SOLVING PLL LOCK PROBLEMS WITH GE RANGER & DELTA RADIOS by K9KA =================================================================
Recently I built a parallel port programmer for the X2212 memory chip used in GE Ranger, Delta, and Phoenix radios. I have been using Niles software to read and create files for the radios and KA9FUR's Windows program to read and write files to the EEPROM. After doing this I found that a VHF Delta SX radio had a receiver PLL lock problem that turning the PLL adjust would not fix on all the frequencies I wanted in the 2 meter band. I just had a similar problem with a VHF Ranger radio, but in this case neither TX or RX PLLs would lock in the ham bands. Here is a description of how I solved these problems for others, whom I sure will find the same problem. 1.) First check out the radio in the design frequency range. A good way to do this is to program in frequencies in 5 or 10 Mhz steps across the band and into the ham band; 170, 160, 150, 148, 146, and 144 Mhz for example. With these frequencies programmed start at 170 Mhz and check RX and TX lock on each channel. I found with my recent Ranger radio that I only had lock on 170 and 160 Mhz!! Next switch to the highest frequency where there is no lock (LED comes on) and try the PLL adjustment to see if you can get it to lock. You can try to walk your way down in frequency and see how low it will go. Do this on both TX and RX. 2.) Next I removed the PLL board from the radio and look first on the topside at where the PLL adjuster is. Then locate the connections for the coil or capacitor adjustment. In the case of a coil (the Delta) I added a small NPO ceramic or dipped mica capacitor across the coil on the backside of the PC board. In the case of a trimmer capacitor the padding capacitor is placed directly across the trimmer on the backside. Use short leads on the the added capacitor and locate it close to the adjuster. You must also avoid hitting support posts on the chassis that the board mounts on. I had this problem at first on the Ranger. 3.) Now re-install the PLL board and re-test for PLL lock in TX and RX as in (1.) above. If you still do not cannot cover the desired frequency range, re-adjust the size of the added capacitor until you do. For example, the Ranger required 3.6 pf on RX and 5.1 pf on TX. Once you get lock on both TX and RX across your desired range, you can re-program the X2212 for the 16 desired frequencies and begin using your new radio. Good Luck. 73, John, K9KA Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
