Hermanus maintenance 20170212

David (ZS1DDK), Jan (ZS1VDV) went to do some maintenance on the Hermanus repeater.

With the last installation of the repeater it was found that the repeater rf sensitivity was not what was expected and needed to be corrected.

The weather was on and off with rain, the same as installation day, which did not make it fun.

Rain, not fun.

Started 06:30 in Bellville.
Pickup and pack equipment in Stellenbosch 07:15

Equipment packed

Left Strand around 08:00
Arrived on site 09:15.
Debug repeater sensitivity. In the process to realign the front-end, it was found that one of the 4 notch filters tuning pots need to be replaced as it was damaged.
The spare repeater was installed, audio aligned and link controller reconfigured for new repeater.
Did some testing with Sam (ZS1OR). The spare repeater is better, but still some areas need to be looked at.
Left site around 11:30.
Extended the power supply power lead with 2m.
Got some “quick” lunch on the way back.
Unpacked at Stellenbosch 14:30.
Back in Bellville 15:00.

Link Installation Hermanus 20170115

ZS1TAF left home at 07:00. ZS1DDK, ZS1VDV, ZS1V and ZS1OR were collected and all the equipment was loaded in 2 vehicles.

The team arrived on site at about 09:45.

View

Unpacking

The weather was windy, misty and there was some rain to complicate matters. The team all got stuck in and many of the tasks were executed in parallel.

Raining, ZS1TAF sealing new UHF antenna, ZS1V keeping rain off ZS1VDV tuning the duplexer

The first step was to confirm the correct SWR on the current VHF installation.  This was found to be an acceptable 1.2:1.

The previous repeater was removed and the hut cleaned out.  A Webb HD400 UHF dipole, fed by half inch Heliax and an LMR400 patch lead, was installed with lightning protection, for the link to Hanskop some 40km away.

ZS1TAF sealing the UHF antenna with ZS1OR

The duplexer was retuned which improved the insertion loss from 3 dB to 1.5 dB, and the rejection from 65 dB to 82 dB).

145.725 duplexer results after tuning by ZS1VDV

The UHF power output was measured at 2W and SWR on the antenna system after installation at 1.1:1.

As with many of the WCRWG repeater installations, the new link controller installation includes inside and outside temperature sensors as well as a DC voltmeter that can be queried by sending DTMF codes.

The repeater power output was measured at 10w after the duplexer.  Due to local noise levels, the squelch of the repeater had to be tightened somewhat.

The team left the site at about 13:00 and everybody was back home with the vehicles unloaded by around 16:00.