RG214 tail removed from 705/Local port feeder705/Local antenna replaced with the new one. The new one has been modified by Rob (ZL3RX), welding up as many of the joints as possible, to avoid corrosion issues and consequent noising up problems.
New south port yagi tried, but does not fit mechanically.
Bracket being manufactured by Rory, and planning to install Easter Saturday.
705/Local antenna tested for noise issues on a couple of occasions since installation, and none

Site visit 22 Apr 2017

Cleared all broom etc around the hut.Removed all braided coax from top pole.
Pulled Ross’s hardline through alkathene duct & into hut with great difficulty.
Tested it & OK.
Fitted pipe rail up NW side of pole.
Disconnected NS south yagi & tested that hardline. All OK.
Moved NS yagi over onto pipe rail.
Removed X50 from top & moved over on to top of pipe rail. Didn’t open & test that coax.
an be done when X50 replaced.
Didn’t get time to get all screws in pipe mounts so need to do that next time.
Mounted new APRS shrouded dipole at top of pipe & connected to 705.
This will be moved to bottom of pipe for APRS when other aerials mounted.
NS local port now on X50 along with APRS.
So all aerial on hardline & no braided coax or chain mounts on top pole.
Didn’t get a chance to do anything on bottom pole. Need to talk to Mt Radio to see
what we can do there. Mike has various readings for coax & aerials tested.
Next step is to decide on what aerials we are going to put up for keeps.
Suggestion is two shrouded diploes for 705 with two feeders into
hut & matching system in the hut. Need to get both feeders exactly the same
length so debate is whether we do it up there or get an accurate
measurement & do the cut & match at clubrooms then take it all up.
Then same for NS local port. But I am inclined to go for a simpler colinear
( but still a professional series if they make one ) for NS local port to
go on top of pipe where X50 currently is?? Keeps other aerials further up the pipe.
Might be an issue getting 2 x hardlines down yellow corrugated duct
so thinking about getting some heavy alkathene & running it on top of
the ground down to hut. With that in mind there is some 6” alkathene
on Trademe at Turners. See 0308421846. A bit of an overkill
but easy to get stuff up & down!! Thinking of offering up to $50
at this stage while we think/discuss it for a few days.
Or what should be our top offer?? $200??

Also – too hard to get new hardlines around 3 corners
into hut central duct so thinking of making a galvanised steel box
on outside & going straight through the wall.

Box = a water/ access trap.

So probably no more up there until we make a decision on aerials & get them made etc.

Rory

Site visit 18th Aug 2017

In summary, January 2016 (using the X50 antenna)

The signal received from 705 using a fixed antenna at my QTH was -53 dBm (with the transmitter running at 100W)

To trigger 705 (with CTCSS tone), I needed - 11 dBm from a signal gen to open the mute, but needed 5 dB more (-6 dBm) to hold the repeater on and hear the test tone (because of 5dB de-sensing of the repeater receiver by it's Tx and site noise).

Today - 18th Aug 2017 (using new antennas)

The signal received from 705 on the same antenna at my QTH is -47.5dBm (with the transmitter running at 58W)To trigger 705 (with CTCSS tone), I need -17 dBm from the sig gen to open the mute, and 2dB to hold the repeater on and hear the test tone (i.e. 2dB de-sense)Performance change

The effective increase in receive performance (including the effects of de-sense) is a 9dB improvement in usable sensitivity

Ignoring the de-sense improvement, the receive performance is 6 dB better than before (i.e. antenna changes only)The effective increase in transmit performance is 5.5 dB (signal level) plus a 2.4 dB reduction in Tx power required to stay legal = 7.9 dB

The repeater receiver improvement is equivalent to a 5W hand- held being able to transmit using 40W.

On the receive side (mobile or hand-held), to get the same the 5dB increase in transmitted signal level in Christchurch, we would have had to run the repeater transmitter at 316W instead of 100W. Instead we have had to reduce the Tx power to 58W to stay within our 200W EIRP license.

Site visit 13 Jan 2017

On Friday 13th Jan 2017 team of seven people (Rory 3HB, Rob 3RX, Rod
3ROD, Mike 3TMB, Morrie 3RP, Steve ZL2UCX and myself 4FZ) spent a
day at Herbert. We met at Diamond Harbour at 0830 and finished
around 1630. We have replaced the mounts with a 48mmOD water
pipe, reinstated the original whip antenna after refurbishment, checked
the duplexer tuning, tested the repeater with Comms Test set, checked
all cables and feeder with VNA. Tidied old feeders and rubbish from the
pole etc.

Net result is 725 is back on air, performance appears by reports so far
(Geraldine/Timaru) to be going well, and measurements from my QTH
support the improvement. Good day, not much wind, good weather, lots
achieved.No change in performance - but this also includes the problem with
this repeater of poor de-sense performance. This shows up with a
base sensitivity of -11 dBm but needing -7 dBm to stop the repeater
pulsing - a 5 dB degradation. Thiswould suggest that at least 11 dB
more isolation is required in the duplexer, OR we drop the TX power
back to 25W, (6dB drop in TX power) which should stop the pulsing.

Swapped out the colinear aerial for a 4 stacked dipole array as a temporary measure while we refurbish the fibreglass colinear.
Checked hardline coax for wear – all OK.
Noted no fuses in repeater DC line. To be rectified at a later date.
Tested old & new aerials with MFJ analyser & all OK, although not exactly 1:1 ( 1.3:1 ) at the repeater frequency.
Put new latches on tank door but someone has stolen the padlock!