The list that follows is not exhaustive or complete, its just the most useful selection of Apps that I can fit on an old Android Tablet with limited memory. It's not my intention either to review of provide an insight into the operation of each application, that I will leave to you to discover: after-all amateur radio is about self learning!
In my selection process I've tried to steer away from programs that duplicate each others abilities and many of them you won't find on the Google App Store. Quite a few were culled from APK file repositories and to use them you have to take on board that some may occasionally carry viruses, that's why I'm using an old machine which is dedicated to the task of portable field operation. You will need to switch off the security measures on the tablet to install them. No guarantee is given to their ability to run on your hardware either. The tablet I am using is a Huawei Media Pad Model BG2-W09, with a kernel last updated in 2018.
Because Huawei fell from favour with Google, you will often see their products cheap in local cash exchange marts or even as scrap on social online markets, as they are no longer sent system upgrades by Google. This can work to our advantage as the newer kernels launched by Google will not run some of these apps, I guess that is why many of them have dropped from the Google App Store.
Robot36, SSTV Encoder, Droid SSTV, Assempix, Shredpix & Hell are image transmission and reception apps. The first four apps cover traditional analogue SSTV, while Assempix/Shredpix provide a new OFCM digital means of sending HD SSTV pictures.
It could be said that Hell. is not strictly a picture mode however, it's a method of sending and receiving text using facsimile technology. It's unique in that the characters are not decoded, but simply "painted" on to the device screen. In transmit it uses a form of raster scan on each letter of text, effectively sending sequentially lots of tiny SSTV pictures. There's nothing new about the Hellschreiber format, it's been around since WWII, back then it used mechanical tech to send and receive the mode.
The Text on Photo app allows you to tag reports, call-sign and welcome messages to pictures before transmission.
Text
This category of application is for sending and receiving text messages. The FLdigi application has become the radio amateurs version of the Swiss Army Knife with reference to digital communications. Its ability to run on modest hardware in both Windows and Linux operating systems is one reason and the other its free. Packed with useful features FLdigi enables communication through a simple sound interface, giving the operator of a amateur transceiver access to dozens of digital modes, including Morse and Hellschreiber.
Several years back FLdigi was ported over to Android in a slimmed down format to provide a small footprint, low power messaging system, to be used in conjunction with portable HF and VHF transceivers. The idea was to provide a lightweight communications terminal on which rescue personnel in areas with zero infrastructure could provide an emergency communications network. The application was renamed AndFLmsg and provided a much simpler user interface than its big brother, while still giving access to the following digital modes:
PSK/PSKR modes, including multi-carrier modes, some of the 8PSK modes, THOR, MFSK, OLIVIA, MT-63 and Domino-Ex modes.
The ARRL "Radiogram" message format used by the application enables the user to send both text message and photo in some of the digital modes.
As AndFLmsg doesn't provide for Morse, RTTY and FT8 modes, the following applications have been included in my list. DroidRTTY, Morse Decoder and FT8CN, and while not a communication mode I've included WSPR tx, as its normally lumped in with and FT8 application on the PC.
Finally there is Rattlegram, a fast text system which can be used with or without a sound interface, you can just hold the Android device near the transceivers microphone and speaker and it will work. When the application is configured correctly it will sends your call sign as a synchronising preamble, which when viewed on a waterfall display can be read as plain text. The digital modulation parameters can be adjusted in the application to enable its use on both the HF and VHF bands.
Utilities
The following applications were chosen to augment portable operation - Grid Square and What Three Words are useful when establishing your portable station. Grid Square will enable you to establish both your Maidenhead Locator and geographic coordinate, while What Three Words will help emergency services locate your position, if the area you are working from gets cut-off.
The addition of the
OS Locate application was to aid establishing your WAB (Worked All Britain) square details. Many portable and mobile stations collect WAB information to ultimately gain the award. A WAB square is a 10 km Ordinances Survey grid square. There was a custom application available to provide square ID but it's has been removed due to it no longer meeting Google's application requirements. The easiest way I have found is to use the OS Locate application, as your WAB square ID is comprised of two letters (which reference the OS Map sheet) and the First number of the Eastings followed by the First Number of the Northings. For example if the grid reference given by the application is SU512385 then your WAB square is SU53.
https://wab.intermip.net/default.phpI take the point that paper and pencil will work in the damp and they don't require power. However, Log Book can be used in their place enabling you to download a log after a contest to process the results. An Audio Recorder application is a good feature to have on both tablet or a phone, to help captur that one prized piece of DX, or record that Morse contact you couldn't quite decode, for review later in the comfort of your shack.
