Re: ubitx - stop press

Ashhar Farhan
 

Try the RD15HVF1. That is the simplest. The only the pin out is different, you will have to twist the the legs and figure how to insert them into the same pinout as the IRF510.

- f

On Mon, Dec 11, 2017 at 12:23 PM, REJIMON G <rejimontkm@...> wrote:
I think C1969  in pushull mode will give constant power in all bands

Sent from my iPhone

On 11-Dec-2017, at 12:16 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

Hfsignals.com write-up also mentions that power out is 10 Watts up to 10mhz, falls off to 2 Watts at 30mhz.
It is tough to drive IRF510's at 30mhz, but the WA2EBY amplifier uses two IRF510's in push-pull
like this to give 40 Watts up through 30mhz from a 28v supply.  Perhaps we can borrow some of the
WA2EBY design to approach that kind of performance.  May require beefier caps and coils.
And maybe an additional driver stage. 
    http://www.golddredgervideo.com/kc0wox/wa2ebyamp/amppart1.pdf
    http://www.golddredgervideo.com/kc0wox/wa2ebyamp/amppart2.pdf

Also in the hfsignals uBitx write-up:  "TIA".
Not found in most dictionaries.
Means "Termination Insensitive Amplifier"
    http://w7zoi.net/bidirectional_matched_amplifier.pdf

Jerry, KE7ER


On Sun, Dec 10, 2017 at 10:18 pm, AndyH wrote:
Just the close the circle, so to speak.  Farhan has additional comments in the sales write-up for the µBITX:
The power chain uses four common plastic 2N3904s in push-pull as drivers. The 2N3904s have enough gain at 30 MHz. The 2N2219s tried  earlier were found to have low gain at higher frequencies.


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