Hi Andy and Andre' it sounds a bit more like....MMMmm we have rather a lot
of those left in the stores....I wonder what we can use 'em for! I have a
feeling that the 'frame-grid' valves ( 'tubes' for Andre's benefit) were
fairly susceptible to grid overvolts. At least a lot more so than the
standard grid structures. That is based on Oceanic submerged repeater
experience, where they see a 15kV pulse when your friendy trawlerman decides
not to wait for the compensation for his snagged nets, and puts his axe
through the cable!. Still I suppose they are still a bit better than
'3-legged fuses'.
I have seen suggestions of transistors like VMP-1s and VMP-4s (a bit old now
but VMOS VHF power devices) for good big signal handling capability at HF,
but you would certainly need static protection on those, which does tend to
defeat the object.
Wasn't the 807 (like Walter's) running about 20-30mA praised up for its
performance as an aerial distribution amp, at Hanslope Park and Bletchly
Park.
Despite the use of many HROs which can put a considerable number of mVs of
local oscillator signal out of the aerial socket. (I have even seen TVI on
Band I from an HRO)
Cheers de Alan G3NYK
[email protected]
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