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Date: Wed, 28 Jun 2006 23:20:29 +1000
To: rsgb_lf_group@blacksheep.org
From: Richard Rogers <vk7ro@netspace.net.au>
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Subject: Re: LF: Re:Spark
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At 11:35 AM 28/06/2006 +0100, you wrote:

snipped

>BTW   I realise I have no idea of the length of the spark gap...anybody
>know?
>
>Bryan G3GVB

G'day,

>From a scrap of original copy (presumably from 600M) from Trevor Watkins,
7AA, later VK7DX who died in 1931 from TB (and too many late nights?) :

23rd May 1923
1.48 am	VIM de VIA	ur spark is not up to tem...
		VIA de VIM	think gap open too much see ltr VIM
2.5		GUJ de GHM	when are u due K
		GHM de GUJ	about 4am
2.10		VIM de VJH	hw this coil nw
		VJH de VJK	coil gdo nw qru SK
		VIA de VIM	wa abt 1 nr 4 inch apart hw
2.15		VIM de VIA	gdo nw VIA tks VIM

My guess is that the abbreviation gdo meant good-oh and that 1 nr 4 meant
one quarter.

VIA and VIM were coast stations in Adelaide and Melbourne and both used 5
KW spark transmitters erected in 1912 and 1911 with an air blast to ensure
a short duration of the spark and hence minimum damping and transmitted
bandwidth.


73, Ric, VK7RO