Wave of the Future

We have had an encouraging learning experience during our DRM test transmissions. The spectrum analyzer display shows the typical "Bart-head" waveform that a DRM broadcast creates. TX6 was able to acheive a "shoulder depth" of at least 32dB, which is quite good.

There are still bugs to be worked out with the data being sent from the content server to the modulator in the transmitter. These bugs are creating occasional breaks in the audio. However, the sound quality is amazing for a shortwave broadcast. We have received listener reports from Japan and Australia. The main beam of the 75KW signal was actually headed toward India.  You can go to www.youtube.com/watch?v=6e2Lnmx2LU4 to hear the signal that was received in Japan.

More Testing

A few more accomplishments at KTWR…
 

75% Power Test

With the Antenna connection completed, we are now able to test The Thomson Transmitter at higher power. On August 31 we were able to bring the Thomson transmitter to 218KW. The transmitter ran smoothly with very low reflected power.

Content Server Test

The Transmitters at KTWR Guam are two Harris SW100 Transmitters (100KW), one HCJB HC100 Transmitter (100KW) and now the two reconditioned Thomson TRE2326 transmitters (250KW).

We have had an ongoing project to upgrade the HC100 Transmitter to DRM (Digital Shortwave) for several years. One of the devices needed to broadcast digitally is a content server which formats audio into the correct form of digital audio.

We have not been able to work on the HC100 upgrade for a long time, due to the Thomson transmitter installation and other complications. We felt it would be a good idea to test the content server so…

We configured the content server to stream Digital content to the new Thomson transmitter because the Thomson is already DRM capable.

Here are the results.

Sept 2^nd 75KW DRM

We are very Happy to report the Content Server Works Very Well!!

Testing, Testing, Testing... and... RF ON!

3 August 2011 Thomson Transmitter status display indicating "Unknown State":

Considerable progress has been made in Connecting Power, Air and Water cooling systems. Most connections were completed just before Marc Moreau (Thomson Engineer) arrived for an Installation evaluation and inspection.

Marc arrived on August 3^rd with the Transmitter in a functional unknown state.

For the next week the project team worked 12 to 14 hour days testing, repairing electrical control components, fixing water cooling leaks, rebuilding computers, etc….

On Tuesday morning August 9^th a temporary antenna connection was made.... and....

We are pleased to report on 9 August 2011

we successfully accomplished an initial power up RF test. For about 10 minutes we aired a station ID test and music tone at 0500 UTC on 31M at 57KW.

9 August 2011 Thomson Transmitter status display indicating all systems "ON":

Thank you for your continued prayers as we move forward to reach the Late October goal for sustained broadcasts using this powerful communication tool!

RF Test Video

Raising The Balun - 2

A balun is a type of electrical transformer that joins a balanced line (one that has two conductors, with equal currents in opposite directions, such as a twisted pari cable) to an unbalanced line (one that has just one conductor and a ground such as a coaxial cable).

This balun weighs around 660 lbs. This really wasn't a big challenge for our riggers who quickly had the necessary equipment for hoisting up the units. The real challenge was the amount of space needed for the large balun unit. It had to be raised and turned from an area half the size of its length.

It was a bit time consuming, but it all went without a hitch, as this was all successfully connected together. The remaining part of this project is to now get the feed lines out through the wall and connected with the curtain antenna

(We did 'raise the roof' as we thanked the Lord for the successful and non-eventful raising of the balun.)

Raising The Balun

This is not like raising the roof (creating a loud noise), or raising Johnny (teaching children the disciplines of life).

This is about hoisting the VHF filter and the Balun to connect them as part of the RF output of the new transmitter. They are raised up to the roof however (suspended from).

The VHF filter unit weighs approximately 300 lbs. This was the first unit raised to connect to the transmitter RF output.

A Chilling Effect!

Chilling on Guam? Or maybe it means we are chilling out - calming down instead of getting wired! NOT!

The water from the cooling system is 'chilled' or cooled in fan cooled radiators. The water flows in and out of the chillers through the copper water lines (previously posted). Here the mounting of the fan units is being done to the chiller units.

Preparation?

"Yes Grasshopper, balance is everything!