KTWR Dual Language!

The First successful decode of Dual Language DRM 30 to Japan and Korea took place today (28 November) on 7500khz from 1228 to 1244 UTC.

Verified by a listeners in Takaoka City Toyama Pref. and  Odate-shi Japan
https://youtu.be/jebYT5L_OCQ

The Dual Languages were enhanced by live text describing the Japanese program and two additional data services featuring slide pictures as well as a test Journaline feed.   A total of 4 services were sent from one transmitter!

We decoded the services on PC + SDR, Tecsun Q-3061 receiver and Smartphone + SDR at the transmitter site in Merizo Guam.

Convert SmartPhone to DRM 30 HF receiver!

Convert Smart Phone to DRM 30 HF receiver!

We are pleased to report successful use of an SDR Dongle used to directly receive and Decode DRM 30 over HF today.

The SDR Dongle is an RTLSDR v3 type connected to an android smartphone using an OTG cable (phone or tablet must be OTG capable).

The Software used:
1. Android driver (free)
2. DRM+SDR Android App ($4.99)

The Frequency of the HF broadcast is directly assigned within the DRM+ SDR app with two settings
1. Frequency in Hertz
2. RF Gain (0-512)

Demonstration video showing Clean DRM decode of AAC Audio and Journaline data along with live metadata.  (our signal was very strong, so only a short wire used for Antenna, DX'rs will need an appropriate Antenna)

** Updated 01/28/2020, SDRPlay type SDR has been added 

Now anyone with a smartphone and a $20 SDR can receive DRM 30 HF broadcasts...

The new KTWR DRM schedule became effective 27 October
** updated 01/28/2020

 Day                        Freq                       Time                                      Region                             Power

Wednesday          9910kHz             1026-1056UTC                    China                                    50kW
Thursday               7500kHz             1226-1245UTC                    Japan/Korea                       50kW

Sunday                 13800kHz            1026-1056UTC                    South Asia                           90kW

Propagation Artwork

Hi Everyone,

When we published the latest KTWR DRM broadcast schedule, we did not include the expected propagation plots for the new blocks. They are shown below to give you an idea of what to expect for coverage. The South Asia plot was done for 75kW, but we will be using 90kW for this season. It should work slightly better than what is shown. The Japan/SK block will still be aired at 50kW.



9900kHz 1215-1245UTC to Japan/SK

15200kHz 1026-1056UTC to South Asia

Yet Another Change

Hi again Everyone,

We are so grateful for the help listeners have given us during the DRM broadcasts we started last month. Based on comments and listening patterns we have seen, we made some more changes to KTWR's DRM broadcast schedule. The new schedule will become effective 12 Sept. for the Japanese block and 15 Sept. for the South Asian block.

 Day                        Freq                       Time                                      Region                             Power

Wednesday        11995kHz             1026-1056UTC                    China                                    50kW

Thursday               9900kHz             1215-1245UTC                    Japan/Korea                       50kW

Sunday                 15200kHz            1026-1056UTC                    South Asia                           90kW

 

We are still trying different broadcast parameter combinations, so we definitely can use your reception reports. We believe that propagation for the new Japan/SK and South Asia broadcasts will be much better than it is with the current schedule.

 

We do hope that the content of the programs has been a blessing to you. We are looking for ways to replace the English language programs with Asian languages in the future. We do not know when that will happen. Stay tuned and 73.

Schedule Change

We hope you have been enjoying participation in our DRM experiment. We are grateful for those of you who have sent reception data to us. We had a request to move the South Asia block from Monday to Saturday. This is to allow more listeners to be at home during the broadcast time. We have received authorization to make that change. Starting tomorrow, 24 August, the DRM broadcast schedule will be as follows:

 Day                        Freq                       Time                                      Region                             Power
Tuesday               11995kHz             1026-1056UTC                   ANZ/South Pacific              50kW

Wednesday        11995kHz             1026-1056UTC                    China                                    50kW

Thursday             11995kHz             1026-1056UTC                    Japan/Korea                       50kW

 

Saturday              11580kHz             1215-1245UTC                   South Asia                           90kW

 

For the remaining weeks in this 8-week broadcast cycle, the audio bit rates will be lower than before. That should make decoding easier.

 

73

DRM Decoding App!

If you would like to lighten the load of your DRM reception hardware, you could off load the work of decoding with a new Android based DRM decoding App.

'DRM30' FREE

https://play.google.com/store/apps/details?id=com.algorkorea.app.drm1

'DRM+' $1.99

https://play.google.com/store/apps/details?id=com.algorkorea.app.drmplus

Although air coupling the demodulated DRM Audio between the receiver speaker / headphone and the microphone input of the Smartphone / Tablet will work to some degree.  Likely ambient noise will be introduced causing the decoding to be less than ideal.  Holding the smartphone microphone near the demodulated DRM output is a quick way to check the SDC.  A direct cable or even a filtered line may be needed to decouple Phone / PC / Receiver noise for a solid MSC and audio decode.

If you use a headphone / microphone multi pole plug (like the diagram below), the decoded DRM audio will automatically route to the Headphone jack, so an Audio Switching App (many available on google play store) can be used to route audio to the main speaker of the phone.

 Let us know if you use this in your tests... And how it works...

More DRM Reception Info

It occurred to us that you may want to see what to expect for coverage of our various DRM broadcasts. I am including propagation plots for September. Some months may be better than others, especially for India and New Zealand.

South Asia broadcast

 

Australia/New Zealand broadcast

China broadcast

Japan/South Korea broadcast

Here are some tips that may help you in picking up our broadcasts. If you live in an area where the signal is weak, you may want to consider turning off nearby CFLs or LED lights to reduce electrical noise. If you are using an SDR with selectable filters, a 12kHz filter usually works better than a 10kHz filter.