So your 148m of wire, coiled up in 945 turns over 38cm space on a 5cm diameter tube with the bottom end grounded will start resonating  around 1Mhz.
Itsu

Itsu
I am aware of this fact. What I am saying is that for maximum voltage output, the 148 meters have to be the 1/4 of the total wavelength which corresponds to a frequency of 500Khz. If I am to use the 1Mhz frequency with my 148m coil, then Secondary's top will produce maximum current and zero voltage (ideally). Look at the attached image.

Jeg,

You have seen for yourself that your 148m kacher resonates at 1Mhz.
If you use a scope probe and move it from bottom to top alongside your kacher, you will see that the amplitude (keep same distance from coil)
will go from zero at the bottom to max at the top pointing to a ¼ wave voltage buildup.

So yes,  "the 148 meters have to be the 1/4 of the total wavelength", but in this case not for 500Khz, but for your measured 1Mhz.

Itsu

Itsu
Yes i see the 1MHz due to specific inductance and capacity characteristics. The point is if it needs to be lowered to 500KHz with a top load so to take out its maximum voltage.
We speak about a standing wave and its nodes-antinodes. I don't understand why it has to be different when using kacher drivers.
Thanks for sharing your experience anyway. 

ps. I just did the probe test as you described and confirms your suggestion. The question is why is that? Anybody? The image above suggests the opposite! I am going to search more for blocking osc.

So with or without the topload there always is a max amplitude at the top even when at different resonance frequencies, see drawing below.

Itsu
Thanks for the drawing

Lets suppose that we use a wire of 74m as a secondary and by inserting a top load we make it vibrate again at 1MHz like in the above case. How is that possible at the same frequency of 1 MHz both of the wires (148m &74m) to present max HV at their top sides as a quarter wavelength does?? Isn't that a paradox???

Any physicist here?? 

Itsu
Thanks for the drawing

Lets suppose that we use a wire of 74m as a secondary and by inserting a top load we make it vibrate again at 1MHz like in the above case. How is that possible at the same frequency of 1 MHz both of the wires (148m &74m) to present max HV at their top sides as a quarter wavelength does?? Isn't that a paradox???

Any physicist here?? 

Jeg,

i am no physicist, hopefully one will explain, but to my knowledge, the (top)loading is doing that, adding capacitance.

By using (according to the javatc calculator) a 5cm diameter tube, put your 74m / 0.4mm diameter wire in 473 turns around it
and use a sphere topload of 16cm diameter at 2 cm above the tube.

You get this then:

Itsu
Thanks for the drawing
Lets suppose that we use a wire of 74m as a secondary and by inserting a top load we make it vibrate again at 1MHz like in the above case. How is that possible at the same frequency of 1 MHz both of the wires (148m &74m) to present max HV at their top sides as a quarter wavelength does?? Isn't that a paradox???
Any physicist here?? 

Hi Jeg. No, not at all, because the resonant frequency of a coil is dependent on both the coil inductance
and its self capacitance. When you add a top load to a coil, you increase the capacitance seen by the coil,
so it will have a lower resonant frequency. It is the same effect as adding a separate capacitor in parallel
to a coil. That will also lower the resonant frequency of the coil. A coil's resonant frequency is not just dependent
on its wire length. So there are many possible combinations of coil size and a top load or an external parallel capacitor
for a given resonant frequency. The magnitude of the current that flows in the coil as well as the max voltage will
vary for different combinations however. In radio, adding a top load to a vertical antenna raises the current node
in the vertical antenna element somewhat, so this probably also occurs in a coil as well, but probably to a lesser
noticeable extent.

All the best...

Hi Void, thanks for the answer. Please see the above post which you have might missed.

Hi Jeg. Looks like you modified your comment to include the answer I gave.
I don't have a lot of experience with tesla coils, but I doubt there is any paradox in there. It is
more likely that you are just misunderstanding how things work with tesla coils. Playing around with
the tesla coil calculator app here should help you to understand how varying the different
parameters such as coil length and size and with different top load sizes varies the
max current and max voltage for a given input voltage.
http://www.tesla.nu/programs/javatc/javatc.html

All the best...

Everything is probable. It would just be great if an experienced Tesla coil builder could answer me on this.

Hi Jeg. I think you need to clarify your question.
I am not clear about what you are asking.
What specifically is your question?

P.S. At any rate, if you play around with the JavaTC program you will be able to
see how the different tesla coil parameters affect the performance.
I guess you are wondering if the secondary coil wire length is approximately 1/4 wavelength
of the tesla coil's secondary resonating frequency when using a top load, if you will get a higher
max voltage on the secondary for a given input drive voltage? You can try that in JavaTC
to see what the result is...

P.P.S. I think the input current draw is higher when you use the top load to resonate closer to 500kHz
because with a larger capacitance there is more charge storage capacity, so the current peaks
are higher in the resonating secondary. To maintain this higher resonating current, it requires a
higher input current draw from your power supply. Contrary to popular belief in these forums,
resonance does not come without a power input cost.


All the best...

Hi Guys

Void Sergh Itsu Nick
I took my answers, thanks a lot. I am playing with a Katcher driver trying to optimize it for best performance. I wounded two Tesla coils for replicating TK's experiment for wireless transferring, but a correctly working katcher is a nice toy for more experiments. I'll upload if anything interesting will occur.

Regards