Maintenance Constantiaberg

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

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

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

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

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

George & Dana Bay Installations

On Friday 8 April a team from the Western Cape Repeater Working Group consisting of Johann ZS1JM, Jan ZS1VDV, Paul ZS1V, David ZS1DDK, Mike ZS1TAF and Rassie ZS1YT left from Cape Town and headed to Mossel Bay to meet up with a team coming from the Eastern Cape consisting of Chris ZS2AAW and Trevor ZS2AE. The mission they had chosen to accept was to recommission the George 145.700 repeater and to reroute the 70cm link that had previously gone from Riversdale to George along a new path via Dana Bay, home of the local 145.600 repeater.

The teams were met at the Dana Bay repeater site at 8am by 145.600 repeater custodian Beat ZS1HB at 8am on Saturday morning where everybody proceeded to get stuck in. Corroded u-bolts and nuts were overcome to remove three antennas, which were replaced with a single, dual band high gain antenna. The old RG213 and LMR400 feedlines were removed and replaced by a 20m length of EC4-50 half inch heliax.

From left: Johann ZS1JM & Mike ZS1TAF

Getting ready.  From left: Johann ZS1JM & Mike ZS1TAF

The 2m duplexer was given some fine-tuning to reduce the insertion loss and improve the rejection. A new 70cm repeater was installed to handle the linking between the Riversdale 145.650, George 145.700 and Brenton-on-sea 145.675 repeaters. In the future the local Dana Bay 145.600 repeater may also be linked into the system.

Fine-tuning. From left: Beat ZS1HB, Jan ZS1VDV, Chris ZS2AAW & Trevor ZS2AE

Fine-tuning. From left: Beat ZS1HB, Jan ZS1VDV, Chris ZS2AAW & Trevor ZS2AE

Antenna going up. Rassie ZS1YT and Mike ZS1TAF on top of the water tower

Antenna going up. Rassie ZS1YT and Mike ZS1TAF on top of the water tower

Jan ZS1VDV, Johann ZS1JM, Paul ZS1V and David ZS1DDK fitting feedline connectors

Jan ZS1VDV, Johann ZS1JM, Paul ZS1V and David ZS1DDK fitting feedline connectors

Dana Bay job done. Dual band antenna visible at the top right. Chris, Jan and Trevor in picture.

Dana Bay job done. Dual band antenna visible at the top right. Chris, Jan and Trevor in picture.

Receive path after fine-tuning

Receive path after fine-tuning

Transmit path after fine-tuning

Transmit path after fine-tuning

By 10.30am the teams had completed the work, cleaned up and packed up. After being treated to some of Beat ZS1HB’s fabulous Swiss cheese and onion pie and some cold refreshments, the teams headed 60km up the road to the George repeater site.

At George, the teams were met by Francois ZS1Q and Peter ZS1PHD. A 2m antenna, a directional 70cm link antenna and two EC4-50 half inch heliax feeders were installed. The 2m repeater and 70cm link were also installed and connected to the battery bank. The repeater and link were fine-tuned for deviation and talk through levels and stations from Cape Town and the Overberg were soon heard propagating through the link system via the Villiersdorp 145.675, Riversdale 145.650 and newly installed Dana Bay 438.725 repeaters.

Mike ZS1TAF fitting the antenna & Paul ZS1V fixing the clamps and feedline.

Mike ZS1TAF fitting the antenna & Paul ZS1V fixing the clamps and feedline.

Mike ZS1TAF sealing the antenna connections & Paul ZS1V fixing the clamps and feedline.

Mike ZS1TAF sealing the antenna connections & Paul ZS1V fixing the clamps and feedline.  Johan ZS1JM and Francois ZS1Q assisting.

VHF duplexer with circulator, 2m repeater & 70cm link

VHF duplexer with circulator, 2m repeater & 70cm link

The tower at George showing the 70cm corner reflector linking to Dana Bay and the 2m collinear for 145.700

The tower at George showing the 70cm corner reflector linking to Dana Bay and the 2m collinear for 145.700

The work was completed at around 3.30pm on Saturday and the teams retired to their respective accommodations. On Sunday morning the Western Cape team headed to the Riversdale 145.650 repeater site with the intention of re-aligning the link antenna that had previously linked Riversdale to George, to point to Dana Bay. The Eastern Cape team headed to the Brenton-on-sea site to assess the work to be done there as the next site along the link system needing recommissioning.

At Riversdale, the antenna alignments were checked and the connections to the feedlines re-sealed. The 70cm link to Dana Bay was adjusted as it was slightly off frequency. In the process, the teams also communicated via the links, proving the intended link path from Brenton-on-sea to Dana Bay is also good.

Rear from left: David ZS1DDK, Paul ZS1V, Jan ZS1VDV, Chris ZS2AAW, Rassie ZS1YT, Trevor ZS2AE. Front from left: Mike ZS1TAF, Johann ZS1JM

Rear from left: David ZS1DDK, Paul ZS1V, Jan ZS1VDV, Chris ZS2AAW, Rassie ZS1YT, Trevor ZS2AE. Front from left: Mike ZS1TAF, Johann ZS1JM

Photo credits: David ZS1DDK

Mike ZS1TAF resealing the Riversdale to Villiersdorp link antenna connection.

Mike ZS1TAF resealing the Riversdale to Villiersdorp link antenna connection.

Jan ZS1VDV getting the Riversdale to Dana Bay link radio back on frequency. Johann ZS1JM and David ZS1DDK in picture.

Jan ZS1VDV getting the Riversdale to Dana Bay link radio back on frequency. Johann ZS1JM and David ZS1DDK in picture.

We would like to thank the numerous donations from individuals and clubs, some of them from outside the service area of these repeaters, that made this effort possible.

-.-. .-..

Maintenance Hanskop 2016-03-13

On Sunday 2016-03-13, ZS1V and ZS1TAF went to Hanskop to further troubleshoot the Jonaskop link problem. It was 5 degrees, windy and raining, limitting the amount of work that could be done outdoors. Nonetheless, several tests were done with a handheld 70cm beam and a handheld radio. Some re-orientation of the Jonaskop link antenna was also tried.

The functioning of the link controller itself was also verified as correct.

The Jonaskop link radio was removed for bench testing. The SWR of the link antenna was found to be unnacceptably high at the link transmit frequency and will be replaced on a subsequent trip.

Maintenance Riversdale 2016-01-30

On Saturday 30 January, David ZS1DDK left home at 5am to take Andre ZS1AN and Paul ZS1V to the Riversdale repeater site. The 2m antenna system had been previously diagnosed as faulty and so the team set about removing the old antenna and feedline and installing a new feedline and upgraded antenna.

ZS1DDK eliminating some redundant adapters.

ZS1DDK eliminating some redundant adapters.

The old antenna had been installed at 6m and was also not clear of some local obstacles. The new antenna, a two stack Webb FDC145 folded dipole system was installed with its centre at about 12m AGL.

ZS1V at the new antenna position.

ZS1V at the new antenna position.

The RX path of the duplexer was checked on the spectrum analyser and found to be good. The TX path showed good SWR.

Duplexer receive path showing insertion loss and TX rejection

Duplexer receive path showing insertion loss and TX rejection

The team rounded off the day with an early dinner in Swellendam and reached home at about 6pm.