[ARC5] ZB discussion!

[Lenox Carruth]

ZB is a totally different system.  The problem with using ZB as a navigation
system is its inherent positional inaccuracy due the lack of distance data.
Even then, the plane is going to fly until the pilot finds where two sectors
meet.  When you begin to leave one sector and enter another you begin to
hear the new sector's letter ID and can correct your flight path to remain
on the line where the sectors meet.  Kind of like the old AN ranges.
Theoretically, you could find the transmitter if you did not have the sector
ID's for the day but it would be much harder as there is no "sense" function
that tells you the direction to or from the transmitter like there is in
modern RDF systems.  The daily sector codes told the pilot roughly which
direction to fly to go toward the transmitter until he found a sector
boundary.  The great advantages of ZB during the war were the frequency,
which was high for the technology that the Japanese had during the war, and
the inability of an uninformed listener, if he even found the frequency, to
detect the sector information or derive the daily sector codes.
 
RDF is a navigation system based on homing to a known station or the
reverse.  Location can be found by plotting the intersection of bearings to
two stations whose positions are known.  Beacon and commercial broadcast
stations are noted on sectional and other navigation charts.  (RDF was
applied to the early manual systems but more modern automatic systems are
known as ADF for Automatic Direction Finding.)  No longer much used.

ILS is not a navigation system, it is a landing aid.  Very short range.
Useless for navigation.  Not really a "homing" system as it provides an
electronic glide slope and runway centerline (localizer) for approaches in
low visibility conditions although it is often used in VFR conditions.
Position information is provided by marker beacons at standardized
locations.  The pilot doesn't care where the transmitters are as he is only
interested in the two "paths."

VOR is a navigation system.  One might say that it is frequently used as a
"homing" system but sophisticated navigation systems can automatically
follow any flight path and even the most rudimentary system will allow
position determination by using two stations whose positions are known.
There are also DME systems that allow position determination from a single
VOR station if the aircraft and VOR are so equipped.

TACAN is a military navigation system frequently co-located with VOR
stations. (then known as VORTAC stations)

Of course there are many hyperbolic navigation systems also as well as the
wartime GEE and OBOE systems.

This entire discussion presumes that navigation is defined as the ability to
know one's position and, therefore, one's flight path and does not include
systems that don't provide for position determination.

I can't let this pass by not mentioning the most common navigation system -
- following the train tracks (technically known as IFR - I Follow Railroads)
Much better than highways - too many towers!!!

Lenox
WA5OVG




-----Original Message-----
From: arc5-bounces at mailman.qth.net [mailto:arc5-bounces at mailman.qth.net] On
Behalf Of Mike Morrow


>ZB is only a homing system and is not useful for navigation.

So much for other homing systems like RDF, ILS, VOR, TACAN, etc.
being "useful for navigation" then, I guess.  :-)

Mike / KK5F
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