You get about 18 dB power gain out of it which is quite right for a FET
amplifier of this kind.
The problem lies most likely with the transformer itself: the 43 material in
the core is optimized for RFI suppression work ( a high tangent loss) and so
it's very dependent on the coupling between the windings. I shall have to
look up the material's properties and then I shall be able to recommend a
replacement and/or an alternative building method.
Alex 4Z5KS
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of sasas asasas
Sent: Sunday, April 18, 2010 10:49 AM
To: amps@contesting.com; David Cutter
Subject: Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores
And how can i repair this problem???
--- On Sat, 4/17/10, David Cutter <d.cutter@ntlworld.com> wrote:
From: David Cutter <d.cutter@ntlworld.com>
Subject: Re: [Amps] 160m mosfet linear amplifier problem with ferrite cores
To: "sasas asasas" <tzitzikas_ee@yahoo.com>, amps@contesting.com
Date: Saturday, April 17, 2010, 12:15 PM
You might consider imbalance in each side of the primary which will cause a
net dc to pass, saturation and over-heating. This may be rubbish but it
could get others thinking along a different path.
David
G3UNA
> HI. i have constructed this linear amplifier 500w rms (2kw pep) (50ohm)
with 12 mosfet irfp360, http://tzitzikas.webs.com/linear500w.jpg for 160m
band.
> When i gave 3watts of driving r.f power, it gave to output only 190w
> at 106VDC (6A current). Two radio amateurs who have construct this linear
claim tha it gives 500w r.f power at 110vdc.
> But when i tried to give 4watts of driving r.f power the ferrite Cores
> (43 material) of transformer T3 broken! Which do you think is the
problem??
>
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