Maintenance Hawequa 20160709

Posted on 9th Jul 2016 by ZS1Z

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

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)

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

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

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

Posted on 3rd Jul 2016 by ZS1V

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. Jan 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

Posted on 5th Jun 2016 by ZS1V

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

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

Photo credit: David ZS1DDK

The team arrived home again around 19.30.

Paul
ZS1V

Maintenance Piketberg 2016-05-28/29

Posted on 29th May 2016 by ZS1Z

ZS1VDV went to Piketberg on Saturday to resolve 3 issues.

The power drops almost 1 second after transmission starts
Add filter to link radio fan
Correct emphasis settings on radios

This was suppose to be a quick 2 hour visit, but again turned out to be much more.

The morning started around 09:00 on site.

The first step was to investigate the circulator as it was suspected to be the reason for the power drop. After checking the circulator and 2nd harmonic filter with a mobile network analyzer they where found to be in order. (about 0.5db insertion loss on circulator and a 40db filter on the 2nd harmonic). It was then found that the duplexer was causing a 1.7 SWR on the TX path. This was very strange because the duplexer was tuned on last visit. The duplexer was removed from the rack and rechecked and found that the possible cause for the hi SWR is wrong length linking cables between the cans. They only onsite solution was to “play” with the tuning of the duplexer (the result was that about 10db isolation was lost). This is not optimal, but would still work. The SWR now was 1.1 between the duplexer and circulator. This however did not take the power reduction away. The last step was to test the repeater on its own with an SWR meter and dummyload. No SWR problem, but the cause for the power reduction was found. The internal filters of the repeater needs to be re tuned and this cannot be done on site.

The filter was added to the fan of the link radio.

Emphasis settings was changed on the link radio and link cable updated on the repeater. Audio was aligned. At this stage it was about 13:30 with no water or food, this became a very long day.

On Sunday ZS1VDV returned to site to recheck the audio alignment and a few small tweaks was made.

TODO:

The repeater and duplexer needs to be swopped out. The repeaters filter re tuned and the proper length linking cables for the duplexer made.

Maintenance Hanskop 2016-05-17

Posted on 17th May 2016 by ZS1Z

It was an early start 05:45 in Stellenbosch. 06:10 Somerset Wes. 06:30 Strand.

ZS1VDV, ZS1V and ZS1YT were on site at 07:30.

Moved temporary brackets further apart to stabilize new 6m galvanized pole.
Stays were added.
Mast groundwire added.
Antennas moved further apart.
All seals were redone in dry weather.
Cable tray was reinstalled.
VHF repeater SWR 1.1, UHF repeater SWR 1.2 and Jonaskop Link Radio SWR 1.7.
New power supply installed (Donated by ZS1K).
UHF repeater and Jonaskop Link Radio is connected to new power supply.
VHF repeater connected to Nova power supply.

Collapsed tower visible on the left. WCRWG temporary installation visible on the far side of the building with Jonaskop link beam at the top.

Default linking moved to all linked.
DTMF updated to measure 2 power supplies.

Home 15:00

Maintenance Hanskop 2016-05-14

Posted on 14th May 2016 by ZS1Z

Jan(ZS1VDV) started to pack all the equipment at 05:15 in Stellenbosch.

Picked up some Heliax and antennas at (Paul) ZS1V 06:10 in Somerset West. From there it was a quick hop over to get (Rassie) ZS1YT.

On our way up to the high site, we noticed that we could not see our tower, but did not think much about it, as it could be the angles from the back or maybe weather.

Tower on the ground

When we got on site (07:50), it was very clear that every plan of what was going to happen was 100% out the door. The first action was to recover all our current Heliax and antennas. We lost a RG214 connector (ripped from the cable), the recovered Heliax still needs to be tested but some real bad bends and marks are visible.

Next was to assess if we could do a temporary hack antenna installation with everything on site, which was not possible. With the help of ZS1V the plan was worked out. Andre(ZS1AN) and Kobus(ZS1K) did a few supply store stops and got a pole, more heliax and other sundries from ZS1V to bring to the high site.

