KØSWI 442.225 FUSION REPEATER’S NEW HOME
The good news first. The 442.225 Fusion repeater is up and operational at full power at the Memorial Park site. Initial coverage reports are excellent, all we could have hoped for, and maybe even more. Yes, we were intending to place the 82 repeater there but the repeater gods were against us.
As was reported at our last meeting, we had secured an updated quote from Calhoun Communications for $4,606.78, which was $1,050.00 less than the original quote. This was possible because the crew was already going to be in the area so the new quote did not include travel expenses. The caveat to this is that we were subject to their scheduling calendar. As it turned out, we received an email early on July 5th that they would be on-site and ready for us at 8:00 AM the next day, July 6th.
Fortunately, the heliax and a lot of the other smaller miscellaneous things were already at the site awaiting installation. However, the DB224 antenna was still at John KB0QKH’s house after he had checked it out. John, Greg N0GR, and Chris KB0FBL made hasty arrangements to transport the antenna to the tower site for the next day. They also took care of some other chores while they were there; completing minor a repair to the outside jacket of the heliax, uncoiling it to ready it for installation onto the tower, and other things.
On July 6th the three-man tower crew arrived and was met by Chris, Greg, John, and Dan KB0TDW. The tower crew geared up, ascended, and rigged the tower. Then they installed the DB224 antenna and hung the heliax. Upon testing, SWR readings of 2.5 and higher were observed with several different analyzers. With the help of the tower crew, a dummy load was sent up the tower for further analysis. The heliax and several different jumpers tested fine, but the antenna continued to measure high SWR.
Suspecting a damaged or malfunctioning node on the DB224, the old 82 antenna, we then asked the tower crew to re-climb the tower and remove the DB224 antenna and install the new Sinclair UHF antenna (the blue antenna in the center of the photo) that we purchased for the 225 UHF Fusion repeater. That antenna also continued to display high SWR in the 2.5 range as well. Results of testing of the DB224 82 antenna on the ground indicated that that antenna is OK, with SWR readings of 1.1 to 1.2.
An anomaly was then observed that when the crew at the top of the tower transmitted on their hand-helds, the SWR readings from the mounted antenna would hit maximum readings on the analyzers. This led us to the theory that the high-power 800 MHz transmitters used by the County on the same tower, and any other nearby transmitters, were interfering with the analyzer readings from our tower-mounted antenna. A UHF bandpass filter was temporarily installed to validate this theory. With the bandpass filter on the analyzers, the SWR readings fell within normal ranges, thus validating the external RF sources theory.
As it was late in the day and our tower crew time was all but used up, a group decision of the committee members involved was made to leave the Sinclair UHF antenna in place and to install the 225-repeater equipment at the Memorial Park site in lieu of the 82 repeater (this had been the original plan for Memorial Park before the Simms site was lost in November 2022).
Our 1-1/4 inch heliax and the new Sinclair UHF antenna purchased last year have been installed/mounted at the top of the Memorial Park tower (by St Albert’s school). The 442.225 repeater is running through this at 200 feet on the tower.
The tower crew from Calhoun turned out to be an excellent crew to work with. This crew worked way above and beyond what was expected.
Chris KF0FBL Station Trustee
Paul WB0GXD, Ass’t Station Trustee