From: Rik Strobbe <Rik.Strobbe@fys.kuleuven.be>
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
Date: Mon, 19 Apr 2010 10:44:28 +0200
Thread-Topic: LF: Dreamers Band update from W1VLF
Thread-Index: AcreSktqgJeLkOFiRU+ZFX8x+l7elABT5TIq
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Hi Alan, Paul,

I think that wether radials or ground stakes give the best results depends=
 on frequency and soil conductivity.
On 136kHz I did a lot of tests and ended up with a system of 6 radials bur=
ried in the soil (about 10 to 20 cm deep) with a 2m ground stake at the en=
d of each radial. The radials were 15 to 25m long (far less than 1/8 wavel=
ength). First I used galvanized iron wire, but after a few years these cor=
roded away and were replaced by isolated iron wire ("fence wire").
All radials come together at the antenna base. An additional ground stake=
 at the antenna base did not affect the loss resistance while disconnectin=
g one (or more) of the radials did affect it.
Disconnecting the radials at the far end from the ground stake also increa=
sed the loss resistance, but not as much as disconnecting the entire radia=
l.
The burried wires probably have a double function: they act radial and as=
 interconnection between the ground stakes.

Today I used the same ground system on 500kHz and noticed that disconnecti=
ng one or two of the radials has little effect.

In general I think that radials do better with a poor soil and ground stak=
es do better with a high conductivity soil.

73, Rik  ON7YD


________________________________________
Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blacksheep.or=
g] namens Alan Melia [alan.melia@btinternet.com]
Verzonden: zaterdag 17 april 2010 18:15
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: Re: LF: Dreamers Band update from W1VLF

Paul dont put a lot of effort into "radials" they are I feel unlikely to
give much improvement. They need to be at lelast 1.8th wavelength long to
have advantage. Just roll something out and measure it with the bridge. Yo=
u
may find that a few more ground spikes under the  wires will help a bit.=
 The
maximum amount of ground current is "collected" from under the highest
voltage point. This would be the remote end of a "L" or "T". The problem
with ground spikes is how far down is true "ground" at this frequency in
your soil (Hence my hapring on about measuring it"

You are doing a great job there keep it up!!

Alan G3NYK


----- Original Message -----
From: "Paul A. Cianciolo" <paulc@snet.net>
To: <rsgb_lf_group@blacksheep.org>
Sent: Saturday, April 17, 2010 3:54 PM
Subject: RE: LF: Dreamers Band update from W1VLF


> 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
>
>
>
>
>
>  -----Original Message-----
> From: owner-rsgb_lf_group@blacksheep.org
> [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Rik Strobbe
> Sent: Saturday, April 17, 2010 10:30 AM
> To: rsgb_lf_group@blacksheep.org
> Subject: RE: LF: Dreamers Band update from W1VLF
>
>
>   Hello Paul,
>
>   congrats on your achievement.
>   Based on L =3D 0.277H and f =3D 8890Hz the antenna capacitance is 1.16=
nF.
You
> must have an impressive amount of wire up in the air.
>   Regarding "ground" : did you try radials ?
>
>   73, Rik  ON7YD
>
>
> ------------------------------------------------------------------------=
--
--
> --
>   Van: owner-rsgb_lf_group@blacksheep.org
> [owner-rsgb_lf_group@blacksheep.org] namens Paul A. Cianciolo
> [paulc@snet.net]
>   Verzonden: zaterdag 17 april 2010 15:53
>   Aan: rsgb_lf_group@blacksheep.org
>   Onderwerp: RE: LF: Dreamers Band update from W1VLF
>
>
>   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  an=
d
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 ear=
th
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
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>    -----Original Message-----
>   From: owner-rsgb_lf_group@blacksheep.org
> [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Markus Vester
>   Sent: Friday, April 16, 2010 4:29 PM
>   To: rsgb_lf_group@blacksheep.org
>   Subject: Re: LF: Dreamers Band update from 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 =3D 5.3 km. As you seem to have quite a bit of mar=
gin
> there, your signal will be detectable very significantly beyond that.
> Assuming otherwise equal receive conditions, QRSS-120 should get you mor=
e
> than 6 times further than QRSS-3.
>
>     Best wishes,
>     Markus (DF6NM)
>
>       ----- Original Message -----
>       From: Warren Ziegler
>       To: rsgb_lf_group@blacksheep.org
>       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 <paulc@snet.net> 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
>       >
>