Roland Turner

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Testing a potential repeater site at West Coast Way

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.


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:

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:

(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!