On 24 June 2020 at 09:07 F6FZU FREE <f6fzu@...> wrote:

Hi Jim,

Can you add me to the list, for one kit, please ?

73 - Philippe F6FZU

On Tue, 23 Jun 2020, 13:35 James Smith via groups.io, <thebigclunk= virginmedia.com@groups.io> wrote:

I found a source of power transistors and decided to try them using John G4BAO's PCB design which is now public domain. He has unfortunately , run out of boards so I made my own with a scalpel to a similar design to test these transistors. results are very good on the first try - 80 watts saturated 70 watts P!dB and a gain of 14.4dB , 28 volt supply at about 5 amps @ 70W.

I am now building another one to test repeatability and if all is good then I will order some boards and look to selling a partial kit of PCB, transistor and ATC caps. No Idea of price yet. 

Since the supply of reliable MRF286's has dried up , this may help as a stopgap until another design comes along.

With great thanks to John Worsnop G4BAO for having done all the hard work in designing the matching and the rest of the PCB.

I won't say yet what device but will let you know soon.

The device used is a MRF5S9070 and I bought them as new old stock NOS from a UK firm who had them in stock for many years

I propose to make them available in partial kit form with a PCB made with Rogers 4350 , power transistor and ATC and C0G capacitors and when all the development is finished I will write an article for here and for CQ-TV magazine.

The expected kit price will be about £30.00
See G4BAO amplifier in photos

Email me if you are interested.

 

 

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there is a driver amp PCB on Ebay -  QO-100 ES'HAIL 30 WATT AMPLIFIER KIT