A whole pile of donation acknowledgement letters were received. All the details in the report right here. Enjoy.
Repeater Status Report 20190709
Here is the latest status report for your reading pleasure.
Hanskop maintenance 20190707
Problem: About 2 months after the big rebuild in September 2018, the UHF repeater was starting to drop out after a few seconds of transmission.
This lead to a long fault finding process with help from the high site managers’ personnel to save on trips to site, on a very bad road.
After 4 months of problem finding, it was concluded that was not the repeater and not the antenna, but most probably the duplexer.
The WCRWG do not have a spare 1.6MHz split UHF duplexer. One was constructed out of spare notch cans. This happened over a process of 2 months, to make up a custom duplexer coax harness and trying to get the pass-through SWR as low as possible. With everything ready, it took some planning to get the vehicle, weather and correct people aligned to go do the swop out repair on site.
It started at around 06:30 today. Packed the repeater, swop-out duplexer and all required tools. Next was the pickup of keys.
The team (Sybrand ZS1SJ, Paul ZS1V and Jan ZS1VDV) got together at around 08:00 to repack all equipment into the 4×4 to go up.
Around 08:15 the trip up started. Sybrand got a few chances to use the 4×4 capabilities of his vehicle.
On site the repeater was reinstalled. Next the debugging of the high SWR around the duplexer was completed. SWR straight on antenna 1.2. SWR through duplexer to antenna 1.8. SWR through duplexer to dummyload 1.0. It was concluded that the current duplexer on site was also not the problem. With a bit of head scratching a short patch lead was added to the antenna feedline. That took the SWR through the duplexer down from 1.8 to 1.3.
The last part was to correct the power sensing of the controller. Suddenly the UHF repeater started to restart on transmission. With some debugging it was found that the 10 A PSU used on the UHF repeater was suspect. This PSU was removed and the UHF repeater moved over to the main 30 A. The total current draw is just below 20A on full transmit. The calibration of the power sensing was updated and the voice responses also updated.
DTMF:
- 8323 – Controller Voltage (This is the main power supply when on mains, and battery when on backup power)
- 8324 – Main PSU voltage
- 8325 – Battery voltage
Everything was packed up and returned home. Home around 13:00 and unpacked by 13:30.
Repeater Status Report 20190702
First report of the month and we get some nice donations. Read all about them inside. 🙂
Jonaskop maintenance 2019-06-29
On 26 June it was reported that the repeater is not functioning and constant keying.
From the detailed fault report it was concluded that a power supply is the most likely problem. However with power problems, there could also have been big equipment failure.
Paul ZS1V and Peter ZS1PDE assisted with the ordering and pickup of a replacement PSU for the site.
Jan ZS1VDV packed for all scenarios on Friday evening. This included making controller link cables for the spare repeater.
Saturday started very early with Sybrand ZS1SJ meeting up with Paul to collect keys and replacement PSU in Somerset West.
Sybrand next was picked up Jan ZS1VDV and loading all equipment in Stellenbosch at around 07:20.
A route via Worcester to Jonaskop the best option, as the Franschhoek pass was closed and the round via Grabouw to Villiersdorp was reported on Thursday to have loads of sand after the winter storms,
Arrived on site, it was very clear that this was going to be a very cold and windy visit. Around -2.5 C and very strong gusts of wind.
As soon as the repeater hut was opened, it was found that the repeater was on backup power (measured to be 12.8V). This was very strange as the repeater never went to backup power during the week. Next the PSU and 220V was tested all over the site, and found the no 220V was available. With out more information, it was decided to swop the PSU.
On the way down, Eskom was found working on the line. At this stage it was clear why the repeater was on backup power. In the process of driving up, Eskom switched of the 11 KV line to work on it. The 11KV line was hit by lightning and an isolator needed to be replaced. With the one line on the delta 11 KV line down, the transformer would have converted to 220V star 3 phase, but the 220V would not have been stable. After about 1.5 hours the repair was concluded. They had to use a gas flame to shrink the heat shrink on the lug.
Returned to site, checked that all power was up and running. It was found the that controller configuration was corrupted and needed to be updated. The main and battery sense DTMF codes was also swopped as listed on the TODO list for the site.
The link radio the Hanskop audio levels could not be realigned as it was just to cold and wind to strong.
The tower guy lines was giving a quick inspection and found that they will need service on next visit.
Unpacked in Stellenbosch around 14:00.
Sybrand last stop at home around 14:30 for a total round trip of 330km.
Repeater Status Report 20190618
This week’s report – a barren inbox.
Sutherland Repeater maintenance 2019-06-11
Transmitter:
Output power: 21.6W
Frequency error: -315Hz
Deviation: 1.49kHz
Receiver:
Sensitivity: 0.683uV
for 12.2dB SINAD (NOT CCITT weighted)
@1.5
kHz deviation AT 1kHz
Squelch Could
not be measured. Comms test set only goes down to 0.350uV
TX Filter unit:
RF power before filter: 42.63dBm
(18.3W)
Return loss: 3.4dB !!!!!!(VSWR 1:5.23)
RF Power after filter: 34.3dBm (2.7W)
Antenna Return loss: 15.7dB (VSWR
1:1.39)
After tuning the filter unit, I got the following results:
RF power before filter: 42.85dBm
(20.1W)
Return loss: 23.2dB
(VSWR 1:15)
RF Power after filter: 40.34dBm
(10.3W)
Antenna Return loss: 15.7dB (VSWR
1:1.39)
RX Filter unit:
Measured loss at intended frequency: 20.6dB
Isolation at plus 600kHz Around
50dB
After tuning the filter unit, I got the following results:
Measured loss at intended frequency: 2.4dB
Isolation at plus 600kHz Around
50dB
Conclusion:
I could probably get better results tuning the filters if I had the directional
coupler with me. Maybe next time. I would have also preferred to have the
manufacturers specifications to test against but did not have at the time. In
my experience the repeater performs well according to what I measured. I tested
the repeater from the town using a 5W hand held radio and got full quieting
from the repeater with good quality audio. I there is someone who can test from
the N1, some feedback would be great.
Report compiled by Neville Gleeson (ZS1NEV)
Site tested by: Neville Gleeson (ZS1NEV) and Deon Lamprecht (ZS1AFU)
Repeater Status Reports: 20190604 and 20190611
Two for the price of one this week 🙂
Hawequa maintenance 2019-06-09
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.
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.
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.
Repeater Status Report 20190528
Still no reports in my inbox.