JRC 1000 radar

[Guest]

I need some advice on what performance to expect from this radar - at present, I dont know whether I have a problem, or whether the level of performance I get is typical.

My set will not pick anything up at the 12 / 16 mile range, and sometimes will not pick up the shore at 6 miles. Small boats appear and disappear then re-appear again.

The set was installed at spreader level on my cat 2 years ago. The cable supplied was 15m long, and since I had nowhere to put the 10m of it that I did not need, I spoke to JRC who said it was OK to cut and then join with a chocolate box type terminal. This has been done carefully, and is well protected.

I've even read the manual on how to set it up!

 

[ParaHandy]

That sounds normal. Shoreline may or may not be detected depending on rock, water content etc.

Just as an aside, does the JRC 1000 have fan cooling in the radome? A yot mag said it did (can't remember which) which I thought was v. unlikely.

 

[ZEBEDEE]

Sounds to me that you might be expecting too mutch from your set.
From what you have said your scanner is only at the most 15/16ft off the ground, if you are only using 5 M of cable therefore you will not have a great deal of range for small vessels. The formula for Radar range is 1.23 x Sq root (Height of scanner + Height of target) therefore if your scanner is 16ft off sea target is 20ft high Theoretical range = 1.23 x Sq RT (16 + 20) = 7.38 Miles. You did not mention height of coast you were looking for but if 250Ft high = 1.23 x Sq rt (16 + 250 ) = 20.06 miles this assumes good conditions etc. The small boats coming and fading is probably being caused by waves acting on both yourself and target shielding it from your scanner.

Hope this helps.

 

[jtwebb]

I had one on my previous boat and the performance was the same. You can not expect much more at that height. If you are getting coast at a greater distance it is often inland hills or the nuclear reprocessing plant near Cherbourg if you are there, good return off that! No fan inside the radome.

J Webb

 

[Guest]

Thanks for all your help. Since everyone agrees, it seems likely that I'm expecting too much.

I suspect that sailing a cat doesnt help. It may not roll much, but it certainly pitches, and it may well be that the vertical beamwidth leaves the horizontal altogether at times.