Search This Blog

Friday, April 18, 2014

Regular Japanese DRM Broadcast

After years of working on getting ready for DRM, it has not quite sunken in that we are now doing regular DRM broadcasts to Japan.  These Sunday broadcasts at 12120KHz at 1057-1156UTC are being eagerly received across the country.  Many listeners use software defined radios (SDRs) to tune us in.  These radios are hardware combined with software running on a PC or a laptop.  Many listeners have sent us proof of reception with screenshots similar to the one shown above.  The narrow peaks are normal analog broadcasts.  The wide "Bart-head" is the DRM signal from KTWR.  Not only does that signal carry audio, but it also has text info such as the station ID and a short message that scrolls across the receiver display.
Most of the early listeners to this broadcast have been shortwave radio enthusiasts.  Japan seems to have more SW hobbyists per capita than any other country on the planet.  They were actually the ones who encouraged us to start these broadcasts.  Most hobbyists will tune in a broadcast they have not heard before once or twice for short times to get a QSL card or other souvenir from the station.  However, we have been greatly encouraged by the fact that these listeners listen to the entire program.  They tell us how much they enjoyed hearing the programs for their content, not just the signal quality.
We do pray that this experiment expands to more days and more countries in the near future.  This technology allows people to clearly hear the gospel while using 1/3 the power of analog broadcasts.  The power savings allows us to expand the ministry to more people groups.

ANT2A is Up

After a little over a week since it fell, ANT2A is back up in the air and coonected to TX7. We are very grateful for the volunteers who worked hard with us to get the job done. The Lord also gave us some good weather for antenna work.  The antenna worked well last night and the transmitter tuned easily to the new hardware.

One difficult part of the repair was in the slew switch. (It looks a bit like a lunar lander in the photos.) When the antenna fell, it bent some components in the switch that were made out of large copper pipe fittings. The riggers were able to make new parts which worked out well.

Now that this work is complete, we can consentrate on building the antenna switch matrix.  The control software work has progressed very well.

Tuesday, April 15, 2014

Major Detour

For the past several weeks, we had been working hard on the antenna switch matrix.  It would have been really helpful if we had that already in operation.  We were hoping to have part of the matrix operational in early May, so that we could increase the power for a TX7 broadcast.

Last week, ANT2A had one of its cable swage clamps fail.  This caused one end to fall to the ground.  This sort of thing tends to break many insulators and cables.  We had to use jumpers to connect TX7 to ANT3 and reconnect TX2 to ANT2B.  This allowed us to continue our normal broadcast schedule.  Without the matrix, we also had to do our Japanese DRM broadcast on TX6 and ANT1 instead of TX7 and ANT2A. 


The antenna has been reassembled and is now back up in the air.  We are still working on repairing the slew switch and its input transformer.  The slew switch is what controls the direction that the radio waves go when they leave the antenna on their way to the listeners.  The transformer is the set of wires needed to adapt the signal from the transmitter to the antenna system.

Once repairs are complete, we can resume work on the matrix hardware.  In the meantime, we do have a short-term visitor who is working on the control software.  We should have a usable software system by the end of the week.