PROPAGATION REFLECTIONS PLUS DX QUICK TIPSSeptember 29, 2020
Sometimes, I wonder why international broadcasters select certain frequencies for their target audiences. It can leave me scratching my head! Take Radio Free Kashmir (RFK), a relatively new clandestine station on the scene. This broadcaster leases time from Radio Romania International via the Tiganesti transmitters.
The station is not audible in Australia when it operates between 0330-0430 UTC on 7355 kHz on Saturdays and Sundays only. Way too much daylight between Tiganesti and Mount Evelyn for propagation along that track at 7 MHz. Which is fine because I’m not the target audience for RFK. The Indian subcontinent, South Asia is where the signal needs to be heard.
Take a look at the great circle signal path (126˚ beam heading at Tiganesti). At 0330 on September 27, most of the path between Tiganesti and South Asia is in daylight. Indeed, at the start of the transmission, it is 9:00am in Delhi. So we can expect that by the time the transmission ends at 10:00am IST (7:30am in Bucharest), there is a continuous daylight path between the transmitter and receivers on 7 MHz, over approximately 4,800 km. The signal cannot propagate reliably with any decent signal strength because absorption at that frequency in late morning (New Delhi time) is just too high.
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| The signal path across darkness and daylight on September 27. |
Furthermore, we are not talking about RRI’s usual ball-busting 300kW output here! Apparently, RFK is paying for a 100kW transmission. The administration behind Radio Free Kashmir is just not getting value for money with this frequency choice! And we can reasonably expect that the engineers at RRI chose this frequency for their client…..for whatever reason!
I decided to check the online KiwiSDRs in different parts of the world to check if the signal was, in fact, making it to the target zone. Here are the results of a quick scan on Sept 27:
New Delhi, India SDR: A very weak signal at sign on 0330 UTC, no trace of it by 0405.
Multan, Pakistan SDR: A fair signal at 0330, very weak by 0400 and gone by 0410.
Two SDRs on Java, Indonesia and one in Hanoi, Vietnam: nothing heard and to be expected.
9K2RA SDR in Kuwait: A fair signal throughout the transmission.
YO3IUL SDR in Bucharest: A weak signal, in the skip zone from Tiganesti.
OL7M SDR (contest station - a big setup!) in Okruzni, Czech Republic: Very good reception throughout the broadcast off the back of the Tiganesti beam!
At this time of year, a better option for South Asian listeners would be the 31mb or even a 25mb frequency. As January approaches, 7 MHz may be somewhat usable to South Asia, but currently, the frequency is just to low and the signal is being lost to high atmospheric absorption. On 7MHz, South Asian listeners are NOT receiving a strong signal from Radio Free Kashmir on 7355 kHz at what we amateur radio operators like to call “armchair copy!” This must be frustrating for the producers of the RFK broadcasts.
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| The fabulous antenna system of the Kiwi SDR at OL7M in the Czech Republic |
DX QUICK TIPS
⭐⭐ 4875.02 BRAZIL. R. Difusora Roraima - Boa Vista RR. I presume this was the Brazilian heard at 1005 with occasional music, chat, jingles and energetic anncts. A weak signal and heavy storm activity in southern Australia on the evening of the vernal equinox, Sep 22.
⭐⭐ 5939.6 (approx!) BRAZIL. R. Voz Missionáira - Camboriú SC. Tuned in at 1030 for discussion program, the occasional “Bom Dia” and “Jesus Cristo” at 1040, ID 1042, station jingles. A weak signal in the noise. Tuned in LSB and narrow filters to minimise heavy QRM from the adjacent 5945 kHz RNZI’s relay of ABC Wantok in Tok Pisin. Sep 22.
⭐ 5985 MYANMAR. Myanma Radio - Phin Oo Lwin. First noted at 1122 playing pops and occasional chat between two announcers. News program at 1130. Difficult to identify the language, perhaps Burmese (Barmar) or a minority language. Fair to weak signal on this clear channel at this time. Sep 22.
⭐⭐ 6070 AUSTRIA. Superclan Radio - Moosbrunn. Looking for CFRX but found this instead at 0700 playing raucous old rock numbers. Very weak signal and fading up and down via the long path. Only clearly identified by cross-checking with the OE3WYC KiwiSDR for confirmation. The broadcast was in English, not German as appears in the Aoki list. Tuning off-freq a few Hertz up in LSB, we could hear the two hets of Superclan and CFRX….so one of them was not exactly on frequency this day. Superclan faded by 0715 (9:15am in Moosbrunn), allowing CFRX to surface at a low signal strength. Sep 20.
⭐⭐ 6185 MEXICO. XEPPM R. Educación - Mexico City. This low powered XE station continues to be heard in my early evenings around 0800 (3am in Mexico - the graveyard shift!). It features some pretty eclectic musical styles including minimalist, aleatoric, and jazz music mixed with occasional popular styles, all seemingly with Mexican origins. Extraordinary selections abound every day! The signals are always on the weak side and accompanied by the usual 49mb atmospheric noises and crashes…..but somehow, those noises seem to add to the atmosphere behind the reception of this station. The station gets swamped after 0900 by the co-channel China Huayi BC s/on. There was talk that R. Educación may not be on shortwave for much longer, which would be a big loss! Sep 18.
7285 VIETNAM. VoV - Son Tay. S/on in French to SEAs at 1200, fair signal, Sep 18.
12050 ENGLAND. R. Ndarason Int’l - Woofferton. Kanuri service beamed to Chad at s/on 0600, with ID and commentaries but no music at all, fair to poor signal. Sep 20.
13590 GERMANY. Dandal Kura Radio Int’l - Nauen. Kanuri to Nigeria at 0735, weak signal and later QRMed by co-channel China, Sep 20.
⭐ 13840 FRANCE. Manara Radio Int’l - Issouduun. Hausa service to WAf with commentaries at 0710, weak signal, Sep 21.
73 and good DX to you all!
Rob Wagner VK3BVW
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