Wednesday, January 21, 2015
Installing an ICOM M802 SSB Radio
Last year we had some cabinetry done in the galley and at the same time I reconfigured the instruments located in the Nav Station cabinet. In addition to working on the instrument panel I had a small cabinet added on top to house the radios, VHF and SSB. We didn't have the SSB radio yet but I knew we would eventually get one so I had the cabinet maker install the cut-outs for an ICOM-M802 head unit and speaker. Because of that the actual installation for that part was pretty simple. I actually sat down and read the instruction manual (ICOM M802 SSB Users Manual) and here I found a bit of information I hadn't considered when I re-did the Nav Station. In the manual it says to place the radio's head unit in a position that's easy to get to from a comfortable seated position, taking into consideration left or right hand use. Geez, good idea, although I'm not really planning on spending hours on this thing. Really just wanted it for weather and simple communications. I think we'll try it the way I have it for a while, years maybe, and see if it suits our needs. Maybe some day I'll decide to reconfigure the instruments again and can place it in a better position. Right. Because I have so much time for stuff like that.
The bigger part of the SSB installation was mounting the transceiver and running the wires. The transceiver weighs about ten pounds and the manual makes a big deal about not hanging it from overhead and being sure to secure it firmly to a flat horizontal surface. It's dimensions are 11.5" x 11.5" x 4.75" so it's not so much huge as it is dense. If this baby broke loose it would do some damage. It also draws 25 amps so it must produce some pretty good heat too. I spent some time trying to find a good location for this thing. I originally had wanted to mount it under the Nav Station desk but that would create a conflict with your legs when you sit down plus it would require a hefty shelf to mount it on. I ended up taking over the cabinet just forward of the Nav Station. It has a louvered door so hopefully it'll have sufficient ventilation. We had been using this as a catch-all for CD's and DVD's and pretty much anything having to do with a computer. Everything was just piled up in there and the space was poorly used. I decided I could build a shelf to support the "stuff" and mount the transceiver and the modem underneath. The cabinet is 15" deep and the shelf is only 12" deep with a gap in front and back so there should be good enough air flow. And yes, I added fiddles to both the front and the back of the shelf.
There are a number of cable connections to this thing. The control head and speaker each have one. The modem has another. There's also a port for connecting GPS. On the back there's three cables that run to the back of the boat and connect to the antenna tuner which then connects to one of the backstays. This has already been set up with insulators at the top and bottom to be used as the SSB antenna. One of the cables goes to a separate antenna for DSC (click here for more info). Running these three cables turned out to be a major pain in the tukhus (click here for more info). They come with connectors mounted at both ends and the two antenna cable connectors are pretty bulky. This makes pulling them through tight spots difficult at best. If the factory would install a connector at one end and provide a kit for the other it would make life soooooo much easier. I first tried pulling all three cables down the starboard side cable-run that goes behind the cabinets in the galley and dumps out in the cockpit locker. This was my number one choice because it's the most direct path and the main antenna cable is big and stiff and only 33' long. I spent the better part of a day trying to get the cables pulled through this location but in the end had to run them under the cabin sole, beneath the galley and then out through the genset compartment. I've only gotten them halfway through so far so I have at least a few more hours of work ahead of me. Even going this way is a tight squeeze and I'm beginning to see that this boat has way too many wires and hoses running down one side. No wonder she leans to starboard 2 degrees! Gonna hafta move all my future projects over to the port side.
While I was working on the physical installation Cheri has been installing the software to run the modem. This will allow us to send and receive e-mail by radio and pick up weather reports from NOAA. The biggest complication so far has been because we have Mac computers and the software is only made for PC's. She had to install Windows 8 to work with the e-mail program and the modem. Dang! We tried so hard but there's just no getting away from Microsoft. We'll see how it all works out when I get the radio up and running.
