Open Array vs Closed

[Dave Batistig]

I have a chance to upgrade the Raymarine Quantum 2 Doppler radome to the Raymarine Magnum 4kw 4 foot open array. What would be the advantages of doing this? The boat is a 1994 SR 500DA. It will be on the Allegheny river for the next 4 years, and on the West Coast of Florida after that.

Thanks in advance for the input!

 

[Skybolt]

I have a chance to upgrade the Raymarine Quantum 2 Doppler radome to the Raymarine Magnum 4kw 4 foot open array. What would be the advantages of doing this? The boat is a 1994 SR 500DA. It will be on the Allegheny river for the next 4 years, and on the West Coast of Florida after that.

Thanks in advance for the input!

I can't see any advantage if your going to be on a river for the next 4 yrs. I can see an advantage if you are going to do a lot of ocean running. The dome radar is typically better short distance for much of the cruising type boats need. Open arrays are not as good at close up because of their power and reflection angles and are more geared towards long distance, as you would find in ocean running.

That said, both are excellent for what cruisers need and comes down to preference. Sorry the above is general rule of thumb. The radar you currently have is excellent and I would only change for more updated features, possibly upgrade when you get to FL. JMO.

 

[Dave Batistig]

I can't see any advantage if your going to be on a river for the next 4 yrs. I can see an advantage if you are going to do a lot of ocean running. The dome radar is typically better short distance for much of the cruising type boats need. Open arrays are not as good at close up because of their power and reflection angles and are more geared towards long distance, as you would find in ocean running.

That said, both are excellent for what cruisers need and comes down to preference. Sorry the above is general rule of thumb. The radar you currently have is excellent and I would only change for more updated features, possibly upgrade when you get to FL. JMO.

Thanks for the quick response! You confirmed what I was thinking, but I didn't want pass on a opportunity without running it by some folks who know more than me when it comes to this sort of thing. Appreciate the help!

 

[Jus Cruisin]

If the cost isn't much, I'd go open array. More for looks on that big boat. But, in 4 years you'll likely be upgrading electronics so don't pay a lot....

 

[dtfeld]

Both will have the exact same effective range. Radar is line off sight, and that range is determined by the height of your transceiver (fixed height above the water) and the height of what ever object your trying to detect. For collision avoidance is roughly 6-7 miles. There is a formula to calculate it.

If your fishing and looking for birds, or keeping track of weather (thunderstorm are very tall) you will get more range out of a more powerful radar and better target definition from a larger array.

The magnum is a Chirp radar, so it does have all the close in performance of the Quantum with better range and target differentiation. If it’s a small amount of money, I’d go for it, but at $6-$10k, no way.

I personally own a quantum 2 and think it’s about as much radar as you will ever need. As Skybolt pointed out, it strength is painting things up close and personal…like a channel marker in the fog 10 feet off your bow.

 

[mquiet]

If cost is not an issue, I would be looking at the needs. The radome has a very small sweep as we know compared to open array. The difference is in the horizontal beam width and vertical separation. The open array will define smaller objects more easily as the scanner does twice the slices compared to radome. I run the ICW a lot and with open array I can mark crab pot buoys versus the radome which can not get the slicing narrow enough to target. So really it depends on your environment and what are your needs.

 

[sbw1]

I prefer the open array for the sharpness of the targets and the ability to track weather. If you end up in Florida you will appreciate what that means. Open array is also excellent in rivers as well.

 

[Stee6043]

My two cents...a dome would look a bit goofy on a 50 footer. Aesthetics matter

 

[b_arrington]

My two cents...a dome would look a bit goofy on a 50 footer. Aesthetics matter

I partly agree with this. I bought my Back Cove 34 new and spec'd a Garmin 24" dome. My Back Cove 37 came with a Garmin 18" dome, and it looks a little too small to my eye.

Depending on the boat, a 24" dome might look OK. Not sure I'd be willing to shell out the extra cash just for looks on an open array though. In the Garmin line, minimum cost difference to go from a Fantom 24 dome to a Fantom open array is $3100, which is 100% of the cost of the dome.

I will say that physical size of the array does make a difference. All things equal, the wider the array the tighter the transmission beam. That translates into better target separation. What does that mean? Basically a tighter beam will present closely-spaced objects as distinct individual targets at a greater distance.

My 24" dome had a 3.7 degree horizontal beam and the 18" dome has a 5.2 degree beam. I definitely notice that the 24" model had better target separation in real world use. When out on the Long Island Sound, smaller boats fishing together can seem like a single target. Garmin's smallest open array has a 1.8 degree horizontal beam so I'm sure they performance is quite a bit better - and that's why they are better for spotting birds.

 

[Irie308]

Just installed my fantom 54 open array from Garmin yesterday. This unit has doppler and replaces my old digital raymarine open array. I have to say the targets are nice and sharp and like stated above the target separation is amazing. I was able to pick up 2 kayakers on the river where I'm dry docked. They were about 100' from each either and about 300 yards from me.

 

[Riptide III]

If cost is not an issue, I would be looking at the needs. The radome has a very small sweep as we know compared to open array. The difference is in the horizontal beam width and vertical separation. The open array will define smaller objects more easily as the scanner does twice the slices compared to radome. I run the ICW a lot and with open array I can mark crab pot buoys versus the radome which can not get the slicing narrow enough to target. So really it depends on your environment and what are your needs.

What you said!
Thank you for posting this I saw this yesterday and was too lazy. The narrow beam width is also noticeable when approaching an opening like a hurricane barrier. A narrow beam width will detect the opening long before the wider/closed array system. Which will initially paint it as solid. For what it’s worth.

 

[jmauld]

My two cents...a dome would look a bit goofy on a 50 footer. Aesthetics matter

This! That big open array spinning around is worth it, if cost isn’t an issue. Plus you get the added benefit of spotting storms farther away.