Thank You Bill,
I served some years in the R Sw Signals (1963-64 1st Regt Uppsala, 1964-65 3rd Bn Boden, 1966-67 2nd Regt Karlsborg).
The carrier-pigeons were since long time gone, but trailers (horse traction) were still found on the Regt:s scrapyard. I also found one in a park in Haparanda - converted to a playing house for children. So I remember those small ventilators close to the roof.
Today it is very warm in Sweden! A cold beer is urgently needed.
I posted a few pictures to Nuyt:s Overvalwagens site.
Stellan