Digital modes compared

This is a link I came across when looking at videos about LongChat (see previous post). I think it was done before FT8 appeared. I think FT8 works down to about -21dB S/N although I have had some decodes at -24dB S/N.

See https://www.pa3fwm.nl/technotes/tn09b.html .

DMR

 Actually, I have never ever used a digital mode like Fusion, D-star or DMR. I used to have an FT-991A that supported Fusion. Currently I have an IC-705 that (I believe) supports D-star. As far as I am aware I can only access DMR via the internet, but I do not (yet) know how to do this. Actually, these digital modes are a knowledge gap that I should try to plug in the coming months.

New MGM (digital) RSGB contests

According to the latest RadCom, the RSGB's VHF contest calendar now includes a couple of contests aimed at digital operators.

See RadCom Feb 2018 p70/71

Digital experiments

In all my time in amateur radio I have never once experimented with microprocessor programming and I have done very little "digital" design.  This seems to be a gap in my knowledge, although I am still not really interested, preferring RF design, especially QRP.  I must say I remain very impressed with Wolf's (W5OLF) tiny WSPR-AXE-CW beacon: this goes to show just how much can be achieved with so little physically. Maybe this is a whole area I should embrace? The trouble is it is impossible to be an expert at lots of things, unless you are very bright. Certainly I do not consider myself a polymath! 

Digital repeaters

As I have mentioned before, I am a rare repeater user, partly because my voice is so poor currently and I don't find operating through repeaters that satisfying. Each to his/her own and if this helps you enjoy the hobby go ahead!

At the moment it is far from clear which form of digital repeater will win: there are several competing digital standards and all have their advocates. For now I shall sit back and wait. A bit like the video standards war in the 1980s, the best system may not win. Let's see. Up to now I have only used FM repeaters.

When I do use voice I use SSB, FM and AM. All modes have their places on our bands. SSB is good on the crowded HF bands, FM useful for nets on VHF, and AM rigs simple to build and there is space on all bands from 10m upwards for all analogue voice modes. A well designed AM rig should occupy less than 6kHz, far less most FM transmissions on our bands. 10m AM, just above 29MHz, is a great mode. I have worked quite a few stateside stations on 10m AM. And I have only used QRP AM.  Let no-one tell you AM is a dead mode!

Digital systems and amateur radio?

At the moment there seem to be several competing digital modulation schemes First there was ICOM's D-star system, then C4FM from Yaesu, and of course DMR, which is gaining ground in the commercial PMR world.  There are even a few experimenting with TETRA, as used by the public services. Like Betamax and VHS, the best system may not win in the end.

At the moment, I am just not interested. I'll wait to see who wins in the end. My bet is DMR will win in the end as there will be a plentiful second hand market from PMR. This will never be so with any proprietary system. DMR is an open standard, so there will be plentiful radios around and at decent prices before too long.