Hi Gary, VLF,
LF,
The locator is JN49IS. In older mails i
have given you the exact coordinates. In google maps you can find the QTH
within a sector of some 10m.
QRG is 8,97000 kHz. The 4mHz settings is
optimal! If the SNR will be good, you can try 8mHz as well or 15, like Markus
did it at the end of the tests. 15mHz seems to be optimal for DFCW-120 but i
will start with DFCW-600...
I will have no internet access until
saturday night, so cu after the experiment.
Hopefully the wind will be strong enough,
the forecast shows about 20km/h from south. This would be
enough...
Stefan/DK7FC
Hi Stefan, LF,
I will be monitoring your frequency using a M0BMU type 30 turn 0.8M
square loop and 9kHz pre-amp into my PC sound card, software is SpecLab
running Marcus's "9kHz_4mHz" configuration. This loop system has increased my
reception of the Alpha signals by about 10db giving up to 25db SNR. Thanks to
Jim for a great design.
Stefan, can you tell me the QTH locator for your Tx site please.
Good luck with the 4th test.
73
Gary - G4WGT.
2010/4/2 Stefan Schäfer
<[email protected]>
Dear
group,
After a break of one week i plan to transmit again on VLF /
8,97 kHz. If the wind will be 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 reflector (Markus ?) we could arrange
various tests. I will also call other local stations for reception reports
during the 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 the 230V (rectified) of the generator. PTT and
VFO input is realised by fiber optic cables. The DC capacitor is 2000µF/350V
and can be put on voltage without a NTC or charging resistor due to the
relatively high output impedance of the small generator (tested). This works
very fine now. Tomorrow i will apply the FETs and the big ferrite core and
it's windings. Then i will do a test on a dummy load at home. If the signal
will be 3dB stronger, we could theoretically change to DFCW-300 compared to
the last experiment. But there are many OMs writing private mails to me and
prepare to be QRV on this next test. Some of them are using E-Field antennas
and/or are more than 860km away, that' why i want to stay in QRSS-600 first.
So there might come a new distance record? In any case it will be exciting
to me watching the new system running :-) Also it will be interesting to see
if the E-field antenna will get the signal!
The primary winding of
the TX coil is increased from 9 to 13 turns due to the higher power 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 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 current is changing.
The
goal is to radiate 4mW ERP. Another goal is to reach as many stations as
possible. So i 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 at about 15 UTC. So the planned LF activity is
not affected :-). Sorry, but i cannot participate on the LF acty later since
the VLF coil takes all the place 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?
