Amateur radio projects from 73kHz to 447THz
old favourite revised with modern SMD coils. Ready built preamp for 136kHz
and a new version for the 472kHz band.
Middle: A 300W Class D Amplifier for 630m. Includes over current and hi ref power protection
Right: A 5W linear amplifier for 136 or 475kHz. (70k - 2MHz)
Kits and components Index.
to Canada on 136k 4300km crossband
Quarter kilowatt linear amplifier for L.F.
A 100W LF Class D Amplifier from 13.8V
LF - HF Reflection Coefficient Bridge
300 Watts on 136kHz. A class D TX. (Jan/Feb 2003 Rad Com)
300 Watts on 472kHz /630m with over current and SWR protection Kit available
A broadband 5Watt linear amplifier for 136 and 475kHz Kit now available 09/2018
AMSAT Oscar 40. Worldwide satellite communication
Helix dish feed kit for 2.4GHz
Gemini : S Band to 10m converter with 0.6dB NF
Laser transmitters / Receivers - 6 pages updated
LF PreAmp and BPF. Make your black box work on LF and MF. New Version. Feb 14
LF On-the-Air Antennas, Photo's, Coil's etc
L.F. Dx-pedition to the Isle of Man.
VSWR Bridge for LF Forward and reverse power at a glance
Where a project has been published, the original
text is reproduced.
Up to-date developments / modifications to circuits are also included.
300W Amplifier for 472kHz / 630m - A 2016 design using 2 FETs in push pull. Ideal for WSPR beacons and CW QSOs
A 5Watt linear amplifier that works from 70kHz to 2MHz.
The ESEO project. An inside view from an AMSAT perspective on this 49kg satellite from ESA Education
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If you have any questions or comments please e-mail
David Bowman G0MRF Site last updated 20th/September/2018