Marconi Instruments Spectrum Analyser

[ParcGwyn]

I came across a picture of this Marconi hf spectrum analyser on eevblog forum. I have never seen one, does anyone have any information on this beast.

Dave

GW7ONS

[ParcGwyn]

i have now found the model number it is OA 1094A, apparently designed by the GPO and marketed by Marconi Instruments, I have also found an instruction manual but would be really interested in looking at the circuit diagram if anyone can help.

Dave

GW7ONS

[Chaparal]

Dave,

found only a block schema.

Peter

[ParcGwyn]

Thanks Peter, I have now found a schematic on a Swedish website,, quite interesting to see how early spectrum analysers were designed. Resolution bandwidth settings are 6, 30 and 150Hz and the maximum visible spectrum width is 30kHz.

Thread can now be closed.

Dave

GW7ONS

[WME_bill]

Marconi OA1094.
I have the circuits for version 1094A/3 and the specification from the 1957 Marconi catalogue. As you have found the circuits, fine. But you may find the Specification interesting so I attach it. wme_bill

[ParcGwyn]

Great, thanks WME_bill, that looks like interesting reading, nice to see a picture of one in use at the Rugby transmitter.

Dave

GW7ONS

[ParcGwyn]

Just noticed the price for the analyser on the document WME_bill posted, £2500 in 1957, this would have bought a house then. In 1992 I was using a Tektronix 2782 s spectrum analyser that also cost the same as a house. If I remember correctly it was around £70000 and my house at the time cost £45000.

Dave

GW7ONS

[Dickie]

Here's a photo of a real one, unfortunately the forum resizing has rendered most of the panel legends unreadable. The plate in the middle says "Manufactured by authority of the General Post Office type W1"

[ParcGwyn]

Thanks Richard for the photograph, it appears that the OA 1094 differed externally at least from the OA 1094A.

Dave

GW7ONS