ZS1VDV working on linking cables

While we where waiting for the supplies, ZS1VDV did a few changes to the controller link cables and audio alignment. A new 20A solid state power supply was installed. The next step was to clean and prep the area for antenna installation.

ZS1YT prepping Heliax

ZS1K standing infront of the tower on the ground, which is not very bright 🙂

ZS1VDV drove down to the gate to open for ZS1AN and ZS1K. They arrived on site around 13:00. As soon as they arrived the weather started to turn for the worse. ZS1AN and ZS1K installed the 2 mounting brackets and ZS1VDV and ZS1YT prepped the new Heliax to be installed. Then ZS1VDV had to install the antennas on the mast in some very big wind and wet weather. A new FDC145 was installed for the VHF antenna, the dipole was reused for the UHF repeater and another UHF yagi was installed and pointed towards Jonaskop. The SWR was measured. The VHF SWR was 1.7 which was a bit high, but in the weather and time frame could not be corrected. The UHF repeater and link SWRs were 1.5 and 1.4. At this point it was also identified that there is a power problem on site as every now and then when touching a coax, a shock was felt. This was not ignored, just not enough time to resolve it at get everything running again.

Sealing cables

In a very small weather opening, the connectors was sealed. The last steps was to cable tie all the new Heliax and clean up the site.

Antennas after install

We left the site around 16:30.

At Strand ZS1AN and ZS1K left for home. ZS1VDV dropped off ZS1YT at home and the recovered Heliax and antennas at ZS1V.

Got home around 18:45 and the vehicle was off loaded by 19:15.

It was one of those days where you leave home in the dark and get home in the dark.

There is a list of todo items for the site. A future maintenance trip will be required.

For the first time ever in the Western Cape Repeater Working Group history. A contact was made between the Piketberg and George repeaters. The path for this contact, Piketberg -> Haweqau -> Bellville -> Hanskop -> Jonaskop -> Riverdal -> Danabaai -> George (8 hops, 15 radios and repeaters)

Maintenance Jonaskop 2016-04-17

Posted on 17th Apr 2016 by ZS1Z

On Sunday (2016-04-17) Jan (ZS1VDV) and Paul (ZS1V) did maintenance at Jonaskop.

Left home around 06:30.
Drove to Jonaskop via Somerset West arrived on site 09:00.
It was very cold on site and windy. This made everything up to 12:00 happen slowly and with cold hands.

Paul turned the Hanskop link antenna from vertical to horizontal polarisation. Had to replace the bracket as the U-bolts broke off due to rust.

Jan resolved the power issue on site. The plastic cap on the positive terminal of the power supply was melted. The reason for this could be that it came loose due to temperature cycles. The plastic was removed and the terminal tightened with a tool.

The next step was to swap around the two GM300 link radios due to deviation differences in the models. Riversdal is 16k0F3E and Hanskop 11k0F3E. Frequencies were updated accordingly. Then the radios had to be realigned as the old Hanskop (now Riversdal) radio was off frequency by 2.8 kHz.

We started the process to change the VXR9000 audio input link from the controller to the correct pin for emphasis. This failed due to a impedance mismatch which could not be resolved on site.

The controller was also found to have speech out problems. For now only the linking macros work and all other have been deactivated till a new speech process chip can be installed.

The duplexer was re-tuned. The insertion losses were close to 2dB and the rejections were around 72dB. After re-tuning the results were: TX (1.6db insertion, 86.08db rejection) RX (1.55dB insertion loss, 81.71 dB rejection).

The circulator was removed as it was giving bad SWR (3).

Left site around 16:45 arrived home at 19:00

George & Dana Bay Installations

Posted on 11th Apr 2016 by ZS1V

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.

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

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

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

Receive 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 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

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

Photo credits: David ZS1DDK

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.

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

Posted on 14th Mar 2016 by ZS1V

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 Jonaskop 2016-03-09

Posted on 9th Mar 2016 by ZS1Z

ZS1TAF went to Jonaskop.

He realigned the Hanskop link antenna but was not successful in re-establishing the link.

On the next attempt, it would be best to have people on both Jonaskop and Hanskop side.