Hi Enrico
The cct diagram is too large for the reflector, so would have to go
direct.
It E pa is vy inter dependent on V/W/Q etc and pse refer to Tonne s/ware
V2.01 for design criteria. Mine is qrp for 500 and works fb and reliable.
No smoke etc hi
Pse listen for me on 502.5 khz and call me on 3533/7033 khz for a xband
QSO.
73 de Mal/G3KEV/IO9SH
----- Original Message -----
From: "Enrico" <[email protected]>
To: <[email protected]>
Sent: Monday, November 26, 2007 7:52 PM
Subject: LF: R: classs E
Hi Mal,
can you please tell me what kind of PA are you using? Have you an
electrical
scheme?
Thank you an Bye.
IW4CXL
Enrico
-----Messaggio originale-----
Da: [email protected]
[mailto:[email protected]]Per conto di hamilton mal
Inviato: domenica 18 novembre 2007 16.54
A: rsgb
Oggetto: LF: classs E
Hi all
I carried out some analysis on my fet pa today to check the waveform for
true class E. Monitoring the drain on a scope revealed that the waveform
was
almost correct but needed a slight increase in capacity for C2 for an
almost
perfect switch at 502.5 khz. Increasing/decreasing the voltage did not
make
a big difference to the waveform, at the design voltage it was only
slightly
better.
Using a DL I altered the freq and found the perfect waveform at 535.9
khz,
so I expect logically increasing the value of C2 would correct the
anamoly
at 502.5 khz. I have not altered it yet because I do not have a suitable
capicator.
I did observe some ripple on the waveform that is probably caused by feed
through from the driver, it was more pronunced at a V lower than the
design
voltage, but improved with a V increase.
In spite of the above observations the PA performs well and seems very
robust.
The RF pwr out measurements using the DL or the Antenna do not vary,
indicating that the antenna is well matched to 50 ohms via the atu at the
base of the inv L.
I thought the above observations might be interesting to would be class E
constructors.
Considering mine was built from junk box bits, including the 60 year old
ceramic ex TU5 tuning unit coil it works very well. The fet is out of an
old marine tx.
Best dx to date VE1ZZ at 549 during ideal conditions last week.
73 de Mal/G3KEV
