[BC] Transmitting and receiving antennas

[Thomas G. Osenkowsky]

 >    Well, similar plans worked to sell antennas for color TV and stereo FM.

Color TV and FM stereo transmission placed additional constraints
on both the transmission and reception ends of the signal. Their
requirements are more stringent. Now add SCA, RDS, SAP and
it becomes even more critical.

Transmitter:
We minimize synchronous and asynchronous AM noise. We strive
for a broadband antenna load. We pay attention to group delay,
linearity and phase response.

Receiver:
Location. Location. Location. Important to minimize multipath in
FM, ghosting in TV. We fool listeners with FM blend and high
end rolloff in automobile receivers. Color ghosts are more annoying
than black & white ghosts. No such thing as color fade, though.

The characteristics of the receive antenna are just as important as
they are in the transmitter antenna. VSWR across the bandwidth,
poor electrical contacts near the antenna aperture, influence of the
mounting structure, etc.

Color TV and FM stereo antenna designs borrowed technology
from transmitting antennas. The elements were constructed of a
larger diameter, resulting in improved bandwidth and VSWR
characteristics. The use of a balun enabled the mating of Monster@
Extremely Low Loss cable. Featuring 99.9999876% velocity factor,
.003141592653589793 dB per 100 meters loss at 700 MHz the system
allowed near perfect reception.

Since IBOC employs sidebands about the main carrier it is important
to maintain symmetry and group delay across the much wider bandpass.
A well designed transmission AND receiving system will ensure CD quality
audio at the receiver.

We cannot ignore details in receiving antennas. TV manufacturers took
away the vertical and horizontal hold controls from us. We cannot and
must not let TV and FM reception antenna manufacturers compromise
on quality or specifications. We MUST take a stand now! I urge the
industry to petition Congress to enact legislation specifying the minimum
specifications for IBOC receiver antennas.

Tom Osenkowsky, CPBE