Digital Couldn't be Cheaper or Easier

Published in the Chattering Relay January 2021

Did you join in on the VHF simplex contest this month and wonder how you could have increased your number of contacts with the equipment you have? Did you just get your license are thought to yourself “what else can I do besides physically talking to other people”? Maybe you have stumbled across the end of the ARES met and wondered what exactly what that modem sound is saying. The answer to all those questions is digital. I’m here to tell you that you can do many digital modes with equipment you already have.

One big advantage we have in 2021 is that we carry a pretty powerful computer in our pocket every day. Some call it a phone, others use the term smartphone, but the reality is today’s phones and tablets are supercomputers compared to computers of the past. I distinctly remember when my family bought our first computer and had its specified and built to our requirements, replacing the few hand-me down dos and Windows 3.1 machines we were using. It was a Pentium II running 450MHz, had 256 Mb of ram and we spent some serious money to grab a 4GB hard drive, and it was one of the first Y2K compliant models. Compare that to most phones released in 2020, 2.4GHz 8-core processors, 6Gb ram and 128 Gb hard drives are the norm, and by definition include sound cards.

Some of you may be aware of a windows program called Fldigi for windows that can be used for decoding and transmitting digital information. W1HKJ and his associates have created an android version that combines most features of Fldigi and Flmsg, called AmdFlmsg that can be run on any current android phone or tablet. Even better, it’s not required that you have any interface cables. It works utilizing your phone’s speaker and microphone, and you only need to hold it up to your radio’s microphone or speaker to transfer the digital transmission between your phone and radio.

AndFlmsg supports the DOMINOEX, MFSK, MT63, PSK, BPSK, OLIVIA, and THOR, including most variants and baud rates. Want to grab the Summit County ARES weekly announcements, open the application and change the mode to MT63_2000_LG, hold it up to the radio and let your phone do the rest. What about the daily digital bulletin from W1AW? That is sent using a rotating set of modes, two of which are BPSK31 and MFSK16 and are transmitted multiple times a day. Check ARRL’s website for the current schedule. If you are transmitting, don’t forget to turn the VOX feature on for your radio.

In the event that you are plagued by environmental noise, or you just want to perform your transmissions and decoding in a quieter method, there are many options for audio cables. Most HTs have a port for external speaker/microphones and there are many options for cables to connect to your radio that are terminated in 3.5mm headphone/microphone male. Plug the cable into your phone and radio and off you go. Toss the cable in your bag and you can always be ready wherever you go.

Enjoy & 73!