Most television and FM radio receiving equipment are designed for medium to high strength signal areas under normal conditions. They perform well in a non-DX context. By contrast, DXers and deep fringe reception listeners require more upmarket specification performance in order to stand a greater chance of resolving weak signal reception under often unfavourable reception conditions. To assist in purchasing suitable equipment, a number of proven models are detailed below based on favourable reports by DXers.
88-108 MHz FM TUNERS
Receivers (AM/FM tuner and amplifier in one unit) are generally not suitable for weak signal reception. Dedicated quality FM tuners that feature digital frequency display, narrow or variable IF bandwidth, high sensitivity and image rejection are the main requirements for successful long distance reception.
Kenwood KT-6040 AM/FM tuner
The Kenwood KT-6040 is one of the most selective and sensitive non-RDS FM tuners. The high selectivity is due to the KT-6040's series of eight filters. For example, the optimum filter combination for fringe DX work is:
Wide: two SFE10.7MHY 110 KHz filters.
Normal: four SFE10.7MHY 110 KHz filters.
Narrow: four SFE10.7MT 80 KHz filters + two SFE10.7MHY 110 KHz filters.
Wide: FL1 (110) + FL2 (110).
Normal: FL1 (110) + FL2 (110) + FL3 (110) + FL4 (110).
Narrow: FL5 (80) + FL6 (80) + FL7 (80) + FL8 (80) + FL3 (110) + FL4 (110).
Installing Murata SFE10.7MF 50 KHz filters in the KT-6040 is not recommended. Several tests indicate that SFE10.7MF filters introduced excessive distortion, but with no apparent selectivity advantage.
As one progressively selects from wide to narrow IF bandwidth, more of the KT-6040's filters are switched in-line, so in the narrow position there are six filters in series, thus producing very steep skirt selectivity.
Preliminary tests indicate that an unmodified KT-6040 (European version) and Onkyo T-9090 II tuners both have similar selectivity and RF image rejection. Once modified, the KT-6040's 80 KHz narrow selectivity is clearly superior to the T-9090 II's selectivity (four Murata 110 KHz filters).
When the 80 KHz filters are switched in, the KT-6040's weak signal sensitivity is high. The high sensitivity is probably mainly due to the KT-6040's 3SK121 GaAsFET first RF amplifier.
The KT-6040's selectivity is superior compared to all other tuners so far tested at my location. One example is how the KT-6040 is able to resolve weak daily aircraft scatter signals from 96.7 MHz 3ABC-FM Taralgon, VIC (407 miles / 655 km) - mp3 audio sample. The Onkyo T-9090 II (four 110 KHz filters) is unable to resolve 96.7 3ABC-FM. This is largely because of the adjacent 96.9 MHz 150 kw local (6km) Nova-FM signal.
Murata filters tend to have a slightly degraded selectivity curve on the high side of adjacent unwanted signals. This is also true for the KT-6040's 80 KHz filters. However, daily meteor scatter reception of 105.9 MHz 3ABC-FM Melbourne and 3ABC-RN Mildura next to local 150 kw 105.7 MHz 2JJJ-FM is not possible on any of my tuners, except the KT-6040 (80 KHz wide FM) and Icom R-8500 (15 KHz narrow FM).
One experienced UK DXer reports that the KT-6040 was more selective against adjacent channel QRM and thus allowing clear audio through from a weak signal that was only 100 kHz away from a 70+dB local station.
For European FM DXers seeking very high 100 KHz adjacent selectivity, a KT-6040, modified with 80 and 110 KHz MUrata ceramic filters, is probably the best option.
In 1991-92 the KT-6040 was officially released in Europe, Australia, and Canada. The KT-6040 isn't usually available second-hand in Australia. However, the KT-6040 appears fairly frequently on eBay Germany. Prices range from approximately 60-150 Euros.
In summary, a modified Kenwood KT-6040 is essential for extremely weak signal reception modes such as aircraft and meteor scatter. The performance is unmatched by any other tuner (including the XDR-F1HD, T-9090 II, and T-85).
