After two really long work weeks, it was nice not to have to set the alarm and to have a Saturday to relax.  We ate a late breakfast, then Jason came from the south part of our duplex to discuss meals for the three extra guests from Latin America that will be staying in both sides of the duplex starting tomorrow.

We went into town for the noon excursion that Virginia arranged yesterday.  We arrived at the Karel Beach Bar where we boarded the Red (semi-)Submarine.  [http://bon-sea.com — Virginia managed to get a better rate than any listed on their website!]   There were only four passengers on board–two Dutch men and us.  The captain, probably in his 20s, told us the water was too deep to see anything at first and had us stay on top for the short trip to the island, Klein(small) Bonaire.

When it started to drizzle rain a couple times, the captain asked if we wanted to shelter below, but we all declined. Once we got to shallow water near Klein Bonaire, we went down into the ‘submarine’ and viewed the marine life through the underwater windows for the next 30 minutes.

It was like snorkeling, but without getting wet and covering a whole lot more territory.  We saw all types of coral and thousands of fish, but nothing big, like turtles, stingrays, dolphins or shark.

Most of the time one side had a good view, while the other side was towards deep dark water with no bottom in sight.

We were grateful that there were lots of empty seats so we could move to whichever side had the best view.  Virginia and I stayed below for most of the return trip.

We wanted to see the marine life near the docking point.  The water is very deep until within about a couple hundred feet of shore.  There the bottom was almost all sand with hundreds of small fish swimming around the piers near shore.

We next went to Kooymans, the large hardware store, to get a 2 foot flourescent tube and some LED bulbs for the duplex.  Kooymans could be compared with a Lowe’s at home, with slightly higher prices.

We went home to eat our Doner lunch and get our suits to go for a swim at Sorobon.

 

 

Virginia and several of the ladies joined us at the transmitter site for devotions this morning, then they cleaned the entrance, hallway, kitchen, lunchroom and restrooms.

Virginia and I worked at cleaning the tall narrow window next to the new transmitter.  It had to be the dirtiest window in the building with large blobs of concrete stuck to the glass.  (I never realized how well concrete can adhere to glass!)  It also had paint over-spray on both sides.  This window is not perfectly clean now, but looks a whole lot better than it was!

I decided to check the voltage on the air handler contactor coil.  The initial voltage was 21 volts with no discernible drop as it was energized and pulled in.  Although the output of the 24vac transformer is lower (due to 105vac input instead of 120vac), there was minimal voltage drop in the output winding, compared to the 8vac drop in the smaller transformer removed yesterday.

The transmitter was operated this morning at 440 kw with normal program on the north and south patterns with no problem.  Later, Dave and I again took field strength measurements at the airport (about 2.5 miles northeast of the transmitter site), while Jonas and Daryl operated the transmitter.  We have been informed that the self (TWR)-imposed maximum should be 1 volt/meter.  We determined that 225 kw would need to be the limit on power in the Caribbean (omni) pattern to meet this requirement.  No governmental limits are known, although when 500kw into a 5/8 wavelength tower was being used, during the first years of operation by TWR Bonaire, the field must have been close to 2 volts/meter at this same airport.  As mentioned earlier, the north (Cuba) pattern and the south pattern, even at 440 kw have much lower field strengths towards the airport.  The main beam of the north pattern, which passes to the west of the airport, is directed toward Cuba.

There was one arc (as detected by an arc detector) in tower 3’s tuning unit last night while using the Caribbean pattern.  This afternoon, Daryl and I went to that tuning unit to observe where the arc might be occurring.  By operating the transmitter at 250kw with heavy modulation, we were able to see the exact location of the arc.  The arc originated from the grounded end of an insulator to a wide ground strap on the floor.   How can you get an arc over an inch long from one grounded point to another ground that are already tied together with a short ground strap?  I cannot explain it (yet), but some unexplainable, strange things do happen with transmitter powers of this magnitude.  We tried to improve the ground connection and will see whether an arc is detected tonight.  [When an arc is detected, the detector shuts down the transmitter for a fraction of a second which extinguishes the arc.  This only happened once last night.]