AOS
When HF conditions become flat you might consider kitting yourself out with a small dual-band (2m/70cm) beam as there are a growing number of low earth orbit satellites (LEO for short), that enable both FM and SSB operation. Nothing too complicated about working through the FM birds, best viewed as a flying repeater with a huge operating footprint - see the AMSAT web pages for details:-
https://www.amsat.org/. Youtube has some interesting videos explaining their operation. Anyhow, I thought a good satellite tracking app. would be nice to have, so I've included the
Ham Sat application which will provide you with Acquisition of Signal information (AOS) - when your satellite of choice comes over your horizon and available for operation.
Beacons & Propagation
Propagation information is invaluable when in the field and no one application provides the full picture, so in addition to HF Prop here are a couple of Internet links you might like to put shortcuts to on your application pages.
https://www.ncdxf.org/beacon/index.html#Schedule The NCDXF global beacon network all share the same frequency and the application provides timing windows to show which of the beacons is currently transmitting. In simple terms if your Morse decoding is not up to scratch you can still make a stab at what beacon you are hearing.
https://vhf.dxview.org/ Is a great indicator of VHF propagation both Sporadic E and Tropospheric, I think the data is collated from APRS VHF packet network data.
https://hf.dxview.org/ Is a great indicator of HF propagation showing activity on individual bands and single if required, again I think the data is collated I think from WSPR and HF packet network data.
Typical plot from the VHF DX Viewer page
Please put a shortcut to the following:-
http://kiwisdr.com/public/. Kiwi online SDR gives you access to a world wide library of online SDR receivers which enable you to monitor your own signal in other countries (am I getting out). While local UK based receivers give you the opportunity to check your audio quality and bandwidth, you see too many stations over-driving their transceivers during digital mode operation. You may find that due to age and limited resources of your tablet this application is a bit clunky, if so it can be run in your browser using the above link, I tend to use Firefox as the html sound generally works first time.
Repeaters and Gateways
If HF conditions are a bit flat I often find myself surfing the local repeaters, and not so local, as it's surprising what a little elevation can do for your signal on VHF and UHF. That's why I've included the Repeater Book application on my tablet, the repeater lists are geographically listed with the nearest sites being at the top of the table. The app. also gives you a quick glance appraisal of each repeaters mode and access codes/tones.
I know it seems a little strange to have a DTMF code application on the list, but I often use old, or Ex-PMR equipment, that have no means of generating these tones. So in order to gain access to many of the features found on analogue gateways, I have chosen the Wolphi application as I found it the most versatile
Lastly but no means least, I have two VOIP applications, Echolink and Peanut. These are not really for field operation although I have used them when doing tests, they are more about staying in touch with amatures back in the UK when I'm away from home. Echolink is an old system now but it works faultlessly and has been given a new lease now VOIP software bridges have been built between the Echolink system and the AllStar network. Peanut if you like, is a new version of Echolink but spans many of the digital VOIP systems both DMR and Fusion. I've had fun too using both apps when conditions were flat, having armchair contacts with hams in all corners of the globe both day and night.
73's
I hope you've enjoyed this whistle stop tour of amateur radio applications available for the Android OS. Tablet computers are now ubiquitous and cheap, together with mobile phones making QRP digital mode operating easy and very portable.
If you're wondering what interface to use between the tablet and transceiver, can I please draw your attention to a previous blog:-
https://www.blogger.com/blog/post/edit/5385360074172497776/5144327314764627061 There are several designs out there but all seem to be home brew. I would say using an old tablet or phone simplifies the interfacing as these devices still rely on the good old jack plug to connect their audio to the outside world.
I've search the halls of Ebay and found a commercial interface. I have no knowledge of it and I would suggest you read a couple of reviews before you race off to buy one. Please see:- "EASY DIGI™ PSK INTERFACE FOR Phones/Pad's/Tablets (Apple and Android)". Unfortunately, it's made in the USA and the shipping rates are astronomic.
It may be possible to use other operating systems, but I have no personal knowledge of them, so I will leave it up to those in the know to write their own blog.
73 till next time. :)
Reference: Please view on Youtube, the excellent videos produced and hosted by Julian OH8STN "Off-Grid Ham Radio OH8STN". He covers the use of AndFLmsg and the craft of hardcore portable operating.