Kenwood KT-6040 AM/FM tuner specifications (unmodified)
Rotary tuning dial.
25 kHz tuning steps
Eight IF filters
Tuning range: 87.50 - 108.00 MHz
50 dB Quieting Sensitivity
Mono - 15.3 dBf
Stereo - 37.2 dBf
Usable Sensitivity (DIN at 75 Ohm)
Stereo: 25 µV
(DIN +/-300 kHz 80 dB (NORMAL))
(DIN +/-200 kHz 80 dB (NARROW))
Image Rejection Ratio (at 98 MHz)
IF Rejection Ratio (at 98 MHz)
Spurious Response Ratio (at 98 MHz)
AM Suppression Ratio
Signal to Noise Ratio (DIN weighed at 1 kHz)
Mono - 83 dB (85.2 dBf input)
Stereo - 76 dB (85.2 dBf input)
Kenwood KT-6040 Photo.
Onkyo T-9090 II
The Onkyo T-9090 was replaced by the T-9090 11. The T-9090 11 is superior to the earlier T-9090 with regard to selectivity, tuning steps, antenna inputs, remote control, and number of memory pre-sets. Note that the Onkyo T-9990 is the European equivalent.
US TV and FM DXer Jeff Kadet compared his Onkyo T-9090 II to the near-legendary McINTOSH MR78, and found that the selectivity and sensitivity on both tuners were virtually identical. However, the Onkyo T-9090 II was preferred because it includes digital frequency readout, 20 memory pre-sets, and 25 KHz tuning steps.
The T-9090 II + indoor wire ribbon antenna combination was sensitive enough to receive 1,400 mile FM tropospheric ducting FM from New Zealand into Sydney, Australia.
The T-9090 II (T-9990) is a worthy addition to any DX shack. Once modified with Murata 110 KHz filters, the T-9090 II serves for general FM DX listening.
Onkyo T-9090 II specifications
Tuning range: 87.5 - 108 MHz
25 KHz tuning steps.
Usable sensitivity: Mono: 0.8uV (S/N 26 dB, 40 KHz Deviation.) DIN
Stereo: 20uV, (S/N 46 dB, 40 KHz Deviation.) DIN
50dB Quieting Sensitivity: Mono: 15.8dBf, 1.7uV
Stereo: 37.2dBf, 20uV
Capture Ratio: 1dB
Image Rejection Ratio: 100dB
IF Rejection Ratio: 100dB
Signal -to -Noise -Ratio: Mono: 95dB (IHF)
Stereo: 85dB (IHF)
Selectivity: 80dB DIN (+/-300 KHz, IF: super narrow)
95dB (+/-400 KHz)
Onkyo T-9090 II reviews by various users.
Onkyo T-4711 RDS FM tuner
The Onkyo T-4711 FM tuner is also highly recommended. This tuner has similar performance to the T-9090 II, but with the added bonus of a tuning dial. Minimum 25 KHz tuning steps is another desirable feature. The T-4711 is now only available second-hand.
Because the Onkyo T-4711 has only four filter positions in the super narrow bandwidth position, the selectivity is down compared to the Onkyo T-9090 II (five filters), or Kenwood KT-6040 (eight filters). The optimum filter combination is 4 x Murata 110 KHz units. Selectivity is high, but lacks flexibility.
Onkyo T-4711 review by various users.
Onkyo T-488F RDS FM tuner
The Onkyo T-488F (T-4970) was initially released about 1993. Performance is very similar to the T-9090 II. However, unlike the T-9090 II, RDS is also included. The DYNAS selectivity feature enables performance approaching the XDR-F1HD. One disadvantage is assymetric DYNAS filter performance (i.e. selectivity tends to be somewhat compromised when tuned to the high side of unwanted stations). Nevertheless, the T-488F and T-4970 are outstanding FM tuners still in demand by DXers.
