UHF Northern Hub & VHF Drop Repeater

New UHF Rptr &
Equipment Rack
Move to
New Building
VHF Repeater
2003 Activity
Repeater Site Activities

July 21, 2003
Battery Replacement and Equipment Rack Changes

The MSR2000 VHF repeater went into service on July 31, 2001, but it was not installed into the equipment rack as the rack first needed to be modified. My official excuse for why this has never happened is - No problems! No problems means no trips to the site and never being on site means never having the opportunity to do any "as long as I am here" or "while I am here" work.

During recent power failures we discovered that the repeater only remains functional for about 2 seconds and from this have concluded that perhaps it may be time to replace the standby batteries. The batteries were old when SARA received them and years beyond their expected service life. Prior to June, 1998, they actually powered all of the NHB repeater equipment and had tolerated years of continuous discharging and charging, especially during and after the Monday night and other nets.

For the past couple of years the batteries have showed signs that they were failing. Water needed to be added several times a year and each time I would further reduce the battery float voltage in an attempt to reduce water consumption. But even with the float voltage at less than 13 volts the batteries continued to use water.

New standby batteries (new to SARA at least) were located and are now installed. Being that they are sealed maintenance free batteries, I guess I can stop stocking distilled water stocked at the site.

The Old Batteries

The New Batteries

While installing the new batteries, I figured that as long as I was there I may as well do some work to get the VHF MSR2000 repeater off the floor and into the equipment rack. When the VHF repeater was installed, two years ago, it was left on the floor and in the event that it developed problems, the old GE repeater was left in the rack and ready to be quickly reconnected. At that time also, a Sinclair VHF duplexer was installed in place of the existing duplexer which required a defective capacitor to be replaced. The Sinclair duplexer, belongs to Brian, VE6BCA, and has been working so well that it's all his fault I have had no incentive to repair the old duplexer. His duplexer can be seen, also sitting on the floor, in the photo.
The MSR2000 VHF repeater does not require the large 12" band pass filter that the GE repeater did so the filter will be removed to make room for the two MSR2000 repeaters to sit back to back. A section of vertical steel mounting rail will also be removed and then a frame will be constructed for the repeater to slip into. (Same way the UHF repeater was installed)



Modified rack with VHF repeater sitting in the new frame. Note: Brian's duplexer was even relocated off the floor.

The VHF & UHF repeaters
back to back in the rack.

The rack was turned 90 degrees and moved to half way along the left wall.

This arrangement permits
VHF repeater access from the front
 & UHF repeater access from the back.

For those who have not
this small building -

With <30 sq. ft. of floor space, one must
carefully plan where things are placed to ensure everything will fit! Note that the site's chair is never seen in any of the photos as it must be placed outside to make space around the equipment rack
to maneuver. The chair's of little use as a chair, but remains on site as it's a useful prop to keep the door open!

Wiring will be cleaned up and covers will be installed when I return to install a repaired duplexer loop assembly and tune the VHF duplexer.
Garrett, VE6RKY, dropped by to give a hand and removed the bad duplexer coupling loop and capacitor for me. He was surprised to find that the coupling loop had a strange resemblance to #14 copper electrical wire. He now knows how to identify a duplexer that someone has modified to work on amateur radio band frequencies.

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