VE3RTC UHF propagation study. By VE3RGW Mar-2004

Transcription

1 VE3RTC UHF propagation study By VE3RGW Mar-2004

2 R.F.Model configuration The study is performed with Radio Mobile software. Terrain model is derived based on NASA s SRTM 3 arc sec data. The initiating parameter for the test model is derived based on last known system information and future planned configuration. This test is to identify possible coverage from a list of selected sites and see if a solution can be derived so as to improve voice quality of Chinese ham repeater network within GTA.. The hope is to find a group of stations that can provide the largest combined footprint but minimum overlap. Target linking will be build via internet but possibility of building private B point to point link is also considered. An assumed factor of 50% city attenuation profile are employed on all test cases. This factor is subject to future calibration based on field test data. The following slides show system configuration and predicted UHF coverage of selected VE3 sites and potential C/I clearance between controlled co-channel application. In order to help future field verification of this predicted result, all link test case will be worked upon mobile user. The later portion of this presentation will focus on their combined effect and cross influence. The selected sites are: VE3RTC (UHF site at Don Mill and Finch) 40 LDF5 between antenna and duplexer. This contributes a lost of 0.2db on UHF (additional connector lost 0.1db per junction). Tx utput power at 12W into duplexer and M500 (HN version) vertical antenna estimated at 12dbi gain. Rx modeled as general grade receiver (0.5uV at 12db Sinad) with a 10db Rx-front end amplifier (nonoptimized for best noise figure). Estimated best case workable sensitivity as 0.15uv (-124dbm noise floor for hot commercial site profile). Duplexer lost estimated at 1db implying a total transmission line lost of 1.5db. Antenna height estimated as 26x4 = 104m. With site s altitude at 196m above sea level and surrounding terrain averaged at 174m considered, HAAT came out as close to 122m. This implies a horizon clearance of 45km (worst case) to 71km(best case).

3 Test cases configuration Initial test model assumes known repeaters as their listed configuration in the previous slide. Mobile users will be stated as a known road junction or known sites. Default configuration will be 15W output, quarter wavelength ground plane antenna on roof of vehicle. Receiver s sensitivity estimated at 0.25uV/12db SINAD and free from off band cross modulation interference. Portable users in the test model are assumed to be 1W output rubber ducky antenna profile with receiver sensitivity at around 0.2uV/12db SINAD. Due to difference in calibration, S meter reading can differ between radio. S meter readings are supposed to be verified with calibrated test unit. Most modern hand held (with LCD bar-graph S meter) are calibrated for as full scale. Special precaution or preparation has to be performed before attempt to verify the predicted reading in the last 2 slides of this presentation with a receiver s S meter. The measuring receiver is expected to be calibrated (S1 for -120dbm level and at -93dbm). For normal user, it is recommend to focus on the extreme conditions (workable or not) and the relative profile changes between good and bad cases.

4 Test points relative position

5 Random Random fade fade zone zone -S6 -S6 Over Over S20 S20 S20- S20- S6-S1 S6-S1 VE3RTC-U estimated transmit coverage (mobile)

6 Random Random fade fade zone zone -S6 -S6 Over Over S20 S20 S20- S20- S6-S1 S6-S1 VE3RTC-U estimated receive coverage (1W portable)

7 VE3RTC Key area performance (best case mobile scenery at open area, blue text are field verified reading) Location Ref. road junction Position Down link Up Link VA3CTR VA3MKO VA3KMJ VA3XWR S4 S5 Markham Hwy 7 / McCowan (VE3JKM) W, N Scarborough north Steeles / Brimley (VA3ADM) W, N Scarborough south Eglington / Brimley (VE3LAU) W, N +20 North York Hwy 401/ Yonge W, N Downtown east Lakeshore / DVP W, N Downtown west Lakeshore / Jamerson W, N S6 S7 New Market east Hwy 9 / Hwy W, N S3 S4 GTA core Hwy 401 / DVP W, N GTA west Hwy 401 / Hwy W, N Airport area Hwy 401 / Hwy /58316W / N Etobicoke QEW / Islington W, N Missisauga east Hwy 401 / Dixie W, N Oakville QEW / Doval W / N Burlington QEW / Hwy W, N S5 S6 St.Catherine QEW / Hwy W, N Bowmanville Hwy401/Hwy W, N S1 S3

8 VE3RTC Key area performance (best case portable scenery at open area, blue text are verified reading). Location Ref. road junction Position Down link Up Link VA3CTR VA3MKO VA3KMJ +20 VA3XWR S3 S2 Markham Hwy 7 / McCowan (VE3JKM) W, N Scarborough north Steeles / Brimley (VA3ADM) W, N +20 Scarborough south Eglington / Brimley (VE3LAU) W, N North York Hwy 401/ Yonge W, N Downtown east Lakeshore / DVP W, N Downtown west Lakeshore / Jamerson W, N S5 S4 New Market east Hwy 9 / Hwy W, N S2 S1 GTA core Hwy 401 / DVP W, N +40 GTA west Hwy 401 / Hwy W, N S6 Airport area Hwy 401 / Hwy /58316W / N Etobicoke QEW / Islington W, N Missisauga east Hwy 401 / Dixie W, N Oakville QEW / Doval W / N Burlington QEW / Hwy W, N S4 S2 St.Catherine QEW / Hwy W, N S6 Bowmanville Hwy401/Hwy W, N S1 No copy