Playing with an old radar setup. Tips for a beginner.

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fredrussell

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I recently bought a Furuno radar set. I don’t really need a radar much for my type of (mostly) day sailing but it was cheap and I thought it might be a fun project to set it up in the garden.
Having set it up at the end of the garden, with the radar on the transmitter is revolving and clutter (I think) is shown on the screen (with gain turned up), but only at a distance of approx 3nm or more, inside that ring, no readings or clutter. If you increase the scale there is still nothing within 3nm or so. I have placed a metal wheelbarrow(!) about 30 metres away in field and tried radar at minimum range (0.125 nm on screen) but still nowt.
Radar dome is sitting on a one metre high workbench in garden, large open field behind. I had to join cable (cut on removal by previous owner) -this I did by soldering and heat shrink, including co-ax part (inner joined and insulated, ditto for outer).
The purpose of this thread is just to check I’m not missing anything obvious as a newcomer to the exciting world of radar. The setup was described as working when removed, and was cheap enough to take a punt on and it’ll be easy enough to recover my outlay on eBay (plotter works fine).

I’ll check all connections, especially the splices I made obviously, but any tips would be gratefully relieved…
 
First tip would probably be to be careful where you're pointing it. Having someone absorbing a full dose of radars, especially at close range, isn't recommended.
Of course, if it's a duffer, this may not be an issue!
 
Both tips taken on board. I’m actually getting somewhere now, which is to say, radar is showing noise/clutter at all ranges, including close up. I think it is working, but looking out over a wet muddy field may not be the environment it’s designed for. Also my research indicates operating an unregistered radar on land is frowned upon by the authorities. I’ll rig it up on boat.
 
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The minimum range at which a target might be detected is normally related to the pulse length - a long pulse means a longer minimum range. Not sure how much manual control you have over the transmitter characteristics but you could have a play with pulse lengths (keep as short as possible) and increase the range to your wheelbarrow target and see if you get a return. The mount angle might also be important when you are looking over a hard target such as your field. Try tilting it slightly so the bottom of the vertical beam is able to paint your target. You should be able to find the vertical beamwidth in the specs. If you assume it is symmetrical around the perpendicular plane of the array you could draw a little diagram to see if you have a chance of detecting your target.
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@fredrussell Well done for buying a radar, even as a fun toy. It’s a much under used and often misunderstood piece of kit within the recreational sailing environment.

I’d recommend Pat Manley Radar Companion as a good learning resource. Very clear, succinct and easy to understand.

It gives useful examples for use in pilotage and for collision avoidance. Even if the set has MARPA, it’s good to be able to construct the OAW Triangle of Motions to determine CPA, TCPA, Aspect and to see the effect of changes in speed and/or direction upon CPA.

The problem with Radar is that it’s easy to forget how to get most out of it so using it regularly, even when not really needed, is good practice.
 
also be aware older sets, even after warming up to awitch on , take a further 20 min in use to warm thoroughly, and the picture be at its best,
 
Furuno put pretty lengthy instructions on the use of their sets and how to tune them in the manual, which might help you with the specifics.

The suggested literature and methodology by skylark I would firmly agree with.

Worth googling radar assisted collision
 
You might not be able to pick up your wheelbarrow (and hopefully you will not need to look for wheelbarrows at sea :) ) but you should be able to pick up rain patches - for which radar is invaluable at sea (and on land as you know when to get the laundry in) - as you might be able to sail between rain patches.

Jonathan
 
Neeves said:
You might not be able to pick up your wheelbarrow (and hopefully you will not need to look for wheelbarrows at sea :) ) but you should be able to pick up rain patches - for which radar is invaluable at sea (and on land as you know when to get the laundry in) - as you might be able to sail between rain patches.

Jonathan
Click to expand...
Depending on the shape of your wheelbarrow, it may be a "Stealth" model!
 
david_bagshaw said:
also be aware older sets, even after warming up to awitch on , take a further 20 min in use to warm thoroughly, and the picture be at its best,
Click to expand...

By "old" are you referring to crt displays? My Furuno 1712 (lcd display) must be around 20 years old by now, takes about a minute on initial switch on and is then up and running. When switched from standby to scan or, timed wake up scans, it starts scanning immediately.
 
Graham376 said:
By "old" are you referring to crt displays? My Furuno 1712 (lcd display) must be around 20 years old by now, takes about a minute on initial switch on and is then up and running. When switched from standby to scan or, timed wake up scans, it starts scanning immediately.
Click to expand...
yes i am thinking of CRT, but magnetrons and klystrons do take a while to warm thoroughly
 
Fred Russell, I wish you well with your 'innocuous' experiments.

However ridiculous it may appear to you, there is law against what you are mucking about with.... and with good reason.
Please do not be surprised if some OfCom cops turn up early one morning ( You didn't know they had a dedicated police force? That they are armed...? ) and have a word or two with you.

Do let us know how you get on....
 
fredrussell said:
... Also my research indicates operating an unregistered radar on land is frowned upon by the authorities. I’ll rig it up on boat.
Click to expand...

zoidberg said:
Fred Russell, I wish you well with your 'innocuous' experiments.

However ridiculous it may appear to you, there is law against what you are mucking about with.... and with good reason.
Please do not be surprised if some OfCom cops turn up early one morning ( You didn't know they had a dedicated police force? That they are armed...? ) and have a word or two with you.

Do let us know how you get on....
Click to expand...

Where did I suggest the law regarding radars was ridiculous? A very strange response.
Yours,
Fred, HMP Wormwood Scrubs.
 
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