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From: reginal..._at_hotmail.com
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Subject: Low power devices - PART 1 of 2 PARTS
Date: Sun, 19 Aug 2007 10:58:25 -0700
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I came across this article at pages 68 & 70 in the August 2007 edition
of "CQ". The first part deals with very low power QRP (low power
transmission). It probably is of limited interest to the group but I
thought that we should be at least aware of this activity. Also, it
may have some utility re tracking devices. In some ways, features of
this mode are similar to the VLF transmissions used to communicate
with submarines.
"QRP
By Dave Ingram, K4TWJ
3994 Long Leaf Drive,
Gardendale, AL 35071
k4..._at_cq-amateur-radio.com
A New Pursuit and A New Kit
Some aspects of amateur radio go through a pattern of ups and downs,
or highs and lows, but through it all QRP [low power transmission -
usually below 5 watts] holds steady and continues to grow. From the
U.S. to the U.K., from South Africa to Brazil, to Australia and Japan,
QRP rocks! As I have mentioned in previous columns, QRP today involves
a pleasant mix of on-the-air operations and home-assembling low-power
projects just for fun. This is truly a wonderful part of amateur
radio, as most activity is on CW [i.e, Morse code] and homebrewing
simple rigs involves working with genuine wire-leaded components and a
soldering iron. These traits are the foundation of amateur radio, and
hopefully they will continue for many years to come.
In support of that good thought, this month we proudly are
highlighting another easy-to-build and fun-to-use project. Before
getting started on that topic, though, let's briefly look at a new and
unique application of that all-time favorite mode - CW.
QRSS
There is a new form of very-low-power activity on the air, and it is
called QRSS, for ultra-slow-speed CW. You unknowingly may have heard
some weak QRSS signals near 10.140 MHz on 30 meters. Now before tuning
up there to check out the action, I encourage you to respect its
hearty pioneers and refrain from blindly transmitting within one or
two kHz of 10.140 MHz (few amateurs operate that high on 30 meters
anyway). Just listen until you are familiar with the general
activities.
How slow are QRSS transmissions and what are their attractions and
benefits? Generally speaking, these transmissions are in the 0.1 to
2.0 words-per-hour category [1 word = 5 characters, letters or
numbers, etc.], and they are proving beneficial for communicating over
exceptionally long distances with very low power. As some eye-opening
examples, VK3DI reported copying 30 meter QRSS signals from WB3ANQ
while running 500 microwatts/0.5 milliwatt, and from V6JY 240 miles
away running 50 nanowatts/0.00005 microwatts on 30 Meters. Close to
home, AA4XX and W0CH have communicated over an approximate 900-mile
path while running QRSS at 50 microwatts on 10.140 MHz. Those feats
average out to over 15 million miles-per-watt! Just imagine the
benefits of QRSS for other pursuits such as moonbounce [i.e.,
communication by reflecting signals off the moon]!
Would you like to try your hand at copying some test transmissions
from QRSS beacon stations on 30 Meters (and no, you do not have to sit
by your transceiver for several hours to do so; a computer can handle
that task for you). The fist step is learning the basic facts
regarding QRSS, and the following steps involve installing (and using)
some free QRSS software on your computer.
......."
Continued in Part 2 to follow.
Reg Curtis/VE9RWC
Received on Sat Mar 02 2024 - 00:57:20 CST
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