"Erik Finskas (csb1_95)" wrote: >It is possible to modify the freq. range, but I don't remember how to do it. From the information that I have gathered so far when the W1 jumper on the processor board (between the display unit and the main body of the radio) is cut, this enables receiving signals from 118 Mhz to 174 Mhz, and also a bit above and below the 440 Mhz range. Next, about 1 inch below this W1 jumper on the same board is a set of small surface mount diodes arranged like this : (note: numbering is my own.. not silk screened on the board) _ W1 |_| _ _ _ _ 1|_| 2|_| 3|_| 4|_| <-- (these diodes are very small) _ _ _ _ 5|_| 6|_| 7|_| 8|_| <-- (these diodes are a little larger) On my radio, 7 and 8 are not there at all. I have been told that the removal of diodes 5 and 6 will enable extened transmit. (thanks harry) (back to the original post).... >Basically, at the processor board (between the display unit and the radio >units) there are normal size diodes, one of them is for wide RX, second for >cross-band repeater enable and third is just there, find no documentation about Erik, for the sake of our studio audience, could you verify which diodes control which functions??? >it. The radio will receive after modification 108-174, 320-480 and 800-950 IF >there is the 900MHz front-end card installed. The front-end card is on the >speaker side of the radio, and it is standing middle of the board. If it is, >you still have one problem, you need a extra antenna connector for 900MHz. I >used a SMA connector (very small) and fitted it to one of the free metal plates >used to cover places for cable connections (there should be one free) If the 900 Mhz front-end card is in place, where should a connection of an additional antenna be?? somewhere on this little card? hopefully obvious. Also, if this card is not present in the radio, where can one be obtained?? from ICOM? > >The sensitivity for AM airband, 108-136MHZ is not so wonderful and they should >do something with the AM detection, it sounds like FM. >136-174 is very sensitive due the wide front end, which will be connected >online when outside 2m ham band 144-146. >320-479 is also sensitive, there is also another wide front end for out band >reception and narrow one for 70cm. >800-950 is a dream, it is just as sensitive as it should be, at cellular band >it does not hear any interference from powerful base stations nearby, just the >channel you are listening. Only problem is, that IF filters are mainly for >25kHz channel step, and cellular phones use mainly 12,5kHz, so if there are two >conversations going on on neighbour channel, they may interfere a bit each >other. > >Erik >-- >Erik Finskas G/OH2LAK >Email Finskase@ee.port.ac.uk >University of Portsmouth, UK >Department of Electronic and Electric Engineering >