I went back at it the following weekend and pulled the cables through to the cockpit locker on the starboard side. Once that was finished I spent some time looking around for a good mounting location for the antenna tuner. I needed a spot about 8" x 16", a good piece of real estate on a boat. Plus it had to be where the high voltage wire wouldn't run near any other wiring because this could induce noise into other systems. This is a pretty high powered radio. I've heard stories about people keying the mike and the lights in the cabin would flash, electric toilets would flush, etc, etc. I don't think we need that kind of entertainment. Let's see now, we've got the wiring for shore power running through from here to there and the wiring for the genset goes over there. Oh yeah, all that wire over there is for the auto pilot. There was plenty of space on the inside of the hull but there's too much wiring it would have to cross and it's further away from the backstay than I wanted to be. I ended up settling on an overhead spot tucked up inside the cockpit coaming. I cut out a board and pre-drilled it to mount the tuner. Glopped it up with 5200 and used gorilla tape to hold it in place on the fiberglass until everything dries. In this 20 degree weather that'll probably take a few days before I can mount the tuner.
Down below at the Nav Station I'm making the power connection to the house bank batteries. The transceiver draws about 25 amps while transmitting and has a 30 amp fuse on the positive power input. They provide about ten feet of #10 wire but I'm using #8 for most of the run to ensure adequate voltage levels. Coming from the batteries located beneath the starboard settee the wire runs through 40 amp fuses, one for each leg. This is simply to protect the wiring in the event of a short. From there it runs up to a terminal strip near the transceiver where it mates with the now shortened #10 wire. I used non-insulated ring lugs with shrink wrap on all wire terminations. Using #8 wire required some heavy duty crimping and I ended up investing in a ratchet type crimping tool. Money well spent. For the shrink wrap I used Cheri's blow dryer. Not as fast as a heat gun but it did the job. After I made some voltage checks I went back and dressed out all the cable runs and neatened things up.
In the radio kit there is a pile of RF "chokes", ferrite clips, that are used to inhibit stray RF in order to reduce noise in the system. These get placed on cables connected to the transceiver by placing a loop in the wire and then snapping the choke in place. I ended up removing pretty much everything I had done last weekend to re-do the cables. I also found that after I installed the choke on the control cable for the antenna tuner I no longer had enough wire length to plug it back in to the transceiver. Now I hafta pull some back from the cockpit locker. Grrr. One step forward, two steps back.
While I was at it I also added some chafe protection where the wires pass through the bulkheads. I used split plastic wire loom, 3/4", and forced it around the inside edges of the holes I had cut out with a hole saw. Even with everything tied down firmly there's a chance the wire will wear against the hard surface, especially where I had cut through fiberglass. This is good insurance.
Another connection on the transceiver is for GPS information. This is displayed on the head unit screen as latitude and longitude and also used in DSC mode so your position is automatically transmitted. Both our VHF and SSB radios have DSC capability. To get the GPS info I'm tying into the NMEA 2000 backbone using a gadget from Raymarine called a "VHF NMEA 0183 to STng converter" (p/n E70196, $75). Only one of these is required for both radios. The input side provides the GPS info and the output from the radio provides location information of the vessel you're in contact with. This might be handy if you're traveling with a group of boats and keeping in touch using the DSC mode. If you're spread out over 20 miles of ocean each boat will still be displayed and identified on your chart plotter with pop-up flags containing all the boat's information. Pretty sweet!
The final connection is for the modem, in our case a Pactor-4 Dragon DR-7400 from SCS (click here). This little unit allows the SSB radio and our Mini Mac computer to communicate, giving us the capability of sending/receiving e-mail and downloading weather information. This thing costs as much as the radio itself but this is the main reason we wanted a SSB radio, being able to stay in touch with friends and family by e-mail, even when we're away from a WiFi connection. Maybe just as important is the ability to pick up weather forecasts anywhere in the world. This little box is a key component for our travel plans.
