2001.07.05 - NLARC Repeater Site Inspection

Reason for Inspection:

The 146.34/94 repeater has been exhibited a squelching problem that has made the transmitter retransmit what sounds like audio oscillations that resemble intermodulation distortion.

Course of Action:

Jim Byrd and John Parker visited the site and performed the following items:

• The power output of the repeater was checked at the repeater to be 7 Watts. Nominal values are 70-100 Watts.
• The antenna/heliax line was checked with a MFJ-259 SWR analyzer. It was determined that the antenna system had a VSWR of approximately 2.8/1. Mechanical shaking of the Ringo-Ranger antenna caused wide variations of VSWR.
• Examination of the 120' or so of heliax (alone) revealed a loss figure of -2.1 db. This is an acceptable value at 144 MHz.
• The edge repeater control cards inside the 146.34/94 repeater rack were reseated. Some mechanical coupling is noted between the physical cards and squelch performance.

Results:

• In the short term it was noted that the squelching problem was no worse.
• The Ringo Ranger antenna is too corroded to be successfully used any longer.

Further Action:

• The next visit will address the power output and antenna problem.
• Continue to look for solutions to the squelching problem.

Web page operations: James E. Byrd
Responsible NASA Official: Richard S. Eckman