Category Archives: Repeaters

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.

    Hawequa maintenance 2019-06-09

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    On Sunday a team of four consisting of David ZS1DDK, Mike ZS1TAF, Markus ZS1MTB and Rassie ZS1YT left home at 7h00 to meet at the site gate at 8h00. The purpose of the visit was to replace the 3 cable stays on the tower with new Stainless Steel cables, clamps and turn buckles.

    Stay replacement

    A 6m dipole was also fitted to the tower for future linking of a 6m simplex radio onto the repeater system.

    Although quite a strong wind was experienced, the temperature on top of the mountain was a very cool 18o C.  Work started immediately with Mike and Markus climbing the tower and David and Rassie fixing the cable stays on the bottom anchor points. The team returned home by about 12h30.

    6m antenna

    The 6m Webb-antenna and Stainless Steel cable was donated by Rassie ZS1YT

    The antenna clamps, cable ties and other hardware was donated by Mike ZS1TAF

    Travelling to the site by ZS1TAF, ZS1MTB and ZS1YT was also donated.

    Onrusberg visit

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    On Sunday 4 November, a team consisting of David ZS1DDK, Jan ZS1VDV and Paul ZS1V visitted the 145.725 repeater site at Onrusberg with the intention of returning the repaired Tait repeater and retrieving the Kenwood TKR-750 which had been put there as a temporary measure.

    David collected Jan at 06:45 and Paul at 07:15.  The team reached the site at around 09:30.  The Tait was re-installed and the Kenwood removed, but despite introducing a bandpass filter to the receive path, the Tait’s front-end was not suited to the high noise on the site.

    Consequently, the Kenwood was returned to service.  The bandpass filter was left in place.

    Photo: ZS1DDK

    Piketberg Visit

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    On Saturday 3 November, Jan ZS1VDV and Paul ZS1V left Stellenbosch at 06:00 to visit the 145.625MHz repeater site at Voorstevlei near Piketberg.

    Towards the end of October the UHF radio for the link from Piketberg to Hawequas locked into transmit.  The link repeater at Hawequas had to be temporarily disabled to prevent the rest of the link network also locking in transmit.

    The team arrived at the Piketberg site at around 8am.  The problem was narrowed to a faulty buffer chip in the link controller.  The chip was replaced with a spare and the fault cleared.  The link controller was also updated to the latest firmware.  A bandpass filter was also added to the receive path.  That eliminated interference from a nearby DMR repeater.

    At 09:45 the team packed up and departed Piketberg for Hawequas.  There, the link controller settings were adjusted and a damaged connector seal on one of the antennas was repaired.

    The exterior temperature sensors at both Piketberg and Hawequa have not stood up to the elements and are faulty.

    The team arrived home just after noon.

    Constantiaberg maintenance

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    On Thursday 11 October, Mike ZS1TAF and Paul ZS1V took a day off work to take advantage of an opportunity to access the Constantiaberg Sentech site, home of the 145.700MHz repeater.

    The site was last visited by Sean ZS1BSD and Paul ZS1V during mid-2017.  At the time, they diagnosed a problem with the antenna/feedline, but there were no Sentech personnel on site and so, despite being certified to climb, Paul could not attend to the antenna problem.  Since then, there have been numerous changes to the management at Sentech and communication has been difficult.  Gustav ZS1NZ, who works for Sentech, alerted the WCRWG to an upcoming Sentech maintenance run earlier in the week and so plans were hastily put in place for Mike and Paul to take leave and visit the site.

    The team met the Sentech technician at the security checkpoint at 9.30am and proceeded up to the site.  Despite the warm weather at the bottom, a cloud on the mountain ensured cold and wet conditions at the mast.  The SWR at the bottom of the antenna feedline was measured at 2.5:1.  The high SWR presumably caused damage to the repeater which was transmitting well below 1W.

    Despite the unpleasant climbing conditions, Mike headed up the tower to open and inspect the connection point between the feedline and the antenna, but this was found to be well sealed and dry inside.  He swapped out the antenna for another and the SWR was measured at the bottom at 1.3:1.  Paul swapped out the repeater and removed the bandpass filter for re-tuning.

    The team left the site just after noon, to enjoy a cold one in a warm and sunny Tokai.

     

    Hanskop rebuild 2018-09-09

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    On the morning of Sunday 9 September, a team consisting of Jan ZS1VDV, Mike ZS1TAF, Rassie ZS1YT, Paul ZS1V, Ohan ZS1SCI and JP ZS1JPM headed to Hanskop to perform a major site re-installation.

