VHF/UHF DX Antenna and Receiver Summary - Todd Emslie

[IMAGE]

Drake R8B, Icom R-8500, Onkyo T-9090 II, and D100 DX Receivers.

[IMAGE]

Icom R8500, Onkyo T-9090 II, D100, and Bolin FM phaser.

[IMAGE]

Drake R8B, Icom R8500, Onkyo T-9090 II, D100 TV tuner/converter.

[IMAGE]

DX shack.

DX Equipment, (left to right):
Icom R71 HF receiver, National TR-505 DU B/W 5" TV, various tunable MosFET RF pre-amplifiers, Icom R-7000 VHF/UHF receiver, Icom R-8500 receiver (not shown), Onkyo T-9090 II FM tuner, Bolin FM phase box, Toshiba C-531 5" TV, home-made TV/FM phaser box (30-230 MHz), D100 TV tuner/Converter, Emotator, and Kenpro rotator control boxes.

[IMAGE]

DX shack.

Most 30-88 MHz VHF DX monitoring is done with a Icom R-8500 HF/VHF/UHF receiver. The D100 and TV set are not switched on without initially checking the memory pre-sets on the R-8500. Approximately 50 pre-sets are programmed with 30-88 MHz utility stations, broadcast harmonics, ham beacons, video carriers, and TV audio frequencies.

Since most quality VHF wideband receivers have front-end noise figures of typically 5-7dB, I decided to use a RDX Labs UA-701 GaAsfet 40-220 MHz pre-amp, for indoor use with the R-8500 receiver. This lowers the R-8500's front-end noise figure to 2dB, which is more than adequate for 40-88 MHz.

The output of the UA-700 pre-amp is connected to a Tratec ES-02 splitter for feeding the D100 TV tuner and Icom R-8500. With this arrangement, video signals can be seen on the TV, while the video or audio carrier is monitored on the R-8500.

The HS D100 VHF/UHF tuner/convertor replaces my old (1987) home-built EG522F varicap TV tuner. The D100 features variable vision selectivity, which is useful for weak video.

The Onkyo T-9090 II FM tuner has two 75 ohm antenna inputs. The horizontal and vertical Triax FM-8 antennas can be individually selected by the Onkyo's A/B antenna switch. The T-9090 II has two selectivity modes: narrow (five 150 KHz Murata filters), or super-narrow (four 110 KHz Murata filters).

The T-9090 II tuner is especially efficient for minimizing overload and cross-modulation (IMD) from strong local FM signals. The T-9090 II features a 100 dB image rejection specification. This is largely due to the five varicap diode tuned RF mosFET front-end.

A home-built BF981 MosFET (1.5dB noise figure) tunable pre-amplifier is used indoors for use with The Onkyo T-9090 II tuner. The pre-amp has a 2 MHz bandwidth when peaked, hence overload is minimal.

Initially, a Andy Bolin FM phase box was purchased. The phasing nulls were impressive. This motivated me to design my own wideband passive 30-250 MHz phase cancellation unit. This is mainly used for cancellation of the local ch2 television carrier.

Frequency measuring equipment is essential for determining the locations of DX TV video carriers. This equipment: TV-derived reference unit, digital frequency meter, and audio bandpass filter, is not shown in the above photo.

[IMAGE]

VHF DX antennas (back).

Top: 14 element 175-220 MHz TV yagi; Bottom: 8 element Triax 86-108 MHz FM yagi, 5 element band 1, 53-70 MHz vertical yagi

The 53-70 MHz yagi is mounted vertically for ~ 15-20 dB attenuation of the local 64.25/69.75 MHz Sydney ch2 TV signal. The coverage only extends down to 53 MHz, because a 45 MHz length reflector element would scrape the roof tiles! Eventually the antenna height will be increased, hence a longer 45 MHz reflector element can be added.

A vertical 53-70 MHz yagi is mainly used for reception of KVZK TV-2, American Samoa, Australian channel 1 and 2 TV, chE2/E3/E4, NZch2/NZch3, and chC1/R1 TV audio. Vertical polarization is essential for viewing NZch3 video (62.25 MHz) and chE4 (62.25 MHz), which are only 2 MHz lower than the strong local ch2 (64.25 MHz) video.

The horizontal 14 element Matchmaster band 3 TV yagi was previously used for channels 6, 8, and 11. On a daily basis, visual reception was possible out to typically 250 miles. Daily SSB 2.4 KHz bandwidth reception of band 3 video carriers was possible out to 450 miles. DX reception on these channels is no longer possible due to strong local DTV. This antenna is now only used for quality reception of ATN 7, Sydney, for use with the 15625 Hz TV-derived reference unit.

The vertical Triax 8 element FM yagi is used for reception of vertical and mixed polarization FM signals. Reception is possible out to typically 200 miles on a daily basis.

The Kenpro KR-400 has given good service since 1982. The plastic bucket helps to prolong the life of the KR-400, by minimizing exposure to rain and sun.

