THE ART OF TV AND FM DX

By Robert Copeman





Since the first days of radio broadcasting, there has been an interest in trying to receive signals outside of the accepted limit of local reception. Like the famous explorers, mountain climbers, etc, DXers dream of new discoveries and receiving signals normally regarded impossible to receive by the average listener, (or viewer in the case of TV).

With AM and SW Radio broadcasts, the best time of year to receive those rare catches are during the winter months, preferably when sunspots are at their lowest activity and mostly at night. With TV and FM, this is completely different. This is because the frequencies are in the VHF and UHF spectrum, where AM, LW and SW are in the HF spectrum.

Both TV and FM reception increase during the summer months and are better during the day rather than late at night. Keep in mind, it is possible to receive TV and FM dx reception at night. Also, during the equinox months, (March, April, September, October), when there is high sunspot activity, vast distances on TV can be received.

TV and FM stations are located on various frequency bands which are:

Band 1TV Channels 0 - 2 (Australia)(VHF)
TV Channels 1 - 3 (New Zealand)(VHF)
TV Channels 2 - 5 (USA)(VHF)
Band 2TV Channels 3 - 5 (Australia)(VHF)
International FM Band (88 - 108MHz)(VHF)
Japanese FM Band (76 - 92MHz)(VHF)
Band 2/3TV Channel 5A (Australia)(VHF)
Band3TV Channels 6 - 11 (Australia)(VHF)
TV Channels 4 - 11 (New Zealand)(VHF)
TV Channels 6 - 13 (USA)(VHF)
Band 4/5TV Channels 28 - 69 (Australia)(UHF)
TV Channels 27 - 63 (New Zealand)(UHF).

With TV and FM DX, there are several modes of reception: Line of Sight:Local or permanent TV that may be received from a distant area. This is also possible on FM.

Tropospheric: Also known as "Tropo". This causes TV reception from distant areas to be received or, in the case of permanent signals, signal strength can increase, during the reception. This type of reception produces slow fading and can hold in for reasonably long periods. The furthest distance is usually restricted to 400 miles from the transmitter, though this can go over 1,000 miles from the transmitter under exceptional conditions. This affects all TV and FM bands. The signals are caused by reflection from the tropospheric layer of the Earth’s atmosphere.

Speradic-E: Also known as "SpE" or "Es". TV and FM reception from distant areas and usually is best in 1,000 mile hops from the transmitter. A hop being the area from the transmitter to the location receiving the reflected signal from the E layer of the Earth’s atmosphere. SpE signals when fading up in strength can almost equal local signals in clarity, however as fading is quite radid with SpE this doesn’t last. Under exceptional conditions, signals can be received well over the 1,000 mile range. This is when the signal is reflected over several areas. This is known as "Double Hop SpE", "Triple Hop SpE", or "Multiple Hop SpE". When a Spe signal is received from less than 1,400 miles it is known as "Single-Hop SpE". This tends to cause a very ghosty signal when received. All SpE signal fading is usually far more rapid than tropospheric reception. Mostly restricted to Bands 1 and 2 though has been known to reach Band 3 on occasions.

F2: Mostly affects TV only as it is usually limited to Band 1. Reception is best during the equinox months, (mentioned earlier), when sunspot activity is at its high peak. This occurs in eleven year cycles, the last being 1989 - 1991. During the period, TV signals from several thousands of miles can be received. Fading is usually quite slow and signals tend to be smeary, even though they can rise to quite strong levels.

MS: Otherwise known as "Meteor Scatter" or "Meteor Shower" reception. Distances around 1,000 miles and more can be received via this mode. Signals only last a few seconds, known as "Pings", but can keep reappearing when staying on the frequency. This mostly affects Band 1 and 2.

Aircraft: Aircraft reflection occurs when a plane flies through a reflected TV or FM signal. The dx signal will suddenly appear with a fluttering affect, strength will increase rapidly, then will decrease soon after the aircraft leaves the affected area. This mostly affects signals in the tropospheric layer of the Earth’s atmosphere. With extremely low power signals from short distances, motor vehicles have been known to cause a similar effect.