    Approximately two years ago, the tower at Hanskop blew over in a storm and all the antennas of the tennants on the site have been temporarily mounted on the building ever since.  The new tower and cable trays have been recently installed and once the owner of the site had moved his own equipment on to the new tower, we were invited to install next.

    The journey to Hanskop has become quite challenging.  The usual access route has been all but washed away, necessitating navigation along some even more minor tracks.  Even those are flood damaged and deeply rutted, some with pools of water 30 to 40cm deep and 50 or 60m long.   The weather on the morning was cold – around 4C – but Hanskop was uncharacteristically wind still and so all team members jumped into action after arrival on site at around 9am.

    While one group removed the temporary antenna pole from the side of the building and removed the antennas from it, another re-organised all the equipment in the rack, moving the equipment up to make space for the new battery backup system at the bottom of the rack.

    New backup batteries

    Rassie ZS1YT constructed a shelf to go over the batteries, allowing the duplexer and bandpass filter for the 2m repeater to stand above them.

    Duplexer and battery charger on shelf

    Equipment reinstalled

    New cable gland plates have been installed in the building. New RG214 patch leads for inside the building were made up and attached to lightning protection devices.

    Feedline connection points for the 70cm repeater, 2m repeater and 70cm link to Jonaskop

    Outside Mike ZS1TAF was left to solo all the tower work after Paul ZS1V was unable to climb due to illness.

    Mike attaching the feedline to the link antenna

    Mike attaching the UHF repeater feedline to the antenna

    Mike installed the three antennas, attached their feedlines and secured all the cables to the mast.  On the ground, Jan ZS1VDV and the rest of the team prepared the feedlines, installing the connectors and routing them in the cable trays to the exterior of the gland plate.

    Feedlines being secured

    Feedline wrangling

    Final measurements showed the antennas reacting well.

    Antennas installed

    The team packed up and left site just after 3pm.

    Maintenance Hanskop 20180707

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    Jan (ZS1VDV) and Rassie (ZS1YT) went to Hanskop reconfigured the repeater controller and did all measurements for the big site power upgrade and antenna migration.

    Most site visits starts the evening before the time with a 1 hour planning and packing session.

    Tools and Spares for trip

    Wake up 06:30, pack vehicle.

    Leave for Strand 07:30 from Stellenbosch.

    Pickup key 07:45.

    Drive to site, which was very long and challenging drive. Had to “find” a way to the top.

    “Finding” the road

    MMMM, where to now?

    Some holes with bakkie for size reference

    08:45 arrive on site.

    With all the power interruptions and no backup power, the site controller’s EPROM got corrupted. Reprogrammed the controller. Changed default for links to VHF and East. (please see updates DTMF updates on Hanskop)

    Did some detail measurement for coax and battery placements.

    10:00 left site.

    11:45 Home in Stellenbosch

    12:00 Finished unpacking.

    Bottelary Maintenance 20180629

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    View from top in mist

    Mast in mist

    ZS1SCI (Ohan) and ZS1VDV (Jan) went to site around 17:00

    UHF repeater ZU9DMR running DMR, D-Star and YSF

    The reconfigured UHF repeater ZU9DMR was reinstalled on site.

    A new gateway was installed for the VHF D-Star repeater.

    Last view of site, with alarm activated

    The site was left around 18:45.  The drive down in the dark and mist was a big challenge.

    Jonaskop Maintenance 20180324

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    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.

    Maintenance Piketberg, Hawequa and Bottelary 20180113

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    Jan (ZS1VDV) and John (ZS1EQ) did a round trip to service 3 sites.

    Started to load the bakkie 07:00.

    Left Stellenbosch around 08:00 and reached Piketberg by 09:45

    At the end of 2017, the Piketberg VHF repeater was removed.  The repeater was serviced by Verstay.  The final transistor was replaced.  A replacement duplexer was prepared during the week. The duplexer was swapped out and VHF repeater reinstalled.  SWR between duplexer and VHF radio was 1.2 and between the duplexer and antenna 1.3.

    Left Piketberg 11:15 and was on Hawequa at 12:45.

    The 10 amp battery charger was swapped out for a 7 amp battery charger.  The 10 amp is designated to go to Hanskop.

    Left Hawequa 13:45 and reached Bottelary at 14:45.

    Removed the UHF DMR repeater for service.

    Back in Stellenbosch and unpacked by 16:15.