Review of DroidPSK Android App for Operating PSK Datamodes

DroidPSK Main Screen

Introduction

I found out about this Android phone app whilst reading Jamie Davies’ book “SOTA Explained: a beginner’s guide to hilltop radio” (published by the RSGB). It was suggested in the book that portable datamodes operation was a viable proposition using either DroidPSK (for Android phones) or PSKer (for iPhones). Since I have an Android smartphone I thought I would I would give DroidPSK a try.

Overview

DroidPSK is a simple program that allows text messages to be transmitted and received using BPSK (binary phase shift keying), via a radio transceiver connected to your Android device. I use the term “connected” loosely here as it is possible to receive and transmit the audio tones via the built-in microphone and speaker in the Android device. However, making the connection via the headset jack and a suitable interface would be a more reliable option.

Features

• Intended to work with Android phones and tablets
• Operates on BPSK31 and BPSK63 modes
• Connects to the radio transceiver via the phone or tablets audio jack, or can be acoustically coupled to the microphone and speaker.
• Produces a ‘waterfall’ display of the received signal spectrum to facilitate finding signals and tuning into them
• Has user-programmable macros for sending commonly used phrases
• Includes a basic logbook

It is unfair to compare this simple app with ‘full blown’ datamode programs such as FLDIGI. It is not intended for regular base station use and is specific to PSK operation. However, the program author (Wolfgang Philipps) also offers apps specifically for RTTY and SSTV.

http://www.wolphi.com/ham-radio-apps/

In Use

I downloaded the app and installed it on my Doro Liberto 820 smartphone. All of the review is based on my experience using the app on my phone (I do not have a tablet).

Before using the app for the first time it is necessary to enter your details such as callsign, location etc. Before I had a suitable interface, I tried using the app with the phones built-in microphone. By holding the phone near my HF transceivers speaker I was able to decode PSK signals received on the 20m band.

Station Info Screen

I designed and built my own interface based on a circuit created by Ivo Brugnera (I6IBE), which I found on the internet. This is described in my post:

https://www.myadventuresinengineering.com/2019/01/portable-psk-operation-with-ubitx.html

The Phone App with Homemade Interface and Radio

The software supplier offers a ready-made interface (Wolphi-Link), but this would have worked out quite expensive after shipping to the UK. I recommend using an interface that automatically keys the transmitter PTT when detecting transmit audio. The interface needs to be adjusted so that the transmitter is being operated below the onset of ALC when sending text. I suggest doing this with the phone volume set to maximum. I found that on my phone I had to reset the volume control each time I started up DroidPSK.
PSK signals are decoded by placing the cursor on signals appearing on the waterfall display. The received station’s callsign, name, QTH and locator can be captured from the received text screen and inserted in messages using the macros. This information can also be transferred to the logbook (more on this later). To capture the text you need to tap on the word to highlight it, then hold your finger (or stylus) on the appropriate field to copy/paste the word. This took a little practice before I was able to do it reliably during a QSO.

To start sending messages you just tap on the Start Tx ‘button’. Tapping the button again returns to receive mode. The default CQ message macro automatically switches to transmit mode. There are several useful messages stored in the built-in macros and these can be edited if desired. The “clipboard” offers an alternative to using the pre-prepared macros for sending messages. However, I think more natural ‘rag-chewing’ type conversations would be tricky using the app on a smartphone, especially in a portable situation.

A minor criticism of the app is that it is difficult to switch quickly between PSK31 and PSK63 modes, necessitating going into the settings menu.

Settings Menu

The app features a built-in logbook, which is a really useful feature when operating in a portable situation. It would be very tricky to manage the phone, transceiver, notebook and pen while on a windy hilltop! Note that the frequency which gets entered in the logbook is whatever you have typed in the frequency box, i.e. the program does not calculate the exact operating frequency.

Logbook Screen

Another useful feature is the ability to override the phone display automatic shutoff. It is a good idea to disable this feature when not needed otherwise this will seriously impact on battery life.

Summary

I have used this app both at home and on a local hilltop and found it performed well and was simple to use. The program can be downloaded from Google Play Store (I downloaded version 3.38). It costs £4.43, which I think is a modest amount to pay for this useful app.

Note that I have no connection with the suppliers of DroidPSK and bought the app for my own use.
Related posts:
https://www.myadventuresinengineering.com/2019/01/portable-psk-operation-with-ubitx.html

https://www.myadventuresinengineering.com/2019/05/understanding-bpsk-modulation.html

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