- as received at my home in Stockport
Romānia Actualita Bucharest 91.0MHz, 18:00z 25 May'09 Sony XDR-F1HD + 5-ele horiz beam
Otocni Radio Kornati, Croatia - 93.2MHz, 18:45z 25 May'09 - Thanks Gregor
Radio Ananas ? 93.2MHz, 18:30z 25 May'09
Radio Cento Cinque 88.2MHz, 18:30z 25 May'09 - Thanks Arvid
Cumulative list of 2013's OIRT Channels reported on SkywavesDX
A clip showing the effect of switching IF bandwidth on the KT-6040 tuner:
A) With adjacent-channel QRM; 0 - 3s 110kHz(wide), 4 - 7s 110+80(medium), 8 - 11s 80kHz(narrow)
B) On a clear channel with no adjacent-channel: 12-17s wide, 18-22s med, 23-26 narrow
a long-ish clip of Tacolneston 101.4 (Oct.09) which is a nice clear channel here, showing what this signal sounds like day in, day out, at 240km. The rx here was the Sony XDR-F1HD, the aerial a horizontal Triax FM5 mounted on the side of the house and fixed at 135°
a clip of 88.7 showing typical marginal reception of Lille here under flat condx. The clip starts with the France Musique morning jazz show and the presenter introducing a Sarah Vaughan track, then includes a few seconds of R2 from adjacent 88.8 Belmont, and ends with the web streaming for confirmation. The rx here was the Kenwood KT-6040, the aerial a horizontal Triax FM5 beaming 140°
some clips of OIRT received in 2010
a clip of Belaruskaje Radyjo on 67.4MHz, 22 May'08
CERAMIC FILTERSCeramic filter markings for the Murata 10.7MHz cerafils
Murata part markings for ceramic filters PDF 201KB
Turned pin sockets suitable for ceramic filters (R-S 227-2572)
ADAPTIVE FILTERINGThe reason that narrow ceramic filters are passing into history is that modern high-end FM receivers are increasingly using adaptive filtering techniques, such as SHARX, DYNAS and PACS which have been used in car receivers for the first decade of the century. PACS is now being seen in home audio systems for cheaper micro systems. The DSP approach to filtering and demodulating FM, as used in the Sony HD receivers, has not continued to be developed for domestic systems, but the Philips/NXP PACS (Precision Adjacent Channel Suppression) system has been used both in car radios and domestic micro systems.
Following on the recommendations of Peter Wilson and Leigh Donaldson, I bought a JVC KD-G342 car radio and evaluated it as a dx receiver, fed from Triax FM5's on a rotator on the roof. The G342 is a relatively inexpensive radio for the retro-fit market, which means it can be fitted in any car or used on its own
Selectivity and sensitivity were substantially equal to a Kenwood KT-6040 tuner, the workhorse tuner of many FM dxers. The 6040 has been modified with narrow filters and carefully aligned. The KD-G342 with its adaptive filtering responds to the noise and interference levels of the wanted signal. and in the case of a weak 'dx' signal adjacent to a strong 'local' the receiver bandwidth and audio 'treble' response are narrowed. I am told that the Blaupunkt Seattle, Daytona or Casablanca SHARX radios have similar or superior dx performance
Here are a couple of brief audio clips of difficult reception conditions, comparing the KD-G342 and the KT_6040
RTE Lyric FM on 95.2MHz (40kW at 292km) with local Radio Manchester (5kW at 24km clear line of sight) on the adjacent channel, first with the KT_6040 and 6 × 80kHz filters, then with the KD-G342. You can hear that the adjacent local shows up as 'splash' on the 6040 but is weak and undistorted on the G431, with noticable treble roll-off
Tacolneston BBC R2 on 89.7MHz (240kW at 243km) with adjacent channel interference from a local tx with the same programme (100W clear LoS at 17km), first with the 6040 then the G342. The distortion due to the narrow bandwidth sounds very similar on both receivers, with the G342 again showing treble roll-off
BANDSCANS
Bandscan from Bewdley (Kidderminster), compiled over several visits. Aerial is 3-ele horiz, beam 90°
Bandscan from Wortham (Suffolk), using a Degen DE-1103 portable. Aerial is the telescopic whip
Bandscan from Keymer (E.Sussex), using a Sony XDR-F1HD tuner (DSP). Aerial is a 2-ele beam 6m above ground
Bandscan from Stockport 2009, using a Sony XDR-F1HD tuner (DSP). Aerial is a 4-ele horizontal 10m above ground pointing due east
Bandscan from Stockport 2009, using a Sony XDR-F1HD tuner (DSP). Aerial is a 3-ele vertical 15m above ground pointing due west
CR Stations - Community Radio stations audible at home location (Stockport)
MAPS, some showing transmitter locationsA map of the British Isles & W.Europe showing the principal high-power FM Tx for Tropo Dx. It shows only those Tx of 100kW+ in good locations, and which are often heard in the British Isles
A blank version of the above map, for you to add your own details
Another Tx map for you to add details
Please send me your version of these or other Tx maps
Irish Tx map showing the main tx locations and the counties of Ireland
Departments of France, with index
The USA, Europe, and the Atlantic to compare the relative distances within the two continents, and the distance between them (but don't take distance measurements or direction bearings from this map!)
Misc photos
Another portable aerial ready for a trip
J.Hardstone 2009 Last updated 25-5-2013
