ARLA/CLUSTER: Foundations of Amateur Radio: O que são os watt.?

[João Costa > CT1FBF]

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*
------------------------------

*•* This article is the transcript of the weekly 'Foundations of Amateur
Radio' podcast, produced by *Onno Benschop, VK6FLAB* who was licensed as
radio amateur in Perth, Western Australia in 2010. For other episodes,
visit http://vk6flab.com/. Feel free to get in touch directly via email:
cq  vk6flab.com

*•* If you'd like to join a weekly radio net for new and returning
amateurs, check out the details at http://ftroop.vk6flab.com/, the net runs
every week on Saturday, from 00:00 to 01:00 UTC on Echolink, IRLP, AllStar
Link, Brandmeister and 2m FM via various repeaters, all are welcome.
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