some mobile apps for ham radio support PTT by RTS, some apps support PTT by GPIO3, almost none support PTT by CAT, but all without exception will work with PTT by VOX. PTT by VOX implementation relies on the audio signals and doesn’t require any support from the software. When the PTT tone or the outbound audio payload is present, the interface keys up the transceiver for transmission automatically. This makes Digirig models with VOX support (Lite, DR-891, VOX cable) most widely compatible.

PTT by VOX inherently has a reaction latency, which is minimized in Digirig but still may require adjustments of software settings such as no-op preamble. If there is a choice of PTT options, the explicitly timed methods such as by RTS, GPIO3 or CAT should be prioritized. VOX PTT by tone on the right audio channel is next best and VOX PTT by payload is the last.

If your smartphone or tablet can accept USB connection directly or via OTG dongle then pick Digirig Lite. If it only has 3.5mm headset jack (directly or through an adapter) then your only choice is VOX PTT Cable.

None of these radios typically support serial CAT control so Digirig Lite is a cost effective and compact option. All you need is audio + PTT and Digirig Lite delivers. There is a use case for Digirig Mobile’s serial port even with the basic radios and it’s for the programming of the internal memory. In some cases this may require homebrew cables, in others cable is included in the kit (refer to cable listings for the info).

The only model capable of serial CAT control at the time of posting is Digirig Mobile. Make sure to select the correct port configuration when ordering [click here for more info]. You may need multiple units in different configurations if you have multiple radios that support different electrical standards for the serial ports. In every case the serial CAT is an optional convenience feature and you are not required to use it if you are setting your radio manually.