Re: Re: LF: VLF dj8wx on 8970.022Hz

[uwe-jannsen@kabelmail.de]

Hello Gerhard,

thanks for confirming the possibility of the high voltage.

concerning the hot part of coil end:
the pvc insulating here is of no use when using 3A radial current.
if hanging  p.e. a one metre long also isolated wire  on the aerial feeder one can see the blue Tesla fire.

best regards
Uwe/dj8wx
 

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Von: rsgb_lf_group@blacksheep.org
Gesendet: 08.03.2011 20:40
An: rsgb_lf_group@blacksheep.org
Betreff: Re: LF: VLF dj8wx on 8970.022Hz

---

Hello Uwe!

Regarding to my experience, the 40kV are real. Considering the high
power (anf thus current) you are running, the voltage would be much
higher on my 550mH coil. 550mh = 31kOhm at 9000Hz = 3A*31kOhm =
93kV.....luckily I just can manage to get about 0.6A and thus Voltages
are lower!

Voltages above 10kV are usual when transmitting on VLF and therefore
every effort should be taken on insulating the "hot" part of the
antenna.

73
OE3GHB
Gerhard






Am Dienstag, den 08.03.2011, 19:27 +0100 schrieb
uwe-jannsen@kabelmail.de:
> Hi all,
>
>
>
> Im doing some measurements trying to find out how low (high?) the ERP
> of my system is.
>
>
>
> the test lead of the oscilloscope in use has a resistor of 10Mohm. The
> oscilloscope advise text says that I have to multiply the result by
> 10.
>
> OK. I added two other 10Mohm in series multiplyed the result by 1000
> and got 40000Vpp
>
> using the twentieth of max TX power. 40kV? Is that possible?
>
> the current from the coile foot into the radials was 0.145A (3 A with
> max power).
>
> I cant measure the Tesla voltage when the power is raised because the
> oscilloscope or other
>
> instruments indicate results without connected to the object under
> test.
>
>
>
> the station is on the air in mode QRSS3600 on 8970.022Hz since today
> 1640UTC.
>
>
>
> current into the radials: one Ampere.
>
>
>
> who will try to calculate the ERP?
>
> the aerial in use can be seen at
>
>
>
> http://dj8wx-dl.de/hompage500kHz/TX%20equipment.htm
>
>
>
> fourth pic on the site. The shown 23m long wire has been lengthened to
> 43m.
>
>
>
> best regards
>
> Uwe/dj8wx
>
>
>
>