charlie@oakhill.UUCP (Charlie Thompson) (10/15/88)
I am looking for schematics for the TI model 9900 LORAN receiver. I have one that is no workie. Any clues as to where I can get schematics would be greatly appreciated. (TI wants $75 for schematics ...!@#$%^&!!) Charlie Thompson WB4HVD
john@anasaz.UUCP (John Moore) (10/15/88)
In article <1572@radio.oakhill.UUCP> charlie@oakhill.UUCP (Charlie Thompson) writes:
]I am looking for schematics for the TI model 9900 LORAN receiver. I have
]one that is no workie. Any clues as to where I can get schematics would
]be greatly appreciated. (TI wants $75 for schematics ...!@#$%^&!!)
(1) You might try Sam's photofacts (I don't know if they have Lorans,
but it doesn't hurt to try)
(2) TI filed a patent around 1979-1980 that gives detailed schematics
of a LORAN receiver. It might be the one you have. You could check
a patent library for it.
--
John Moore (NJ7E) {decvax, ncar, ihnp4}!noao!nud!anasaz!john
(602) 861-7607 (day or eve) {gatech, ames, rutgers}!ncar!...
The opinions expressed here are obviously not mine, so they must be
someone else's. :-)jim@mnetor.UUCP (Jim Stewart) (10/17/88)
In article <1572@radio.oakhill.UUCP> charlie@oakhill.UUCP (Charlie Thompson) writes: >I am looking for schematics for the TI model 9900 LORAN receiver. I have >one that is no workie. Any clues as to where I can get schematics would >be greatly appreciated. I wonder if somebody could give a basic theory of operation for LORAN C. I have read the basic theory presented in a user's manual of a friend, but they don't get too technical. From what I understand, around the world there are certain 'chains' of 5 stations each. For a given chain, one's location is determined from the timing of a pulse from the master and the best two of 4 slave stations. All stations around the world operate on the same frequency 100 kHz ?? Some of the things that I don't understand: - the manual says a given 'chain' is determined by its repetition rate, but how is this actually done? Like how does the timing of the various chains fit in time with respect to each other? How is the information for a given chain recovered, how is the recovery actually implemented? Something like a slow-speed software PLL?? - how is the 100 kHz selected out of all of the RF crud in the world? It can't be filtered with an IF like regular signals, because the manual mentions something about the master producing 5 cycles of the 100 kHz, and the receiver locks onto the third for accuracy, but the user can soft-select a different cycle for various reasons (the 5 cycles, etc could be wrong, this is from memory). - the manual mentions something about having a backup master station, if the first one can't be read reliably, how does this work?? tnx, jim -- Jim Stewart, VE3SRJ UUCP: {decvax|allegra|ihnp4|linus|utcsri}!utzoo!mnetor!jim ARPA: mnetor!jim@seismo.css.gov BELL: (416)475-8980 x303