Showing posts with label beacon antenna. Show all posts
Showing posts with label beacon antenna. Show all posts

5 May 2011

Ultra low voltage oscillators

Thinking a bit more about my crazy idea for a mains hum powered QPRp beacon TX, I chanced upon this page which discusses FETs running from extremely low voltage supplies. See http://www.dicks-website.eu/fetosc/enindex.htm. Some of the zero threshold voltage MOSFETs (ALD110900A) used in sensitive crystal sets may also be useful in this application. The link shows an FET oscillator powered by just a thermocouple producing only 13mV! Incredible. See also http://cap.ee.ic.ac.uk/~pdm97/powermems/2009/pdfs/papers/069_0209.pdf and http://www.aldinc.com/pdf/Ultra%20Low%20Power%20Oscillators.pdf

31 Jul 2010

136kHz QRP QRSS3 beacon video


This is a video showing the 2W QRP beacon for QRSS3 on 136.93kHz. Using a 20m spaced earth electrode transmit "antenna" it has been copied 8.6km away using an E-field probe antenna.

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/