Re: LF: VLF - G3XIZ - Now QRT

[M0FMT <m0fmt@yahoo.co.uk>]

Hi Chris and LF

 

A big thank you to you Chris for all the work you have put into this exercise. Hope the results to date have been worth it. I guessed you had gone off but you were into the noise with me by then. The noise really comes up on VLF at night around here.
 

73 es GL Pete M0FMT IO91UX

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From: Chris Osborn <g3xiz@yahoo.co.uk>
To: LF Group <rsgb_lf_group@blacksheep.org>
Sent: Sun, 17 April, 2011 19:07:06
Subject: LF: VLF - G3XIZ - Now QRT

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