Feet–Sand–Waves

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!

Steve Shantz, Daryl (behind Steve), Dave and Jonas using tone to test the transmitter

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.

The ‘wire nut’ that was found at the faulty air handler’s motor.

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!

How not to start your day!!  Morning devotions were to be held this morning at the studio on the other side of town, so we were ready early to get in the car.  I used the car key to open the trunk and quickly put my lunch bag and computer in.  Then I opened the gate so the car could be driven out of the yard, then returned to the car, but the car key had ‘disappeared’.  We searched the trunk and the ground between the gate and the car for about 15 minutes.  Eventually we caught a ride to devotions with Jason from the other side of our duplex.  At the office, we were fortunate to be able to get the spare car key so Virginia could do shopping later today.

After devotions, I caught a ride to the transmitter site with Daryl.  I took my computer and lunch into the site office and decided to open my lunch bag.  Pulling out all the items in the bag,  there in the bottom of the bag was the key!  Because of the trip to the office this morning, Virginia had put my lunch bag inside a special cooler bag.  It was this cooler bag, with the lunch bag inside, that was put into the trunk.  How the key managed to get inside the bag that was inside the cooler bag, when both were closed, is beyond me!  What a relief to find that key!!

This morning two ships were at the pier. Ships are coming into Bonaire almost every day during January.

Now for how to start your day!!  After not being able to get the transmitter higher than 260kw last week due to ‘Fast RF Shutback’, we decided to examine the directional coupler that provides the signal for the ‘shutback’.  There are two small ‘doorknob’ capacitors attached to the output plate to provide a voltage sample for the coupler.  The top of these two stacked capacitors are close to a hole in the top of the transmitter cabinet.  This hole was covered by the coupler box.  When I reached into the hole at the top of the transmitter, I could not feel anything attached to the top of the two capacitors.  Therefore, I removed the coupler box from the top of the transmitter and inside I found a wire with a ring terminal that was not connected to anything.  I connected this wire to the capacitor and reattached the coupler box with confidence that the transmitter would go to full power now!

The yellow wire inside the coupler box is supposed to be connected to the top of the capacitor seen just inside the hole.

NOTE–The transmitter assembly instructions were reviewed about installation of the coupler box. Connecting this wire was not mentioned anywhere, although two other connectors were specifically mentioned.

The transmitter now came right up to 440,000 watts on the dummy load and all three antenna options with no problems.  Praise the Lord with us for this answer to our (and your) prayers!!

Jonas watches the transmitter’s computer screen as the output power nears 440kw.

We recalled that some of the antenna protection circuits had not been fully implemented for the new transmitter, so Jonas took some time to activate these protection circuits before proceeding further with testing.

Meanwhile, I worked on the panel on the dummy load that was removed to install the capacitor on Friday.  We couldn’t get all the screws and holes to line up when reinstalling the side panel.  I managed to get the holes to line up, by shimming up the frame on one side of the opening by 1/8″.  Obviously, the concrete pad on which the dummy load sits is not perfectly level, which caused the frame to shift when this panel was taken off.

Testing was now begun with tone modulation on the transmitter.  This stresses, and tests, the transmitter and antenna system to the maximum.  The north and south patterns are designed to handle the full 440kw.  Today these two patterns were tested to 350kw with 100% tone modulation. We purposely will did not test higher than 350 kw until we determine the capability of the incoming power lines and equipment to handle the load required for testing with tone at 400kw or 440kw.  With normal program content, operation at 400 or 440kw will never reach the limits of the incoming power capability.

We could still see the two ships at the pier from the transmitter site.

Another view of the ships from the beach at the airport

Virginia and I were invited to join Donna and Lois for dinner tonight at Hillside [http://www.hillsidebonaire.nl] restaurant, so I caught a ride home just after 5 pm to be there at 6 pm.  We managed to arrive, without getting lost, just after Donna and Lois arrived at 5:45.  Virginia ordered spare ribs and I ordered the special for the night, Bami (a pasta dish with chicken and salad).  The food was very good,

We would appreciate your prayers for wisdom and safety as we continue to test the transmitter and the antenna system.

The congregational singing at International church this morning was amazing with nearly everyone participating!  There were songs in three languages, English, Dutch and Papiamento.

