Historical repeater engineering data.

12 Comments

1. Historical. Site visit 1 Feb 2013. Solar controller found to be disconnecting the load above 12volts. The controller replaced with a new one Powetech MP3129. Low V cut off 11.50V float 13.5 V. Batteries load tested with a cranking battery tester at 200 amps and found ok. Battery restraints replaced. Hut is clean and tidy. Cruising club batteries are swelling.
2. Historical. Site visit 4th April 2014. Swapped out the co-linear aerial for a 4 stacked dipole array as a temporary measure while we refurbish the fiberglass co-linear. 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 analyzer & 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! Batteries Sonnenshien A412 100 AHr installed 2008 they had been damaged in transport and been repaired with white silicone. They tested at 98AHrs in 17/12/2008. There are no battery fuses installed in the system.
3. Historical. 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. This would 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. Site visit by Chris Hellyar ZL3LF for VHF field day 7/12/13 photos sent to ZL3HB
4. Historical. Site 725. S43.41.366 E172.55.465 Alt 924. CTCSS 123Hz full gating. CTCSS 123Hz for full sensitivity. Signal strength at zl3ue 24/4/2017att on S60 over 9++ IC706 S60/9. Dual band antenna on roof apex.
5. Historical. Site visit 18th Aug 2017. 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. In summary, January 2016 (using the X50 antenna). The signal received from 705 using a fixed antenna to my QTH was -53 dBm (with the transmitter running at 100W) To trigger 705 (with CTCSS tone), I needed – 11 dBm rom 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).
6. Historical. 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 dipoles 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 co-linear ( 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 galvanized 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.
7. Historical. Site visit 16 Mar 2013. Both heliax feeders checked and found AOK .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 no Signal strength at zl3ue 25/1/2016 att on S5 IC706 S60/9. Dual band antenna on roof apex. Signal strength at zl3ue 24/4/2017att on S60 over 9++ IC706 S60/9. Dual band antenna on roof apex. Batteries HAZE HZY12-120 Gel technology 3 12 volt blocks installed 2005
8. Historical. Author’s comment February 9, 2020 at 4:14 pm Edit Site visit 17 October 2018. Last visit with Ross and Dennis ZL3DEN on Wednesday 17th I noticed water ingress with a pool settled on the batteries.(where the duplexer used to be sited). There are several roof cracks that have previously been repaired but have to say its been a rough job. Am not sure whether this is cause of the problem. Sometime in the future we will smooth out internal crack “repairs” and weather fill as required. We (Ross 3TFK and moi) proposing to revisit next week and will carry out a closer inspection on interior and exterior to determine whether cracking is cause of problem or other possible issues then plan a required course of action. Along with roof inspection extra work includes the current 705 duplexer shelf removed off site and modified to accommodate the new duplex hardware with extra filters. The current duplexer to be temporarily re-positioned until new shelf completed and re-fitted together with Richards newly re-tuned 705 duplexer unit installed. The older duplexer (ex Herbert) to be recovered back to Idris Rd for checking and storage. Mike and Ross
9. Historical. Author’s comment February 9, 2020 at 4:14 pm Edit Site visit 22 October 2018. Mike and Ross visited Marley’s today 4.30pm. Removed duplexer shelf for modification.Existing duplexer temporarily re-sited. Will get the new hardware installed soon. Ross’s carpentry skills proving valuable in designing suitable mounting arrangement. On arrival noticed a UHF antenna mounted on roof (see below) Internal max / min thermometer installed. After our arrival Mountain Radio team including Martin Balch ZL4JH arrived onsite to sort out technical issues with their gear. They had earlier (Friday) temporarily mounted a 7 element UHF antenna on hut roof – looks like they had similar problem we had with our engineering link antenna – we departed before their problem sorted.Significant to note that the MR temporary antenna install and testing occurred around the same time the Friday “drainpipe” effect was noticed. I checked their log book. Not suggesting this a possible cause but simply noting a coincident event…Hummmmm Anyone experienced further “drainpipes” since Friday ??
   Mike and Ross
10. Historical. Site visit 24 October 2018. Duplexer uninstall.
11. Historical. Site 705. Site Location S43 36.583 E172 38.013 500m Alt. CTCSS 123Hz for full sensitivity.
12. Historical. Author’s comment February 9, 2020 at 4:16 pm Edit Site National System. Site Location S43 36.583 E172 38.013 500m Alt. CTCSS 123Hz for full sensitivity. Site visit 30th March 2013 South facing Yargi replaced. Signal strength at zl3ue 25/1/2016 att on S5 IC706 S520/9. Dual band antenna
    on roof apex Signal strength at zl3ue 24/4/2017att on S60 over 9++ IC706 S60/9. Dual band
    antenna on roof apex.