Hi John,
Am 04.03.2012 13:35, schrieb John Rabson:
You recently mentioned that you were using an H-Bridge amplifier for
137, but I seem to have lost the details. Could you post them again,
please? I am finding that I am rather good at blowing up class E PAs
and think I should look for something that is rather more robust (and
more tolerant of variations in load isimpedance).
Well i have done some drawings and pictures in the last time, concerning
my PA and LPF and matching system.
Here they are:
http://dl.dropbox.com/u/19882028/LF/DK7FC_137kHz_TX_antenna_and_PA_schematic.jpg
http://dl.dropbox.com/u/19882028/LF/PA%20output%20filter.jpg
Hm, sorry i'm missing the photo of the drawing of the exciter. I know i
have it on a sheet but maybe i forgot to scan it. Will so that next
week. Pse ask me agn if i forget it.
BTW the blue output transformer in the photo handles at least 1.5 kW CW
at 137 kHz. Usually if people ask what type of ferrite is used in a PA,
the answer is like "it is taken from a SMPS or old TV and unknown
origin", "found it in the junkbox"... But here i know the exact type and
even a distributor and even the price! ;-) It is even avaialable in
quantity = 1 :-)
It is a B64290L0699X830. Datasheet:
http://dl.dropbox.com/u/19882028/Datenbl%C3%A4tter/B64290L699X830.pdf
(page 3)
Available e.g. @
https://www.buerklin.com/default.asp?event=ShowArtikel(84D258)&l=d&jump=ArtNr_84D258
for 10 Euro :-)
73, Stefan/DK7FC
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