[DSP-10] DSP-10 ext ref

[DC9UPGermany at aol.com]

Hi  Andy....2 Vss is good enough for the ext. reference. 
Just  couple it with a capacitor and it will work fine. 
Your  PLL unlock comes from miss-adjustment of one of the PLLs. 
Check  the range of each PLL according to KA7EXM method explained  at: 
_http://users.easystreet.com/rhayward/dsp10/pll_tuneup.html_ 
(http://users.easystreet.com/rhayward/dsp10/pll_tuneup.html)  
best 73 de DC9UP,  Hermann