NO5W Mobile
Here is a brief description of
the NO5W mobile setup. The diagram below shows the
configuration (configuration 2 from the What You Need document)
currently being used.
The Configuration
From an interfacing standpoint the heart of the
configuration is the
Navigator by US
Interface.
While this box is not inexpensive it is well-built and has a
lot of capability that is ideal for my application requiring only one
USB port to interface the radio, WinKey, and an RS-232 GPS to the Dell
D400 laptop running XP. The Navigator is powered from the USB port so
no separate power source and associated cabling is required. In
addition it supports digital modes with its own internal sound card.
Before obtaining the Navigator I used a Keyspan 1 USB x 4-RS232 port
expander along with a separate WinKey to achieve a somewhat similar
configuration. That approach is a less expensive option but of
course doesn't have the digital mode capability and requires a separate
WinKey box and associated cabling. I was also concerned about RFI
getting into the plastic
enclosure of the Keyspan device and/or the cabling to the WinKey,
although that never happened.
I thought that the Navigator, with its aluminum cabinet, would
be
much less susceptible to RFI. Actually RFI has not been a problem with
either of the devices. One thing to keep in mind regarding use of the
Navigator is
that a radio-specific wiring harness is required for each type of
radio. Diagrams for building your own wiring harness are on the
Navigator website or you can purchase them from the vendor.
Auxiliary Battery and Interface Compartment
The Navigator, an auxiliary 75 AHr Deka AGM battery, a West Mountain Radio
Super Power Gate, and a Rig Runner are housed in a compartment of
the platform that contains all of the gear in the rear of the vehicle.
The
battery/Power Gate is setup in the W1ZR configuration with the
auxiliary battery supplying power to the radio, the laptop (via a Lind
DC/DC
converter), the GPS which is a simple Garmin PC-18DLX receiver
mounted on the driver's side window of the rear compartment, and the
MFJ 1924 antenna controller. When we
are underway with the engine on the vehicle battery shares the
load and keeps the auxiliary battery charged via the power gate.
Connection of the vehicle supply to the power gate is from a small
compartment on the passenger side of the Pathfinder and an Anderson
power pole bulk head connector. When we're stopped the auxiliary
battery has enough charge to power everything for several hours even
running the radio at maximum power output. A nice advantage of
having the auxiliary battery is that everything can be left in a
powered up state at fueling stops and other breaks. Here
are a
couple of shots of the rear platform. The silver container in
the
photos is the Navigrator interface box. When we operate multi-two from
the mobile power for everything for both stations is supplied by the
auxiliary battery except for the second radio which is supplied by the
vehicle battery.
Radios
I've
used a number of different radios in the mobile
including IC-706 MKIIG,
IC-7000, and the Elecraft K3. Currently I'm using the K3 and taking
along an IC-7000 for backup. The backup IC-7000 is mounted on
a
small board and is attached to the top of the rear compartment just
above the Navigator with all connections, except the one to the
Navigator, present and ready to go. The main difficulty in changing to
the backup radio is the connection to the Navigator since there is
little room between the Navigator and the auxiliary battery in which to
work on the connector.
Of course the K3, although small
and relatively lightweight, was not designed
for mobile
operation in the
same way as the IC-7000 so there's no remote control head and no
mounting bracket. Control of the K3 is via the K3 Remote that I've
recently developed for CQ/X. The K3 is secured on
the rear platform using
materials from the local home improvement depot as shown
below. The tie downs consist of rope threaded
through pipe insulation
and,
to avoid slippage, the platform surface under the
radio is
lined with "waffle cloth" that is often used for lining kitchen
drawers. The tie downs are tied to two small cleats on the left hand
side of the radio to enable quick removal of the K3 from the vehicle.
The entire rear platform is "connectored" using appropriate connectors
(automotive trailer connectors, Anderson power poles, etc) for easy
removal from the vehicle since this is primarily a contesting setup,
not a
permanent day-to-day mobile installation. When there's a long stretch
between QSO parties all of the gear, with the exception of the cabling,
is removed and used in my fixed station.
Antenna System
I originally started out using the venerable hamsticks on
tri-mag mounts
for antennas and they worked quite well. However, several years ago I
decided to upgrade the antenna system and purchased a HI-Q
4/80
from Hi-Q
Antennas.
That turned out to be a good decision as the HI-Q antennas
are
very well-made and provide excellent performance. Tuning of the antenna
is via an MFJ-1924 controller mounted on the console near the
operating position. Two proximity switches mounted 90 physical degrees
apart on the antenna shaft provide control pulses to the
MFJ-1924.
Originally I used only a single proximity switch but have found that
the
antenna is much easier to control with the higher resolution provided
by
the additional switch. I also experimented with automatic antenna
controllers but found them to be too slow and somewhat unreliable. A
few
hours spent with an antenna analyzer to determine the presets for the
MFJ-1924 is all that's required and moving from band to band, although
not instantaneous, is fairly quick. Prior to each QSO party I spend an
hour or two verifying that the presets are still good and revising them
if necessary. A Unun from DX Engineering
provides impedance matching at the base of the HI-Q and grounding is
via a two-inch copper strip from the antenna mount on the trailer hitch
to the Pathfinder frame. Here are a some photos of
the
antenna system installation.
The Operating Position
The operating position consists of the above MFJ-1924 antenna
controller mounted on the console and a lapdesk containing a Dell D400
laptop, a Palm Paddle, and Heil Pro Set headphones.
Connections
for the Navigator USB cable, headphones to the radio, paddle to the
Navigator or to the radio, and power for the laptop are all made under
the operator's seat. GPS data lands on CQ/X via the Navigator
USB
connection and is passed to Streets and Trips via a pair of
virtual serial ports. The main use of Streets and Trips is to allow the
operator to help the driver in case we make a wrong turn or there is
confusion about the route. Waypoints are defined in CQ/X as decision
and/or turning points so that the distance to the next turn is always
available to enable the operator to keep the driver informed. The Where
Am I function in CQ/X can be used to quickly determine closest waypoint
to ensure that the proper waypoint is selected on the CQ/X GPS
panel. The convention we follow when defining waypoints is to name them
so that given a current closest waypoint the next waypoint is
easy
to determine. The label we attach to them is of the form
A-<Waypoint
1>, B-<Waypoint 2>, etc so that alphabetical
arrangement of
them in the combo box results in the proper order.
Glare is one of the main physical problems in using the laptop in
mobile contesting depending on direction of travel, time of day, etc.
We take along a small hood for the laptop in case the glare gets really
bad. However, the hood tends to pop off from time to time and
somewhat limits the visibility of the screen so we only use it when
absolutely necessary. Here are some shots of the operating position.
[Photos to follow]
Copyright: C.W. Sanders, NO5W
Last Updated: 04-March-2010
