July 2005
Home Up WMCU

On July 31, 2005, we made a trip up the tower.  A few issues we went to check:

bulletAPRS Digi went to channel 2, 146.76 for some unknown reason
bulletThe 147.000 was getting 'deaf'  Not hearing signals as well as it used to.
bulletThe repeater failed during the last tropical storm.

The week before we attempted a trip up but the elevator failed and crashed to the bottom of the tower with three of us in it.  This week we had a similar problem, but it seemed to be okay with just one of us on board.  Even with just one, it still slipped a few times at higher levels.   

Issues found:

bulletThe digi wasn't near anything that could have pressed the channel button.  The new EEPROM can be swapped on another trip when we have two people up there.   
bulletI saw a antenna connection that looked like it was stressed.   We need to open it and replace the jumper.
This is a close up of the back of the Mastr II voting receiver shelf.  The black rectangle is actually a multipin connector that brings power, audio, speaker and COR leads in and out of the receiver shelf.

One power input connector for the 146.40 receiver was broken off.  You can see a red wire hanging with a solder on the tip.  The wire is actually black, the red is from the red side of the zip cord.  That was the ground.  The shelf was getting a ground elsewhere.  

The red positive one broke off during inspection.  This meant No power to the controller or the receiver due to this open.   

John, KF4ACN is totally rebuilding this wiring harness.  

You can see the full image below.


Done today:

bulletThe receiver, exciter, controller and the cable harness was brought down the tower.   
bulletThe antennas and transmission lines were inspected visually.
bulletThe stability of the cabinet was checked.  About 1.5 inches of movement when the cabinet is rocked  hard.  It could be more stable.  Maybe a stiff-arm could be installed from a tower member.
bulletPictures were taken of everything.

This week:

bulletThe harness will be rebuilt with a new receiver connector.   Hopefully with shrink tubing to reduce the effect of corrosion.
bulletThe receiver will be PM'ed  (Preventive Maintenance to make sure it's up to spec.)

Next tower trip:

bulletThe equipment removed 7/31/05 will be reinstalled.
bulletThe connector to between the downlead and the jumper will be replaced.
bulletPaint on the cabient will be touched up.
bulletThe low current connector fuse may need to be replaced since the power to the controller shorted as it fell off.
bulletReplace EEPROM in the Digi with one that only does APRS.

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    South Florida FM Association, 2003   

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