Navnet 1724C VX2

[Mickeyrouse]

I have what I hope is a tuning, adjustment, or set-up problem on my Navnet 1724C radar/plotter.
Since we use this with our FAS-50 AIS in chart plotter mode, we rarely use the radar. We have found the identification of AIS makes bridge-to-bridge communication more reliable when requesting passing instructions with heavy traffic in the Gulf ICW. Thus, we go long periods without switching to radar mode.
When last engaged, the screen image of the radar sweep was so small as to be unusable. Zoom doesn’t increase the sweep circle. In reviewing the manual, I find nothing that indicates this can be changed. No doubt I have done something inadvertant to minimize this, but I have no idea what. Is this fixable, and if so, how?

 

[Johnny Electron]

It isn't clear to me what you mean. Are you splitting the screen or conducting radar overlay? The radar should allow you to RANGE in/out just like you do with a chart. What do you mean by zoom?

 

[Mickeyrouse]

Sorry for my tardy response- been dealing with Hurricane Laura here.
What is happening is the radar circle image on the screen is very small- 3/4 inch. The rest of the background is white. I can zoom (Range may be the proper term) in or out and the range circles change accordingly, but the circle size of the sweep doesn’t change, though I can clearly see that the area in the circle is appearing to respond to the circular sweep of the scanner, with the dim area just before sweep suddenly getting brighter as the sweep comes around. But the circle of the swept area is too small to be useful.

 

[Johnny Electron]

So when you hit DISP and select full screen RADAR as a choice; your radar is only 3/4 of an inch?

 

[Mickeyrouse]

That is correct- 3/4” at best. Also, this small image onLy appears on the 1/8 and 1/4 Mile ranges- totally absent on greater ranges. For comparison, I switched to simulate mode and all functions respond to the soft keys and other controls as expected. Reverted to live, and same old story. I activated the zoom box, and it shows the same tiny image.

 

[Johnny Electron]

So I am confused, the range scale and everything is small or are you talking about just the radar returns?

 

[Mickeyrouse]

The range scale (rings?) appear to be normal size. The returns are (what I’m calling the swept area for lack of a better term) the tiny multi-colored circle.

 

[Johnny Electron]

If the radar return is only in the first ring something is really off. It is hard to say what without testing the radar with a radar simulator. Can you turn off the rain and clutter (to zero) and then take the gain to 100% and fill the screen?

 

[Mickeyrouse]

I’ll have to do that tomorrow. Not at the boat at present.

 

[Mickeyrouse]

I tried changing rain and clutter to zero and increasing the gain to 100%- no change. Is there any way I can send you a photo of what the screen shows? I also went to Simulate, and tried all three variations. They all work full screen, with all controls (gain, range, screen colors, zoom box, etc.) responding as expected. No change in live image..

 

[Johnny Electron]

You can open a support case with tech support and send photos. It sounds like the dome needs to be evaluated. It almost sounds like a 10" dome was used on the 7" radar or something really strange. Even if the MAG is blown, you should be able to speckle the entire screen due to the IF amp being cranked up.

 

[Mickeyrouse]

I’m in no position to say whether the radome is a mis-match for the display, but I purchased them as a unit when I installed them. The radar image was the full-screen size for a long time, though I have rarely used it much. I periodically check radar, though rarely these last few years because we don’t sail at night or in fog as much these days. Last time I checked, the image was full size, though that was likely a year ago.
How do I open a support case?

 

[Johnny Electron]

If Furuno USA is your distributor it is on the website - SUPPORT - ASK a question. That is the official support channel for Furuno USA.

If you have seen the radar working full screen then the combination should be fine. I must have confused your post with another. If you can't speckle the screen with Gain all the way up it is most likely the IF amp board or a cable issue. If the radar video line gets a poor connection it can cause your video to do that. If you have any cable splice boxes they should be checked for water or corrosion. It might be that you will need to send the dome in for repair evaluation. The problem is more likely to be in the scanner than the display; if the cable is good.

 

[Mickeyrouse]

Because of the cable length, there is a connector strip. Sounds like that could be a leading candidate, since it was installed about 11 years ago. I’ll let you know what I find.