Auroral: Auroral activity such as the "Southern Lights", (Aurora Australis), normally occurs during solar flares and is most active during high sunspot activity. In the northern part of the world, the "Northern Lights", (Aurora Borealis), occurs at a similar time. When aiming ones aerial at the Aurora, directly south for Australia and New Zealand dx'ers, signals can be received on TV and FM from about 400 miles or more in the opposite direction. The signals pass the dx'ers location, reflect off the Aurora and bounce back. This can cause reception from stations, not normally received via any other mode, to be received.

KED: Otherwise known as "Knife Edge" reception. This happens when the dx'er is located directly at the bottom of a mountain and is receiving a dx signal transmitted from a point past the mountain above them. The mountain can occasionally reflect the signal at right angles to the dx'er.

Points to remember for TV and FM DXing:

*Always use TV's and radios with manual tuning, automatic search tuning usually misses the good signals.

*Never use equipment containing a mute. This will block most dx signals. Mutes are used on most expensive TV's, videos and Hi-Fi equipment, so the cheaper the better, unless one can obtain a good piece of equipment and have the mute switched off. A mute appears on TV as a silent screen, (either black or blue), when on a blank channel.

*Turret or varicap tuners are best on TV. The turret tuner is the old channel selector used on B/W and early colour TV's. Varicap tuners can either be in the form of a radio type tuning knob or small wheels used in push button TV's. Push button TV's will work, though may cause problems when wanting to check for several channels at once. One can only put a limited number of channels into the memories.

Obtaining a scanner, which includes 30 - 108 MHz, can increase the possibilities of catching that dx reception. Just enter in all possible TV dx vision and audio frequencies and FM frequencies. This will make it far easier to identify that rare catch. Scanners that do not include 30 - 50MHz, will not be able to tune in the main TV DX frequencies, so make sure it has what you want before purchasing. Some TV frequencies to enter into the scanner's memory are as follows:

*45.240MHz, 45.250MHz, 45.260MHz (New Zealand TV Ch1) (Vision).
*46.170MHz, 46.240MHz, 46.250MHz, 46.260MHz (Australian TV Ch0) (Vision).
*48.240MHz, 48.250MHz, 48.260MHz (Europe/Middle East/Malaysia TV ChE2) (Vision).
*49.740MHz, 49.750MHz, 49.760MHz (China/Russia TV ChC1/ChR1) (Vision).
*50.740MHz, 50.750MHz, 50.760MHz (New Zealand TV Ch1) (Audio).
*51.670MHz, 51.740MHz, 51.750MHz, 51.760MHz (Australian TV Ch0) (Audio).
*53.740MHz, 53.750MHz, 53.760MHz (Europe/Middle East/Malaysia TV ChE2) (Audio).
*55.240MHz, 55.250MHz, 55.260MHz (New Zealand TV Ch2/USA TV ChA2/Europe/Middle East/Malaysia TV ChE3) (Vision).
*55.247MHz (American Samoa TV ChA2) (Vision).
*56.240MHz, 56.250MHz, 56.260MHz (China/Russia TV ChC1/ChR1) (Audio).
*57.240MHz, 57.250MHz, 57.260MHz (Australian TV Ch1) (Vision).
*57.740MHz, 57.750MHz, 57.760MHz (China TV ChC2) (Vision).
*59.240MHz, 59.250MHz, 59.260MHz (Russia TV ChR2) (Vision).
*59.740MHz, 59.750MHz, 59.760MHz (USA TV ChA2) (Audio).
*59.747MHz (American Samoa TV ChA2) (Audio).
*60.740MHz, 60.750MHz, 60.760MHz (New Zealand TV Ch2/Europe/Middle East/Malaysia TV ChE3) (Audio).
*62.740MHz, 62.750MHz, 62.760MHz (Australian TV Ch1) (Audio).

Anyway, that's just a summary on how TV and FM DX is possible. So, give it a go and good luck with the hobby. Without doubt it is satisfaction guaranteed.



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