Hello Paul,
Also congrats to the QRSS3 5km distance!
:-) Who is the next station that can receive your signal?
1nF / 345mH sounds very good! 1250 Ohm,
is that the overall (loss) resistance? If not, how much power do you have to
apply to get the 200mA and how do you measure the current?
Have you tried to connect your house
mains to the VLF earth? I would try that! ;-) If the current increases with
house earth connected to the system, try to reduce the power so that I is
200mA again and check, if your signal is as stong as before (at the RX side)
to check if the radiation resistance was reduced by this step. Again choosing
the same power than in the QRSS3 QSO will show the antenna efficiency
change...
Your coils look good on the photos! I
would estimate that the coils can stand at least 50kV rms. Paul, you have to
make QRO after checking who could be the next receiving station, hi ;-)
Wish you good luck and fun!
BTW: Do you have a good VLF / Dreamers
band/ RX? As you know, i will try to get this 300m vertical permission! I
already have the confirmation of my insurance ;-)
Stefan / DK7FC
Hi
Rik,
I think that I
must have omitted something.
The blue barrel
is the 277 mhy not counting the coils on top of the
barrel.
Total L was 345
mhy which was too much and forced operation to 8890Hz
Still this is
close to 1 nF
No not yet I
did not try radials yet and will make this step soon
For some
reason the bridge I made for 9Kz is not working, that needs to be
fixed.
Then I can experiment with ground radials rods
etc.
PauLC
W1VLF
Hello Paul,
congrats on your achievement.
Based on L = 0.277H and f = 8890Hz the antenna
capacitance is 1.16nF. You must have an impressive amount of wire
up in the air.
Regarding "ground" : did you try
radials ?
73, Rik ON7YD
Markus
Valued
commentary as always. Plans are to continue making improvements in the
station.
What are your
feeling about the ground at 9 KHz?
Currently I
am using 3 2 meter ground rods spaced 2 meters apart and 1
meter distant from the concrete basement wall of my
shack.
This setup is
not optimum I understand and was never intended to be final ground system
for my regular ham station.
As a very
quick and crude test I pounded an aluminum pole into the earth 2 meters deep
near the 9 KHz coil.
When this was
connected to the existing ground there was a very small increase in the
current meter.
Antenna
system impedance here is about 1250 Ohms with and antenna current of
approx. 200 ma.
Lots of work
to do!!!
I will make
another post on grounds to the group as well.
Thank
you
PauLC
W1VLF
Dear Paul and Jay,
this is an excellent result, well done!
The crossover between reactive nearfield
(E ~ r^-3) and farfield (r^-1) occurs at lambda/2/pi = 5.3
km. As you seem to have quite a bit of margin there, your signal
will be detectable very significantly beyond that. Assuming
otherwise equal receive conditions, QRSS-120 should get you more than 6
times further than QRSS-3.
Best wishes,
Markus (DF6NM)
----- Original Message -----
Sent: Friday, April 16, 2010 8:05
PM
Subject: Re: LF: Dreamers Band
update from W1VLF
Paul,
Great work! Nice looking coil! How much power can you crank
through it?
At 5kM, I believe that you are still in the near field
(9kHz
wavelength is 33km), so signal will fall off at the 3rd power
of
distance until you reach far-field conditions.
--
73
Warren
K2ORS
WD2XGJ
WD2XSH/23
WE2XEB/2
WE2XGR/1
at 1:51 PM, Paul A. Cianciolo <[email protected]> wrote:
> Hello
Folks,
>
> Today we made our first outdoor transmission on
VLF.
>
> The system resonance forced the transmissions to
take place on 8890 Hz at
> least until I can get a variometer
worked up.
>
> The distance is only 5 KM but the signal is
quite good on QRSS3.
>
> I can only wonder how far the
signal would go using QRSS 120???
>
> Please comment if you
can, this a great learning experience for me
>
> Thank
you
>
> PauLC
> W1VLF
>
> http://www.rescueelectronics.com/9-Kilohertz.html
>
