The Weigh to Success

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Introduction

As part of my training as a young engineer with Phillips, I was seconded to the Value Engineering department in the section of their business that dealt with mobile radio equipment. At the time, they were looking at the Value Engineering of hand portable equipment. The work involved taking hand-portable radio equipment apart and weighing each section. Each section was then assigned to a specific function (transmitting, receiving, enclosure etc). The idea was to look at the ratio of these weights in our own equipment and that of our competitors to try to see where we could save money and weight. That was 25 years ago and I have never done anything similar - until today.

Application

Adventure Radio is all about getting more performance with less weight and so I have started to weigh all of the items that I take along, with the objective of reducing the overall weight without compromising performance. So I weighed all of my equipment.

Adventure Radio weights

Grams

Earphone 11 Ear buds
K1+KAT1 660 Transceiver + auto ATU
AA (Alkaline) 23 Battery
AA (NiMH) 25 Battery
ZPY key 149 Iambic paddle
8 batt holder 16 Empty with short plug lead
KAT1 50 Auto ATU alone
40m dipole 480 includes reel, 9.95m feeder, feedline choke, 2x7m string ends
Reel 178
Wire 5 Per metre

Using this information, I have looked at what I carry about on a normal sort of trip. The following table shows the main parts of a typical set-up with a K1 transceiver, a 40m dipole fed with 10m of RG-174 co-ax.

Item Weight (Grams) Notes
Headphones 11 Earbuds
Key 149 G4ZPY minature paddle
Radio 610 K1, no internal ATU
Power 217 8 NiMH cells plus holder
Aerial 302 Dipole including coax and feedline choke
Reel for aerial 178
Total 1467 Excludes portable mast

This is interesting but it is more revealing to see it as a pie chart.

wpe19.jpg (22361 bytes)

Looking at the distribution, a couple of things show up straight away. The reel that I use to wind the aerial on contributes nothing to my signals but weights 12% of the total weight. The paddle that I use, while important, is not really essential (I could use a micro-switch) - and save most of its weight. I was surprised to see that the power source was only 15% of the total weight that I carry.

So far so good. It is interesting to see where the weight goes but I want to use this information to analyse my choice of antenna. The K1 has an internal ATU option. It adds 50gm to the overall weight of the radio. I can then use a wire antenna with two radials. Will I save weight or not?

Using the first table I have built up the following analysis. The aerial configuration that I have assumed is a radiating element 5/8 wavelength on 40m plus 2 1/4 wavelength radials.

Item Weight (Grams) Notes
Headphones 11
Key 149
Radio 660 with ATU
Power 217 8 NiMH cells plus holder
Aerial 243 40m 5/8 plus 2 radials, string and connectors
Reel 178
Total 1458 Excludes mast

So by switching to this aerial configuration (see my Kites page to see how I might use this), I have saved just a few Grams - however, I can use this aerial on two bands (40m and 20m) so it is probably worth the change.

Conclusion

It is too early to say if this technique will prove useful to me but is has been interesting. I have now got another way of judging equipment that I take along with me - and will be sure to save some weight. Backpackers sometimes say "look after the ounces and the pounds will take care of themselves"; good advice!

 

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