With the introduction of the new Sony XDR-F1HD and XDR-S3HD DSP FM tuners, IF selectivity / audio fidelity performance has reached a pinnacle. For many DXers, portable radios, ceramic filter tuner modifications and most other available tuners will be largely uneccesary. However, ceramic IF filter modifications are still useful with high performance tuners such as the Onkyo T-9090 II and Kenwood KT-6040. The writer almost exclusively uses the XDR-F1HD on DXpeditions. Serious DX installations usually incorporate a range of receivers and tuners for specific requirements. The Sony XDR FM tuner series will be an important component of any serious DX installation.
Korner 15.11 FM Yagi
The Korner 15.11 FM Yagi is currently the best commercially produced antenna currently available for 88-108 MHz deep fringe FM reception. The 15.11 has delivered exceptional performance on numerous DXpeditions, including FM DX reception up to 2850 miles (4600 km). For futher details, visit the VHF Teknik.
Matchmaster FMG8 8-element FM Yagi
The Matchmaster FMG8 8-element FM Yagi is currently the highest performance Australian antenna for general DX.
Australian FM DXers use the following range of 88-108 MHz FM antennas:
Matchmaster FMG8, eight element 88-108 MHz yagi.
Hills 3-4-5, eight element 88-108 MHz FM/band 2 TV yagi.
Triax FM8 Yagi (now unavailable).
Korner 15.11 Yagi.
The best portable radio which has been tested by Australian FM DXers is the Tecsun PL-390. The PL-390 is currently available from several Chinese online (eBay) retail outlets based in China. Priced at around AU $70-80, the PL-390 is quite affordable. The PL-390 employs a DSP chip resulting in selectivity performance similar to the Pioneer Supertuner. Selectivity is approximately equal to an unmodified Kenwood KT-6040.
A good quality scanner is essential when attempting to log long-haul exotic FM and TV DX. The Icom R-8500, 7100, and 7000, and AOR AR5000 are all recommended, especially the R8500.
When using the R8500, it is suggested that the stock two 230 KHz filters should be replaced with 110 KHz SFE-MHY-A Murata IF filters.
Car radios for FM DX
Pioneer DEH-580MP Supertuner.
The Pioneer Supertuner car tuner series has been used with good results in Australia. The DEH-580MP is one model worth considering, although other Supertuner series models also perform well. Selectivity is sufficiently high enough to separate DX stations 200 KHz adjacent to strong signals. Meteor scatter signals are also received, which indicates high RF sensitivity.
Is the Icom R-7000 suitable for 88-108 MHz FM DX?
When I first tried my unmodified R7000 for FM DX, I was disappointed by the FM wide selectivity. This is because the R7000 only used (1) 230 KHz, and (1) 150 KHz Murata ceramic filters. With this arrangement, I found that the adjacent (+/-200 KHz) selectivity was relatively poor.
I replaced the stock filters with two 110 KHz Toko ceramic filters. The selectivity was considerably better, and I also found that tuning +/- 200 KHz of locals signals produced mainly white noise.
The only disadvantage was 1-2 dB reduced sensitivity. This is because the Toko filters had higher insertion loss. This did not concern me because I use a tunable 88-108 MHz Mosfet pre-amp, which compensates for any slight losses in the IF stage. The pre-amp also partially compensates for the R7000's untuned RF front-end. In city areas, you will find several images of local stations across the dial. A tuned pre-amp, or bandpass filter will improve the R7000's image and overload problems.
My next project is to replace the two Toko 110 filters with Murata SFE10.7MHy-A 110KHz filters. The Murata filters typically feature lower signal loss and improved shape factor.
I once compared my modified R7000 to the TEAC T-515 FM tuner (60dB +/- 300 KHz selectivity). The R7000 was better, though not as good as my Onkyo T-9090 11 (80 dB +/- 300 KHz). I would estimate that the R7000, with two 110 KHz filters has a selectivity specification of ~ 70dB +/- 300 KHz.
Television DX Receivers
Choosing a receiver for Television DX is quite difficult because most TV sets were initially only intended for local reception. I have found only one TV tuner, which was especially designed for reception of long distance Television reception.
