This page was last updated:  11/19/08
 

Pocket-NAV

Please explain the real working of the "total energy final glide" feature.
Why do I have to input the pilot data into my 1520 Pocket-Nav before every flight?
Why do the tracks display in the simulator mode, but not when I am flying?
Why is the SUA altitude unit of measure different from pressure altitude?
How can I make my own interconnect cable?
When I connect my Palm-PC to my PC it doesn't communicate?
What are the power requirements for the Pocket-NAV?
Will the Pocket-NAV work with any Palm Computer running Windows CE?
Will the Pocket-NAV work with the Palm Pilot?
Will the Pocket-NAV display data in color on Palm PCs utilizing color screens?
Will the Pocket-NAV work with the S-NAV as well as the L-NAV?
Will the Pocket-NAV totally replace the GPS-NAV Display?
How does the Pocket-NAV connect to the GPS-NAV?
Does the Pocket-NAV upload the Navpoint database from the GPS-NAV?
Will the Pocket-NAV work without the L-NAV?
Does the custom interconnect cable provide power to the Palm PC?
Will the use of the Pocket-NAV require an upgrade to my GPS-NAV and L-NAV?

Please explain the real working of the "total energy final glide" feature.

If you are flying at 100 knots on your final glide, your glider will gain more than 300 feet when you pull up and start your landing pattern. The kinetic energy (speed) of your glider can be converted into potential energy (altitude). The L-NAV adds this altitude to the gliders altitude in the computation of altitude required for the final glide. When flying with this feature, you will notice that the computed differential altitude required will be independent of the glider's airspeed. This was not the case with our earlier design that did not take the glider's kinetic energy into account.

When you increase the MacCready setting, the L-NAV tells you to fly faster. If you actually fly faster, you are moving to a part of the polar curve that makes the glide less efficient. You will get there faster, but you will be lower when you arrive. This is why the L-NAV shows an increased Altitude Required when you increase the MacCready setting.

In the latest version of the Pocket-NAV, you can make the L-NAV and Pocket-NAV talk to each other. This means you can change the MacCready setting on the L-NAV, and the change will appear on the Pocket-NAV.

Why do I have to input the pilot data into my 1520 Pocket-Nav before every flight? Is it necessary to do this before every flight or only when the Pilot or plane info changes? Does the GPS nav retain the info from the previous flight?

The GPS-NAV retains the pilot info. If you go to the pilot info in Pocket-NAV with the GPS-NAV connected, it reads and shows what is stored in the GPS-NAV. If your GPS-NAV is not retaining the information there is something wrong with it (eg. a dead internal battery.) In this case, flight logs will indicate that the seal has been broken.

Why do the tracks display in the simulator mode, but not when I am flying?

The Tracks On feature is only available in the Plus version of the Pocket-NAV program, as is the ability to transfer flights via the Pocket-PC or flash card.

Why is the SUA altitude unit of measure different from pressure altitude?

The SUA altitudes in meters is an error in the program in displaying the data. It should, and will in the next version, display what you choose in SUA Alts under units. This is separate from other altitudes (EG. final glide) because many European pilots fly in meters and talk to controllers in feet.

How can I make my own interconnect cable?

You can purchase a serial data cable from Compaq and connect it to your GPS-NAV data port using a DB-9 null modem adaptor. You can purchase the adaptor from Radio Shack or any shop that sells computer supplies. If your GPS-NAV is at V5.4 or later your GPS-NAV will provide NMEA 0183 data to the Pocket-NAV. It will not provide power to the Palm-PC. You will either have to run the Palm-PC off of the internal battery (good for about 2 hours) or provide external power via the external power connector on the Palm-PC. You can do the same with Casio. To provide power to the Compaq Aero from the GPS-NAV you must purchase an interconnect cable from us.

With Palm-PCs other than the Compaq Aero 1520/1530, 2110/2130 and the Casio E10/11/15, we cannot provide information regarding an interconnect method as we have not worked with them.

