All the model 20 Cambridge camera box loggers have this garmin gps 25 engine as well as early aluminium case 302 vario (not the newer black case ones). Many now are displaying this March 1995 date yet are still acquiring satellites & navigating which I find strange.
At this stage I am replacing 302s with a garmin GPS15 engine which is smaller but with adapter fits. I can replace the GPS25 battery and then reset the clock (adding UTC time and lat and long approx & maybe they will kick start again) but is a real pain. Anyhow if you have a Cambridge mod 20 or non black case 302 then check date and if 1995 you WILL have issues. I ask the question how many electronic items do you have 20 years old? Not many I suspect. The model 10 brick box is over 20 yrs old and most model 20 loggers are over 15 years old. So maybe upgrade time is coming and remember all vario makers have made significant improvements in varios over the years. Ian Mcphee On 10/11/2014 11:55 AM, "Mike Borgelt" <[email protected]> wrote: > > If you have a Volkslogger, it is working fine and it does the job for you, > keep using it. It uses a Garmin 25 module for the GPS receiver running at 5 > volts. The backup battery in the Garmin 25 module is INSIDE the metal rf > shielding and I'm not sure if you replace the battery that you don't need a > special factory firmware file to get the thing going again. Even if you > buy a discontinued Garmin 25 module from a stockist it will have been in > storage for a long time and the battery will likely be near the end of life. > > There are only 3 wires connecting it to the guts of the VL and it would > be very simple to put a uBlox module in it running at 3.0 volts by using a > small linear regulator EXCEPT that this would invalidate the IGC approval > and the VL would require re-sealing for security. This would also cost > about half what a new FR would. Do yourselves a favour. If your VL goes > wrong, buy a new flight recorder. > > We currently sell EW MicroRecorders. The only known issue with the current > production standard is that the Ni-MH battery is good for 3 to 4 years but > replacement DOES NOT require re-sealing of the recorder and we generally > keep a spare battery or two in stock. > > There are many other similar ones on the market and like the EW, all have > GPS modules newer than the Garmin 25 in the VL (incidently is also the one > in the CAI 302 vario according to some igc files I just looked at.) and > have features like data storage on a SD card. The SirfStar II module in the > EW is a particularly good one for GPS altitude. I've seen others that > aren't as good for GPS altitude. Some GPS modules seem to be designed for > surface vehicle use. Better ones like the uBlox and SirfStar can be user > configured for the expected use. We set uBlox modules for aviation > dynamics, no dead reckoning. > > You can see what GPS module and pressure sensor your FR uses by opening > the *.IGC file in Notepad. The relevant stuff is in the top few lines. > > Consider any glider avionics as about a 10 year thing, currently. Gliders > haven't improved much in 35 years(1979 original Ventus A with full carbon > wing and custom designed airfoil, neither have motorgliders - the PIK guys > got the two stroke retractable engine about right in 1975) but avionics > have improved greatly. > > From flow sensor type varios relying on thermistors or hot wires to > silicon pressure transducers, sunlight visible colour LCDs for moving maps, > GPS, Flight recorders, inertial MEMS sensors and now our soon to be > released Dynamis system there has been huge development in glider > instruments. By the time a modern instrument breaks it is likely obsolete. > > A little GPS history: > > Early GPS receivers were of the sequential type, looking at each satellite > in turn. > Later receivers used the parallel method but most of the early receivers > had a problem with getting an initial fix if they didn't know the time or, > roughly, the position. > > Hence the solution of using a real time clock on board which was > maintained by battery backup. That way the receiver knows the time and can > acquire satellites quickly. The time gets updated and corrected as soon as > the first satellite is acquired. > > Modern GPS receivers do not need this. The ones we use from uBlox will, > from a cold start (no backup battery, no time etc) get a time in about 25 > seconds or slightly less and a full 3D position fix in 45 seconds. Adequate > for gliding. Faster if they have a time to begin with but as we aren't > firing them from guns in artillery shells or dropping them from the bomb > bays of B-52s or B-1s(JDAM, GPS guided bombs) it doesn't seem necessary to > use a backup battery to keep the time alive for ultra fast starts. > > Mike > > > > > > > > > *Borgelt Instruments* - > *design & manufacture of quality soaring instrumentation since 1978 * > www.borgeltinstruments.com > tel: 07 4635 5784 overseas: int+61-7-4635 5784 > mob: 042835 5784 : int+61-42835 5784 > P O Box 4607, Toowoomba East, QLD 4350, Australia > > _______________________________________________ > Aus-soaring mailing list > [email protected] > To check or change subscription details, visit: > http://lists.internode.on.net/mailman/listinfo/aus-soaring >
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