[Amps] How light can you make a 500W amplifier?

[Rich]

The lightest weight power supply would likely be a voltage-multiplier 
type operating direct from the electric mains.  With a x6 V multiplier 
and 230V mains, c. 1600vdc could be produced for c, 1kg in ps weight.  
With a 4cx800, 1600v would produce >500w.  A foolproof screen supply 
could be derived from the anode supply using a zener-string shunt 
regulator.   My guess is thar a total weight of 4kg should be do-able.  

>While exchanging tall tales at the bar at the RSGB HF Convention over the 
>weekend the discussion came round to the need for an amplifier specifically 
>optimised for solo DXpedition use. The holy grail is 500W output on the HF 
>bands at an all-up weight of around 10Kg. The well known semi-pro MOSFET 
>amplifier on the market has a dreadful reputation for IMD and is pretty much 
>unobtainable anyway. Thermionics seem more appropriate, but their power 
>supplies are heavy.
>
>What is the listís collected wisdom? Solid state? Valves, perhaps with SMPS? 
>Theorising is OK (after all, it was a bar room discussion), but what would 
>really get my attention is a URL to an actual example of a 500W/10Kg 
>product.
>
>73
>
>Alan G3XAQ
>
>
>
>
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-  Rich..., 805.386.3734, www.vcnet.com/measures.