Need RADAR advice

[Steve Lusardi]

I have just purchased a used FURUNO antenna and gearbox. I have not received
it yet. It was made in 2005 and has been used on a commercial ship. It is
probably safe to say heavily used, but the price was right and it is sold as
functioning well. I will, disassemble it, repaint and mechanically inspect
and repair as necessary, but my question is about the magnetron. Furuno
states the magnetron is rated for 2,000 to 3,000 hours. I have no
maintenance history, but is to safe to think that without recent
replacement, the magnetron is used up? Should I just replace the magnetron
as just a general service replacement? It is an RSB0074-0062 12KW.
Thanks in advance,
Steve

 

[Bruce in alaska]

I have just purchased a used FURUNO antenna and gearbox. I have not received
it yet. It was made in 2005 and has been used on a commercial ship. It is
probably safe to say heavily used, but the price was right and it is sold as
functioning well. I will, disassemble it, repaint and mechanically inspect
and repair as necessary, but my question is about the magnetron. Furuno
states the magnetron is rated for 2,000 to 3,000 hours. I have no
maintenance history, but is to safe to think that without recent
replacement, the magnetron is used up? Should I just replace the magnetron
as just a general service replacement? It is an RSB0074-0062 12KW.
Thanks in advance,
Steve

If it was "Me". I would install the radar, and run it for a day or so,
BEFORE I made any decision to replace the Magnetron, since the Maggie is
the MOST EXPENSIVE Replacement Part in a Radar of this class. Your
looking at $200 - $400 US. While I had the TR Pan out I would look at
the Maggie and see if it had been replaced already, or was the original
Toshiba OEM Unit. Once you have run the thing for a good 24 Hours, you
will burnt all of the moisture out of the Maggie and Waveguides, and
then can evaluate the state of the Maggie. Look for Double Targets on
the same bearing and very close together. This is caused by Double
Pulsing, and a sign of a Very Aged Maggie. Check the Tuning Range, of
the receiver and see if the Maggies Frequency is still near the Center
of the Receiver Tuning Range. High Hour Maggies tend to drift Off
Frequency and be near the tuning Range Edges. I have seen those Toshiba
OEM Units in Furuno Radars that still had plenty of life after 10 years,
of activity on Fishing Vessels.

 

[Steve Lusardi]

Bruce,
Thank you, that is the advice I needed. In my previous life, many years ago,
I repaired airborne radars and all the maggies I changed, the frequency
driftted beyond the the ability of the LO to track. In those days, I had at
my disposal a spectrum analyser, which I no longer have. I never saw one
that double pulsed. From your information, it looks like I do not need any
special test equipment, but a dummy load would be nice. I'm not sure
radiating my neihborhood for 24 hours would be appreciated. Are there any
available at reasonable prices that would fit the Furuno slot-line antenna
mount?
Steve

 

[Steve Lusardi]

Larry,
60' steel sloop.........lots of electric power.
Steve

 

[Bruce in alaska]

Bruce,
Thank you, that is the advice I needed. In my previous life, many years ago,
I repaired airborne radars and all the maggies I changed, the frequency
driftted beyond the the ability of the LO to track. In those days, I had at
my disposal a spectrum analyser, which I no longer have. I never saw one
that double pulsed. From your information, it looks like I do not need any
special test equipment, but a dummy load would be nice. I'm not sure
radiating my neihborhood for 24 hours would be appreciated. Are there any
available at reasonable prices that would fit the Furuno slot-line antenna
mount?
Steve

To be technically, and legally correct, you should NOT operate a Marine
Radar while on shore, without possessing a Maritime Support Station
License. I wouldn't worry about radiating you neighbors, as the Power
Density of ANY Commercial Marine Xband Radar, 6 Inches in front of the
Slotted Waveguide Antenna, is well below that required to cause ANY
microwave heating, and so far below any Ionization, as to be
inconsequential. When I was doing a lot of radar work, I used a Military
Xband Radar Test Set that included a Xband Load that I adapted to fit
the Standard Furuno T/R Pan Waveguide Connection. One of my old Friends
who is still in the Biz, uses the same setup but feeds the T/R Pan
Output thru a similar connection to a 40ft piece of Xband Waveguide
that goes up a tower at his shop, and then gets feed back into an
modified FR240MkIII Antenna. When I visit him, I know he is in the shop
because I can see the antenna turning from 1/2 mile away. No Turning,
don't bother stopping by, cause no one is home.