This afternoon James 9V1YC, Ben 9V1KB, and I tested the likely coverage area for a proposed new repeater location at the home of Harish 9V1HP. The test went better than expected. We expect to establish a repeater at this location in the near future.
Background
SARTS currently has an Icom FR5000 VHF repeater which Jaya 9V1AI has hosted at his home on Dover Crescent for a number of years. This installation is usable but has a couple of problems that are proving time-consuming to resolve:
- The antenna in use is not ideal for this application so propagation is poor, which tends to exclude most use with handheld transceivers (aka HTs or walkie-talkies) and makes use marginal even for fixed stations in much of Singapore. The project to install a better antenna is an intricate operation which involves at least six organisations (SARTS, IMDA, HDB, WCTC, a security firm, and an engineering firm), has been underway for a number of years, and doesn’t appear likely to complete any time soon.
- The lightning protection arrangements are inadequate, so any time an electrical storm approaches or Jaya is not at home it is necessary to completely isolate (unplug) the repeater thereby rendering it unusable for that period of time. Jaya reports that on occasion when he has failed to do this, even the mere approach of an electrical storm has tripped the ELCB in his apartment’s electrical distribution board. Resolving this requires completing the installation of the new antenna, and likely the installation of a single point ground panel (SPGP) with gas discharge tubes etc. as well. (There is a further complication about the presence of Jaya’s other radios in the same crowded shack: either the whole lot has to use the same single point ground panel — which requires more connectors, discharge tubes, and re-wiring — or there has to be careful isolation between SARTS repeater equipment and all of his other equipment — which requires some reorganisation of his shack and likely a separate cable route from the roof for the SARTS antenna.)
Recently Harish volunteered to host a SARTS repeater at his home at West Coast Way. At the SARTS Council meeting on October 29 I proposed moving forward on siting our currently inactive Icom FR6000 UHF repeater there, starting with a coverage test. Council agreed. Harish’s apartment has a small balcony of sorts which is unused as the only means of access is by climbing through a bathroom window. It is 13 floors up has a largely unobstructed 180° north-facing view covering a large chunk of Singapore.
The test
Although we conducted the test as part of preparation for siting the UHF repeater, it seemed an interesting idea to test VHF coverage while we were at it, so we planned tests to happen this afternoon at:
- 3:00-3:15 145.550MHz
- 3:15-3:30 433.625MHz
(We messed up and announced the UHF test as being on 438.425MHz. Hopefully everyone who wished to participate on UHF heard about the frequency change during the VHF part of the test! Our apologies to anyone we missed because of this error, we’ll review announcements more carefully in future.)
James, Ben, and I visited Harish’s place at about 2PM. We set up a Diamond V2000 on a tripod on the balcony, a short run of coax, and a radio inside the apartment.
(The antenna was purchased ex-stock from Boy at R-One in Sim Lim Square on Friday afternoon after it became apparent that I’d mislaid my 70cm antennas. Had he not had something like this in stock I’d have had to spend much of Saturday making an antenna!)
