Re: LF: VLF - G3XIZ

[Chris Osborn <g3xiz@yahoo.co.uk>]

Thanks for all suggestions and comments.

I quickly wound in and then rewired the aerial reel with heavier copper wire.
As Mal says the original wire was just too fine to work with.

I'm using 10 inch helium- filled  party balloons - 8 at present.
Intermediately placed balloons seems a good idea to spread the loading but they touch the aerial wire and then burst.

Again I'm up to 50m almost vertical with no wind.
The aerial current is ok too at 0.15 - 0.2A
I can tune the system by winding in/out the aerial wire but must remember to turn off the TX first - ouch!

I'm on QRSS 60 for a while but will revert to QRSS 600 soon

73
Chris G3XIZ

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From: Stefan Schäfer <schaefer@iup.uni-heidelberg.de>
To: rsgb_lf_group@blacksheep.org
Sent: Fri, 31 December, 2010 12:12:07
Subject: Re: LF: VLF - G3XIZ

Chris,

This sounds good. Trying in 600 is a good starting point and a 50m vertical is fine too. How big are the balloons? Do you use helium or hydrogen? ;-)
Using 0.2mm diameter wire may cause some partial discharges ("sparking"). This is causing resistive losses and lower the ERP. Thus it is better to use a bigger wire, maybe 0,5mm. But then the weight could become a problem. Anyway, its sound like the best system you run on VLF so far.
When running 0.15 A into a 50m vertical at 8970 Hz you should get about 9 kV rms.

Sadly i am not near my grabber PC in Heidelberg and cannot move the window to your frequency but before there will be a reception in Germany there will be a reception in UK at farer distances what will be satisfying for you i assume ;-) Just like in my tests your personal ODX should rise in "small" steps since this is causing the most fun :-)

73 and good luck!

Stefan/DK7FC

Am 31.12.2010 12:38, schrieb Chris Osborn:

The balloons are still holding up.

I'm transmitting 'XIZ' at QRSS600
QRG: 8.971 846 kHz
The aerial current is down for some reason although the system's resonant.

73
Chris G3XIZ