Message-ID: <FDB275DA9FE143C1A8F3B4161B486C12@AGB>
From: "Graham" <g8fzk@g8fzk.fsnet.co.uk>
To: <rsgb_lf_group@blacksheep.org>
References: <CAA8k23Qqo4ZagVGLdEiUqGSU-HL_XNpues+rPAr7NwOhiyd1zQ@mail.gmail.com>	<4F0CC679.2010206@charter.net>	<4F0D81E5.4010602@iup.uni-heidelberg.de> <CABP+t7Y47ePqNug_tWozoBVux9MJKRd0gyWS-aNLsqnMndoWfQ@mail.gmail.com> <4F0D966E.9060208@iup.uni-heidelberg.de>
In-Reply-To: <4F0D966E.9060208@iup.uni-heidelberg.de>
Date: Wed, 11 Jan 2012 18:05:56 -0000
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Subject: Re: LF: QRP 1W /PA circuit
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S .  Would  be  interesting to see  how   far  OP30  would  go  with  1  w 
Ae  feed , would  you  reach  Gary ?

G.

--------------------------------------------------
From: "Stefan Schäfer" <Stefan.Schaefer@iup.uni-heidelberg.de>
Sent: Wednesday, January 11, 2012 2:02 PM
To: <rsgb_lf_group@blacksheep.org>
Subject: Re: LF: QRP 1W /PA circuit

> Hi Doug,
>
> Thank you for your continued interest :-)
>
> I enabled SpecLab's "beacon mode" so it will run endless until i stop. And 
> i will stop when the new FETs arrived here :-)
> However i see no chance at all that you will receive anything at all, not 
> even in DFCW-900000000000000 ;-). I'm transmitting 1W TX power, not 1W 
> ERP!
>
> Iceland may be the best DX to be expected, if conds are good and QRM is 
> low.
>
> Back soon! The new FETs have excellent data: Higher VDS, lower Rdson, 
> lower input C, faster switching times. The recovery times and dv/dt are 
> much better too (not really a FREDFET though) so i will keep the RC 
> circuit...
>
> 73, Stefan/DK7FC
>
> Am 11.01.2012 13:40, schrieb Douglas D. Williams:
>> I'll give a listen tonight, Stefan, if you are still in QRP mode.
>>
>> Doug
>>
>> On 1/11/12, Stefan Schäfer<Stefan.Schaefer@iup.uni-heidelberg.de>  wrote:
>>
>>> LF,
>>>
>>> Last night i shot my PA again :-( No replacement FETs were available so
>>> i had to stay quite during the night. Replacement parts are ordered now
>>> and will arrive tomorrow :-)
>>>
>>> During that time i will run a *LF beacon on 136.172 kHz running _1W TX
>>> power_ in DFCW-90*, starting in the afternoon. If someone can receive
>>> that weak *QRPP* signal, then a* report is very apprechiated :-)*
>>>
>>> Also i will do some optimisations on my recently posted PA output stage
>>> (http://dl.dropbox.com/u/19882028/LF/DK7FC_137kHz_TX_antenna_and_PA_schematic.jpg),
>>> just in case someone wants to build a similar design and is interested
>>> in general:
>>>
>>> -R= 100 Ohm/2W (In series with C, across  Drain-Source)
>>> -C= 220pF/WIMA FKP-1 2kV  (In series with R, across Drain-Source)
>>> -MOSFET: The IRFP460
>>> <http://dl.dropbox.com/u/19882028/Datenbl%C3%A4tter/irfp460.pdf>  will 
>>> be
>>> replaced by a SPW20N60C3
>>> <http://dl.dropbox.com/u/19882028/Datenbl%C3%A4tter/SPW20N60C3.pdf>  :-)
>>>
>>> 73, Stefan/DK7FC
>>>
>>>
>>
>