Piketberg Visit

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.

Maintenance Piketberg, Hawequa and Bottelary 20180113

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.

Maintenance Hawequa 20170625

Today Jan ZS1VDV and David ZS1DDK went to the site to service the power problem.

It was found that the DC power distribution box was faulty and replaced.

VHF repeater SWR was tested (1.2)
UHF repeater SWR was tested (1.4)
Backup battery voltage was measured (13.8V)

Maintenance Hawequa 20170617

Jan, ZS1VDV went to Hawequa to investigate why the 650 VHF repeater was not working.  The worst was suspected, that the mast did not survive the storms.  Luckily this was not the case.  The mast and building was in good condition.

It was found that the repeater was on, but as soon as it started to transmit it restarted.  After long debugging, it was found that the repeater was not at fault but the dc power distribution box and power supply.  The fault was corrosion on the conductors in the connectors (dust and soot blasted in by the storms, as well as intermittent power would have caused this), as well as crackling sound in the power supply.

The power supply will have to be replaced on a next visit and serviced.

It was great to see the water flowing off the mountain.

Maintenance Hawequa 20170221

The morning started early and ended late. The wind on site provided an extra challenge, gusting at near gale speeds.  Paul (ZS1V) started at 05:30 and met Jan (ZS1VDV) to load equipment in Stellenbosch at 05:50 before arriving on site at 06:20.

Battery was tested (12.6V).
Eskom power was down on the site, so no further debugging could be done.
Back in Stellenbosch 08:00

Left Stellenbosch 18:10.
On site 18:45.
Labelled all plugs.
Reprogrammed controller. (Flash memory in controller was corrupted after too many reboots.)

Sunset

Tested everything and left site 19:45.
Back home 20:45.

Hawequa maintenance 20170128

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 Hawequa 20161009

ZS1YT, ZS1VDV and ZR1SWB went to Hawequa to investigate some errors after big Eskom/power outages/instability the last few weeks.

Vehicles Parked

Vehicles Parked

Wellington view

ZS1VDV and ZR1SWB

The morning started at around 07:00 with packing all tools and equipment. Left Stellenbosch around 08:00. On site at around 08:45.

First checked all voltage levels. It was found that the Benton Charger again was off and not charging the battery. The charger was replaced by an 10A Victron Energy charger which was donated by ZS1FX.

The link controller opened, and no damage could be seen. The audio paths was traced and all seemed in order. A complete firmware reload and configuration reprogram was done. At a stage last week the controller was rebooted numerous times(by power outages/spikes) and this caused the configuration to go faulty.

Left for home around 10:15.

Home and unpacked by 11:30.

Maintenance Hawequa 20160709

Jan (ZS1VDV) and a friend departed to Hawequa around 09:00

Arrived on site 09:45, little to no wind and about 5 degrees.

View towards Worcester from Hawequa

View towards Worcester from Hawequa

Started to try reproduce the current interference problem. Could only get it to happen when our repeater started to transmit first and the the commercial repeater in our hut second.

Next step was to measure our duplexer and bandpass filter (RX) and second harmonic filter after the circulator. I did not check SWR, because this was checked on the previous visit. Nothing could be found wrong with our filters and duplexers. (The bandpass filter on RX does add about 2dB insertion loss on 145.050 Mhz and will need to be replaced as this sets our total insertion loss for the duplexer and bandpass filter to about 4 dB).

145.650 Duplexer (Sinclair Q202)

145.650 Duplexer (Sinclair Q202)

Bandpass filter in RX path

Bandpass filter in RX path

Then scanned with a SDR spectrum analyzer. Found that the commercial repeaters RX and TX frequencies was labelled wrongly. Could not find any strange signals. About -85 dB filter on the TX frequency of the commercial repeater in the input path.

SDR Spectrum Analyzer

SDR Spectrum Analyzer

So the only conclusion was that the interference is a mix of our output signal, but mixed with the commercial repeaters signal. The second harmonic filter was replaced by a bandpass filter to make sure that our transmission path is clean.

New bandpass filter installed

New bandpass filter installed

This did not solve the problem.

For now removed the CTCSS on TX path. Will check in with commercial repeater owner to add a circulator to their repeater.

Resolved the battery voltage that was reading wrong. The sense wire got damaged and was replaced.

Left for home around 13:50, about 9 degrees.

Arrived home around 14:30

Maintenance Hawequas 20160703

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 Hawequa 2016-03-05

ZS1V and ZS1VDV responded to investigate the UHF repeater outage.

Left Somerset Wes at around 21:15,

On site it was found that the main switch again failed. The switch was bypassed for now.

Higher rated and better quality switches must be sourced.

Arrived home around 00:20.