Aw: Re: LF: My transmit converter description

["Eike Katzera" <dl3ike@web.de>]

Hi Dimitros,

the pulse shape in this picture does not look good: http://people.physics.anu.edu.au/~dxt103/472/nltt/vk1sv-drain.jpg

The reason seams to be the duty cycle at the gate. Please try to change R5 to a 100k potentiometer and trim it to a clean single Pilse an the drain. I solved the same problem tha way in my PA, wich killed my IRF540.
Kind regards

Eike DL3IKE

PS: sorry for my english ;)

Gesendet: Dienstag, 05. Februar 2013 um 08:45 Uhr
Von: "Victor van Kooten" <V.A.G.van.Kooten@sron.nl>
An: rsgb_lf_group@blacksheep.org
Betreff: Re: LF: My transmit converter description

Looks very nice Dimitris,hope to see/hear you soon,

73

Victor

>>> Dimitrios Tsifakis <dtsifakis@gmail.com> 05/02/2013 01:50 >>>
Hello group,

My transmit converter is now finished and tested - it survived two
sessions of 50% duty cycle WSPR transmissions on 475 kHz and the
results are great. I thought others may find this useful, so I have
put a write-up on my web page:

http://people.physics.anu.edu.au/~dxt103/472/nltt/

It is a 50 W class-e PA designed for 50 ohm impedance, so there is no
need for an impedance transformer. Doesn't get simpler than that :-)
The driving circuit is based on G3XBM Roger's design with the
difference of a 10 MHz OCXO LO and the addition of a beefy MOSFET
driver.

73, Dimitris VK1SV