Modified HF KW Amplifiers converted to 6M Click here to go back to the home page



With 6M popularity as a real DX band steadily increasing, the need for more power to make a contact under marginal or crowded band conditions is also increasing.

I have been converting commercial HF ham amps to 6M since 1964 when I worked for National Radio and converted a NCL 2000 prototype. That amp is still in use today.
I built my first 6M station in 1958, a plate modulated 829B and tube converter into a HQ129X.

There are many good conversion candidates available with various Heathkit SB series being the most popular due to cost and ready availability. Other brands & models include Ameritron, Dentron, Collins, Drake, Amp Supply, Hunter, Henry, Alpha, Tokyo High Power, Yaesu and more. Virtually any amp that has a tube(s) that will operate at 50 mHz is a candidate. I have converted them all over the past 40+ years.

All conversions are strictly 6M mono-band; not a parasitic loaded, 45% efficient and horrible harmonic attenuation compromise which results from trying to add 6M to a HF design. We virtually strip the entire RF deck and start from scratch. Efficiency is often better than original.

We DO NOT use conversion articles from magazines, I have yet to see a properly thought out design that is consistently repeatable. Some are absolutely horrible and it is inconceivable that they were even published.

Instead we have developed our own expertise and procedures utilizing both sound engineering as well as quality test equipment.

Some of our best customers are those who have tried to follow a magazine article and wind up sending us the basket case!

Drive levels of 10 to 100W are supported, with tetrode tubes being the easiest to drive. The NCL2000 for instance will do 1200W out with 10-12W of drive, a nice companion to a DEM transverter. The Heathkit SB200/201 will deliver a clean 650-750W key down with 80-100W of drive and the SB220/221/HL2200 will output 1000-1200W with similar drive. PEP on SSB will be a bit more.

The best news is the price! The SB200/201 is only $695 SHIPPED in the lower 48 USA if we provide the amp and $395 shipped if we convert yours. (this assumes that your amp does not require any major repairs). The SB220/221/HL2200 is $995 and $425 respectively. Relay keying is a low current 12 VDC that is compatible with all transceivers. Compare this against current $2000+ 6M amps with $600-1000 tubes. We also ship worldwide, contact us for information.

All conversions are thoroughly tested for performance with Bird and HP test equipment; nothing is left to doubt or compromise.

BOX 973
Pelham, NH 03076
Phone: 603-635-2235
FAX: 603-635-7761

Life’s too short to wait in pileups......Carl, KM1H, RADIOKIT

Don't forget to mention the UKSMG web site if you call him!

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