The folded unipole
The fundamentals of the folded unipole have not changed much since 1952, but experience has provided several improvements as well as some weaknesses.
IBOC and combiners
Some transmitter manufacturers have already announced the availability of FM IBOC transmitting equipment, and offered actual equipment at the NAB show. FM IBOC requires considerably more equipment than the AM version, and it is more expensive.
Variation on the Shielded-Loop AM Antenna
A variation on the antenna's construction.
Top loading, part 1 of 2
Engineers charged with the job of designing a new AM transmitter facility nearly always try to plan for the tallest tower possible. This is not just an ego trip; it's because the taller the AM radiator, the higher the field strength developed in the listening area with a given power.
Shielded-Loop AM Antenna
Build a shielded-loop AM antenna.
The useful folded unipole
One of the advantages claimed for the folded unipole is its broad bandwidth. However, years of experience have shown that this can vary greatly depending on several factors, mainly overall tower height.
More on IBOC Antennas
The article titled "Transmission: Implementing IBOC" in the October 2001 issue of BE Radio is very informative, but one concept in it may need further clarification.
Impedance matching
We have all been taught that the load impedance must match the generator impedance in the case of non-DC voltages in order to obtain the most efficient transfer of power. In DC work it seems that loads with an improper resistance fail to work because the supply voltage is too low, or else burn out because their resistance is too low for the applied voltage, and simple Ohm's law applies.
CFA Tests in UK Postponed
UK tests will wait a little longer.
Tall AM towers
Usually, bigger is better. But in the case of AM towers, taller is not always better. A very tall AM radiator is not always the best radiator. In fact,
Transmitters, towers and antennas at NAB2001
Discussions with FM engineers unearthed concerns about radio's future when considered with reference to streaming, DAB/IBOC, RBDS, satellite radio, and
Detuning unwanted reradiators
Like mushrooms after a heavy rain, unwanted reradiators sometimes appear almost overnight in the near field of AM antennas.
Antenna basics
The author Gertrude Stein once said a rose is a rose, is a rose is a rose. Maybe an antenna is an antenna, is an antenna also applies, but an AM antenna
Parasitic radiators
A look at the theory of controlled parasitic reradiators and possible directional arrays using parasitic elements.
The self-resonant folded unipole antenna: Measured Results
An article in the October 1999 issue of BE Radio described the design of the self-resonant antenna for use with medium-wave or long-wave broadcasting.
Parasitic radiators
A radio engineer's definition of a parasite might be something that obtains its power from another's energy. In other areas of broadcast engineering it