Pastor Doug Searle’s message was titled, “Resting Labor”.  The main text was from Matthew 11:28-30 “Come unto me, all ye that labour and are heavy laden, and I will give you rest.  Take my yoke upon you, and learn of me; for I am meek and lowly in heart: and ye shall find rest unto your souls.  For my yoke is easy, and my burden is light.”  Recordings of the services can be found on FaceBook and at http://ibcbonaire.podbean.com

We planned on having leftover baked spaghetti for lunch, but the Kings brought us some BBQ takeout from Bobbejan’s.  It was delicious and there was enough meat to last us for two meals.  So tomorrow evening it will be one, or both, of these leftovers!

Virginia helped Vera clean the south duplex for three new guests coming this afternoon.  Tom and Joshua also helped as they were pretty well packed and ready to catch their flight home.  I put the sheets and towels in the washing machine, then hung them on the clothesline.

Jason Helmholdt was the first guest to arrive.  He and his wife have four children and are raising support with the goal of arriving on Bonaire in about six months.  Steven Shantz, TWR International VP of Latin America & the Caribbean, and his brother arrived a little later on the same airplane that the Kings left on.

Just before sunset, we went to Bachelor Beach for a cool-down swim–our first swim since we have been here.  It appeared to be high tide and the waves were crashing against the rocks on shore, so Virginia opted to watch while I swam for a while.  Although she was watching, the waves got her wet, too!   Steve and his brother were also there for a quick swim.

We came home and had popcorn (our normal Sunday evening fare) and iced tea then used Skype to call my mother in Colorado.

We plan on getting to bed earlier tonight.  We anticipate this coming week will be a busy one.

Please pray with us that it will be possible to get the 400,000-watt transmitter up to full power early this week!

Tom and Joshua King delayed their return home to the U.S. until tomorrow to allow more time to fine tune the antenna system.  We have not worked previous Saturdays, but we thought it best to do so this Saturday starting at 8:30 am–that’s the time the 100,000 watt AM transmitter signs off.

Tom and Joshua making minor adjustments in the phasor room

Tom and Joshua started fine tuning in the phasor room, while I continued trying to find what could be causing the 270 kw limit mentioned yesterday.  I decided to check the tightness of all the RF (radio frequency) power connections inside the transmitter and to make sure there were no tools or packing materials left in the transmitter.  It is possible that either of these could be the cause.  I only found one connection, out of hundreds, that was loose and it could only be tightened less than 1/4 turn.  Result–no change in 270kw limit!

One bolt on the left side of the capacitor on the top right needed slight tightening.

Next, Daryl and I bypassed the antenna/dummy load switch to see if that could be the source of the problem.  Result–no change in 270kw limit!

It was noticed that the new transmitter was showing that the dummy load was not as good a match as some of the antenna selections.  I asked Tom, whose company manufactured this dummy load, whether it was adjustable.  Tom said the it could, so we removed a side panel of the dummy load only to find the adjustment capacitor was not there!  It seems the padded box containing the capacitor was not clearly marked as being for the dummy load, so it ended up being stored as a spare part.  After Tom installed this capacitor, the matching and reflected power was considerably improved.  Result–still no change in 270 kw limit!

When we opened the dummy load side panel the place where the tuning capacitor was supposed to be located was empty. Notice the hundreds of load resistors to each side.

Tom and Joshua continued to fine tune the antenna system and managed to adjust all three patterns to within 2% of 50 ohms– a very good match!!

Tom and Joshua reviewing the results of the change just made.

The transmitter’s computer readout does not agree with Tom’s measurements and indicates the matches to be closer to 45 ohms.  The above 50 ohm readings were from using a network analyzer (seen in above photo).  As another way to do the same measurement, we decided to use an operating impedance bridge  utilizing 5 kw of transmitter power.  Tom and Joshua made the measurements and confirmed that the 50 ohm measurements from the network analyzer were indeed accurate.   We need to ask Nautel why their transmitter measurements are different.

Joshua and Tom using the Operating Impedance Bridge to confirm the impedances of the three antenna configurations.

The time was now 7 pm.  Tom and Joshua began packing all their specialized equipment in preparation for leaving tomorrow.  Tom decided to store some of it at the transmitter site as he is returning next week with his wife for the dedication.  That way it will be here if further measurements are desired.  He can then take it back on that return trip.

Got back to the duplex about 7:30 pm.  Virginia made baked spaghetti and garlic bread for supper and took some to share with Tom and Joshua.  They plan to return to the site around 8:30 to see if they can observe an arc trip that seems to occur every evening about that time.

I worked on our blog until 11:30 pm and made some progress on getting it up-to-date.