The Radar Room

TECHNICAL
Chain Home Radar demo valve lineup

Chain Home demo valve lineup

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As there are always a number of people visiting our display who are interested in the technology used by our exhibits, we’ve created this page to give a random assortment of images showing our equipment in a more disassembled state. Either as obtained, or during and after restoration. Enjoy!
R3645 under test vertically with RF27 unit ARC-5 receiver six valves plus IFTs all shoe-horned in
Wurzburg azimuth tube development

Wurzburg azimuth tube development

ARC-5 receiver six valves plus IFTs all shoe-horned in
Loran APN-4
Loran APN-4

R3645 under test (vertically!) with RF27 unit
Loran APN-4

Our Loran APN-4 has to be the most complex rebuild undertaken by the Radar Room to date. Aside from a few modern bits and pieces needed to replicate the signal parts that are no longer

transmitted, a large percentage uses portions of the original circuit and no less than 22 valves to make it work. At the time of writing , the Radar Room does not own an example of the matching receiver R-9B APN-4.
GEE original plus a 50s valve

Our Gee indicator uses more ‘modern’ components than the Loran. Including this EF80 valve from the 1950s.
GEE indicator

GEE indicator with row of VR65 valves
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Side view of the ASV radar showing a row of VR91 (EF50) valves along with an EF80. As the remains of our original indicator didn’t have a case, we thought that the best approach was to make a see-through version.
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GEE under construction
GPO lever switches for GEE GEE new front panel

Two ex. GPO lever switches tracked down for the new GEE front panel.
R1155 rRX replacement dial and labels

At this point in the GEE rebuild the tube is now green but there are no controls on the blue front panel we’ve yet to change.

The heavily modified Radar Room GEE example turned out to have a monochrome tube! Check out that front panel!
R11 receiver test circuit for direction finding
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GEE RF24 unit rebuilt from the underside. Note the mixture of original and modern passive components used.

Some bench experiments undertaken to produce circuitry for the R1155 receiver direction finding.

R1155 receiver replacement dial and labels
R1155 spot the new components

R1155 receiver rebuild. Spot the new components.
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ASV original

Hardly anything remained of our ASV radar indicator. Not even the original tube as it was cracked.

R1155 receiver DF transformer as original to the left and after resplacement of wires and components to the right. The rebuilding and restoration of these receivers is a long and tedious job which needs a lot of patience. Don’t let anyone try to tell you otherwise!
ASV radar two spots on screen

Two spots on the chosen cathode ray tube
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More circuitry for two lines

A bit more circuitry and we have two lines
Choosing a tube

Choosing a tube for a project

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Wiggly lines = working Y amps