 Introduction to
TV/FM DXing
by George Sherman
"Can I really DX FM and TV? Isn’t that limited to
line of sight (nearby) stations? I’ve 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, you’ve 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 ID’s (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 I’ve 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
doesn’t 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.

Back
to the MDXC Home Page
Club History
Club Activities Club
Meetings Radio Information
ANARC
[ Home ] [ Up ] [ Minnesota DX Club ] [ Altered Photos ] [ Pavek Museum ] [ PVC Loops ] [ Links ] [ E-Mail ]
Loop Antennas Summer
SW List Winter SW List
This page was last updated on
12/20/03.
Any comments or suggestions can be made from my E-mail
Page
|