Decca Navigator Mk IV - UK Vintage Radio Repair and Restoration Discussion Forum

Tez Burke · 29th May 2008, 12:27 pm

Hi all, just picked up one of these proto-GPS devices, made by RACAL and dating from, I'd guess, the 1980s. It runs on 12v dc and came originally from a glider. Anyone familiar with these things, and can any of you think of any use it could possibly be put to now? It appears to come with some kind of active antenna.

Steve Smith · 29th May 2008, 12:54 pm

Can you post a picture?

Betwen 1985 and 1988 I worked for a company who made ship's navigation equipment including items for Decca.

If I remember correctly, the Navigator was just a fluxgate compass and the pilot was the compass with an auto-steering system.

Neither of these sound like the item you have unless you are confusing the 'active antenna' for the compass detector. These were made from black (usually) ABS, were about 5" tall and 4" diameter and had a flat base with three mounting slots. On top were two adjustment points to correct for magnetism inherent in the ship.

Decca also used the Navigator name for their low frequency radio system so you may have one of these.

Either way, I would like to see a picture if possible.

Steve.

Variometer · 29th May 2008, 1:52 pm

Decca Navigators were extensively used at sea until satellite navigation tooK over. They are of no practical use now because the Decca transmissions were discontinued some time ago.
Bob

dsergeant · 29th May 2008, 6:08 pm

Indeed the Decca Navigator chain closed down around 1999. I remember hearing them in our at that time 73kHz allocation. After they had closed down some amateurs were given access to the masts for experiments on the amateur 136kHz band, with good results - and also some of the equipment at the stations such as Litz wire was distributed among 136kHz experimenters. See one report using the Puckeridge mast at http://homepage.ntlworld.com/mike.de...cca/decca5.htm

Like the old Loran chain on 1.95MHz (which I witnessed going off air in the mid 1970s) the Decca system is now in the history books. Guess you can only use that box for spares.

Dave (G3YMC)

dseymo1 · 29th May 2008, 10:01 pm

Is your device rather like a larger version of a current GPS device, with an orange display? I had one like this given to me a few years ago - it appeared to work, but displayed a 'no signal' icon, whatever I connected to the antenna socket; presumably any local transmitters had already been shut down.

russell_w_b · 29th May 2008, 10:59 pm

Quote:

Originally Posted by dsergeant

Like the old Loran chain on 1.95MHz (which I witnessed going off air in the mid 1970s) the Decca system is now in the history books. Guess you can only use that box for spares.

Dave (G3YMC)

The new LORAN chain is strong as ever on 100kHz, however, with e-LORAN providing a 'harbour-mouth' accuracy navigational fix, as well as offering services (not yet taken up) that currently rely on GPS.

Your local e-LORAN station is at Anthorn, Cumbria.

majoconz · 22nd Jun 2008, 5:21 am

Good explanation in Wikipedia. I remember using it on the Geordie Collier "Sir William Walker" in the mid 60's. Supposedly accurate to about 10metres, I remember having to tie up to a mooring buoy off Gravesend in thick fog. We had been told on VHF radio that there would be a dockyard matey on the buoy so using the Navigator we edged our way forward to the charted position and shouted "Ahoy" - he accused us of trying to run him down!

29th May 2008, 12:27 pm	#1
Tez Burke Retired Dormant Member Join Date: Jun 2006 Location: West Yorkshire Posts: 12	Decca Navigator Mk IV Hi all, just picked up one of these proto-GPS devices, made by RACAL and dating from, I'd guess, the 1980s. It runs on 12v dc and came originally from a glider. Anyone familiar with these things, and can any of you think of any use it could possibly be put to now? It appears to come with some kind of active antenna.

29th May 2008, 12:54 pm	#2
Steve Smith Retired Dormant Member Join Date: May 2008 Location: Isle of Wight, UK. Posts: 24	Re: Decca Navigator Mk IV Can you post a picture? Betwen 1985 and 1988 I worked for a company who made ship's navigation equipment including items for Decca. If I remember correctly, the Navigator was just a fluxgate compass and the pilot was the compass with an auto-steering system. Neither of these sound like the item you have unless you are confusing the 'active antenna' for the compass detector. These were made from black (usually) ABS, were about 5" tall and 4" diameter and had a flat base with three mounting slots. On top were two adjustment points to correct for magnetism inherent in the ship. Decca also used the Navigator name for their low frequency radio system so you may have one of these. Either way, I would like to see a picture if possible. Steve.

29th May 2008, 1:52 pm	#3
Variometer Retired Dormant Member Join Date: May 2008 Location: Preston, Lancashire, UK. Posts: 428	Re: Decca Navigator Mk IV Decca Navigators were extensively used at sea until satellite navigation tooK over. They are of no practical use now because the Decca transmissions were discontinued some time ago. Bob

29th May 2008, 6:08 pm	#4
dsergeant Octode Join Date: Mar 2006 Location: Bracknell, Berkshire,UK. Posts: 1,173	Re: Decca Navigator Mk IV Indeed the Decca Navigator chain closed down around 1999. I remember hearing them in our at that time 73kHz allocation. After they had closed down some amateurs were given access to the masts for experiments on the amateur 136kHz band, with good results - and also some of the equipment at the stations such as Litz wire was distributed among 136kHz experimenters. See one report using the Puckeridge mast at http://homepage.ntlworld.com/mike.de...cca/decca5.htm Like the old Loran chain on 1.95MHz (which I witnessed going off air in the mid 1970s) the Decca system is now in the history books. Guess you can only use that box for spares. Dave (G3YMC)

29th May 2008, 10:01 pm	#5
dseymo1 Retired Dormant Member Join Date: Dec 2007 Location: Shropshire, UK. Posts: 3,051	Re: Decca Navigator Mk IV Is your device rather like a larger version of a current GPS device, with an orange display? I had one like this given to me a few years ago - it appeared to work, but displayed a 'no signal' icon, whatever I connected to the antenna socket; presumably any local transmitters had already been shut down.

22nd Jun 2008, 5:21 am	#7
majoconz Heptode Join Date: Jan 2008 Location: Ashhurst, Manawatu, New Zealand Posts: 571	Re: Decca Navigator Mk IV Good explanation in Wikipedia. I remember using it on the Geordie Collier "Sir William Walker" in the mid 60's. Supposedly accurate to about 10metres, I remember having to tie up to a mooring buoy off Gravesend in thick fog. We had been told on VHF radio that there would be a dockyard matey on the buoy so using the Navigator we edged our way forward to the charted position and shouted "Ahoy" - he accused us of trying to run him down!