NASA AIS ("radar")

[Graham_Wright]

I have a boat around 100 metres from me transmitting which I can see on Marine Traffic but there is no indication on my instrument.

As far as I can tell, the antenna is operational (by swapping below with the VHF cable).

Are there any tests I can do to find the problem?

The GPS input is missing as I have mislaid the cable but the instrument declares it is using an historical GPS position.

 

[Talulah]

They will only be transmitting every 3 minutes so make sure you wait long enough to see it on your display.

 

[TernVI]

Early versions of the NASA thing were only one AIS RF channel at a time, so could lose class B vessels.
The historic GPS position could be wrong? Can it see anything else? Can you check the position? Range set to max?

The marine traffic info could be out of date, from before the other boat parked and switched off.

 

[pvb]

The GPS input is missing as I have mislaid the cable but the instrument declares it is using an historical GPS position.

Is the historical position correct for your current position?

 

[Graham_Wright]

They will only be transmitting every 3 minutes so make sure you wait long enough to see it on your display.

Welcome back!
The instrument was on all day.

 

[Graham_Wright]

Is the historical position correct for your current position?

No but it isn't far out. Why would that make a difference?

 

[BabySharkDooDooDooDooDoo]

It is actually transmitting rather than reporting its position via an app?

 

[neilf39]

There is a free app for your phone that updates marinetraffic. They may have been using that and not an ais transponder.

 

[RAI]

Does the NASA AIS Radar display an output if it has no GPS input? I have got one and I don't think it does. It needs its own position to work out where to display a received target.

 

[GHA]

Does the NASA AIS Radar display an output if it has no GPS input? I have got one and I don't think it does. It needs its own position to work out where to display a received target.

It will display all received data, it's in list view. And the manual

 

[RAI]

I am away from boat, receiver and handbook. The unit needs tuning to its antenna to get the S/N ratio right. It can listen alternately to channels A and B. I now use mine only to check if my Digital Yacht AIS class B is transmitting.

 

[pvb]

It can listen alternately to channels A and B.

Don't you have to manually select which channel?

 

[RAI]

Don't you have to manually select which channel?

It gives a choice, A, B or both.
In the latter case it switches regularly between A and B.

 

[pvb]

It gives a choice, A, B or both.
In the latter case it switches regularly between A and B.

Ah, shame Nasa didn't put that in the manual.

 

[vas]

which ver of the NASA black box do you have? (assuming the "radar" you're saying is 2 things, the black box and the display)
I used to have black box v2 and got a free upgrade to v3 (a DIP16 iirc chip) from NASA. That helped me see more things (again iirc) and was faster (I think!)

V.

 

[RAI]

Ah, shame Nasa didn't put that in the manual.

I had fun with it, but it persuaded me to go the whole hog and get a class B unit. In my case the class B displays targets on a SH plotter overlaid with radar targets and charts.

 

[pvb]

I had fun with it, but it persuaded me to go the whole hog and get a class B unit. In my case the class B displays targets on a SH plotter overlaid with radar targets and charts.

Using AIS data on a plotter is a much better idea than the rather crude Nasa display.

 

[vas]

Using AIS data on a plotter is a much better idea than the rather crude Nasa display.

yep, sold the NASA, bought a Garmin AIS600, integrates nicely on the plotter, plus it broadcasts my position.

V.

 

[GHA]

Ah, shame Nasa didn't put that in the manual.

Really couldn't be much more obvious in the on screen help when setting up.

 

[Pye_End]

Using AIS data on a plotter is a much better idea than the rather crude Nasa display.

I quite like both. The NASA gives a very quick view of what is around without having to concentrate to make sure you havn't missed anything. It can be set on say a 8nm alarm when offshore and just left to its own devices. On the plotter there is often a lot of other data, and may well be set on a scale for pilotage. On the other hand the plotter displays contacts in a much better contextual way. I wouldn't rate either above the other.