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 burried
in the soil (about 10 to 20 cm deep) with a 2m ground stake at the end of each
radial. The radials were 15 to 25m long (far less than 1/8 wavelength). First I
used galvanized iron wire, but after a few years these corroded 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 disconnecting one (or
more) of the radials did affect it.
Disconnecting the radials at the far end from the ground stake also increased
the loss resistance, but not as much as disconnecting the entire radial.
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 disconnecting
one or two of the radials has little effect.
In general I think that radials do better with a poor soil and ground stakes do
better with a high conductivity soil.
73, Rik ON7YD
________________________________________
Van: [email protected] [[email protected]]
namens Alan Melia [[email protected]]
Verzonden: zaterdag 17 april 2010 18:15
Aan: [email protected]
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. You
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" <[email protected]>
To: <[email protected]>
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: [email protected]
> [mailto:[email protected]]On Behalf Of Rik Strobbe
> Sent: Saturday, April 17, 2010 10:30 AM
> To: [email protected]
> Subject: RE: LF: Dreamers Band update from 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
>
>
> --------------------------------------------------------------------------
--
> --
> Van: [email protected]
> [[email protected]] namens Paul A. Cianciolo
> [[email protected]]
> Verzonden: zaterdag 17 april 2010 15:53
> Aan: [email protected]
> 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 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
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Markus Vester
> Sent: Friday, April 16, 2010 4:29 PM
> To: [email protected]
> 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 = 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 -----
> From: Warren Ziegler
> To: [email protected]
> 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
> >
>
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