Showing posts with label low power. Show all posts
Showing posts with label low power. Show all posts

7 May 2010

Shoe power source (from Elector Newsletter)

A novel way of generating a small amount of power using a piezo-electric generator within a pair of shoes is shown in the latest Elector Newsletter.

14 Apr 2010

Free power transmitters

Mike AA1TJ has sent me an interesting letter about using thermoelectric modules to generate a few milliwatts of power from body heat. This got me thinking about the other ways of "harvesting" free energy from vibration, movement, heat, mains hum fog, RF from radio stations etc. One bizarre idea from a few years back was a leg-brace that powered a mobile phone by leg movement (see left). There are ICs coming onto the market that scavenge energy from various sources allowing low powered devices to be powered for free. The challenge for us QRPers is to think of creative new ways to generate a few milliwatts to get signals across oceans. Who will be the first to work DX using RF rectified "off-air" from the local FM radio or TV transmitter?

29 Mar 2010

A new personal WSPR DX record

This evening I put the WSPR beacon first on 20m and then 30m running 1W into the 5m long vertical matched with the Elecraft T1 auto-ATU. First came a report from a VE6 in Alberta on 20m then a new DX record on 30m with a report from VK2/VK6DI at 16969kms. Not bad going for 1W to an indifferent antenna. Some of the European reports suggest that I'd still have been heard in Europe with just 5mW. VK6DI is a QRSS and weak signal mode enthusiast: see his site at http://www.users.on.net/~davroz/vk6di/

20 Feb 2010

2010 ARRL International DX Contest

Conditions on 15m were good enough for some solid CW QSOs across the pond this afternoon. Worked stations in New Hampshire, Connecticut and Virginia when running 5W QRP. I did also check up on 10m but didn't hear any stations when I listened between 1600-1720z.