MO QRP Test - November 8, 2004

OK, I admit it, I'm a QRP'er, I like to operate with low power just for the enjoyment of it. One of the things that QRP'ers enjoy is playing the "Limbo" game, seeing how low we can go. That's low in transmit power in case you are wondering. This gives us a real test of our station performance. I've played the Limbo game on 30 meters using QRSS and have passed information from Missouri to North Carolina with as low as 10 microwatts of power.

Today Laurence, KL1X, over at Bartlesville, Oklahoma tuned his grabber to the 185.300 kHz Lowfer watering hole. Beacon MO was being captured in real time with a very strong signal. The path distance from MO to Bartlesville is about 75 miles, and the availability of Laurence's grabber made a Lowfer limbo test easy to accomplish.

Here are the results of today's test, started at 1853 CST:

The screen capture above shows MO as received at KL1X's QTH. The four ID sequences are (from left to right) 1 watt, 500 milliwatts, 100 milliwatts and 25 milliwatts of transmitter DC input power.

The second screen capture shows four ID sequences with MO's power input at 25 milliwatts, 10 milliwatts, 2.5 milliwatts and 1 milliwatt of DC input power.

The first three ID sequences in the final screen capture are with MO at power input levels of 1 milliwatt, 500 microwatts and another time at 500 microwatts. The final ID sequence on the far right is without the PA stage, using the exciter connected directly to the antenna loading coil. Unknown what the exciter power level is, but it looks very similar to the 25 milliwatt traces above.

Today's test shows that an ID could be copied at 1 milliwatt of power. That figures out to 75,000 miles per watt.

Thanks to Laurence, KL1X for the use of his grabber! That's an outstanding use of the Internet to further low frequency research.

If anyone wants to play limbo, let me know, and I'd be happy to QRP (lower power) for you.

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