Introduction toTV/FM DXing
by George Sherman
"Can I really DX FM and TV? Isnít that limited to line of sight (nearby) stations? Iíve never heard/seen any distant FM/TV stations"
This is the way some DXers would probably react to a suggestion that they might try (and enjoy) FM/TV DXing.
Once convinced that FM & TV DX is really possible, many still believe that it is necessary to have very expensive FM & TV receivers, with big antenna and amplifier mounted on a tall mast. While these things are helpful, FM & TV DX can be received with simple and inexpensive equipment. Therefore, anyone can be an FM/TV DXer.
"But why should I want to be an FM/TV DXer?" you might ask.
Well, if you want to stay active in radio DXing all year around, youíve probably noticed that most weak signals below 10 MHz are almost continuously covered up by thunderstorm static. So what else is there?
"What can I expect to see/hear on TV/FM?"
Glad you asked that Question! TV/FM stations can travel up to 1,500 miles or more. Therefore is possible to receive at least 48 states, several Canadian provinces, plus Mexico on FM. These areas have several of FM stations on 100 frequencies, Hundreds of TV stations from there are possible, too.
Distant FM and TV stations arrive at our locations by several types of propagation. Tropospheric bending results in signal enhancement of stations within a radius of a few hundred miles. Farthest stations will often be the weakest. All directions MAY be received equally, thought this is not always the case. This reception is usually weather related, with good times to check being sunrise and sunset, when cooling and heating occurs. a variation of this is tropospheric ducting, with more distant stations possible, but usually only from one direction Oddly enough, a station 800 miles distant might be received through one 300 miles distant in the same direction! (Strength stays pretty constant as distance increases.) Perhaps more exciting, but also more frustrating is meteor scatter which can bring in stations up to 1,000 miles or more away. Usually a single meteor falling and burning in the atmosphere will produce a distant signal for only a second or two. Best chances for FM/TV IDís (by meteor scatter) is during meteor showers. Several meteors falling one after another can provide almost continuous reception for up to two or three minutes. However, most multiple bursts last for only several seconds. This still leaves a fair chance for an ID if bursts occur at the top of the hour. Check on TV channels for Ch.2 through Ch.6 that do not have a local on them, plus FM. FM offers many dozens of channels and FM tuners are usually more sensitive than TV tuners.
An outdoor antenna may be needed for meteor scatter on channels 2 - 6. Meteor scatter rarely if ever is seen/heard on channel 7 and up. The best meteor shower is August 11th - 13th during the midnight to 6:00 AM period, though there are several meteor showers at different times of the year.
Another type of propagation available for FM DX year around is Auroral propagation. Signals are very weak and distorted, requiring DXers ears. Aurora signals are bounced off the Aurora Borealis, so you may get best reception by pointing your antenna north. Listen for a high A-index on WWV. The farthest south Iíve heard Aurora is Tennessee and the farthest east was New York City, and the farthest west was Colorado.
Perhaps what really "hooks" most potential FM/TV DXers is experiencing Sporadic E-skip. Usually MINIMUM distance is 700 miles! (Closer signals "skip over"). Maximum distance on a single hop is about 1,500 miles. A double hop is theoretically possible, but unlikely because of interference at the signal hop distance, and most areas 1,500 to 3,000 miles from Minnesota are in water (no stations there!)
What excites TV/FM Dxers most about E-skip (besides the distances) is that TV/FM DX E-skip signal strengths can be nearly equal to those of local stations! E-skip fades more than "trops", and usually doesnít last that long. Stations may come in from one area, then fade and be replaced by stations from another area. On June 11 1986 I received 28 never-before-heard (by me) stations, bringing my total to over 1,000 FM stations since about 1970. States heard that day were SC/GA/FL/AL/MS/LA/AR/MO/TX/KS/OK/NM/AZ and CO. (14) Equipment used was an old Scoot 300C with wide selectivity and only a line cord antenna, plus a GE SuperRadio with a telescopic whip antenna.
TV/FM E-skip is heard/seen in Minnesota mostly from May through mid August (so hurry!). Only once out of several times does E-skip at channel 2 climb up to the low end of the FM band (88 MHz). E-skip is extremely rare on channel 7 an up ( and probably unknown on UHF), so FM Dxers should check channels 2 - 6 where skip will show up first. Check channels with no locals (channels 3 and 6 in the Twin Cites) for fading signals that are not normally there. Also look for thick dark lines/bars of co-channel interference (CCI) on local stations. These are warnings that FM may "come alive"!
You might get more helpful TV/FM DX info by joining the Worldwide TV/FM DX Association (WTFDA). The address is available through ANARC or the club section of Monitoring Times.
This page was last updated on 12/20/03.
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