It has not been as cold in the mornings with temperatures around mid 50F the past couple of mornings.

Today the problem with the ‘ground switch down’ indicator not functioning on TX3 was addressed.  Graham removed the grounding switch assembly and it was discovered that the ‘cam’ that is supposed to operate the ‘down’ limit switch was jamming on the end of the limit switch lever.  We checked the other two transmitters and found that each one had this switch mounted differently.  The one in TX2 was mounted upside down compared to TX3.  This reversal virtually eliminates any possibility of it jamming, so it was decided to remount TX3’s limit switch in this configuration.  It did require carefully marking out and drilling two new mounting holes.  It was mounted back into the transmitter and now works great.

This afternoon, another intern, Samuel, from Canada arrived via the bus from the Johannesburg airport.  Did not meet him yet, but hope to see him tomorrow.

This evening, Virginia and I were invited over to Steve and Lorraine’s for desert.  They had also invited Jonathan, whose 23rd birthday is today.  We had cake and tea, then played a few rounds of Mexican Train dominoes.

When we got back to our house, I forgot to remotely switch off the alarm.  The alarmed sounded for a few seconds, but I managed to get it switched off before it started alerting anyone via cell phone text messages!

After staff meeting this morning, we celebrated Jonathan’s 23rd birthday with cake and tea.

Today was a work Wednesday, but, since everyone else had to shop for various supplies to take to the site, I went home to wait for someone to pick me up to go to the site.  While waiting, I did some cleaning and waxing on the car that we have so graciously been allowed to use by a missionary couple on deputation.  We are also staying in their house.

My work today did not involve directly working on the transmitters, but mostly on correspondence.  TWR’s Africa Regional Office received a DX (long distance listener) report from Pennsylvania claiming to have heard a test transmission on 10 June 2013.  I was asked to verify the validity of this report.  After looking through the logs and reviewing what had been done, this person had heard part of an hour long transmission that we had done on 15,475 kHz while testing TX3 after getting it to tune on higher frequencies.  His report was exact including the exact times of a break in the transmission and of its ending.  This is quite amazing considering this listener was over 8,000 miles away and to the side of the main beam of the antenna, where the power radiated is less than 3% of what it is on the main beam!

Occasionally, we receive a questionnaire from a supporting church that we need to complete.  Often these ask for things like ‘what were your past personal and ministry goals?’, ‘were they reached?’, ‘what are your future goals?’ and other similar questions that can not be completed in a couple of minutes with ‘yes’ or ‘no’ responses.  Today, I completed such a questionnaire.

On the way to and from work, several of us engineers have been having an interesting discussion on sunrise and sunsets around the time of the solstices — the longest and shortest days of the year.  Did you know that the latest sunrise, nor the earliest sunset, occurs exactly on the winter solstice?  We notice this because we are driving to and from work at these times.  The winter solstice (in the southern hemisphere) was on June 21, but the earliest sunset actually took place about June 9, while the latest sunrise is not expected until about July 2.  We have learned that the same is true for the summer solstice, but not as pronounced.  This phenomena is also more pronounced at the equator than higher latitudes.  To check out this for where you are (or anyplace) check out http://www.gaisma.com [this site also has an interesting ‘Sun path diagram’] or http://www.timeanddate.com/worldclock/sunrise.html

Having noticed this, the discussion has turned to why this is so, which is not so simple to explain.  Did you know that a solar day is not always the same length  as a clock day?  At the solstices, the solar day is about 20 seconds longer than 24 clock hours, and at the equinoxes, the solar day is slightly shorter than 24 clock hours?  One of the more understandable scientific explanations that we found was at — http://www.larry.denenberg.com/earliest-sunset.html and one of the more simplified explanations was at —http://earthsky.org/tonight/earliest-sunset-today-but-not-shortest-day.  Here are two more interesting explanations talking about the analemma —  http://www.sciquill.com/analemma/page2.html — and — http://www.analemma.com

This evening the Bible study at EBC was on Revelation 11.  This is the chapter about the two witnesses who were killed and returned to life.

I remembered a humorous thing (to us) that happened on Sunday.  There is an intern pastor who leads the opening of the service.  At some point he referred a young fellow as a ‘guy’.  Later in the service, he apologized for using the word.  In this culture, it must be an unapproved slang expression.  We did notice that when he apologized there was a suppressed congregational chuckle, which seemed to indicate that it is probably more accepted now than in the past.

