Author Archives: ZS1V

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.

Maintenance Constantiaberg 2017-07-25

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On Tuesday 25 July, Sean ZS1BSD and Paul ZS1V headed to Constantiaberg to attend to the 145.700 repeater which was transmitting, but not modulating.   The weather was only a few degrees above freezing and it was raining with only 10m visibility at times.  The lower part of the road was muddy an churned up by the heavy logging equipment in use in the area that is still clearing up the remains of the fire that devastated the area about 18 months prior.

Although the Motorola appeared to be working after a reset, it was removed for further testing and diagnosis and the PRF1050 backup repeater was installed in its stead.  The PRF1050 has been fitted with a new CTCSS decoder, courtesy of Sean ZS1BSD.  The required CTCSS deviation level is now more in line with typical commercial repeaters and not the very high levels required by the previous CTCSS decoder on the PRF1050.

Access to the site remains challenging.  Specific access arrangements had to be made with the nature conservation officials with the help of Sentech.

ZS1BSD appreciating the fine conditions

 

Jonaskop maintenance

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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.

Hawequa maintenance 20170128

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Paul ZS1V went to the Hawequa 145.650 repeater site on Saturday morning 28 January, to diagnose a fault that was causing the link to operate in one direction only.

The effects of the recent fire were evident.  The veld had burned on both sides of the access road and to within 1m of our building that houses the repeater.  Fortunately, both our building, tower and the area in between where the coaxial cables are in the cable tray, were spared.

The destruction was quite wide-spread.  The poles supporting the electrical feed to the site have been burned and will likely need to be replaced.  For now, the power is still on.

Some diagnostics on the link controller were done and some settings adjusted.  The link is functioning correctly again, albeit still with slightly misaligned audio.  This will remain the case until firmware fix is provided by the link controller suppliers, enabling the return to the required configuration.

Maintenance Hawequas 20160703

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Jan ZS1VDV, Dirk ZS1VDB and Paul ZS1V departed Stellenbosch for the Hawequa 145.650 site at about 9.30am on Sunday 3 July.  It was sunny but cold, with a light dusting of snow on some of the nearby peaks.  Dusting of snowJan applied a filter to the cooling fans and a modification to the 2m repeater linking cable.  The latter being necessary as part of a correction to the incorrect emphasis on audio from the links to the 2m repeater.  The change necessitated a complete re-alignment of the audio through the link controller.

Soldering in a tight space

The SWR on the 2m antenna system was tested and found to be satisfactory.  An inspection of the antennas and the coaxial feeds also found everything in good order.

A source of interference on the 2m repeater was also identified and this will be taken up with the operator of the equipment in question.

Ice on the rocks

The team returned to Stellenbosch at about 2.30pm in dire need of hot coffee.

Paul
ZS1V

Maintenance Jonaskop 2016-06-05

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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

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.

FLTR Paul ZS1V, Jan ZS1VDV and Andre ZS1AN

FLTR Paul ZS1V, Jan ZS1VDV and Andre ZS1AN

Photo credit: David ZS1DDK

The team arrived home again around 19.30.

Paul
ZS1V