July Engineering Committee Notes & July Work Day

Because of the STL heat, the Engineering Committee held a “learning day” inside, instead of it’s usual repeater work day in July, to help share the vast team knowledge with other members.  Learning a new skill is a great aspect to this hobby so we took advantage of it. The team met at MoBAP Hospital and we divided the session into two parts.

Part one was covered by Joe (WØFY) regarding general repeater hardware, software and configuration.  With Joe’s years of electronic and repeater experience, he put together slides that covered everything from how a CAT1000 controller is programmed, to how to notch out frequencies with a spectrum analyzer for typical repeater duplexers.

The second part was covered by Kyle (AAØZ) regarding documentation and VPN access into the site.  The team also covered what to do for emergencies if a transmitter gets stuck and needs to be powered down.  It was a good session and the knowledge sharing helped the team be more rounded.  We plan on having another session in the winter.

If you did not get the communication earlier in the month, a CTCSS output tone was installed on the 146.850 repeater in July.  Over the years we’ve had some complaints with members in our southern area hearing the 146.850 repeater in Southern IL, especially the “Get ’em To Work” net every morning starting at 6:00 AM.  If you’re experiencing this QRM for the SLSRC 146.850 repeater, please check your manual and use a 141.3 CTCSS TSQL to only open your squelch if you hear the SLSRC repeater.

Read more about the 141.3 CTCSS output communication here.  http://www.slsrc.org/2018/07/22/slsrc-146-85-repeater-ctcss-communication/

During the July general SLSRC meeting, Kyle (AAØZ) completed a presentation on the Repeater State of the Union to update the membership on all the engineering activities since the first of the year.  The presentation was recorded, so be looking for that presentation email around the end of September to review if you missed it.

One of the discussion points during the meeting was linking some of the existing repeaters together to help fill coverage gaps and get more activity on the repeaters.  The committee has started to look at potential linking strategies and ways to complete this via our 5Ghz IP network.  One method we are looking at is AllStar.  This system uses a Raspberry Pi with an audio to USB decoder which can plug directly into the back of a repeater to provide communications.  Since the Raspberry Pi uses digital communication with very little bandwidth, we’re able to produce full duplex conversations at very high quality.  The system is fully configurable, and allows dynamic linking via DTMF to turn on/off during times of disasters or nets.

August will be a busy month for the committee, as we have a laundry list of items to complete.

  1. We are going to remove the spare DB224-E antenna from the 146.850 site (this was a spare antenna mounted on the west side of the building) and install it at the 146.970 site in September.  We’ve been fighting antenna problems at the 146.970 site with water in the antenna and coax since late spring.  Installing a quality antenna will help troubleshoot the issues.
  2. During the early summer, we traded in a Fusion DR-1X for a new Fusion DR-2X, which we will install at the 146.940 site.  The existing Fusion at 146.940 site will go back to Yaesu for a firmware upgrade and will then be installed at the 146.970 site in September.
  3. Engineering work day will be at the 146.940 site to help label, asset tag, and check power output, duplexers and SWR for both the 146.940 and 442.100 repeaters.

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