This morning we slept in until 8am then had a leisurely breakfast. We drove around town and took lots of photos:

NOTE — To see a bigger (and in some cases, expanded) version of any of the

images in this blog, just click on the one you want to see.

Before Peter Stuyvesant was Governor of New Amsterdam (later New York City) he was governor of the ABC islands (Aruba, Bonaire, Curacao). A tour guide told us that while he was governing New Amsterdam,

Stuyvesant sent some American Indians to settle on Bonaire. We have not been able to verify this so far, but this may be why there are so many American Indian symbols on Bonaire.

As expected this morning, there were no cutbacks overnight. We do not expect any more while using Amplitude Modulation Companding (AMC), unless a lizard or other creature ‘bridges’ an arc gap.

After devotions this morning, my first project was to investigate why the studio’s on-air monitor for 800kHz sounded so distorted. Our receiver at home sounded OK. My investigation, using headphones, found that the unbalanced RCA plug output of the on-air receiver sounded fine, but the balanced ‘line output’ for the monitor amplifier sounded bad. I pulled the receiver out of the rack and took it to the engineering lab only to find it would not receive any stations. I concluded that the lab must be shielded, so moved the receiver to an office. There it received the signal on 800kHz plus several Venezuelan stations. Opening the receiver revealed that a small circuit board had been built up and added to provide the balanced line output. Of course there was no schematic of this, so I thought about tracing one out. Before doing so, I decided to poke around a bit, with no success, until I touched the tiny on-board potentiometer for controlling the line output level. The distortion cleared up, so I ‘turned’ it back-and-forth a few times to clean up the dirt or corrosion, put everything back together and the problem was solved.

I then wrote up the procedures that we used yesterday to set the AM transmitter up for AMC operation, focusing on the steps that are not included in the manual. This is to be added to the manual, so it can be set up next time without having to contact the manufacturer.

After a lunch of toasted cheese sandwich, cauliflower and baked french fries with the ever present glasses of iced tea, I spent the afternoon at the transmitter site.

The next project, in order of priority, is to finish installation of, and activate, a new security system. There is an older system in service, but this new one will provide expanded protection and has greater capability of informing authorities of any problem. It has a computer for the ‘brains’ of the system and ‘tons’ of options. It has been partially installed, so I have to determine what has already been done and what still has to be done. There was even a question whether the control keypad near the door was even functional. It has a display on it, but it appeared to be totally ‘dead’.

After reading through about 100 pages of various manuals for the base unit, keypad, sensors, and optional accessories, I was finally able to figure out how to bring the display to ‘life’. Now it was possible to enter the security code and determine how various options had been programmed. At one point I was entering numbers to looks at some of these options, when all of a sudden the system was ‘armed’. The display read, “SYSTEM ARMED, you have (x) seconds to exit”. This was a shock to me, as I did NOT know how to ‘disarm’ the system yet! Shortly, it started beeping more loudly and a ‘siren’ outside sounded. Fortunately, I knew where the siren was connected and quickly disconnected it. I also removed the power and battery backup.

Before reconnecting it, I decided it might be good to learn how to ‘disarm’ it! After sorting through several more pages of instructions, I learned how and I powered it up (except for the outside siren!). It came back on, saying it was ‘busy’ (apparently ‘booting up’ its computer) then switching directly to being ‘armed’. It took a few times running to power the system down, before getting the security code and disarm keys entered in the right sequence and at the right time, so the alarm would not trigger. It would have been quite a sight if someone had seen me running madly back and forth!

I now feel comfortable ‘arming’ and ‘disarming’ the system. Also have some idea of which sensors are working, or not. Hopefully it will be possible to begin getting everything working next week.

It was approaching 5:30pm, the time the AM transmitter signs on, so I decided to wait for it to come on before leaving for home. It came on for a fraction of a second, dropped off, then came right back on at normal power, but with the backup exciter. I decided to switch back to the primary exciter. This required switching from ‘remote’ to ‘local’ control, then making the exciter switch. I then had to switch back to ‘remote’ control. Immediately up switching to ‘remote’, the transmitter came down and switched to the backup exciter again. I tried it again and the same thing happened, except this time I noted the transmitter was in ‘standard’ modulation mode when in ‘local’ control and switched to AMC when switched to ‘remote’. Joe was in town and made the switch from the secondary to primary exciters remotely and everything worked OK because the transmitter stayed in AMC with no switch to ‘standard’ modulation. It looks like the macros for starting the transmitter will all need to be changed for smoother transitions while using AMC.

I got home tonight to find cars parked everywhere along the road and in the space between the curb and our fence. Fortunately, the ‘no parking’ sign on our gate worked and there was just enough opening to park the car in our carport. I checked out the beach and verified, as we had suspected, that swimming there tonight was out of the question.

For supper tonight we had leftovers from last night — still yummy! Instead of papaya for desert, we had a treat — a little ice cream and chocolate.

Today, I helped begin to clean out of one of the TWR houses. They are preparing to make this house handicapped accessible for a new family who has a child with spinal bifida. TWR will be adding a handicapped accessible bathroom and another bedroom. So, Rhonda Barker and I were removing the linens, dishes, etc. We were checking them over for stains, tears, cracks, etc. We ended up with several bags of discards. If you ever come to visit Bonaire, be sure to bring towels, small rugs, and sheets. They are more expensive and of lessor quality than those from the States. I wish I had realized the need and I would have been sure to pack some in my luggage.

