September Engineering Committee Notes & September Work Day

The Engineering Committee work day was re-scheduled for later in September due to most of our committee works the Bike MS event.  Bike MS was canceled due to the remains of Hurricane Florence, so that gave the team some time to get things in order for our work day as we had a lot to accomplish.   

If you can remember from last months Engineering Committee notes, we removed the Andrews 2m aluminum 4 bay antenna from the 9666 Olive Blvd site that was a spare at one time for the 146.850 repeater.  That spare antenna was on the west side of the building, but due to a large power source on the other side of the wall, it rendered the antenna useless from QRM. With a little work and elbow grease we tightened all the screws and removed all the old coax seal with some mineral spirits, we brought the antenna back to new condition after it had been unused for a year plus.  This antenna had a new home at the 146.970 repeater site.

This month we were back at the 146.970 site working on that repeater.  Slated to be completed was the install of the Andrews 2m aluminum dipole antenna we removed from 9666 Olive Blvd location, removal of the existing Vertex 5000 with a new Fusioni repeater and replacement of the coax from the duplexer to the antenna.

First order of business was trying to get the antenna up to the roof.  Charlie (KCØHXB) had visited the building a few weeks before to check out the freight elevator to find it not working, so it looked like we had to haul the antenna up 26 plus flights of stairs.  The 24 foot antenna splits into two 12 foot pieces and just by our sheer luck, we had only an inch to spare in the stairwell. Two people in 8 flights per shift carried the antenna up the stairwell all the way to the penthouse.  It was a strenuous task and everybody burned some extra calories that day, but we made it to the top.

Once on the roof, AJ (KDØWWR), Dan (KE0ØZU) and Sterling (NØSSC) made short order of the antenna install with removing the old dual band fiberglass antenna and installing the new aluminum 4 bay antenna.

During the antenna install, Dan (N9RZR), Bob (KEØOWL) and Steve (KEØDWB) started to pull out the old existing coax and hardline.  After the old cable was out they fished the new coax down the cable shaft and into the duplexer cabinet for the new install. The team ended up pulling out three cables total, one hardline, one LMR600 and a temp probe.  This was a dirty job from all the pigeon poop caked on the cables from years of sitting outside.

Alexandra (AEØDN), Max (KØAZV) & Charlie removed the old Vertex repeater and installed the new Fusion repeater.  Joe (WØFY) set the squelch tail, squelch settings on the new repeater, checked the duplexers with his spectrum analyzer and completed some SWR calculations after the antenna and feed line were completed.  With the new antenna and coax and the repeater running on low power, the swr at 146.970 is 1:1 and the repeater puts out about 13W after the duplexer, probably around 10W at the antenna, so we are happy with the results.  

The Engineering Committee, and others, have been testing the range of the repeater in the past week and we found it can be heard past mile marker 41 on Hwy 64 in Illinois, but realistically someone with a quarter wave antenna can get into it reliably around Scott Air Force Base.  To the south we are getting good reports around Arnold and we can hit the repeater with 25 watts from Eureka with no issues. To the north with the exception of some pockets, we are getting good signals, but we still have yet to receive any reports deep in West County area, so please let us know your signal reports!

We set the 146.970 repeater in AMS mode, so you’ll need to set CTCSS or tone squelch on your radio to 141.3Hz who do not have a C4FM digital Yaesu radio.  If you don’t set this tone, you’ll hear digital hash when a digital conversation is happening. If you do use the radio in C4FM please use digital narrow with AMS mode selected.  

In August we promised to bring the WØSRC-1 APRS digipeater & iGate online at the MoBAP location.  We are still planning on installing this, but ran into some roadblocks regarding hardware, so we have pushed this off until the October time frame.  It will be deployed with a Raspberry Pi, TNC-Pi running Raspbian Lite OS, APRX software and an ICOM FS-121S radio running at about 25W output. It will be configured to beacon out all the SLSRC repeater frequencies with information about nets, meetings, coverage ranges (Power, Height, Gain) and even Winterfest 2019 announcements!

The Engineering Committee decided to take the month of October off from our regular work day, but we are still working on repeaters for future dates.

  • We will purchase equipment to start testing an All Star node internal repeater link via our 5Ghz point to point links.
  • In November Rick Crockett (WØPC) will inform the Engineering Committee about AREDN mesh IP network and how to deploy such a solution in the STL area.
  • In December we will replace a cabinet at the 146.940 site and install the smaller 4 can duplexer we had as a spare.  The 6 can duplexer coming out of the 146.940 site will be reconfigured for the 146.850 frequencies and will become a spare in case 9666 Olive becomes uninhabitable during a disaster.

If you have questions about the Engineering Committee or want to help volunteer, please see Kyle, AAØZ either at the next SLSRC club meeting, or shoot me an email via my QRZ page.

Below are pictures from the September engineering work day.

[Best_Wordpress_Gallery id=”29″ gal_title=”Sept Work Day”]