As we were ready to go by 2:30 we started early. We ended up logging 18 VHF calls in 45 minutes and 8 UHF calls in 15 minutes:
VHF 145.550MHz calls
| Time (UTC+8) | Callign | Our report | Their report | Location | Height | Transmitter | Antenna |
|---|---|---|---|---|---|---|---|
| 14:28 | 9V1DK | R2 | R3 | Dairy Farm Estate | 6m (L3), facing south | 1W HT (Icom 218?) | rubber ducky |
| . | 9V1AW | R5 | R5 | Woodlands | 27m (L10), facing north | 5W | dipole |
| 14:33 | 9V1KZ | R5 | R5 | Choa Chu Kang | 24m (L9) | 5W | 3dB Diamond RH-770 (3dB at VHF, 5.5dB at UHF) |
| 14:35 | 9V1LC | R5 | R5 | Whampoa | 80m HASL | 5W | 5dB 7/8ƛ double-lobe |
| 14:39 | 9V1PL | R3 | S9+10dB | East Coast | 25m HASL, facing SW | 5W HT | yagi |
| 14:41 | 9V1MH | R4 | S7-9 | Lorong Chuan | 40m HAGL | 5W | 4.55dB colinear |
| 14:44 | 9V1JM | R3 | S3 | Choa Chu Kang | 27m (L10) | . | portable J8700? |
| 14:45 | 9V1XV | R2-5,S7 | R2 | Boon Keng | 15m | HT | Diamond RH-700 |
| 14:47 | 9V1KT | 59 | R5 | Bukit Panjang | 42m (L15) | 5.5W | 5/8ƛ |
| 14:48 | 9W2BAF | 57 | 59 | 25km from Johor Bahru | 15m AGL | 5W | S-23? |
| 14:58 | 9V1TG | R1-2,S1 | . | . | . | . | . |
| 15:00 | 9V1YP | 59 | 59 | Clementi | . | 5W HT | rubber ducky |
| 15:00 | 9V1TG | 59+ | 59 | Yishun | . | 5W HT | . |
| 15:02 | 9V1DT | 59 | 59 | Jurong East | 21m (L8), facing south | 5W HT | rubber ducky |
| 15:04 | 9V1KG | 45 | 57 | Bedok Reservoir | 48m (L17), facing west | 15W | 5 element log periodic |
| 15:05 | 9V1BF | 47 | 58 | Pasir Ris | 33m (L12) | 150mW! Icom 2E | 5/8ƛ vertical |
| 15:10 | 9V1JH | 59 | 56 | Yishun | 0m (L1 carpark) | 10W HT | magnetic base |
| 15:13 | 9V1CD | 59 | 59 | Bedok North | 30m (L11) | 20W | 0.5ƛ |
We also had an unsuccesful check-in at 15:14 from 9V1AQ in Geylang East; thanks 9V1PL for relaying.
Note that the 18 calls are 17 stations as 9V1TG had trouble initially and then checked in successfully later.
UHF 433.625MHz calls
| Time (UTC+8) | Callign | Our report | Their report | Location | Height | Transmitter | Antenna | |
|---|---|---|---|---|---|---|---|---|
| 15:17 | 9V1YP | 59 | 59 | (as above) | . | . | . | |
| . | 9V1LC | 57 | 49 | (as above) | . | . | 5/8ƛ 3 element (?) | |
| 15:19 | 9V1XV | 59 | (none; estimate R2 from description provided) | . | . | . | . | |
| 15:20 | 9V1KG | 51 | 53 | . | . | . | . | . |
| 15:22 | 9V1KZ | 59 | 59 | Choa Chu Kang | 24m (L9) | 5W | 3dBi RCH-770 | |
| 15:24 | 9V1PL | 51 | 53 | . | 25m facing SW | 5W | yagi | |
| 15:26 | 9V1AW | 31 | R5 | Woodlands | 27m (L10), facing north | 5W HT | rubber ducky | |
| 15:28 | 9V1JH | 31 | . | . | 27m (L10) | HT | . |
What we learned
This is a superb site for a repeater! The various contacts in the centre and north of the island are largely as expected; Bedok North and Pasir Ris are frankly surprising, particularly at 150mW for the latter.
Between botching the announced frequency, the shorter period of time (it would in retrospect have been wise to continue for another 10-15 minutes), and the less widespread ownership of UHF gear, it seems likely that the UHF results would have been closer to parity on a like-for-like basis.
Checkins on both bands were overwhelmingly HTs with rubber duckies, which is great news. Apart from reflecting what people actually own, this points to at least some realistic potential for widespread mobile use, at least when operating from elevated locations.
Next steps
I’ll put all of this onto a map to make the situation clearer, but it’s already apparent that coverage is excellent.
Assuming that council agrees to go ahead, we’ll need to sort out specifics of the proposed installation (antenna mounting, lightning protection, where to site the equipment inside Harish’s apartment, …), clear the change with IMDA, then perform the installation.
I have been wrong about timelines too often so far to be willing to estimate dates, but I’d point out that this is a much simpler situation than at Jaya’s place. We’re talking weeks or months, not years.
Thanks to everyone involved, and especially to Harish for volunteering this great location!