I was warned that there were scorpions in that house, so I tried to be careful when I pulled things out of the cupboards, etc. We didn’t see any live ones, but did find a dead one.

I brought home some of the sheets to wash and they came out nicely. Only one set will probably have to become a rag. It was rather tattered.

Larry was supposed to come home a little ‘early’ (before 6:00) so we could find a place to swim. Unfortunately, the transmitter was not working properly, so we will not be going swimming tonight. It is too busy across the street where we usually swim. ‘Happy hour’ is well under way and payday was today.

NOTE — To see a bigger (and in some cases, expanded) version of any of the images in this blog, just click on the one you want to see.

When I woke up shortly after 6am, I checked the transmitter, via a computer at home, and found there were once again no overnight cutbacks. I increased the modulation another 0.2dBU to 8.3dBu to see if I could induce a cutback. [If it would have cutback, I have the ability to remotely return it to full power] No cutback occurred, so will leave it at this level for tonight.

We managed to contact Nautel today and found that there are some adjustments, not mentioned in the set up procedures, that would bring the no modulation power level with AMC back up to 100kw, instead of 80kw. One of the setup procedures is to set the ‘gain balance’ so there are 0 volts between two specified points. We had done this procedure as explained in the manual. What was not mentioned, is that, after everything is set up and AMC switched on without modulation, this same ‘gain balance’ control can be adjusted, while switching between AMC and ‘standard AM’, so that the power levels are the same. This procedure must be done starting with low power, then repeated while increasing the power in steps to 100kw.

This afternoon, we followed these additional instructions. Now everything seems to function properly on AMC and when switched back to ‘standard AM’. We did some tests switching between the two and found that we could switch quickly from ‘standard AM’ to AMC. Switching from AMC to ‘standard AM’ resulted in multiple faults that shut the transmitter down and it could not be turned on again without shutting off the mains and turning them back on. I then carefully watched what was happening during the switching off of AMC and noticed that the power output would jump to over 130kw. I suggested putting a time delay before the transmitter was allowed to come back on after switching AMC off. This worked, if the delay was over 10 seconds. I then suggested an alternative to switch the transmitter power to 25kw at the same time as switching AMC off, waiting for about 2 seconds, then switching to 50kw. After another 8 seconds, then the switch could take place to 100kw. This way there is dead air for only one second instead of 10 seconds. Two macros, for 50kw and 100kw, was set up to automatically go through this process when switching dynamic carrier control (AMC) off.

Test programming was now successful run with AMC for about 30 minutes. We felt comfortable allowing AMC to be used for this evening’s broadcast. It is now after 10:30pm. The transmitter has been running for 5 hours and seems to be performing well. With this method of dynamic carrier control, AMC, the voltage peaks are considerably less than with ‘standard AM’, so I do not anticipate any problems with cutbacks.

We got our evening swim in tonight. We’ll have to make other plans for tomorrow because it is Friday night AND payday. We suspect there will be a BIG party!

Supper tonight was chicken strips on rice, with green beans, and the rest of the papaya for dessert.

We had another night with no cutbacks, As a result I increased the audio input another 0.1 dBu to 8.1dBu

This morning, like most mornings, I wrote a report to give to Joe Barker on my previous day’s work to have a record of what has been done and report things that have been discovered which need attention.

I also read up on Amplitude Modulation Companding (AMC), which is one of three types of dynamic carrier control available on the Nautel transmitter. It has been decided to use AMC starting shortly, but it does require some special setup procedures before implementing it. Joe plans to meet me at the site at 3pm to go through the setup process. For technical geeks, you can read more about AMC at:
http://downloads.bbc.co.uk/rd/pubs/reports/1988-15.pdf
OR
www.nautel.com/Resources/Docs/Presentations/NAB2009/BECR07_Tim_Hardy_Energy_Conservation_in_AM_Transmitters.ppt

Now that the PA Module is repaired, I have been reading up on other equipment at the site that I have been asked to modify or repair. There is a security system TWR would like to have fully operational. There are also the following functions that would be nice to have added to the remote control system:
1. The ability to switch the tower lights on or off remotely as a backup for the photo cell.
2. The ability to remotely switch off the air conditioner for the transmitter site’s office in the event it is inadvertently left on when everyone is gone. This could save a lot of electricity cost.
3. The ability to check additional voltages on the transmitter that would help diagnose faults, and possibly correct them, remotely.

When Joe Barker arrived at the site, we followed the procedure for setting up the transmitter for AMC. When we enabled AMC, we found that the transmitter power only returned to 80kw instead of 100kw, like it should have without modulation. We decided to call Nautel tomorrow for their advice. For tonight we will continue using standard AM modulation. Once set up, the transmitter can operate with standard modulation or AMC by switching it locally or remotely.

It was nice to swim tonight, especially after missing last night due to the party on the beach. The relatively cool water (82F) cools by lowering body core temperature. Its amazing the length of time one feels cooler after a 30 minute swim!

While swimming, and for some time after we got back to the house, we heard drums and brass instruments playing in the distance. It reminded us of marching band practices at Concord High School that we hear from almost a mile away at our house in Elkhart. We have heard this for several nights, so decided to locate where it was coming from. What a surprise when we found, about a half mile away, a group practicing in the parking lot of a supermarket that was closed. It was a group of about 6 men playing their loudest! Not sure what they were practicing for, but they should be impressive. Maybe we will have a chance to ask them.

For supper tonight we had toasted cheese sandwiches, green beans and papaya (for dessert).