We left the site just after 5pm this evening and, unless something unanticipated happens, we don’t plan to return until Monday morning.  Hopefully tomorrow (Saturday) will be a relaxing day.  Virginia purchased tickets for us to take an unusual excursion tomorrow at noon.  Stay tuned for tomorrow’s blog!

On Sunday, lots of people start arriving for the dedication.  Planned activities start with a lunch buffet at noon Sunday and continue until a ‘BBQ at the beach’ on Thursday evening.  Pray for unity and stamina as the small TWR Bonaire staff (including us) are involved in so many ways and that God’s grace might shine through us.

 

 

 

 

 

Last night, Virginia made a pan of brownies to take to the transmitter site as treats for those that worked there today.  The brownies were all gone by the time to go home!

Work today was a little more relaxed for me than normal because Jonas spent nearly the whole day programming and rewiring the automation system so that the new transmitter will be able to take over the broadcasts of the older, less powerful transmitter.

On Tuesday, it was mentioned that our camera battery was close to ‘dead’ and that we forgot to pack its charger.  Yesterday, Kevin brought in about 5 different camera battery chargers.  None of them came close to being usable for our battery!  Therefore, I made a slot in a small block of wood for the contact side of the battery to fit into.  Then two holes were aligned, drilled and tapped so that the ends of two small brass screws would make contact with the + and – battery terminals.  A tie wrap (a rubber band would have worked too) was used to insure that the screws securely contacted the battery terminals.  An adjustable bench power supply was used to charge the battery.  The voltage was adjusted until the  charge rate was 0.1 amp, then the current limit was adjusted to prevent the current from going any higher.  The battery charged for four hours this afternoon and was put it back in the camera to take home for the evening.  The camera indicated it was about 2/3 charged.  This morning, the battery was again charged but was obviously nearing full charge as the charge rate kept dropping.  This afternoon, the battery had reached full charge.  I need to remember to take a photo of my ‘wooden block’ charger!

This morning, the investigation of the low voltage to the air handler contactor coil at startup continued.  The control contacts of the automation were measured with no indication of any voltage drop there at startup.  The voltage output of the 24vac transformer was then measured and found to drop to 16 volts at startup–way too low and obviously the source of our problem.    This transformer, that was mounted in the automation rack, looked way too small for supplying the control voltage for such a large air handler and this transformer is wired to supply two such air handlers.  The search began for a larger 24vac transformer, but none were found.  Then a transformer wired for stepping 127vac down to 105vac was found.  By wiring its two 12vac windings in series and its two 120vac windings in parallel we now had a 250va transformer for 24vac.  It was too big to mount where the smaller (~30va) transformer had been, so it was set on the floor of the automation cabinet. It was wired into circuit and the contactors now pulled in with a sharp ‘clunk’, like they’re supposed to.

At noon, an email request was sent to Ralph VanderWerf to see if he could bring two (one for a spare) larger transformers on Sunday.  Within minutes his son, Jim, supplied two 75va transformers to Ralph and they were already packed at 5pm!

In the afternoon, I helped with some rerouting of wires in the automation rack and rearranging equipment in their racks.

By the time broadcasts were to begin, the new transmitter was ready to begin broadcast under automation control.  Just seconds before the start of the 5:30pm broadcast, the automation turned on the air conditioners for cooling and then turned on the transmitter.  The new transmitter was now broadcasting TWR programming for the first time!  Praise the Lord with us!!   www.facebook.com/twr.bonaire/videos/1844991108845988/

The new transmitter has purposely been  limited to operating at 225kw maximum for tonight’s broadcasts.  That’s still more than double the power of the old transmitter!  Pray with us that any ‘bugs’ in the automation program, transmitter, or antenna system will be found quickly as we progress to a full 440,000 watts for Tuesday’s dedication.

