Message-ID: <4F0D966E.9060208@iup.uni-heidelberg.de>
Date: Wed, 11 Jan 2012 15:02:22 +0100
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <Stefan.Schaefer@iup.uni-heidelberg.de>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3
MIME-Version: 1.0
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>
In-Reply-To: <CABP+t7Y47ePqNug_tWozoBVux9MJKRd0gyWS-aNLsqnMndoWfQ@mail.gmail.com>
Subject: Re: LF: QRP 1W /PA circuit
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: quoted-printable
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
X-AOL-SCOLL-URL_COUNT: 0  
x-aol-sid: 3039ac1dc1484f0d96a03940
X-AOL-IP: 195.171.43.25
X-AOL-SPF: domain : blacksheep.org SPF : none


Hi Doug,

Thank you for your continued interest :-)

I enabled SpecLab's "beacon mode" so it will run endless until i stop.=20
And i will stop when the new FETs arrived here :-)
However i see no chance at all that you will receive anything at all,=20
not even in DFCW-900000000000000 ;-). I'm transmitting 1W TX power, not=20
1W ERP!

Iceland may be the best DX to be expected, if conds are good and QRM is l=
ow.

Back soon! The new FETs have excellent data: Higher VDS, lower Rdson,=20
lower input C, faster switching times. The recovery times and dv/dt are=20
much better too (not really a FREDFET though) so i will keep the RC=20
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 Sch=E4fer<Stefan.Schaefer@iup.uni-heidelberg.de>  wr=
ote:
>   =20
>> LF,
>>
>> Last night i shot my PA again :-( No replacement FETs were available s=
o
>> i had to stay quite during the night. Replacement parts are ordered no=
w
>> 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 stag=
e
>> (http://dl.dropbox.com/u/19882028/LF/DK7FC_137kHz_TX_antenna_and_PA_sc=
hematic.jpg),
>> just in case someone wants to build a similar design and is interested
>> in general:
>>
>> -R=3D 100 Ohm/2W (In series with C, across  Drain-Source)
>> -C=3D 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
>>
>>     =20
>   =20