Foundations of Amateur Radio

What's in a Watt?

We need more power. I'm giving her all she's got, Captain! She cannae take anymore.

I'm sure your Scottish ancestors are rolling in their graves right now, but in our community of radio amateurs we have a tendency to advocate the use of more power. More power fixes all problems and hides all sins.

Another way to look at that is to think of the station with more power as an aligator, all mouth, no ears.

Before you dismiss this as another avocacy for QRP or low power, let me point out that more power creates more interference, more potential for harm, more electricity consumption, more wear and tear and more cost.

Previously I've spoken extensively about QRP communications, making contact with 5 Watt or less, but let's have a look at how much less.

I've shared with you that I managed to contact a station on the other side of the planet with only 5 Watts, Perth to Cuba and for me that was proof positive that all this was possible, even feasable.

We're doing much better than that.

One measurement is to calculate how many kilometers per Watt you achieved. My example of 5 Watt between Perth and Cuba is the equivalent of 3592 km per Watt. The maximum distance to the opposite side of our globe is about 20,000 km and my contact did nearly 18,000 km.

If you think that's amazing, I should warn you, my contact was special, for me, but as low power contacts go, it's not that amazing.

The first solid state radio contact made across the Atlantic ocean managed over 76,000 km per Watt. That was on 18 September 1956. You'll find the radio on display at the ARRL Laboratory, together with the bug and station log showing the contact between Chelmsford, Massachusetts and Copenhagen, Denmark between Gus W1OGU and Bo OZ7BO, on a radio made of two germanium transistors and built by Gus W1OGU, Al W1OSF and Dick W1UBC, who built the diminutive gadget on a lark to see if they could Work All Continents with it.

If you can copy the 40 microwatt CW beacon run by the North American QRP CW Club, you too can join in the fun. The current record stands at just under 22 million km per Watt when Bill W4ZV managed to copy the code word OMAHA from the N2XE beacon from New London, North Carolina.

Just to be clear, we're talking about a signal that travelled the equivalent of 22 million km using 1 Watt of power.

If you think that was amazing, Pioneer 10 managed to achieve 1.3 billion, that's 1.3 thousand million km per Watt in 2003. Mind you, that record was achieved with a slightly bulky antenna, the Deep Space Network.

Are you ready for more?

The current record stands at just under double the Pioneer 10 record, just under 2.6 billion km per Watt. That was achieved by Dick KL7YU and Bill W7BVV who made contacts between Alaska and Oregon in December 1969 and January 1970. A distance of 2655 km using one micro Watt.

Yes, you can throw a Kilowatt at the problem, or you can take your time, do some work and have some fun with low power.

You can call it QRP, or you can call it just enough to get the job done.

I'm Onno VK6FLAB