[SBE] 950 STL curious problem

[Jonathan Solomon]

Henry-

I'd bet on an external source at his point.  From your description of
the frequency of occurrence, I'd wonder if it might be a RADAR tower
of some sort.

On Mon, Jul 20, 2009 at 11:53 AM, <A9xw at cs.com> wrote:

> Follow with me, this is wierd.

>

> Day 1,  14 mile STL path for radio, Moseley Starlink 9003Q with LanLink.

> Signal level  - 77.   Less than expected. Turns out trees in middle of path.

>

>

> Waise receive antenna 50 feet and signal level improves to -73. All nice and

> stable.

>

> 2 months later, suddenly signal level drops to -80.  Check coax, (1/2"

> Heliax)  couple of bumps.  By pass LanLink box at TX end, gain 2 db.  Bypass

> LanLink box at RX  end gain 5 dB.  Back to -73.

>

> Receive level unstable, jumps from -73 to - 93 and back every few seconds.

>

> All connections checked, and rechecked.  RX does not work at -93 (below

> threshold). Patch in Comprex line.

>

> Replace 1/2" line with 7/8" line. No improvement in signal level.  -80 with

> Lan link in, -78 with TX lanlink out, -73 with TX anbd RX Lanlink out and

> signal begins jumping again -73, -93.

>

> OK, Lanlink serves as bandpass filter but only other signals on site are 2

> class A FM's.

>

> Can't find cause of  -73, -93 signal level jumps ( a couple seconds between

> levels and fairly regular). No improvement in signal level with increase in

> coax, that should have gained about 2 dB since 1/2" had 4 dB of loss)

> (260').

>

> Antennas check good. (Scala grid type)

>

> Only other signal is 950 STL at 90 degrees and distant channel.  Rotating

> antenna shows typical and smooth lobes and is dead on.

>

> Called Moseley, tech says he would bet his house it is not receiver.

>

> Any guesses other than LGM?  Nothing within 2.5 miles of RX site,  path is

> clear and not near intersecting anything else.

>

> Henry

>

>

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