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.

We Are Still Around

I know many of you may have wondered what happened to this blog. We have had so many things happening at KTWR that we just lost track of keeping up with this. We hope to make our entries more regular again.

There is some exciting news that is worth sharing. KTWR will resume regular DRM broadcasts next week. The schedule will be as follows, starting the week of 5 August through at least the next seven weeks and probably through the end of the A19 broadcast season:

 Day                        Freq                       Time                                      Region                             Power

Monday               11580kHz             1215-1245UTC                   South Asia                           90kW

Tuesday               11995kHz             1026-1056UTC                   ANZ/South Pacific              50kW

Wednesday        11995kHz             1026-1056UTC                    China                                    50kW

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

Each week will have different broadcast parameters that will affect decode rates and audio quality.

Set-up	Profile	P-Level	QAM		Sample Rate	audio bitrate	SBR	Mono/ Stereo	Target Environment
			SDC	MSC					Ionosphere Hops	Range	Noise
Aug 5-8	A	1	4	16	24000	18360	No	Mono	Single	Short	Low
Aug 12-15	B	2	16	64	24000	19980	No	Mono	Single	Short	Low
Aug 19-22	C	3	16	64	24000	19980	No	Mono	Multi	Medium	Low
Aug 26-30	C	1	16	64	24000	16440	No	Mono	Multi	Long	Medium
Sep 2-5	D	3	16	64	12000	13980	No	Mono	Multi	Long	High
Sep 9-12	C	0	16	64	12000	13700	No	Mono	Multi	Long	High
Sep 16-19	B	0	4	16	12000	11560	No	Mono	Single	Medium	Medium

 
We are asking listeners to report as often as possible during this season. This will help us determine the best compromises to make in setting up broadcasts to various regions. Some of you will be able to hear all four broadcasts each week. Others may only hear one each week. That is due to the antenna patterns we will be using. Reports may be sent to ktwrdrm@twr.org or using the embedded form below.

We would love to hear about your hardware / software / antenna and if you tried to test a new smartphone / tablet App to decode DRM (Android based, we hear Apple is on the way)

If you have DRM Logging capability (DR111,  DREAM Logs, etc...) We would appreciate receiving this data!

To capture DRM Data with DREAM DRM Decoding software:

           - Open the “Evaluation Dialog” Window

             - Click the “Log to file” box

    Two logs (DreamLog.txt and DreamLogLong.csv) will be written to the root folder of the DREAM software.

                                  Please upload your Data log files HERE

We have created a special form for DRM broadcast reception reports: