WB4IUY's Random Blog

I've been in Amateur Radio since 1974, and still find new and interesting things to do. I like to build, restore, and operate on the air. This is a blog of various info about my Ham Radio operations and activities, projects, and opinions. Visit www.WB4IUY.net for the lowdown at WB4IUY.

Tuesday, December 4, 2012

More work on the 147.39 repeater...

More repairs were made to the 147.39 repeater yesterday (Sat, 12/1). I met with Matt, Alex, Sam, Roger, and even Jose (for a few minutes) at the site, and work started. Over the next four hours, several things were accomplished.

We retuned all of the receive & transmit cavities, and found them all to be out of adjustment...some by quite a bit. They were last adjusted back in 2002. We changed the configuration of the cavities to improve isolation, and have an additional pass cavity on the receive and transmit ports. De-sense is gone, and all is well with that aspect of the repeater, now.

All 4 cooling fans were replaced. They run non-stop, and have turned many revolutions since the installation of this repeater at the Clayton site in 2002. All of the heat sinks are cleaned, and the repeater is running nice and cool.

A temporary repair had been made a while back with a jumper lead, and that was removed and hard wired to correct a control logic problem. There is one more similar issue, but I forgot my glasses and couldn't see the terminal that needed to be soldered :-)

Weak signal tests were made, and it is responding to signals that are right down in the noise, so we're pretty happy with that. A few programming changes were made, and that wrapped up the work for the day.

The "to-do" list is getting short now with only a few items left like: replacing a defective PL encoder board on the transmitter, repairing a control logic issue for the 2nd voice announcer module, and replacing a backup battery on the voice IDers.

Next, the work on the Clayton site begins...

147.39+ WB4IUY Repeater work...

147.39 repeater work underway... A good bit of work is being done to the 147.39 repeater. Chris, Sam, Alex and myself went out to the site last Saturday (11/24/12) and found the dirtiest repeater in operation on this planet...really :-) To qualify this, the repeater has been running hands off for at least 2 years, maybe 3, so I had no reason to go to the site to check on things. I had no idea the site/repeat er/tower/antenna had deteriorated to such a sad state...

The property owner now stores hay for 18 horses in the rear of the barn in the area where the repeater lives. The floor was at least 6" deep in hey stems and very finely ground chaf from hey. The upper & lower repeater cabinets were completely clogged with hay, chaf, and cobwebs/spiderwebs. The fine dust, which had some of us coughing and sneezing, was at least an inch deep inside of the repeater on some of the electronics to such a point that much of the wiring was completely hidden and all 5 cooling fans were seized up. Heat sinks on driver, power amp, voltage regulators, etc were clogged with the same stuff. I honestly don't know why the repeater had not blown up and/or caught fire. Additionally, the lower cabinet where the duplexers and other items live were in the same condition. It also seems that a dog had found an opening into the rear of the enclosure and has been using the lower section of the bottom cabinet as a toilet and was literally covered in copious amounts of doggie poo.

We pulled out all of the repeater releated equipment, loaded it up, and hauled it off for cleaning and re-installation. It has now been cleaned pretty well, reconnected at a clean site, and is receiving some much needed repairs while keeping it on the air as best as possible. It is suffering from some desense issues at the moment, but more work is planned for Saturday. It should be up and running well in time for the Tuesday night net. We'll also be making some controller and other changes that should improve coverage and functionality.

Tower: We discovered several serious antenna related issues. The tree that had grown up into the tower has been trimmed and the most pressing parts cut away from the tower. There are still a couple of limbs to remove, and I'll get to that shortly. The more significant issue is where someone has run into the southwest elevated guy point and sheared off the backup restraint that ties it to the primary anchors. This allowed the elevated guy point to pull towards the tower, loosen the 3 lower SW guy wires, and allow the bottom 1/3 of the tower to slowly curve towards the northeast. I've got to repair that right away, before an ice storm and tower loading causes the tower to fall. There are also a few ice splits in the lower section that have to be repaired.

Antenna: Examination of the top mounted 4 bay dipole array that has served 147.39 for about 20 years revealed more problems... One of the top folded dipoles has loosened and turned towards the mast about 90 degrees. Another of the folded dipole loops is completely missing and no where to be found on the property. The link antenna has blown around and the multiband vertical is twisted in a pretty bad band. Again, I'm amazed that the system was still working as well as it was.