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[Harald]

(04-15-2016 03:59 PM)PANAMATIK Wrote:  Hi Harald,

Thanks for the feedback. I still collect experiences for the GPS module. I made some measurements today with my GPS HP-25E (HP-25C hardware, see image below), No copper foil used.



Clear blue sky, sunny day, 15:15 to 15:20 UTC (17:15 Uhr MEZ) some clouds, half moon visible, calculator held in left hand, stopwatch in right hand.

From Roof top 100% sky visibility:

Cold Start:
after 50 sec indicating 3 satellites, after 1 Min 10 sec GPS valid with 4 satellites (later 7-8).
Warm start (switched calculator off and on again):
after 11 s GPS valid.

From Garden, approx. 30% sky visibility:
Cold Start:
after 1 min 50 sec 3 satellites, after 1 Min 52 sec GPS valid 4 satellites
Warm start:
after 11 s GPS valid.
Warm start when switched off 30 minutes
after 10 sec one satellite, 20 sec two satellites 28 sec 3 satellites, 42 sec GPS valid

I got feedback from another HP-25E GPS user, who reports also very fast Cold Start times. He additionally uses the copper foil (not grounded). I couldn't comapre directly and don't know for sure, whether the copper foil really increases the sensibility.

Thanks for all that information. I will try and take a couple of notes of my observations as well.

(04-15-2016 03:59 PM)PANAMATIK Wrote:  If you get 5 minutes Cold Start TTFF, when having clear visibility, then you should find the reason by repositioning your module somehow or find some electrical reason. You should make some experiments to get more sensibility.

Perhaps you can post a picture of your placement?

I'll take a picture on Monday. And also will try different positions of the GPS module.

(04-15-2016 03:59 PM)PANAMATIK Wrote:  Keyboard:

The GPS version is intended for HP-25 hardware, therefore I didn't test any other hardware. But normally it should work except for showing different digits in the display. If the keyboard mapping is wrong, then your HP-21 hardware was not detected correctly. The HP-25E reads the external ROM at startup and if HP-21 ROM code is found, the keyboard mapping is adjusted.

Yes, I know. And it used to work with the "old" V107. But with the "new" V107 it stopped working. I guess by fixing the startup bug you unintentionally dropped that functionality.