Author Archives: ZS1V

Bottelary repairs 20200530

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On Saturday 30 May, John ZS1EQ, Paul ZS1V and Jan ZS1VDV visited the Bottelaryberg highsite that hosts the 145.575 DSTAR and 438.300 multimode digital repeaters. While both repeaters were operating correctly, the internet link to the site had been down for several months, limitting the utility of these repeaters.

The internet link was re-established and a general health check of the site was performed. The gateway unit for the VHF DSTAR repeater was found to be faulty and removed from the site. As a consequence the UHF multimode repeater is now fully functional, but the DSTAR repeater is not linked to the internet.

A battery switch over and low voltage cutout unit on the backup batteries was installed.

Jonaskop maintenance 20200509

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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.

Hawequa Maintenance 20200425

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On Saturday 25 April, ZS1VDV, ZS1V and ZS1RK visited the Hawequa site, home of the 145.650 repeater and 438.800 link repeater between Piketberg and CPUT. The 4 x 200AH backup batteries donated for the purpose were installed with their fusebox and charger.

In addition the Vertex/Motorola repeater system swapped out for a pair of Kenwoods, a TKR750 VHF and a TKR850 UHF.

Kenwood TKR-750 and TKR-850

The waterproofing of the antenna connectors was also inspected and found to be in good order for the coming winter.

ZS1RK inspecting the UHF antenna

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.

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.

Helderberg 70cm DMR repeater installation

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On Wednesday 27 September at about 16:30, Paul ZS1V, Jan ZS1VDV and Wiaan ZS1WB met a representative of our Internet sponsor at the Helderberg high site to install one of the WCRWG Motorola SLR5500 DMR repeaters.  The Helderberg high site is one of the easier ones to access due to its relatively low position at around 500m ASL and its proximity to the urban area of Somerset West.

Despite the relatively low elevation in comparison to other WCRWG high sites it is quite prominent above the 100m ASL average ground level.  Good coverage is expected over most of the False Bay side of Cape Town, the Cape Flats and Northwards to Stellenbosch.

The team installed a Webb HD400 UHF dipole antenna and a short run of about 8m of EC4-50 Heliax.  Shielded and UV resistant UTP cable was run from the repeater enclosure to a nearby enclosure for the DMR repeater’s Internet access.  The SLR5500s configuration was updated to reflect the new IP environment before everything was tested and found to be satisfactory.  Antenna SWR was measured at 1.2:1.

A first QSO on the new repeater was had on talkgroup 655 between Paul ZS1V and Koos ZS5KDK before the team wrapped up and left the site just before 19.00.