HS Publications (7 Epping Close, Derby, DE22 4HR, England), sell the D100 TV tuner/converter. This tuner uses a MOSFET varicap tuner covering 45-860 MHz. It also features variable IF bandwidth to improve selectivity. The D100 also converts the TV audio to 95-100 MHz for use with a FM tuner. TV audio can also be received on 36 MHz using a scanner. A excellent combination is a D100, and Icom R7000 modified with MURATA SFE10.7 MHY-A, 110 KHz filters. The output frequency of the D100 is at UHF. Veteran TV DXer Bob Cooper has also used the D100. The D100 is used extensively in Europe, and has received rave reviews from DXers.
HS Publications TV FM DX 2003 equipment catalogue - home of the D100 DXTV tuner PDF version.
MULTI-STANDARD NTSC, SECAM, AND PAL TV SETS
It is next to impossible to find TV sets which are both multi-standard, and also suitable for DX TV. The following extract from
HS Publications D100 PDF.
will explain why:
"At first, a multi-system TV receiver may seem the ideal choice for TV DX-ing but it does not address the complex reception problems encountered, particularly in VHF Bands I and III where interleaved channel allocations exist.
Multi-system receivers are mainly intended for the traveler or for use in countries where more than one TV system is available. The main drawback with such a receiver for DX-ing is its inherently wide vision I.F. bandwidth, which is necessary for high-definition pictures.
Although good results may be obtained with local-quality signals, the shortcomings of such a receiver begin to show if attempting to resolve anything other than a strong solitary signal.
Other drawbacks associated with current TV receiver trends include video channel muting, when the signal level is considered inadequate for domestic viewing, plus complex set-up menus and tuning arrangements.
The enthusiast relying on an `up-converter' device(VHF to UHF frequency converter) for viewing VHF signals via a UHF TV receiver will also experience shortcomings due to the use of the wide vision I.F. bandwidth of the TV. Not to mention the problem of locating the channel in the absence of a signal!"
Multi-standard TV sets are likely more common in Europe, because of neighboring countries that use different standards. For example, if you lived in Switzerland, you would be able to receive pictures from France, Germany, Italy, and Austria on a daily basis.
The German companies Grundig and Blaupunkt make quality VHF/UHF multi-standard TV sets.
TV DX antennas
Channel Master 3617B, 28 element Crossfire deep fringe log periodic antenna.
Anthony Mann (Perth, Western Australia), used a CX28 Crossfire from 1971-1998, with remarkable results. His overseas TVDX included: England, Sweden, Finland, Germany, Russia, China, American Samoa, and other countries. The CX-28 has now been discontinued.
Hills DL4 45-230 MHz deep fringe Yagi antenna.
The Hills DL4 TV Yagi has design coverage over 45-230 MHz. The DL4 is currently the best available wideband antenna for general VHF TV DX reception. The DL4 also covers 88-108 MHz FM, albeit with modest gain.
USA TV DXers have used the following antennas for 55-83 MHz chA2-A6 low band DX:
Channel Master 1126, 10 element chA2-A6 yagi.
Wineguard (Prostar) YA-1026, 10 element chA2-A6 yagi.
Wineguard (Prostar) YA-6260, 6 element chA2-A6 yagi.
Antenna Craft (Tandy) Y10-2-6, 10 element chA2-A6 yagi.
ChA2-A13 wideband USA VHF DX antennas:
Channel Master 3600A.
Channel Master 3601A.
Antennacraft CS-1100, 33 element log periodic.
Antennacraft CS-1000, 30 element log-periodic.
Australian DXers have a limited choice regarding TV antennas suitable for DX work:
Hills 205/02, 5 element 45-70 MHz yagi.
Hills DL/4, ch0-12 45-230 MHz log periodic.
The CLP5130 log periodic 50-1300 MHz antenna is currently very popular for DX TV and FM reception in Japan.
Scanners and receivers for DX TV monitoring.
Copyright © 2012 Todd Emslie.