At 02:23 PM 02/09/2008, you wrote: >Doug, > >I have had some similar experiences here in the RB skunk works. I thought I >was the only one to come across this phenomenon. I first noticed it with the >batch of 5 or so that I got around the first of the year. I'm not sure if >they changed to a different op-amp mfg or what. > >My experience was the same as yours that I merely jumpered the input to the >output - bypassing the TS-64 and the whole setup runs great. (no decode of >course). > >On the ones I ran into, I merely turned down the pot in the disc. and then >adjusted the input pot on the controller to compensate. I am scratching my >memory, but I think I *was* able to re-produce this behavior on the test >bench with a sine wave generator. > >Please let us all know what you find out. > >Scott > >Scott Zimmerman >Amateur Radio Call N3XCC ---------- Hi Scott. Well I am glad I am not the only one who noticed this... I was originally looking for a wiring error. I did talk to ComSpec and the gentleman I talked to indicated he was not into the engineering of the thing. However he did kind of indicate that the last batch they made they changed the op amp. He seemed to indicate that they would be changing it on the next batch also. That leads me to think that they may be aware of some problem. He did feel that one volt hitting the input was a bit high and suggested some resistance in series with the input. Mine was bought in March of this year..
Since he did not know what the output level of the MSTRII receiver was, I rather took it that he was not involved in its development. I put a .005ufd disc ceramic capacitor across the sq/v/hi terminal and the sq low terminal and that cleared up the 'grass', but with a rx output of 500mv, I lost the squelching that I wanted. I increased the receiver output to 950mv and that seemed to fix things. The output wave form from the HP filter is looking very good. No noticeable distortion and no tendency to take off. I am presently waiting for a op amp from SCOM Bob for my mrc100 and then I will be able to listen to the repeated audio. So for now, I am going to let it sit.... It eventually will be connected to a 7k. The capacitor does take out some of the hf noise component thus the squelch problem. Hope this helps. I'll look at it again when I get the controller working.. 73 Doug VE5DA
