At 01:32 PM 01/21/08, you wrote: >At 01:14 PM 1/21/2008, you wrote: > > >This sort of behavior is far from normal for an MSF - thus it would > >seem that you should look for a problem in your station such as off > >frequency, skewed IF response, noisy RX VCO, etc. > > ><----Receiver performance is spec otherwise and the IF appears to be >centered in the passband. > > > >If your tests have been conducted using a mobile or portable to > >initiate the test transmissions, I suggest that you re-test using a > >service monitor. Turn on the generate output first [RF carrier], then > >see how long the station takes to decode when you activate the PL > >modulation. It should be less than 250 ms.[nominal 200 ms.] > ><---I've tried both radios and service monitor generated RF and the >PL decode performance is horrible regardless. > > > >There was one issue with PL detect time in the CXB MSF5000. The PL > >limiter/filter is sensitive to subscriber units that initially > >transmit off frequency. This causes the output of the limiter to rail > >for some time. > > > >Stations shipped after September 1, 1994 do not have this issue. If > >your station was earlier than that [initially had SSCB firmware 5.45 > >or earlier] you could try the following fix with the caution that > >making this modification will increase DPL decode time. > > > >By removing capacitors C8164 and C8165 on the SSCB, the limiter can > >recover faster from keyup transients. > ><---As this radio won't be DPL'd, I'll give this a try, thanks. > >Ken
I talked to a friend who runs a couple of MSFs and asked him about slow decode. He said to check the power supply busses around the CPU (which does the PL decoding). The caps go bad with age and any hum on the analog supplies or the CPU supply confuses the CPU. One symptom of this is slow decode. Mike WA6ILQ
