Re: LF: VLF - G3XIZ - Now QRT

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Hi Chris

Yes I think you have now established the coverage with the inverted-L on VLF pretty well with the reports from your regular fans in SE England and from Paul Nicholson. There are still new stations eager to copy you (such as G3PLX in Cumbria and DK7FC,) so some further tests would be appreciated.

Your situation on VLF is much as I was with QRPp on 136kHz last winter: a stepwise improvement in ERP is needed to extend the range significantly. BTW I hope to make this step on 136kHz in good time for next autumn, although I have no immediate plans for serious radiated tests on VLF, but you never know.

Some G3XIZ portable operation would indeed be worth a try and I look forward to looking out for you when you try this. In the meantime, if you want me to look for you at any time you know I'm keen and usually able to look.

Thanks again for giving us all the challenge of copying a UK station on VLF.

73s
Roger G3XBM

On 17 April 2011 19:07, Chris Osborn <g3xiz@yahoo.co.uk> wrote:

LF,

I went QRT on VLF at about 17.00Z today.
Many thanks for all reports over the weekend and I shall give a summary later in the week.

Balloon (and kite) launching from my home QTH is difficult and at times quite stressful.
I have to be ever vigilant that the balloons (or kite) don't hit local houses (TV / FM radio aerials) or come down in the adjacent playing field (children + EHT !)

I have a reasonable PA which if properly matched could give several hundred watts of RF.
At present I get at best about 140 watts.
I am still using the mains matching transformer between the PA and the loading coil and this has a step-up ratio of 1:24

Energizing the PA with a higher voltage than its present 30V is not an option as the matching transformer is already running over-voltage and would doubtless break down.

It has been suggested that I use link coupling to the loading coil from the PA but the one time I tried this caused damage to both the PA and the coil, so you will sympathise with my reluctance to try that again!

I will continue for a few weeks and see if I manage to get 'real' success with the balloons or kite assisted aerials.

I was considering taking apart an old PC PSU and using the output transformer from that instead on my present iron-laminated mains transformer.
I believe that PC types will be more suitable and handle higher voltages.

I plan to transmit over the Easter holiday but beyond that I am uncertain.
I have a plan to try /P during the summer but this depends on gaining the permission of the land owner, which I am waiting for at present.

I am getting consistent reports from my 'regulars' but now need a step change in my VLF progress.

73
Chris G3XIZ

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