This morning, Virginia and Mariette, the station director’s wife, went to Sorobon (at Lac Bay on the east side of Bonaire) to relax and swim.  They had a good, and much needed, time together.  This afternoon, Virginia did some shopping in town.  There were two ships docked again today–one was the Carnival Sunshine, so there were a lot of American tourists everywhere.

Immediately after devotions, WEB arrived to increase the voltage going to the new transmitter.  In preparation, we had increased the voltage by one tap on the transmitter transformer.  Apparently the voltage from the WEB transformer increases about 5% per tap and the transmitter transformer by about 12% per tap.  WEB went up by two taps and the voltage from the output of transmitter transformer went down by 2%, which was too low.  The main breaker tripped for some unknown reason.  We decided to go back the original taps on the transmitter transformer and go up only one tap from WEB.  Everything seems to work well with this 5% increase in voltage.

While WEB was present, we decided to run a test to find out what percentage of tone modulation at 440kw it would take to reach the 955 amp limit of WEB’s transformer.  We gradually increased the tone modulation until at 75% the current was 950 amps.  Our circuit breaker is set at 960 amps, so we did not go any higher.  Checking my calculations from yesterday, I found that my notes indicated the limit would be at 75% tone modulation.

Dave and I took a field strength meter to the airport to record the field strength level there.  At 300kw carrier, the Caribbean pattern gave a reading of 1.2 volts per meter, while the north and south patterns were under 0.8 volts per meter.  These levels should be within the maximum allowed at the airport.

Back at the site, I installed the 220 volt LED indicator lights in the emergency stop button enclosures.  Now there is a visual indication that this circuit is functional.

The air handler that was repaired yesterday seems to be functioning well.  The second air handler has been having problems starting.  The motor starter box would ‘hum’ without starting the blower, but when I gently bumped the box, the contactor would then pull in and the blower would start right up.    There is a switch on the motor starter box that selects between ‘Manual’ and ‘Auto’.  This switch is normally set to ‘Auto’ to allow for automated control of the blower.  When I switched to ‘Manual’, the blower would start immediately every time.  When switched to ‘Auto’, the contactor would hum and sometimes eventually pull in after a few seconds.  The starter box was next opened to measure the voltage on the contactor coil.  In the ‘Manual’ position, the coil voltage was immediately 23 volts.  In the ‘Auto’ position, the coil voltage was only 15 volts.  The wiring is the same length for both positions and, as far as I know, the only difference is the contact in the automation system.  Hopefully, we will get a chance tomorrow to measure the voltage drop across that contact to see if it is the source of the problem.

Toward the end of the day, Jonas was busy programming the automation system for the 400,000-watt AM transmitter to take over broadcasts from the old 100,000-watt transmitter.  There was too much programming still to be done to allow the change to take place this evening.  Hopefully, it can happen tomorrow.  The initial transmitter power used will likely be 200,000 watts with the increase to full power at the dedication on Tuesday 30 January.  More testing at 440,000 watt during non-broadcast hours will be taking place in the remaining days.

 

 

The location for devotions returned to the site this morning and I caught a ride with Jason.  For finding the missing  wire connection yesterday, I was presented with a surprisze (100ml bottle of maple syrup straight from New Brunswick, Canada!) by Steve Shantz.  Jonas also got a ‘prize’ just like mine for his work on the transmitter.

Daryl, Jonas and Dave began testing the Caribbean pattern which is rated at 350kw maximum compared to the north and south pattern’s 440kw rating.  They were getting some ‘shutbacks’ as they approached 300kw with tone modulation.  They found and corrected some minor arcing problems at the antenna tuning hut for tower 3–the main tower used for the Caribbean pattern.  The bottom hinge on the safety gate just inside the door to the tuning hut was found to be glowing red hot.  They ended up putting a ground strap across the hinge and tying it to ground.  It is amazing what can occur at such high power levels!

They began to do a lot of readings on the transmitter and setting up of the transmitter computer menus.  While they did this, I tried to make myself useful on other projects.

