This past July (2000), while I was setting up to work the Museum Of old ships from our club station of many years, I was approached by Kim Sincox who is Museum Service Director on the ship. Kim wanted us to move from our location behind the bridge to another location on ship. The ship wanted to open the room that we used for years as a display.
The following week our club president Frank - N2EMR,went over and met with representatives from the ship. From that meeting came a new partnership between the Azalea Coast ARC and the battleship. We would move from our location on the bridge to the location of our choice. The ship would also help us by providing their electrician, Terry Kuhn, to work with us one morning a week. The ship asked our help with some of their projects which included the " Charlie the Alligator Party " (Kids Day on the Battleship) and help with restoring some of the old radio equipment.
The next 6 weeks a large group of the clubs hams helped to get 3 antennas up and working. Our new radio room was to be the original ships radio central room , which is located below the water line on deck 4. We have a 3 element Yagi for 2 meters, an original ships vertical for 40 & 15 meters and another ships vertical for 20 & 10 meters. Thanks to Terry, the ship's electrician, we located the original ship coax and was able to splice into them to get the coax from the super structure to the radio room.
The first problem we had with our antennas was that they just didn't work at all. We imagined a lot of things like the coax we spliced into were bad or the impedance of the lines was way off. We have no idea what the impedance of the original coax is. The problem turned out to be that when we patched the coax, we patched them in the wrong jacks. We had continuity on the lines but when we took a ohm meter reading we found that we had a high reading, 600 ohms on each line. The point that we patched at carried a 600 ohm terminating resistor. After we move the patch to the correct jack things worked a lot better. Another problem was we had to clean the patch field cords and plugs. We had a lot of trouble getting connections through 60 years of neglect.
In radio central the original jacks are not like anything we use today. The ship wanted to keep the equipment in it's original condition so we cut one of the patch cords in the middle to plug into the jack and we put a PL-259 on the other end to mate to our radio's. When I cut that coax I was astounded to see how it was constructed. The dielectric was solid Baklite about 1 1/2 inches long and put on the center conductor like beads.
Thanks to a lot of hardworking club members we now have a good radio room on the battleship. I am sure some other problems will come up but we can iron them out.
After completing the club antenna project, the battleship wanted us to restore one of the ship's original transmitters .The TBM7 was selected for several reasons, best reason was it had the least damage from scavengers and it had CW and AM modes of operation. This transmitter will tune any frequency between 2.0 MC and 18.1 MC with 500 watts out on CW and 350 watts on AM. The transmitter sits in 2 six-foot bays; bay 1 is the modulator bay for the AM operation and bay 2 is the transmitter. It requires 440 volts, 3 phase, which was normal ship power. The 440 v runs a motor generator that supplies all the voltages to the radio.
Going into the project we knew we had some challenges to overcome. Missing equipment, missing antennas and no power.
Carl, KC8BQT, Terry, shis electrician and myself studied the job and came up with a plan to attack this job. Scavengers at some point had removed 2 meters from the transmitter and 2 meters from the modulator bays. Carl started to work on getting meters and Terry started to work on getting power to the radio. I found a job that I could do; it required skill with a broom and a vacuum cleaner. The transmitter room had not been cleaned well in 60 years.
I should explain at this time, we only work about 3 hours a week on this project. Normally on Tuesday mornings from 9:00am to about noon. This is the time that the battleship has allocated their electrician to work with us.
About a month into the project we had 2 current meters installed in the transmitter bay and we had 440 power to the power panel in the radio room. We decided not to worry about the 2 missing meters in the modulator for the time being. No AM operation planed any time soon.
The next step was to check all the power leads with an ohmmeter in preparation to power up the transmitter. A lot of equipment had been removed and some was just cut out with bare wire lying around. All leads checked out good. We were looking forward to the next visit to crank the motor generators. We had checked the grease in the motors - generators and they were ready.
The following week we arrived with our voltmeters and fire extinguishers. We were ready to power up the transmitter. The start button was mashed to start the motor and nothing happened. Back to the drawing board and schematics. A week went by before we found that an interlock switch in the modulator bay was not making contact. There is about 8 interlock switches in the 2 bays. These switches are not complicated at all, just a piece of metal that wedges between 2 other pieces of metal. The connection seems to be good but must have had a film over the connection. The metal was cleaned with sandpaper and we got a good connection. We decided to wait until our next visit to try again to start the motor-generators.
On our next visit, with great anticipation the motor start button was pushed. The sweatiest sound you ever heard, it cranked and ran like a sewing machine. We were ecstatic, the tubes were lighting after 60 years. It didn't take long to figure out that although the motor-generator was running we had no DC voltages. Back to that drawing board with the schematics. We could find no reason for us not to be getting the voltages. Time to go home for this week.
During the next week we were asking around for ideas on our problem. Clarence, KB4AKH, came to our rescue. He came over the next couple of weeks and cleaned the armatures and brushes and brush holders on both of the generators. This fixed our DC problem, we had all the voltages. Time to take another baby step forward.
On our next trip over we had current meter readings on the master oscillator but that was all. We decided to key the transmitter via a test key on the front panel. Nothing ! Back to the drawings. Everything looked good. Carl reached up and tried to manually operate the keying relay, it was frozen solid. We had to repair the relay; a new relay was out of the question, another challenge for the team. The next couple of weeks were spent trying to get the relay out and repaired. The challenge was met after a lot of prayer, mediation and a few other words.
