W0BCR, Boulder, CO, TV Repeater Coverage Maps - Radio Mobile Jim Andrews, KH6HTV

Size: px

Start display at page:

Download "W0BCR, Boulder, CO, TV Repeater Coverage Maps - Radio Mobile Jim Andrews, KH6HTV"

Charity Warner
6 years ago
Views:

p. 1 of 8 Application Note AN-34 copyright October, 2016 W0BCR, Boulder, CO, TV Repeater Coverage Maps - Radio Mobile Jim Andrews, KH6HTV www.kh6htv.

1 p. 1 of 8 Application Note AN-34 copyright October, 2016 W0BCR, Boulder, CO, TV Repeater Coverage Maps - Radio Mobile Jim Andrews, KH6HTV The hams in Boulder County, Colorado have had a TV repeater since It was an analog, NTSC, VUSB-TV repeater. Recently in September, 2016, the repeater received a major upgrade to add high definition (1080P), DVB-T, digital TV capability, both for receive and transmit [1]. Summary details about the repeater can be found at enter the call sign W0BCR. The purpose of this application note is to document the coverage area of the new DTV/ATV repeater. The previous, similar, application note, AN-32, [2], used the on-line, rf propagation prediction program, CRC-COVWEB to generate repeater coverage maps. I was not impressed by the spatial resolution of the resulting maps. They seemed to be painted with a very broad paint brush. Further, more recent, research turned up another free, online, rf propagation prediction program called Radio Mobile - Online It was written and copyrighted by Rodger Coudé, VE2DBE. It is dedicated to amateur radio use and as such will only accept input frequencies in the amateur radio bands. The mathematical model is a mix of the Longley-Rice model, the two rays method, and the land cover path loss estimation. It appears to be a more powerful program compared to CRC-COVWEB and provides much more detailed spatial resolution. It also includes the ability to generate point-to-point rf path profiles. Comparing it's point-to-point predictions with the results from actual, mobile, field measurements has shown excellent agreement. The repeater coverage maps also correlate well with the mobile field measurements. For additional details on rf propagation and Radio Mobile, see AN-33 [3]. Input Parameters: Radio Mobile requires one to input to the on-line program, all of the following parameters: (note the values listed are those used for the Boulder TV repeater) Tx Ant Height (10.7m = 35ft); Tx Ant Type ( cardiod); Tx Ant Azimuth (67 o); Tx Ant Tilt (0o); Tx Ant Gain (11.2dBi); Tx line loss (1dB); Tx Frequency (423MHz); Tx Power (4 Watts); Rx Ant Height (1.5m - for mobile); Rx Ant Gain (2.2dBi - for mobile); Rx line loss (1.1dB); Rx threshold (5.6μV = -92dBm, adjustable as desired); Required Reliability (70% - default); Strong Signal Margin (10dB - default, adjustable as desired);

2 p. 2 of 8 Strong Signal map Color (light green - default); Weak Signal map Color (light yellow default), Opacity (50% - default); Max. Range (choices are - 10, 25, 50, 150, 200, 250 & 300km); Resolution { choices are low (601x601), med (1001x1001) or high (1668x1668 pixels)} and selection of using either or both "land cover" and/or two rays modeling (I used both). REPEATER COVERAGE MAPS: All the new Radio Mobile repeater coverage maps for various settings are in the Appendix at the end of this App. Note. Based upon the Sept mobile field survey [2], in no case was I ever able to receive a mobile DTV signal weaker than -92dBm. This was while using a low noise pre-amp in front of the DVB-T receiver. Thus for the map, Fig. 2, showing the max. extent of mobile DTV coverage, the weak signal limit was set to -92dBm (= 5.6μV). Fig. 1 shows the farthest extent of the coverage using an excellent receiving yaggi antenna (11dBi) at a height of 30ft. The furthest distance for a -92dBm contour predicted was about 100km (60 miles), primarily to the north-north-east, extending a bit beyond Ft. Collins and Greeley. The farthest TV-DX confirmed with the mobile field survey was 34 miles to the south-east out as far as the Denver International Airport. Figs. 3-6 show mobile reception coverage areas for successively stronger signal areas in 10dB steps up to -52dBm. REFERENCES: 1. "Digital & Analog TV Repeater", Jim Andrews, KH6HTV Video Application Note, AN-31, Sept. 2016, 24 pages 2. "Boulder, CO - DTV/ATV Repeater Coverage", Jim Andrews, KH6HTV Video Application Note, AN-32, Sept. 2016, 10 pages 3. "TV Propagation" Jim Andrews, KH6HTV Video Application Note, AN-33, Oct. 2016, 10 pages. note: KH6HTV Video Application Notes are available for free download as.pdf files from the web site:

3 p. 3 of 8 APPENDIX: W0BCR-TVR COVERAGE MAPS Fig. 1 TV Repeater Max. Coverage Area with an excellent receiving antenna, 11dBi yaggi at 30 ft -- Yellow = >-92dBm, Green = >-82dBm, 100km radius, resolution = 200m/pixel The red tear-drop symbol denotes the location of the TV repeater transmitter. It is in Chautauqua Park, Boulder, Colorado.

4 p. 4 of 8 Fig. 2 Max. Mobile Coverage Area -- Yellow = >-92dBm, Green = >-82dBm, 100km radius, resolution = 200m/pixel Max. distance confirmed in the mobile field survey was 34 miles to the Denver International Airport (DIA).

5 p. 5 of 8 Fig. 3 Mobile Coverage Area -- Yellow = >-82dBm, Green = >-72dBm, 50km radius, resolution = 100m/pixel

6 p. 6 of 8 Fig. 4 Mobile Coverage Area -- Yellow = >-72dBm, Green = >-62dBm, 25km radius, resolution = 50m/pixel This area is confined to the City of Boulder and immediate suburbs.

7 p. 7 of 8 Fig. 5 Mobile Coverage Area -- Yellow = >-62dBm, Green = >-52dBm, 10km radius, resolution = 30m/pixel

8 p. 8 of 8 Fig. 6 Mobile Coverage Area -- Chautauqua Park, Uni-Hill & Univ. of Colorado Campus -- Yellow = >-62dBm, Green = >-52dBm, 10km radius, resolution = 30m/pixel

TV Propagation & Multi-Path Effects Jim Andrews, KH6HTV

AppNote7b-TVprop.doc (kh6htv, 10/30/2014) p. 1 of 7 Application Note AN-7b copyright - Oct. 2011 rev. - Oct. 2014 TV Propagation & Multi-Path Effects Jim Andrews, KH6HTV www.kh6htv.com Note: The original