We learned this morning that the 50,000-watt transmitter for Swaziland will likely be packed in Elkhart yet this week into a 20 foot container brought by the shipping company. Two hours are allowed to pack it after which an hourly charge is assessed.

Virginia needed the car to do some shopping, so she took me to the site after lunch.

I began to trouble shoot the problem with the spare PA Module and found that one of the Modulation modules and the two RF modules that it supplies appeared to be shorted. [There are a total of four Modulation modules and eight RF modules in each PA module.] The interconnecting strap between the Mod and RF modules also showed a short. I disconnected the RF modules from this strap and the RF module short disappeared. I then unplugged the Modulation module and found that it still showed a short. Problem found!! Not so fast – I decided to measure the interconnection and found it to still be shorted. There is a filter board between the Modulation module and the RF modules. The FET used for this filter board for a crowbar protection circuit was also shorted. Will continue working on this tomorrow.

Before the time for the 100,000-watt AM transmitter to come on the air, I tested each of 16 PA Modules in the transmitter to ensure they were all performing properly. By inhibiting them one-at-a-time, it was determined that they were all OK. The power when each one was inhibited dropped the output about 11,000 watts. Calculations indicated that this was correct. Also, if ¼ of a PA Module failed, as is the case with the faulty one that is being repaired, a calculated loss of 3 kw compared to good RF Module would be expected and that is exactly what we had observed.

When I checked my email this evening, I learned the shipping container for the 50,000-watt AM transmitter will arrive at the Elkhart technology center first thing Friday morning.