GPSII Cylinder Clock

Cylindrical GPSII GPS Satellite Controlled Clock

Here is the Cylindrical GPSII Clock. A total of ten were assembled.

The GPSII cylindrical enclosure was designed and manufactured by Mike Matter.

It is electrically the same as the acrylic boxed GPSII. The cylinder is 4 inches in diameter. End caps are machined acrylic, the tensioning rod and hardware are stainless steel. It is an amazing item to look at. And very popular with celebrities.


GPSII is always accurate to within 500ns (nano-seconds) of the GPS Satellite transmission -Far superior to local oscillator and AC line referenced clocks.


GPSII features:

Giant 50mm digits glowing inside the Nixie Tubes.

Chronometer precision, using GPS.

Auto setting on powerup (no battery backup needed)

Menu items are permanently stored in EEROM.

12 or 24 hours display.

Programmable display disable at night.

Safe 12vdc 300ma operation.

Professionally engineered.

Craftsman assembled.

Very Limited production.

Variable Scrolling display of all features.

Concealed magnetic switches -no buttons!

PM indicator for 12 hour display.

Temperature sensor with quarter degree resolution.

Nine chime choices (including Morse code)

Alarm Clock feature.

Addressable colon indicators.

Leading zero blanking in 12hr display mode.

Programmable display brightness level.

Automatic DST offset (USA, Europe, Australia, manual N and S hemisphere)

GPSII receives the satellite transmission using a compact "puck" style 1.5Ghz antenna. Indoor locations can provide adequate satellite reception when the antenna is placed inside on a window sill. Some congested hi-rise environments will require an external antenna mounting to achieve an adequate sky view. The hi-gain active antenna includes magnetic base for easy mounting, and is weatherproof. 10' of coaxial lead is included, and supports extensions up to 50'.

GPSII incorporates a unique method of operation in areas with "spotty" reception due to limited antenna mounting through use of a secondary time source. In the event of satellite signal loss after successful startup; GPSII will continue operation using the high precision 1pps signal pulse from the GPS receiver. The lower right colon lamp will extinguish to indicate the clock is operating from the local precision, then relight when the satellite signal has been restored. If power is lost, a lithium battery will maintain GPS receiver ephemeris, and quickly resume operation when power is restored. No typical cold start TTFF (Time To First Fix) delay is incurred when GPSII is re powered. The initial startup acquire after installation may take 10-20 minutes, location dependent.


Professionally engineered and skillfully handcrafted. Only the finest components were used in the construction.Though the term "rare" has been exhausted by others, the GPSII Cylinder was built on special request only.

The clock is powered by a compact 12vdc wall adapter. The clock is fully isolated from the line voltage. Connections to 12vdc power and the GPS antenna are made at the side of the clock. The Oncore GT+ GPS receiver is visible at the upper back, mounted on standoff posts.