Welcome to NORAC The North Okanagan Radio Amateur Club

Summary:

Battery service was done, followed by a check of the VE7RSS repeater and peripherals. An Olds Communications Inc. VHF bandpass filter was installed in the antenna feedline between the duplexer antenna port and the lightning arrestor.

Attendees:

Ralph VA7NU, Bud VE7KBK, Lorne VE7LWK, Mike VE7KPZ with remote testers Ted VE7UIH and Mike VE7AM.

Access:

As this was a regular SilverStar winter ski season day, the main office on the third floor of the building that houses the rental shop was open. Mike VE7KPZ checked in with reception and the resort manager graciously offered us 3 VIP passes so that Ralph, Bud and Lorne could ride the gondola for free. How nice is that!?! Mike used his regular season's ski pass to ride the gondola.

We also received some news: the area under our shack had been converted from an old pole and sign storage locker into the main Ski Patrol hut. The Patrol members graciously allowed us to sneak upstairs into the repeater room just before they started their daily meeting on the floor below us.

Once our work was complete, we thanked the remaining Patrol members and proceeded back down the gondola to the village. Mike returned the VIP passes to the main office and reiterated our thanks for SilverStar's continued support of our efforts.

Our new NORAC business cards were handed out to all in the main office and the Patrol hut. All were invited to visit our website and review this article.

Task 1 - Battery Service

Lorne was drafted to be prime on the battery service, not actually because he is a very qualified industrial electrician, but because he was the most physically agile member of the team. The batteries are in a tight spot, so a slightly smaller frame and physical agility is required to access them. Thank-you Lorne for taking on this critical task.

Battery voltage readings were taken with battery 1 being closest to the repeaters and counting clockwise from there. Battery 1: 6.649V, battery 2: 6.648V, battery 3: 6.650V, battery 4: 6.649V. Total voltage of the 2S2P pack: 13.270V. Note that these are really just float voltages so they don't give any indication of pack health. They do, however, indicate that we have balance in the pack.

In order to really assess battery health, we'd need to let the batteries sit off-float for 24 hours and then measure the voltages. Or, check each cell with a hydrometer and review specific gravity readings. Or perhaps on our next visit do some load testing with Mike's battery load tester.

For the main event, battery water levels were checked and topped up. Battery 1 needed the most water, but no cell in any battery had a dangerous water level exposing their plates. Lorne brought each cell up equally utilizing the full 1.5 litres of distilled water that Mike had brought on site. This leaves the cells below their max fill lines, but with plates well covered.

Lastly, the battery terminal bolts were snugged up to ensure reliable current transfer between the pack and the DC loads.

Task 2 - VE7RSS Check-up

We started off with a scan of the feedline and Sinclair 210C4 antenna with Mike's RigExpert AA230-Zoom antenna analyzer. The plot showed relatively flat response over the entire bandwidth of the antenna, although the VSWR was reading a little high (1.5:1).

We then scanned each side of the duplexer with a dummy load attached to the antenna port. The plots showed that each required frequency was still passing ok and being blocked well respectively. There was a bit of an interesting plot (double dips on the pass) on the receive side of things so Ralph recommended that we possibly grab a spare VHF duplexer, tune it up and swap it in so that we can bring this duplexer back to Ralph's lab for review via Ralph's network analyzer.

We also scanned the additional bandpass filter installed on the RX side of things between the duplexer RX port and the Daniels receiver. It showed a VSWR dip right on 146.280MHz as expected.

Of course all of these plots are just plots of perceived VSWR. The true test is to install a VSWR bridge inline and do some transmit tests. We utilized Mike's Surecom SW-102 VSWR bridge/power meter/frequency counter for the following tests:

TX via the Daniels amp directly into a dummy load: 22.5W with a VSWR of 1.06:1 at 146.880MHz.

TX via the Daniels amp at the antenna port on the duplexer into a dummy load: 12.5W with a VSWR of 1.04:1 at 146.880MHz.

TX via the power amp at the antenna port on the duplexer into a dummy load: 44.2W with a VSWR of 1.10:1 at 146.880MHz.

We then proceeded to install the VHF bandpass filter (Mike's personally owned filter and patch cable) in between the duplexer and the lightning arrestor.

TX via the Daniels amp at the antenna port on the bandpass filter into a dummy load: 11.9W with a VSWR of 1.10:1 at 146.880MHz.

TX via the power amp at the antenna port on the bandpass filter into a dummy load: 40.5W with a VSWR of 1.17:1 at 146.880MHz.

We finally removed the dummy load and attached the output of the bandpass filter to the antenna port. A quick check confirmed 40.5W with a VSWR of 1.17:1 into the antenna feedline at 146.880Mhz.

Our plan is to leave the bandpass filter in until summer as a bit of an experiment. Your observations and feedback on repeater performance are greatly appreciated. If you notice any differences in RX or TX performance, please let us know by emailing This email address is being protected from spambots. You need JavaScript enabled to view it..

Task 3 - Make Sure Everything Still Works Before Departing

We were able to confirm the SIRG UHF hub still worked and the APRS digipeater still worked before leaving. The LIME link radio was left untested.

Outstanding

1. See if the every-5-second burst of interference is gone when repeating weak-RF-input-signal transmissions with VE7RSS. If not, bring up a spectrum analyzer to the site to hook up to the VE7RSS antenna to figure out where the burst comes from and devise a filtering solution to implement.

2. Sort out the "machine gun after unkeeing" issue with VE7RSS. Terry VE7TRZ will confer with Jesse VE7LYD on what might be the possible cause and solution. Terry has some new theories.

3. Transport the old Trojan batteries down for recycling. These old batteries have been sitting in the shack since they were swapped out a good couple of years ago. It would be good to free up some space in the battery area for easier maintenance of the active pack.

FYI,
Mike VE7KPZ
NORAC Vice-President 2017-2019, Technical Committee member