On Monday night, when our guests left our house after supper, we noticed that the alarm did not give the usual ‘squawk’ as they walked across the yard.  Tuesday evening, I checked the motion sensors and noted that they were working.  Tonight, Steve brought some fruit over that his wife bought and was splitting a box with us.  I asked Steve to help figure out what was happening.  We found out that there was a blown fuse in the Auto Bleep — that part of the system that automatically sets the various levels of alarms and calls cell phones, if there is a problem.  The basic alarm system was still working, if set manually, which we do every evening, or when away from the house.  The fuse was replaced, but Klaus had to come with his laptop, plug into the Auto Bleep and set it to the correct time.  Now everything is working normally again.

The past two mornings, the temperature at the transmitter site has been 44F at 8am.  By 9:30am it had already warmed up to 62F.

I forgot to mention something in out list of unanticipated events yesterday.  About an hour after the morning broadcasts ended, the automation system went ‘berserk’ with lights flashing and bells ringing.  Fortunately we were off the air and broadcasts were not affected.  The problem was traced to low voltage from batteries.  The special circuit inserted in series with the battery charger to prevent overcharging had failed resulting in no charge.  Graham and I decided to use a resistor to replace the special circuit until Hans, the designer of the circuit, can repair it.

About an hour before transmissions ended this morning, the monitor on TX2 went blank.  We installed a replacement monitor, but it too did not work.  I tried the replacement monitor in the other transmitters and it worked in both.  This pointed to a problem with the TX2’s video card.  Since the transmitter still functions without the monitor, we waited until transmissions ended.  Before swapping monitors, Klaus pressed the reset button on the TX2’s computer and the old monitor started working again.  Problem solved!

Next it was decided to test the 10,000 uf capacitor that had given problems on TX2 on Saturday and had ‘returned to life’ on Monday.  We were concerned that it might be electrically leaky, or losing capacitance.  When it was removed from the transmitter, it was charged to 35 volts.  When measured with a digital voltmeter, the voltage was dropping at a rate of about 0.001 volts per second.  This is about right considering the loading effect of the meter.  We then calculated that a 1,000 ohm resistive load would cause a drop from 30 to 10 volts in about 10 seconds.  This proved to be true.  We then checked all the solder connections that could have caused the problems, but could find no bad ones.  The mystery remains, so the spare capacitor with clip leads, ready for a quick connection, will remain for a while, just in case the problem should return.

This afternoon, I calibrated the RF Drive Controllers on both TX1 and TX2.  This involved tuning each transmitter to all the frequencies and antennas that it uses, finding out which one needs the most RF Drive, then calibrating the RF Controller on that one.  Doing this on both transmitters took most of the afternoon.

When I got ‘home’ this evening the temperature was 70F, both inside and outside the house.  We had a supper of leftovers and hope to get to bed earlier tonight.

Today was a day of the unanticipated !

When the  morning broadcasts ended, we decided to remove the capacitor that we put in TX3 on Saturday to analyze what had failed and to be able to explain the reason for the symptoms that we had seen.  Lo and behold, everything was working properly with none of the symptom we had observed for several previous days!  We looked all over for possible bad connections, but found none.  This left us uneasy about the possibility of the return of the problem.  Since the operator on duty is not allowed to open any doors or panels without another person on site, we left a capacitor inside the cabinet with two clip leads at ground potential extending outside.  If the problem reoccurs, the operator has been instructed to connect the two leads together, thus connecting the spare capacitor into the circuit.

Next, we had noticed that one of the door interlock lights on TX1 was on dim.  When the problem door was checked, it was discovered that the interlock switch was not working.  Opening the interlock switch enclosure, it was noticed that one of the connections was corroded as if it had been wet.  The switch and some of the corroded wiring was replaced.  Everything tested OK.

Just as the repair was being completed, Graham felt a drop of water hit his head.  Our next detective work was to find out where the drop was coming from.  Looking from the top provided no clue.  Next, several air filters were removed to allow gain access from the side.  A puddle of water was seen on the top plate of the transmitter and Graham was able, with the light from a ‘torch’ [flashlight], to see that the threaded pipe into the bottom of the heat exchanger [large radiator] was leaking.  Because of air ducting that has been installed on site for cooling, it was necessary to remove all the back doors of the transmitter and the top trim to gain access to that area for repair.  The threaded pipe was not very tight, so we removed it, renewed the Teflon tape on the treads and retightened the pipe, then put everything back together.

