Hanskop maintenance 20190707

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Problem: About 2 months after the big rebuild in September 2018, the UHF repeater was starting to drop out after a few seconds of transmission.

This lead to a long fault finding process with help from the high site managers’ personnel to save on trips to site, on a very bad road.

After 4 months of problem finding, it was concluded that was not the repeater and not the antenna, but most probably the duplexer.

The WCRWG do not have a spare 1.6MHz split UHF duplexer. One was constructed out of spare notch cans. This happened over a process of 2 months, to make up a custom duplexer coax harness and trying to get the pass-through SWR as low as possible. With everything ready, it took some planning to get the vehicle, weather and correct people aligned to go do the swop out repair on site.

It started at around 06:30 today. Packed the repeater, swop-out duplexer and all required tools. Next was the pickup of keys.

Vehicle packed and ready, All in good spirit after the coffee ZS1V provided

The team (Sybrand ZS1SJ, Paul ZS1V and Jan ZS1VDV) got together at around 08:00 to repack all equipment into the 4×4 to go up.

Hanskop in the clouds

Around 08:15 the trip up started. Sybrand got a few chances to use the 4×4 capabilities of his vehicle.

On site the repeater was reinstalled. Next the debugging of the high SWR around the duplexer was completed. SWR straight on antenna 1.2. SWR through duplexer to antenna 1.8. SWR through duplexer to dummyload 1.0. It was concluded that the current duplexer on site was also not the problem. With a bit of head scratching a short patch lead was added to the antenna feedline. That took the SWR through the duplexer down from 1.8 to 1.3.

The last part was to correct the power sensing of the controller. Suddenly the UHF repeater started to restart on transmission. With some debugging it was found that the 10 A PSU used on the UHF repeater was suspect. This PSU was removed and the UHF repeater moved over to the main 30 A. The total current draw is just below 20A on full transmit. The calibration of the power sensing was updated and the voice responses also updated.

DTMF:

  • 8323 – Controller Voltage (This is the main power supply when on mains, and battery when on backup power)
  • 8324 – Main PSU voltage
  • 8325 – Battery voltage
Team photo in the clouds with tower in the back

Everything was packed up and returned home. Home around 13:00 and unpacked by 13:30.

Jonaskop maintenance 2019-06-29

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On 26 June it was reported that the repeater is not functioning and constant keying.

From the detailed fault report it was concluded that a power supply is the most likely problem. However with power problems, there could also have been big equipment failure.

Paul ZS1V and Peter ZS1PDE assisted with the ordering and pickup of a replacement PSU for the site.

Jan ZS1VDV packed for all scenarios on Friday evening. This included making controller link cables for the spare repeater.

All equipment ready and packed

Saturday started very early with Sybrand ZS1SJ meeting up with Paul to collect keys and replacement PSU in Somerset West.

    Sybrand next was picked up Jan ZS1VDV and loading all equipment in Stellenbosch at around 07:20.

    Sybrand driving 330km for the day

    A route via Worcester to Jonaskop the best option, as the Franschhoek pass was closed and the round via Grabouw to Villiersdorp was reported on Thursday to have loads of sand after the winter storms,

    Arrived on site, it was very clear that this was going to be a very cold and windy visit. Around -2.5 C and very strong gusts of wind.

    Sybrand hiding from wind

    As soon as the repeater hut was opened, it was found that the repeater was on backup power (measured to be 12.8V). This was very strange as the repeater never went to backup power during the week. Next the PSU and 220V was tested all over the site, and found the no 220V was available. With out more information, it was decided to swop the PSU.

    Isolator after lighting strike

    On the way down, Eskom was found working on the line. At this stage it was clear why the repeater was on backup power. In the process of driving up, Eskom switched of the 11 KV line to work on it. The 11KV line was hit by lightning and an isolator needed to be replaced. With the one line on the delta 11 KV line down, the transformer would have converted to 220V star 3 phase, but the 220V would not have been stable. After about 1.5 hours the repair was concluded. They had to use a gas flame to shrink the heat shrink on the lug.

    Eskom replacing isolator

    Returned to site, checked that all power was up and running. It was found the that controller configuration was corrupted and needed to be updated. The main and battery sense DTMF codes was also swopped as listed on the TODO list for the site.

    Jan using repeater hut door to hide from wind to configure controller

    The link radio the Hanskop audio levels could not be realigned as it was just to cold and wind to strong.

    The tower guy lines was giving a quick inspection and found that they will need service on next visit.

    Unpacked in Stellenbosch around 14:00.

    Sybrand last stop at home around 14:30 for a total round trip of 330km.