Well moving right along now, the test key will key the keying relay. Problem is that we still don't have any meter readings on the next stage. Back to the drawing board! We worked on this problem the next week and Terry found a loose resistor in the screen grid circuit of the second stage. These resistors plug into clips in the bottom of the bay. Hey! Hey we are getting all the meters to read !
On our next trip I brought a power meter and a dummy load to test with. After reading the lineup procedures we were getting 60 watts into the dummy load.
Now we don't have any idea what impedance this transmitter is looking for. From what I understand back in the days of this transmitter SWR had not been discovered yet. They never give it a thought, there is nothing in the Navy's book that mention SWR. There are large tuning inductors and capacitors in the antenna tuning circuit and you tune them until you get the reading on the finals that you want. The transmitter has a plate on it that says that the antenna is 108 feet in length. In other words the heavy cable coming out of the transmitter (1/2 inch in diameter) going up through the ship to a vertical antenna is all part of the antenna. They used the same antenna to work any frequency between 2 to 18.1 MC and no tuner. Tubes are a lot more forgiving with SWR than transistors but this is very different.
Well, we are happy, we have power out. The next step is to hook up a real CW key to the transmitter. The next week I wired in a CW key through the patch field and tried it. You guessed it, it don't work. After checking the drawings we found out that we have a bad switch on the transmitter. This switch is a remote or local operation switch. The back of the switch has several sets of contact on it much like a relay. The contacts have little arms on them and several of the arms are bent bad. This brings us up to date. We are trying to figure out how to get at the contacts to repair them.
The Project Continues 1 year
The bad "Remote- Local" switch on the TBM-4 transmitter proved to be difficult to repair. After looking over the job the entire team agreed that the only way to get the switch out for repair was to cut all the leads and then splice them to get them back in. The next week we started on this repair. We cut the switch out and marked all the leads and then we had the switch in our little hands . It took another week to get the contacts adjusted to our satisfaction.
On our next visit we reinstalled the switch but, to our amazement, we still could not key the transmitter. Our first thought was we had installed the switch incorrectly. We checked all the wiring against the drawings and were convinced that the switch was installed correctly. After two more weeks of troubleshooting we decided that the problem had to be in the switch itself. We removed the switch again to check it once again and immediately saw the problem. A contact had slipped out of place when we put the switch back on the first try. After realigning the contacts and installed the switch for a second time ( this was a lot faster than the first time ) everything worked and we could key the transmitter with a hand key.
The next step was to be able to key the transmitter from radio central. To accomplish this you must use a patch cord in the patch panels in order to pick up the keying leads in Radio Central. When we checked the patch cords we found that almost all were bad. Carl,KC8BQT took the cords home and rebuilt them. On the next visit we checked the leads from Radio 2 to Radio Central. All the wiring was good so we are ready for the big test. Before we can test the transmitter from Radio Central we need some voice contact between the two radio rooms. Clarence, KB4AKH and I worked on the existing telephones and got the telephone in each radio room to work. Now that we have voice contact we are ready, Terry, ships electrician, and Carl were in Radio 2 and we are in Radio 1. Clarence had the honor of pushing the motor start button and the motor generators in radio 2 cranked up. Beautiful! We let the motor generator run a few minutes and then I operated the hand key in Radio Central and Carl who was watching the transmitter in Radio 2 immediately let us know we are keying the transmitter.
After almost a year of work we have a transmitter that will work. Progress is slow but steady; we still don't a complete antenna on our transmitter. About 45 feet of the transmission line from the 02 level to the vertical antenna is missing. The ship sent Terry to Norfolk and to get more transmission line and connectors. We got lucky when the ships crew was able to use a contractors scaffolding to remove the vertical antenna . With the antenna on the deck we see that it needs a lot of work. The connectors are rusted off and a lot of the bolts holding the antenna were in bad shape. For the next 3 weeks we scraped paint and rust in order to refurbish the antenna .Now that it is painted and put back together the antenna is ready to go back up when ever we can get the use of some scaffolding to put it up .Up in the air the insulator on the bottom of the verticals don't look to big but when it was on the deck I found that it weighs at least 75 pounds ! It's going to take a block and tackle and a lot of muscle power to get the antenna assembly back on top of the smokestack.
While we were working on the transmitter we found outs some bad news from the ship. The idea that we had from the beginning was to operate from Radio Central. We have everything that we need there: antenna, keying leads and good operating condition. The problem is that the ship requires a fire watch in Radio 2 for insurance purposes when the transmitter is in operation. This means that if we operate from Radio Central that someone must sit in Radio 2 with a fire extinguisher.
To solve this problem we plan to operate the CW Transmitter from the transmitter room , Radio 2. To do this we need to patch a receiving antenna to a working receiver in Radio 2. This is what we are presently working on. Terry had received approval to work on the air handling equipment for Radio 2 and last week he was able to start the air handler in Radio 2. Then the fun started !That air blower had 60 years of dust, dirt and corrosion in it and the fan blew every bit of it out those ducts, covering everything in Radio 2 with a thick coating of grime . We spent all day with vacuum cleaner, mops, brooms and dust rags cleaning up Radio 2. It was worth it, we now have good air movement in radio 2.Let me tell you it's been hot down there this summer with no air moving what so ever!
At the present time we are waiting to get the antenna back up on the smoke stack and working on getting a working on getting a vintage receiver working in radio 2. The project continues!
Jack WD4OIN