2 radars?

I would assume incase one fails, a second is available.

Different ranges and sensitivities, due to different base frequencies. With the new digital wide band ones that could drive some to having 3!

Having 2 give you more eyes
One set longer range one set close range
inter coastal i run one at 6 miles and one at 1 mile
In harbour i drop to 1 1/2 mile and 1/2 mile Harbour range lets you know of any smaller boats sneaking up in blind spots (sometimes playing in your wake)
Out of harbour the 6>12 mile range i can keep an eye on larger ships courses and make small course adjustments rather than a major one and the 1 mile range is the main working or safety zone
On the west coast will all the islands and commercial traffic AIS is another helpful tool

Remember When has 3.

For this and as a backup, but if I have 2 radars, I run 2 different ranges and also compare signals between the 2.

God I love having multiple radars for the reasons stated above. But for those with only one please remember to change the range often. Things 1/4 mile ahead will most likely not show up if your radar is set at 1.5 miles, etc. Also, please use your radar at all times a) you are expected to use all safety and navigation equipement available, and can find liability if something happens and you didn't, and b) you need to practice with it when you can visually see what the radar sees so you can recognize it when you have no visability (more than a few boats have crossed between a tug and it's tow thinking they were 2 completely seperate vessels). Dense fog or dark night is not the time to first try to figure it out. As you approach something (like an inlet) continually range in and you'll go through like playing a video game. Also, practice using the EBL and proximity alarms. I once had an owner get upset with me for using the EBL on a ship coming into the Delaware because he was afraid we wouldn't be able to get it off his screen. When the ship was about 3 miles away he contacted me to ask my intentions for crossing. He was very happy to find that I'd been tracking him also, and my owner got his lesson. (I also taught him how to clear off the EBL)

if you have two, you can, and should set them on different ranges and run them both at the same time.

it works great, I really like 2 radars working at the same time

My Furuno NN3 has dual range capability side by side on the same screen

Also, the best thing for a radar is to run it as much as possible. The Magnetron is only recharged when the radar is actually running, and leaving it for long periods of time without use, is like leaving a dead battery dead for a very longtime and very detrimental to it's longevity.

It is also really good for the Flux-capacitor.....

I wasn't aware of this.......thanks for the information.

Must say that's a new one on me also, but I'm from the "use it or lose it" school anyway.

I and never heard anything like that as well. And it made no sense to me based on my understanding of how a magnetron works, so I asked Furuno and this is what they had to say about it:

"Magnetrons are not "recharged". They are either energized or not. When they are energized, they get warm. When they are not energized, they are not warm.

It is the heating and cooling of the Magnetron that shortens the life, more than anything else. A magnetron that is never energized, should last quite a long time. Ones that are energized and left that way for extended periods, also tend to last much longer, at least, than those that are frequently turned on and off. Magnetrons that are turned on and off frequently, are the ones that tend to come up short on the "average" life span."

Which part of the radar is the actual Magnetron?

I´ve sailed on a 80-feet sloop from Spain to Sweden with a Furuno, probably 1990´s, and we normally turn it to standby mode after a reading every 20 minutes.
That is to save the batteries!

Is that bad or good for the radar itself?

That raises a related question for me that I'd like to piggyback on this if anyone has the answer. Considering the extra juice needed to fire anything up, would you actually save anything when you fire back up every 20 minutes since the unit is on the whole time. It occurs to me that you may have taken a risk without much reward considering that 2 boats traveling toward each other at even 10 kts would have gotten almost 7 miles closer in that 20 minute span. If you checked at the 6 nm range he'd be on you before you checked again.

A boat radar is generally rated at 4KW to 6KW. It must derive that power from the electricity on a boat, which usually ranges up to 240V but nowhere near the 4KW or 6KW.

The magnetron is the electronic circuitry that actually creates that high power and the pulse from the magnetron is what the transmitter/receiver sends out through the antenna. It's the return of that pulse from a target that is received by the antenna. The pulse is then routed to the receiver.

The time difference between the transmitted pulse and the received pulse is what the radar uses to determine the distance and direction to a target and the speed that the target is moving relative to the antenna.

When you turn the radar control to standby, it gives the magnetron a rest, but the magnetron does not fully power down. When you turn the control back to the transmit position, the magnetron is again fully powered and the pulses generated again.

As to Matt's comment about turning it to standby for 20 minute periods, I'll give them the benefit of the doubt that if they saw a target on the radar screen they probably would watch it for enough time to determine if it presented a hazard before they turned the radar back to standby.

With the radar transmitting it uses up a fair amount of battery capacity. Left on, it could drain the batteries in a sailboat that didn't have an adequate charging system. Turning it to standby would save the batteries, but could also shorten the life of the magnetron.

Let us not forget these bad boys:

Talkin' Big Boats that Belch Black Smoke!

Product Detail - DRS25A

Koden MDC-2520-9 LCD RADAR, 25KW, 96NM, 9' Open Scanner PSICOMPANY.COM

Specifications for TX25s Open Scanner | Simrad Yachting

Thanks GFC for the clarification - I just wanted to be certain I understood correctly!

Of course we use the radar, especially nighttime, to make sure that we don´t sail into something, or somebody... and normally we sweep through the 6 miles up to 13 miles ranges just to be certain we have the bearings and speed of the targets we receive.

Also interesting to hear about the possible shortened life-cycle of the radar when using the stand-by mode.
I´ll talk to the Skipper about it!

BTW - the sailing sloop is the Swedish Caprice originally built for Jan-Eric Österlund who later commissioned the 180ft S/Y Adéle.

/M@tts