Short Performance of “Voice of Turkey” on 21140 kHz

The good contacts of the German DARC-MONITORING SYSTEM Intruder Watch with the German telecoms. authorities “Bundesnetzagentur” (BnetzA) and Chief Engineers and Technicians of the HFBC Frequency Management of Turkish Radio-Television Corporation had quick results in removing the “Voice of Turkey” off 21140 kHz. Here is the full story:

On October 23, 2006 and the following days Wolf Hadel DK2OM and I found a BC station on 21140 kHz in the 15-m-band. The program lasted only one hour from 09.30 to 10.30 UTC. The signal strength maximum was S8 with a 3-element beam antenna “Fritzel FB-33”, and the signal was coming from south-east direction. The program language was Romanian. Sometimes Wolf and I could hear a second BC program “under” the Romanian voice. Which BC station was it, and how did the signal on 21140 kHz build up? Was the BC station transmitting on groundwave, or was it a harmonic or spurious radiation? As there were two different programs audible at the same time the signal possibly was an intermodulation product. 

First I listened on 10570, “half” of the frequency of the intruding BC. No signal heard! A 3rd harmonic was impossible, because you can’t divide 21140 kHz by “3”. So I went looking for the same program lower or higher in frequency around 21140 kHz. And on 9560 kHz I found the fundamental with a signal of S 9 + 20 dB! At full hour I waited patiently for the station announcement: At 10.00 UTC the announcer came with the ID in 10 languages, included English:

“This is the Voice of Turkey” (VOT).

Later Google search engine was a big help to me: Soon I found the transmitting schedule of VOT when hitting www.trt.net.tr/voiceofturkey/high.htm. I looked for transmissions which were at the same time from the same transmitter site as 9560 kHz, which was indicated as Cakirlar. There were only two frequencies active: 11955 kHz (08.00 – 17.00) and 15350 kHz (08.00 – 15.00).

Intermodulation Products 3rd Order always follow the same “knitting pattern”: Take “Frequency 1”, multiply with 2 and subtract “Frequency 2”. The result is “Frequency 3”, the frequency of the IMproduct.

The result matched for the frequency 15350 kHz: 15350 kHz x 2 minus 9560 kHz = 21140 kHz

On October 25 I informed the German telecoms. “BnetzA” and “Voice of Turkey”. BNEtzA Konstanz is the official “input bureau” of German Bandwatch, and cooperation is excellent. Also, with the HFBC Management Bureau of Turkish Radio-Television, there is a good partnership because earlier we had solved problems with their tx-er. So I sent my complaint to Mr Sedef Somaltin and Mr Kiymet Erdal by fax and email. Already the next day I received their answer by email:

26 October 2006
Dear Mr Bihlmayer,

I contacted with the responsible people in TX in Emirler. The two transmissions, namely 15350 kHz (Turkish between 07 – 14 UTC) and 9560 kHz Romanian between 0930 and 1030 UTC) are transmitted from Emirler Site. They could not locate the problem yet, however from today 26 October on they will change the transmitters of both of these programs. Could you please monitor and inform us it the problem is solved or not? Thank you for your cooperation in advance.

Sincerely,
Sedef Somaltin, Chief Engineer HFBC Frequency Management
Turkish Radio-Television Corporation – TRT “

Already on October 27 the interference on 21140 kHz had ceased, and I thanked my “partners” at Voice of Turkey for the quick action. In his last letter Mr Erdal wrote to me:

30 October 2006
Dear Mr Bihlmayer,
Thank you for your monitoring reports. We have contacted the colleagues from the transmitters, they have checked and made some adjustments on the TX with the transmissions on 15350 kHz. They have informed us now that the output of the TX is o.k. Could you please monitor again and inform us about the results? Thank you very much in advance.

Best regards,
Kiymet ERDAL
HFBC Frequency Management International Technical Relations
Turkish Radio-Television Corporation - TRT