WLLH early evening problem

chris2526 chris2526@comcast.net
Fri Apr 11 02:26:15 EDT 2008


If anyone noticed something strange listening to WLLH late afternoon / 
early evening, it was failure of the WLLH Lawrence Composite STL receiver 
front end.
While driving home on I-93 about 7:00 PM as I passed route 125 I punched the 
WLLH button and got all kinds of audio phasing in and out.
My first thought was that one of the external GPS referenced oscillators 
unlocked on decided to take a little stroll.
By the time I hit Dascomb Rd. it was clear that one of carriers was on 
without
audio... but which one?
As I passed 495 it was pretty obvious that the audio failed in Lawrence 
which was now very close with little audio the closer I got.

I was able to rule out the failure of the PA stage of the STL transmitter at 
Wood
Hill in Andover, years ago the PA output stage failed and would only put out 
ony 1/4 watt.
Lowell even with an Annixter Marl 6 foot receive dish has very poor
path that skirts the top of another hill and never gets more than a marginal 
signal
At 1/4 watt Lawrence with a 3 mile line of site path still received a very
strong  signal but even with the receiver squelch full open Lowell  was DOA

When working properly Lawrence might possible work with a paper clip for an 
antenna!

As it tured out the Lawrence receivers front end amp failed, because the 
receive signal has always been so strong I had to use the 10 DB pad.

Its functioning with the stage patched around with the squelch fully open, 
it seems to be getting enough signal to work OK until another receiver is 
sent out.
At least to this point so far so good....I'm keeping my fingers crossed.

Chris Hall



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