After the high power testing yesterday, Daryl and Jonas noticed that the temperature in the power room had increased to over 115F.  They decided to have a small air conditioner installed.  The wiring for the air conditioner had been put in already, but a 220-volt 2-pole circuit breaker needed to be installed in the 800 distribution panel.  Because the circuit breakers in this panel are all the bolt-in type, power to this panel had to be shut down.  [I’m guessing most electricians have a special tool to do this without shutting down power]  I thought of making such a tool, but decided that would take much longer than the minute, or two, of ‘power off’ time required to bolt the breaker into place.   Also, the transmitter testing could continue, since the transmitter is connected to the 380 volt panel and the 220 volt auxiliary equipment needed is powered through the UPS.  The air conditioner people doing the work can do a split unit installation in around one hour.  By the time they were ready to test the unit, i had already connected the power to the split units and the 220 volt breaker was ready to be switched on.

One of the two air handlers for cooling the transmitter was tripping its breaker.  Since this is a fully redundant system, the second air handler was put into service.  Each air handler uses a 10hp motor to turn its blower.  The faulty motor would hum, but not turn, upon applying power.  I suspected that it was ‘single-phasing’, meaning one phase was not connected.  After checking voltages at the motor starter and finding one phase with normal voltage and the other two with reduced voltage, I decided to check the connections at the motor.  When I opened its electrical box cover, everything inside was covered with black soot.  The soot could be rubbed off two of the three connections, but it was obvious that the third connection had a problem.  The ‘wire nut’ used to make the connection was melted.  I suspect that one of the two wires had not been fully inserted into the ‘wire nut’ when it was screwed on.  I cleaned up the burned wires, reconnected them and this air handler has now been returned to service.

While talking to the engineers today, I asked what power level the people at the dedication would expect to see on the transmitter’s computer screen.  Of course, they would want to see full power–440 KW!  TWR Bonaire will normally use a type of modulation  called AMC (Amplitude Modulation Companding) to save on electric costs without losing listeners.  AMC operation will show varying instantaneous power levels on the screen, depending on the level of modulation.  To show 440 KW continuously, will require the use of standard AM operation.  This requires more power input and will test the limits of WEB’s (the power company’s) equipment.  With normal programming at 440 KW, we should be just within the WEB’s limit.  I asked about a clamp-on ammeter to measure the 380 volt line current, but no one knew of one that large enough.  At the end of the day, Daryl came carrying a 1,000 amp clamp-on meter. Its calibration had last been checked in 1983.  We were able to verify that it was still working properly when measuring current in the main cables while the transmitter was operating at 440 KW (no modulation).  We are now confident that we can do testing tomorrow with modulation, and ‘push the limits’ without exceeding the limits of WEB’s 630kva transformer.

Jonas informed us before leaving the site, that WEB will be out in the morning to increase the voltage from their transformer.  This means we will have to also change the taps on the transmitter transformer.  I have been advocating for this to lower the current (and losses) in the power cables and breaker between the WEB transformer and the transmitter transformer.  Only the transmitter uses this 380 volt source, and since the transmitter transformer has taps going up to 440 volts, why not take advantage of reducing loss by using higher voltage and lower currents to provide the same amount of power?!

I rode home with Daryl this evening arriving around 6pm.  After supper of leftover spare ribs and baked spaghetti [we still have leftovers of the latter!] and salad, I walked over to Dave’s house to pick up some 220v LED indicator lights to install in the emergency stop button boxes to show that they are functional.

We also forgot to bring the charger for our camera battery with us to Bonaire and Dave thought he might have a cable that might fit the DC input for our camera.  Unfortunately, no such luck.  Dave previously brought in the charger for a Panasonic Lumix, which is the same brand as ours.  It was obviously not the same model, because the battery pack sizes and contact placements are ever so slightly different.  Kevin said he will bring his camera chargers in tomorrow.  Hopefully one of those will work.  If not, we will try to rig up a way to charge it with one of the site’s adjustable power supplies.  The major challenge is making, and maintaining, contact with the tiny ‘pads’ on the edge of the battery pack.  Tried earlier today and was not successful, but I have an another idea!

It looks like we might finally be able to get 8 hours of sleep tonight, for a change!