References: <CAA8k23T6k1D1xssvY0wNeLik8JxKcYPaTcG9=OUZ6TMm+Zz2YA@mail.gmail.com>
 <4EA63FCADF204DB7B5E2936098C9A416@AGB>
 <CAA8k23RMenAqFcQQ3pv88kB9w+9uEPOMrtfQW1LMfHAd67Oc-Q@mail.gmail.com>
To: rsgb_lf_group@blacksheep.org
From: pa3abk <pa3abk@kpnmail.nl>
Message-ID: <56903ECC.6090801@kpnmail.nl>
Date: Fri, 8 Jan 2016 23:57:16 +0100
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101
 Thunderbird/38.5.0
MIME-Version: 1.0
In-Reply-To: <CAA8k23RMenAqFcQQ3pv88kB9w+9uEPOMrtfQW1LMfHAd67Oc-Q@mail.gmail.com>
Subject: Re: LF: Linear Amp for LF
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Status: RO

Maybe you must look for simply one of early days HiFi audio amps.
Someone gave me recently a SONY F420 (1990 design!). 2X 70W @ 4 Ohm flat 
response up to 100kHz.
I put  the Ultimate 3S on it and indeed almost 200W @137kHz could be 
dissipated in resistors here without any mod.
The unit has a "direct drive" mode, input full flat connected to the PA.
I don't have space/suitable antenna for 2200m :-(

Even 470kHz came thru but not at this power with some fiddling best 40W.
But assume when the circuit is modified (redesign feedback circuit), MF 
can come in the picture.

Maybe you can have a look at a "recycle centres"

Some idea? http://www.w1tag.com/XESTX.htm

Jan/pa3abk


On 8-1-2016 23:08, Andy Talbot wrote:
> No Graham -
>
> I don't want an EER design - that may be for another project in the
> future.  And I'd certainly not do it by
>   trying to regenerate a signal using analogue techniques.   EER has its
> place, but only when the siganls are generated ion polar form in the
> first place.    Class E amps are just asking to be used in that way - my
> measurements suggest they exhibit and impressively linear power out vs.
> Vdd characteristic.
>
> But for reproduction of signals generated via an upconverter, I'm
> looking for a conventional proven linear type amp
>
>
> Andy  G4JNT
>
> On 8 January 2016 at 21:59, Graham <g8fzk@g8fzk.fsnet.co.uk
> <mailto:g8fzk@g8fzk.fsnet.co.uk>> wrote:
>
>     __
>     M0BMU from 2007
>     http://w4dex.com/projects/EER_Transverter_v2.pdf
>     G,
>
>     *From:* Andy Talbot <mailto:andy.g4jnt@gmail.com>
>     *Sent:* Friday, January 08, 2016 9:45 PM
>     *To:* rsgb_lf_group@blacksheep.org
>     <mailto:rsgb_lf_group@blacksheep.org> ;
>     rsgb_lf_group@yahoogroups.co.uk
>     <mailto:rsgb_lf_group@yahoogroups.co.uk>
>     *Subject:* LF: Linear Amp for LF
>
>     Are there any proven reliably designed LF amplifier designs power
>     amplifiers  for 137 / 475?   Wideband, covering both ideally
>       Rated for at least 300 Watts output, and ideally a lot more.
>
>     I saw G3YXM's low-HF design, and it looks promising for low
>     frequency use, but he appears to have not gone that way and went for
>     a switchmode version at LF/MF
>
>     Of course, I could just redesign that, or something similar, using
>     suitable ferrite and a bit of feedback ,but it would be nice to
>     avoid reinventing too many wheels.
>
>     Using switching MOSFETs as linear amps still doesn't feel quite
>     right, but enough people seem have managed it now (including my own
>     design for a low power one) that it looks a sound-enough route to
>     follow up.    The one thing that does bother me about the technique
>     is bias compensation with temperature.   It is really asking for
>     active bias control, but in a class-B or -AB design, where bias just
>     affects standing current, that gets more-than a bit tricky as a concept.
>
>     Andy  G4JNT
>
>

-- 
pa3abk <-> dordrecht jo21it
Sent by Philips STB-75 with T100