Weight Matters

This article was written nearly 10 years ago and in that time, the weight of equipment has fallen. However the technique of weight analysis remains useful.

The Summits on the Air award programme (SOTA) has given rise to a great increase in interest in portable radio stations that are small enough to carry and yet efficient enough to guarantee contacts from even the most remote locations in theBritish Isles. SOTA participants seem to fall broadly into two camps; those who have taken it up to add interest to a flagging amateur radio career and those who have come to the programme from a background of backpacking and mountaineering. The different approach of these two groups to weight to be carried is interesting.

The first group (“the radio amateurs”) usually concentrate on the radio equipment side of things, often taking equipment that they have used for occasional portable forays over many years. They carry quite heavy equipment and take spares for everything. They carry gear for bands they seldom actually operate on “just in case”. They are happy when they return home with their second 7 ampere-hour gel cell still with plenty of charge left. One devotee of this type of operation has recently reduced his pack weight to less than 25 kilos (radio gear and other walking equipment).

The second group (“the mountaineers”) look at what is to be achieved and searches out the lightest option for each piece of equipment with just that objective in mind.. For them a pack weight of 10kg is more than enough …and they are ecstatically happy if their battery goes flat towards the end of what was to be their final contact!

Carrying excessive weight gives rise number of potential problems:

1) In hot weather you will have to work harder to get to your portable location – that means that you will need to carry more water (even more weight).

2) If you carry a heavy pack, you will want to use the shortest and easiest way up onto your chosen hill – this may not be the most enjoyable route.

3) As you increase your pack weight, the risk of stumbling and injuring yourself increases (risk is highest on descent).

4) With a heavy pack you increase your risk of back strain – particularly when putting your pack on or taking it off.

A technique that I adopted many years ago and that has served me well is one of weight analysis. It came about from working as a young engineer where one of the tasks I was set was to analyse the handportable equipment manufactured by our competitors. Each radio was taken apart and the weight assigned to different functions (e.g. TX, RX, battery, enclosure). This was quite revealing and was used to suggest to our engineers ways in which our own products might be reduced in weight.

Portable operators can easily adopt the same technique. Categories for radio systems might be:

  • Aerials and feeders
  • Mast and guying system
  • Transceiver
  • Battery
  • Ancillaries.

These can be shown as a Pie Chart which will help you see if there are any excessively heavy components that add little to the functionality of the station. The results of such an exercise are shown below. The first Pie Chart shows the original set-up. This alerted me to the fact that the reel for my aerial and my Morse key were both rather too heavy.

chart1.jpg

A little re-engineering gave the following result – much better!

chart2.jpg

Of course lightest way to do some portable operating is with a simple 2m FM handy. Mine weighs 335gm and will usually yield a few contacts from hilltops in the Northwest of England (where there is still a fair amount of 2m FM activity). However, this approach is liable to fail away from activity hot-spots or on lower hills. A more sophisticated portable station will increase the fun.

To give you some targets to aim for, here are two proven portable stations used by me in the mountains.

2m SSB (FT-817 + batteries, microphone, 4m mast, guying kit, 5 element DK7ZB beam, feeder, logbook): total weight 2.8 kg

HF CW (Elecraft KX1 + batteries, Palm Paddle, 7m mast, guying kit, wire antenna, logbook): total weight 1.8 kg

And even these weights could be reduced!