Although I mainly prefer QRP, it's quite nice to be "loud" occasionally. I've always wanted to construct a high power amplifier. I used to positively drool over the photos in the ARRL handbook and QST of linear amplifiers. Buying a commercial amplifier doesn't really interest me, although the QRO Technologies amplifiers do have a classic look about their internal construction.
This is somewhat of a long term project. I started collecting parts in 1969, when I was given some
Many years have been spent in making a decision of which design to use. As I'm of the belief that a Radio Amateur should only ever build one amplifier, careful consideration should be given to the design chosen.
The original plan was to build a
G2DAF Linear Amplifier which uses
Sometime around 1989, I became enthusiastic about the G2DAF design again and purchased a 900VA toroidal mains transformer from Peter Rodmell at Linear-AMP UK.
This is the transformer used on the Hunter Amplifier, so would be overkill for the G2DAF design. I ordered a case from Morgan-Smith to build the amplifier in.
Unfortunately, I bought a surplus
This led to another 10 years of turmoil over which design to use. As time passed by, so did valve technology.
Valves are a horrendous price nowadays and surplus stock of glass envelope transmitting valves is drying up quickly. The
Dick Thornley, G2DAF's original amplifier at the RSGB Museum, Potter's Bar 2003
Here's some visual evidence of me operating QRO. The top photo was taken during the 2001 CQ WPX SSB Contest, operating AG1C. The Alpha 89 is running 1500 watts output.
The bottom photo was taken at ARRL HQ, operating W1AW with a kilowatt on 15 metres.
|Richard Measures, AG6K||- Anti Parasitic and QSK kits|
|Fair Radio Sales||- surplus QRO parts|
|Max-Gain Systems||- Vacuum relays and other QRO parts on the President's pages|
|WD7S Productions||- Kits for QRO Amplifiers|
|Ian, G3SEK's Site||- Control boards for triode and Tetrode amplifiers|