The bottom crossbeam is non-metallic, hence distortion of antenna polar patterns is minimised.

All antennas are used with 300/75 ohm balun impedence transformers, and Hills DCS2.1 75 ohm coaxial cable (similar to RG-11 cable).

[IMAGE]

VHF DX antennas (front).

Top: 5 element 45-60 MHz band 1 TV yagi; Bottom: 8 element Triax 86-108 MHz FM yagi, 14 element 175-225 MHz band 3 yagi. A bucket is used to protect the rotator.

[IMAGE]

VHF DX antennas (back).

TV-FM DX aerials (Top: 14 element ch6-11 TV yagi; Bottom: 8 element Triax 86-108 MHz FM yagi, 5 element band 1, 53-70 MHz yagi).

[IMAGE]

VHF DX antennas (front).

TV-FM DX aerials. Top: 5 element 45-60 MHz band 1 TV yagi; Bottom: 8 element Triax 86-108 MHz FM yagi.

The 45-60 MHz yagi is mainly used for 30-55 MHz F2 / TEP utility and TV DX. The reflector is cut to resonate at 45 MHz, folded dipole 50 MHz, and 3 directors 60 MHz.

On a daily basis, visual band 1 TV reception is possible out to typically 250 miles (ABMN0 Wagga). Daily tropospheric scatter reception of band 1 video carriers at a maximum distance of 450 miles, is heard using SSB 2.4 KHz bandwidth on the Icom R-8500.

Scatter reception can be further enhanced by the use of very narrow bandwidths. A 30 Hz filter makes a significant improvement. Extremely weak signals (EME) or long-haul tropospheric scatter signals are detected using DSP PC programs such as Spectrum Lab, and SpectraLab. The typical bandwidths used on these programs are less than 2 Hz.

A horizontal Triax FM yagi is mainly used for sporadic E DX. Since most Australian FM transmitters use vertical polarization, horizontal is beneficial for reducing the strength of local FM tx's.

The rotator is a Emotator model. All cable runs are Hills DSC2.1, connected to Electrocraft 300/75 ohm baluns.

[IMAGE]

Perth TV DXer Tony Mann with Todd Emslie (Sydney 1995).

[IMAGE]

45.24 MHz TV-1 ch1 Te Aroha, New Zealand received via 1,400-mile Sporadic E in Dec 1984.

[IMAGE]

57.24 MHz SEQ1 Gympie, Queensland, Australia, received via 650-mile Sporadic E in 1983.

[IMAGE]

46.26 MHz SBS0 Melbourne, VIC, PM5544 card received via 450-mile Sporadic E in 1984.

[IMAGE]

95.25 MHz ABMV4 Mildura, VIC, PM5544 card received via 520-mile Sporadic E in 1985.

[IMAGE]

87.27 MHz ABTQ3 Townsville, QLD PM5544 card received via 1,000-mile Sporadic E in 1985.

[IMAGE]

48.24985 MHz Dubai UAE chE2 PM5544 with no centerpiece. 6,000-mile F2 on 23/11/91.

[IMAGE]

57.25 MHz ABTN1 Taree, NSW via 170-mile tropo.

[IMAGE]

CBN6 Dubbo test card received via 200-mile tropo in 1993.

[IMAGE]

TEN 10 Sydney local test card F photographed in early 1980.

[IMAGE]

189.258 MHz CBN-8 Orange, NSW via 130-mile tropo in August 1982.

[IMAGE]

182.26 MHz CTC-7 Canberra, ACT. 160-mile tropospheric DX logged in 1982.

[IMAGE]

45.25 MHz ch1 Hedgehope, New Zealand via 1,350-mile Es received on 21st February, 1980.

[IMAGE]

6,000-mile F2 reception of 49.75 MHz chR1 Vladivostok, Russia (1991).

[IMAGE]

6,000-mile F2 reception of 49.75 MHz chC1 Chinese PM5544 test card (1997).

[IMAGE]

6,000-mile F2 reception of 49.75 MHz chR1 Vladivostok, Russia letterbox test card (15th Feb 1981).

[IMAGE]

450-mile Es reception of 46.25 MHz SBS channel 0 Melbourne PM5544 test card (1981).

[IMAGE]

1979-1982: My first outdoor Hills 104/0 five element channel 0 TV yagi.

[IMAGE]

TV FM DX antennas used in 1986-1989. Two Triax FM-8s, 45-70 MHz 5-el band 1 TV yagi, and 14-el band 3 TV yagi.

[IMAGE]

TV FM DX antennas 1990-1993.

TV FM DX antennas used in 1990-1993. One Triax FM-8 (horizontal), One Triax FM-8 (vertical), 45-70 MHz 5-el band 1 yagi, 45-52 MHz 5-el channel 0 yagi, two 14-el band 3 TV yagis, and Jaycar 91-el UHF TV yagi.




Copyright © 2009 Todd Emslie.