Message-ID: <001a01cad234$34aaedb0$0201a8c0@Clemens04>
From: "Clemens  Paul" <cpaul@gmx.net>
To: <rsgb_lf_group@blacksheep.org>
References: <o2kfc7eccec1004010402n7f00e1c3l8b88ea090c0fb8bb@mail.gmail.com><001d01cad190$aa92e590$0901a8c0@lark><841031C22EC944FEB2BB3E1DC237717E@acer3f31164f8b> <n2mfc7eccec1004011258m4c2f8fc4m7950cb33f9bbefe8@mail.gmail.com> <38A51B74B884D74083D7950AD0DD85E82A1BBF@File-Server-HST.hst.e-technik.tu-darmstadt.de>
Date: Fri, 2 Apr 2010 09:14:57 +0200
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Subject: LF: Re: 4th VLF experiment by DK7FC/p
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Hi Stefan,

this time I'm at home and will be watching out for your signal.
RX is a Perseus,antenna is my 2x46m dipole with 42m open feeder.
The latter is running 8m vertical out of the shack,the rest is horizon=
tal.
I'll connect the legs.
Alpha stations are consistently audible (and visible) here with up to=
 25dB SNR.

73
Clemens
DL4RAJ

Loc:S=FCdostbayern,12,90006=B0O/48,4150=B0N (Gridloc:JN68KJ)
Perseus mit Dipol 2x46m

----- Original Message -----=20
From: "Stefan Sch=E4fer" <schaefer@hst.tu-darmstadt.de>
To: <rsgb_lf_group@blacksheep.org>
Sent: Friday, April 02, 2010 2:38 AM
Subject: VLF: 4th VLF experiment by DK7FC/p


Dear group,

After a break of one week i plan to transmit again on VLF / 8,97 kHz.=
 If the wind will be=20
enough i will come up on saturday, 3. April, at arround 10 UTC.

The DFCW-600 mode was a good choice in the last experiment, so i will=
 keep this mode.

If Markus/DF6NM has time to make QSP on the mobile phone to the reflec=
tor (Markus ?) we could=20
arrange various tests. I will also call other local stations for recep=
tion reports during the=20
transmission.

There will be some new components to test:

Today i started building up the 600W class D PA (at least 600W) that=
 is directly fed out of=20
the 230V (rectified) of the generator. PTT and VFO input is realised=
 by fiber optic cables.=20
The DC capacitor is 2000=B5F/350V and can be put on voltage without a=
 NTC or charging resistor=20
due to the relatively high output impedance of the small generator (te=
sted). This works very=20
fine now. Tomorrow i will apply the FETs and the big ferrite core and=
 it's windings. Then i=20
will do a test on a dummy load at home. If the signal will be 3dB stro=
nger, we could=20
theoretically change to DFCW-300 compared to the last experiment. But=
 there are many OMs=20
writing private mails to me and prepare to be QRV on this next test.=
 Some of them are using=20
E-Field antennas and/or are more than 860km away, that' why i want to=
 stay in QRSS-600 first.=20
So there might come a new distance record? In any case it will be exci=
ting to me watching the=20
new system running :-) Also it will be interesting to see if the E-fie=
ld antenna will get the=20
signal!

The primary winding of the TX coil is increased from 9 to 13 turns due=
 to the higher power=20
that will be applied. Otherwise the current will become to high.

I will mount the amperemeter (analog, 1A) into the coil. That makes it=
 easier to adjust to=20
resonance and watch the stability and maximum and average (estimation)=
 current.

Finally i will try to apply some copper rods into the earth and will=
 look how the antenna=20
current is changing.

The goal is to radiate 4mW ERP. Another goal is to reach as many stati=
ons as possible. So i=20
would be pleased if YOU would be one of them. :-)

Since the QRM/QRN comes up in the late afternoon and transmitting for=
 4...5 hours i will close=20
at about 15 UTC. So the planned LF activity is not affected :-). Sorry=
, but i cannot=20
participate on the LF acty later since the VLF coil takes all the plac=
e in my car ;-)

I looking forward to this experiment and wish you good luck and fun by=
 receiving  :-)

73 es gl, Stefan/DK7FC

PS: Could you give me a short feedback if you plan to be RX?






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