It was a challenge to predict the correct maintenance slot for Jonaskop. The weather changed a few times in the week.
David ZS1DDK picked up batteries, which was fetched from him during the week by Jan ZS1VDV. Rassie ZS1YT facilitated all payments.
John ZS1EQ delivered the automatic switchover and LVD (Low Voltage Disconnect) / OVD (Over Voltage Disconnect) box to Matt ZS1MTF on Friday evening.
A team consisting of Matt ZS1MTF, Nic, James ZS1RBT, Paul ZS1V and Jan ZS1VDV went to Jonaskop to upgrade the emergency battery capacity, install the automatic switchover and LVD/OVD box, replace all cable ties (lasted about 8 years in the sun) and tension the tower stays.
Saturday morning started at 06:00 packing the vehicles.
Left home around 06:30.
08:30 stopped at site. The weather was not cold with a moderate breeze, which turned into a strong breeze as the day progressed.
On Saturday 9 May, Jan ZS1VDV and Ralf ZS1RK visitted the Jonaskop 145.675 repeater site. High wind conditions prevented close up inspection of the antenna connections on the tower, but the SWR of all the antennas were checked and found to be good.
The VHF repeater squelch was adjusted. The audio levels were re-aligned and one coax connector was seated correctly.
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.
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.
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.
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.
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.
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.
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.
Jan ZS1VDV and Paul ZS1V left Stellenbosch at 10am for the Jonaskop repeater site, home of the 145.675 repeater. It has been some time since the last visit to the site and the access road condition has deteriorated significantly. Somewhat delayed by a puncture to one of the bakkie’s tyres, the team arrived on site just after midday.
Antenna SWR measurements on the VHF stack and both link antennas were found to be acceptable. Output power of the repeater and both links, was also as expected.
Jan patched the link controller to take care of a slight crackle on the audio, most easily noted in the 2m repeater tail.
Jan busy with the link controller
Some more tests pointed to a problem with the Hanskop link radio (possibly off frequency). This was removed and the team departed at around 15:00.
Pleasant conditions at around 15C, overcast and no wind
Jan and Paul arrived back in Stellenbosch just after 17:00.
On Saturday 2017-05-20, Paul ZS1V and Rassie ZS1YT headed to Jonaskop to investigate a problem with crackly audio on the 145.675 Jonaskop repeater and to attend to some pre-winter preventative maintenance.
The weather was sunny, but cold, with a fresh cold breeze that could be felt as soon as one was a few meters up the tower. Most of the area to the South and East of Jonaskop was under thick cloud.
Overberg under a blanket
The SWR of the VHF antenna was found to be good. On previous visits water had been found in the connection between the feedline and the 4-stack antenna, despite there being a good water seal at that point. The phasing harness has a plastic tube section and extra precautions against moisture entering the system at that point were taken.
The link controller was also attended to, and audio crackle eliminated by re-seating some of the ICs.
An adjustment was made to the repeater configuration to make it go back to the desired setting after a power interruption.
On Sunday (2016-04-17) Jan (ZS1VDV) and Paul (ZS1V) did maintenance at Jonaskop.
Left home around 06:30.
Drove to Jonaskop via Somerset West arrived on site 09:00.
It was very cold on site and windy. This made everything up to 12:00 happen slowly and with cold hands.
Paul turned the Hanskop link antenna from vertical to horizontal polarisation. Had to replace the bracket as the U-bolts broke off due to rust.
Jan resolved the power issue on site. The plastic cap on the positive terminal of the power supply was melted. The reason for this could be that it came loose due to temperature cycles. The plastic was removed and the terminal tightened with a tool.
The next step was to swap around the two GM300 link radios due to deviation differences in the models. Riversdal is 16k0F3E and Hanskop 11k0F3E. Frequencies were updated accordingly. Then the radios had to be realigned as the old Hanskop (now Riversdal) radio was off frequency by 2.8 kHz.
We started the process to change the VXR9000 audio input link from the controller to the correct pin for emphasis. This failed due to a impedance mismatch which could not be resolved on site.
The controller was also found to have speech out problems. For now only the linking macros work and all other have been deactivated till a new speech process chip can be installed.
The duplexer was re-tuned. The insertion losses were close to 2dB and the rejections were around 72dB. After re-tuning the results were: TX (1.6db insertion, 86.08db rejection) RX (1.55dB insertion loss, 81.71 dB rejection).
The circulator was removed as it was giving bad SWR (3).