Another early and crisp morning, Matt, ZS1MTF, Mike, ZS1MJT and Jan, ZS1VDV, met to go to the Jonaskop high site to assess the linking problem being experienced.
Matt collected Mike at 07h00 Sunday morning, also at 7 degrees.
We met Jan in Stellenbosch at 07h45 and loaded equipment we would need.
Departed Stellenbosch 08h00. A beautiful and scenic drive out to the high site.
We arrived at 10h15 and proceeded with assessing and fault finding. The weather was clear and favorable, but there was an extremely cold wind blowing.
After swapping out equipment and doing various tests, we found that there were a couple of issues with repeater, controller and radios on site.
The 2 linking radios, and the controller were removed and the 2m repeater was left on site, as it was working ok independently.
The removed equipment will be repaired and tested and then replaced again.
We left site around 12h40 and arrived back in Stellenbosch 15h20.
A special thanks to Jan, ZS1VDV for coordinating the site visit and his preparation of equipment for the day.
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.
Replacing cable ties and working on 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.
Matt ZS1MTF, JP ZS1JPM and Jan ZS1VDV investigated the power outage at Jonaskop. The sun was out, some wind was blowing and some left over snow was visible.
An upstream Eskom breaker was reset.
With the storms, the hut took a bit of a beating. The one air vent cover needed to be replaced and the outside temperature sensor wire repaired.
The backup battery distribution was upgrade and fuses installed. The site is now ready to take an easy install of 2 more batteries.
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.
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.
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
Local population
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 5 June, the team consisting of Jan ZS1VDV, Paul ZS1V, Mike ZS1TAF, David ZS1DDK and Andre ZS1AN headed to Jonaskop to attend to a number of issues at the 145.675 repeater site.
It was a sunny, but cold day at around 1C when the team arrived, but warming to a comparatively pleasant 7C by the time we left at around 5pm. A light breeze aided in keeping everybody’s hands cold.
Jan ZS1VDV selecting the correct scalpel
The following tasks were completed:
Replacement of a faulty speech chip in the controller and re-enable temperature and voltage measurement macros
Correction of the audio emphasis for audio from the links to the 2m repeater
Realignment of audio talk through levels
Installation of a second backup battery
Reinstallation of the VHF ferrite circulator and harmonic filter after the latter was retuned
Improve station grounding
Install vent covers on the equipment housing
Investigate and correct interference problem on the 2m repeater – VHF SWR was high (> 2.5)
Mike ZS1TAF and Paul ZS1V attending to the VHF SWR
At the end of the day, a light crackle in the repeater tail was traced to the audio mixer in the controller. This was also corrected.
