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