In the process of checking out the door interlock light problem, it was noticed that the ‘ground switch down’ light was not working on TX2.  The grounding disc was contacting the bleed resistor but not dropping far enough to contact the ground contact.  The spring on the grounding disc was too hefty, so we located a replacement, but this required some modification.  With a little work, using the lathe and modifying a washer, it was possible to make it work correctly.

While this was being done, I noticed that the optical arc detector light was not on.  Since it is sensitive to light, it should come on when the door is open.  After using several drawings to assist in tracing the wiring , it was found that this detector should have been connected in parallel with a second detector (from the same area) on a terminal block behind the control panel.   When the connection was made, everything worked as it should.

After this discovery, the other two transmitters were checked out.  TX1 was OK, but TX3 had the same problem.  This was also corrected.  I could not determine whether this was left out when the transmitter was assembled in Elkhart, or was removed after it was installed here.

It was also discovered that the ‘ground switch down’ indicator light was not functioning on TX3, while the switch was actually down.  It looks like the limit switch needs to be adjusted — a job that will have to wait until tomorrow.

TX2 came up for the evening broadcast with no problem, but I did notice that the calibration of the RF drive controller needs to be checked.  This will, also, have to wait as multiple bands will have to be part of that calibration.  TX1 should also be checked out.  TX3 has already been done.

Just before leaving the site, TX2 was manually switched on about 10 minutes early for its second transmission, just to make sure the problem from Saturday had not reappeared.  All was OK.

After I left for work this morning, Virginia learned that we would be having a family over for dinner this evening.   Greg and Ingrid, and their two young children are here for a week.  Greg had been in  Bratislava and in Swaziland at the same time Allan and Joyce were in these places, but Greg was single then.  He is here from TWR’s Africa Regional Office in South Africa to work on the security system in the Manzini office.  Ingrid and children came along, since they are on vacation from school.

This Sunday morning a delegation of three members of a ‘daughter’ church expressed thier thanks to the EBC congregation for the assistance provided to their small church.  The first lady spoke in English and the second lady spoke in SiSwati.  The third person was a young man, who helps with youth.  The started by saying in English, “You’ve heard us speak in English and in SiSwati.  Now I’m going to speak in Spanish.  Do you have an interpreter?”  This got a chuckle from everyone.

Just before his sermon, Pastor Philips sang a duet with Irene.  He said that they had sung it at a funeral on Saturday.  It was a song I have not heard before — “Jesus, You’re the center of my joy.

CHORUS    Jesus, You’re the center of my joy      All that’s good and perfect comes from You        You’re the heart of my contentment        Hope for all I do Jesus,        You’re the center of my joy
VERSE 1     When I’ve lost my direction        You’re the compass for my way        You’re the fire and light        When nights are long and cold        In sadness, You’re my laughter        That shatters all my fears        When I’m all alone,        Your hand is there to hold
CHORUS
VERSE 2     You are why I find pleasure       In the simple things in life       You’re the music in the meadows and the streams       The voices of the children, my family, and home       You’re the source and finish of my highest dreams
[ From: http://www.metrolyrics.com/jesus-youre-the-center-of-my-joy-lyrics-richard-smallwood.html ]

Pastors’s message this morning was from Ephesiana 1:15-23 with an emphasis on Christian knowledge.

After the service, one of the ladies from the ‘daughter’ church came to us and assured us that there would be a multitude of believers in heaven because of the technical work we are doing to broadcast the Gospel.   We do not know her, nor why she singled us out to tell us this, but it was such an encouragement!

Ruth invited us over for dinner after church again.  Like previous times, we provided her transportation home.  No one else was there this time.  Her meal was simpler than the previous ones but very good.  She prepared meat loaf patties and fried potato wedges with a salad.  We then had cake and tea.

We got home about 2pm and spent the afternoon relaxing and doing some blog entries.

We finished the evening with a snack and several rounds of Rummikub.  I then made a Skype call to my mother before turning in for the evening.