Another week went by before I got the antenna tuner mounted in the starboard side lazarette. The location I settled on is basically up inside the aft coaming. This works well for a short direct run to the backstay but once it's mounted on the board most of the connections are facing away towards the center of the cockpit and have to be made by feel. That's OK, I can do this with my eyes closed. The only really difficult part was the wing nut for the ground connection. Because of it's shape it's pretty tough to get it started by feel alone and I managed to drop two of them before finally getting it on properly. This is one of those locations where anything that falls instantly rolls out of sight, in this case under the genset. At $2.42 each, it's already a pretty pricey collection down there.
At the ground lug I made connections for the RF ground and the green ground wire for the control cable. The RF ground is a critical component in the SSB system. The actual backstay wire between the insulators is really only half of the antenna. The other half is the ground which enables the RF signal to jump free of the antenna. This RF ground has to be totally separate from any other ground on the boat or you stand the chance of getting noise in the system. Noisy system equals lousy signal transmission. There are different techniques for creating a suitable RF ground on a boat. One is to mount a bronze plate on the outside of the hull below the waterline and connect a heavy gauge 4" wide copper tape between the mounting bolts inside and the ground lug of the antenna tuner. This uses the ocean as the ground plane and is pretty effective. The drawback is that the bronze plate gets fouled and requires cleaning to keep the transmission optimum. Another method is to run that copper tape along the inside of the hull and connect it to through hulls and deck mounting plates. They recommend you use about 100' of copper tape for this. The copper tape can also get fouled and would require periodic inspection.
I'm going to try something a little different called a tuned radial counterpoise made by KISS-SSB (click here). This is a series of wires cut to exactly 1/4 wavelength for the most common frequencies used on the SSB radio. The tuned wires are contained in a heavy tube about 9' long that is run inside the hull and connects to that same ground lug. This sells for $149, requires no holes in the hull and installation takes about 10 minutes.
The high voltage output at the other end of the antenna tuner was pretty straight forward. It has a boot that slips over the insulator to prevent any moisture running down the wire from getting inside the tuner. It's designed so it can be mounted outside in the weather and that would explain the need for the boot. Probably not needed in this location but it went on anyway. I drilled through the back side of the coaming and installed a weather-proof feed through. The wire used to connect the antenna tuner to the back-stay is GTO-15, originally designed for use with neon signs. Since this is a high voltage cable I ran it through conduit with 1.625" stand-offs attached to the non-insulated part of the back-stay. I placed the stand-offs every 6" to give the conduit plenty of support and it's strong enough to be used as a grab handle while moving around the cockpit. The conduit exits through a PVC cap at the top of the conduit just above the bottom insulator and makes a gentle 180 degree turn before connecting to the back-stay with a "GO-To Bug" clamp. I sealed it up with tape but then read the "Sailor's Quick-Start Guide" where I found that this clamp is supposed to be left exposed to weather to keep it accessible for cleaning on a regular basis. OK, gotta go back and fix that.
The final part of my work this weekend involved installing an earth ground for the antenna tuner. I decided to go with this after discussing it with some friends with the same SSB radio and KISS counterpoise. The radio comes with 10' of 4" wide heavy copper foil. I ran this from the ground lug on the tuner down to the packing gland nut on the rudder post. Anywhere it changed direction I folded it over on itself to form a 90 degree turn. At a convenient spot I cut the tape across and mounted it to a block of wood, leaving a gap between the two ends. Across this I soldered four capacitors (0.15uf, 100v) to create a DC block that will prevent electrolytic corrosion. I then covered the edges of the foil with Gorilla tape to hold it in place and prevent injuries from the sharp edges.
As I was cleaning up at the end of the day I found the wingnuts I had dropped, both securely wedged in the wiring beneath the genset.
We fired up the radio and did a listen test to see if we could hear anything. Picked up some dudes chatting down in Miami. Cool! Now I gotta learn what all those knobs and buttons do so we can do some chatting of our own.
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