To connect the Palm-PC to a device that outputs NMEA 0183 data such as a Garmin 100 or Volkslogger, the following information may be of use. The pin-out on the DB-9 connector of the serial data cable is as follows:

Cambridge Aero Instruments cannot be held responsible for any damages incurred by individuals fabricating their own cabling. Nor can we provide technical assistance with a particular GPS device.

When I connect my Palm-PC to my PC it doesn't communicate?

Try connecting without the Pocket-NAV software running.

What are the power requirements for the Pocket-NAV  vs the normal GPS-NAV Display? 

This is a factor as on our world record attempts on which we have to plan on 13-14 hours of continuous logging. If we run out of power and the GPS fails to record all of the flight, NO record.  We usually carry camera and barograph backup but some of the early AM camera shots are dim and there is not much room in a 27 for the old reliable Winter Barograph...

"The Pocket-NAV adds ~50 mA to the 150 mA nominal current drain of the GPS-NAV. This should not significantly reduce battery life. If you are planning to depart at oh-dark-hundred, you should note that using the "front-light" on the Compaq Aero 2110 adds another ~ 100 mA to the current drain."

Regards,
Dave Ellis

Will the Pocket-NAV work with any Palm Computer running Windows CE?

We have been testing many of the presently available devices and have found that the offerings from Casio and Compaq seem to perform the best. Due to issues pertaining to the interconnect cable we are now only recommending the Compaq 1520 and 1530. We found that each manufacturer uses different operating voltages and interconnect cables. As there is no standardization for voltage or interconnect, it is difficult to have interchangeability between our GPS-NAV and the Palm PC. There also seems to be variances in the screen contrast as well as the sensitivity of the touch screen.

Will the Pocket-NAV work with the Palm Pilot?

The Palm Pilot was the first palm PC we evaluated, but found that it did not meet our needs. Only until the year 2000 did Palm offer a device with a Compact Flash card slot. The ability to transfer flight logs and SUA files via the CF card is an important part of our product line. 

Will the Pocket-NAV display data in color with Palm PCs utilizing color screens?

The initial releases of the Pocket-NAV will display in monochrome.

Will the Pocket-NAV work with the S-NAV as well as the L-NAV?

Yes.

Will the Pocket-NAV totally replace the GPS-NAV Display?

The Pocket-NAV can functionally replace the GPS-NAV display, though it does not display as much information as the GPS-NAV Display.

How does the Pocket-NAV connect to the GPS-NAV?

The Pocket-NAV connects to the GPS-NAV DB-9 Data Port connector. This is accomplished with either our custom Pocket-NAV bracket or one of the interconnect cables. If you are using the Pocket-NAV Starter version you can use one of the custom interconnect cables and the Power Conversion PC Board. Our custom interconnect cable serves two purposes, it supplies power to the palm-PC as well as the transfer of data between the palm PC and the Flight Recorder.

Does the Pocket-NAV upload the Navpoint database from the GPS-NAV?

The Pocket-NAV can upload a database from the GPS-NAV. Also, you can load a database into the Pocket-NAV from your PC, and then load it into the GPS-NAV.

Will the Pocket-NAV work without the L-NAV?

Yes. The Pocket-NAV / GPS-NAV combination will calculate final glide around multiple turnpoints. It will not calculate Headwind.

Does the custom interconnect cable provide power to the Palm PC?

Yes, in addition to the transfer of data between the Pocket-NAV and he GPS-NAV, our interconnect cable provides power to the Palm PC via the GPS-NAV's connection to ship's power.

Will the use of the Pocket-NAV require an upgrade to my GPS-NAV and L-NAV?

The GPS-NAV must contain Version 5.5 or later. Due to the need to re-seal the instrument, it must be sent  to the factory or a Cambridge Aero Service Dealer for the upgrade. The L-NAV must be at Version 5.7 or later and may be upgraded by the pilot.

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