TABLE of CONTENTS. Item Description Page. 2.0 Simplified System Block Diagram 2

Transcription

1 TABLE of CONTENTS Item Description Page General Simplified System Block Diagram The Path from Boeing Seal Beach to N6BOX Moreno Valley Calculate Signal at N6BOX at Various Tx Output Levels from 456 4,5,6 Boeing Building 5.0 N6BOX Repeater Test, Saturday February 14th, ,7 6.0 Modify Path loss numbers to reasonably match the test above 7,8,9 7.0 Calculate Signal levels from N6BOX at various distances toward 9,10,11 Boeing Building. Use the modified path loss numbers based on -150 db at 48.3 miles 8.0 What output power will be required at Boeing to overpower N6BOX 11 signal by 6 db at 10 miles from Boeing 9.0 At 5 watts output power, at what distance will we overpower N6BOX 12 from Boeing? 10.0 What happens at Irvine Park? 12, Conclusions 14 File: RacesRepDsgnDoc.pdf Page 1 of 14

2 1.0 General: This design is for a low level 440 Mhz repeater system for the Seal Beach/Los Alamitos RACES.The Repeater will be located on top of the Boeing Building on Seal Beach Blvd, specifically at 2201 Seal Beach Blvd., Building 80, Seal Beach, California GPS Coordinates are: 33 deg min N and 118 deg min W. The Antenna will be about 100 feet AGL (above ground level). Ground level at the location is about 30 feet +/- above sea level, mllw (mean low low water) That puts the antenna at about 130 feet above sea level. The repeater system will have an omini directional pattern, and will be designed to cover the cities of Seal Beach, Los Alamitos and most of Cypress. It will also cover the current unincorporated area known as Rossmoor. N6BOX operates a repeater on our selected frequency, Mhz, down 5 Mhz from Moreno Valley, approximately 48.3 statue miles away, on a 3000 foot mountain top with 50 watts repeater output power. Output power of the new RACES repeater will be limited to the power required to limit interference to N6BOX at 48.3 Statue Miles and still allow reliable communications within our desired coverage area. 2.0 Simplified System Block Diagram: 6.0 dbd Omni Directional Antenna 75 feet LMR 400 Coax LMR 400 Coax Duplexer LMR 400 Coax (85 db isolation) Transmitter Receiver (5 watts output) (.25 mv Sensitivity) Control Line Controller Control Line 120 VAC 120 VAC Back-up Telephone Control 120 VAC Input 13.8 vdc From Emergency Power System 13.8 vdc 13.8 Volt 13.8 vdc Battery Backup System File: RacesRepDsgnDoc.pdf Page 2 of 14

3 3.0 The Path from Boeing Seal Beach to N6BOX Moreno Valley Topo USA by DeLorme was used to develop the following plots: For all intensitive purposes this is a "Line of Sight Path". Very little "Knife Edge Refraction" occurs at 27 miles. File: RacesRepDsgnDoc.pdf Page 3 of 14

4 4.0 Calculate Signal at N6BOX at Various Tx Output Levels from Boeing Building Seal Beach RACES Transmitter Calculations Coax Loss: LMR 400 = 2.7 db/100 ft at 450 MHZ. At : 100 feet loss = 2.7 db Connector loss: Assume all Type"N" 4 at.1 db/ea = 0.4 db Duplexer Loss: 1.5 db Total loss (L)= 4.6 db Antenna System Gain in db, G = Antenna Gain - (L) Antenna Gain = 6.0 dbd (Hustler G6-440) Gain in dbi = Gain in dbd = 8.2 dbi Antenna System Gain (G)= db Gain N6BOX has Diamond X50 NA Antenna Antenna Gain = 7.2 dbi N6BOX has 120 feet of Andrews 7/8" Hardline Coax loss= 0.89 db (.74 db/100ft ) N6BOX Duplexer Loss (assumed) Duplexer loss= 1.5 db N6BOX Ant Sys= 4.81 db Gain Free space Path Loss is calculated as follows: Path Loss db = * log10 (freq in Mhz) + 20 x Log10 (distance in miles) This loss does not take into account atmospheric conditions such as atmospheric gases (oxygen & Water Vapor), Rain, Fog and Clouds which really don't come into play below 10 Ghz. What is the noise floor at N6BOX? In the absence of any detailed noise measurements, several assumptions will have to be made. First of all at 440 Mhz basic noise theory places the noise floor at roughly.35 microvolts or -116 dbm. Since this is a hilltop with many RF sources I'll assume we have at least 6 db of noise on top of that. That makes the noise floor at -110 dbm. Receiver sensitivity, typical, is.25 micro volts or -119 dbm. (9 db "headroom" seems reasonable). I'll assume anything less than -110 dbm won't be heard. Transmitter Output (PEP) PEP = 15 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Multiplying py factor M= 10^ G/10 M = Dimensionless so ess Transmitter Output (PEP) PEP = 10 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 9 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path P Loss+N6BOX Ant Sys Signal Level= dbm > dbm File: RacesRepDsgnDoc.pdf Page 4 of 14

5 4.0 Continued Transmitter Output (PEP) PEP = 8 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Path loss= db at: 449 Mhz at: 48.3 miles Transmitter Output (PEP) PEP = 7 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 6 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 5 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 4 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Multiplying factor M= 10^ G/10 M = Dimensionless Transmitter Output (PEP) PEP = 3 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 2 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 1 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Path loss= db at: 449 Mhz at: 48.3 miles Transmitter Output (PEP) PEP = 0.5 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm File: RacesRepDsgnDoc.pdf Page 5 of 14

6 4.0 Continued Transmitter Output (PEP) PEP = 0.25 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Path loss= db at: 449 Mhz at: 48.3 miles Transmitter Output (PEP) PEP = 0.10 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm So it appears that we should be full quieting into the N6BOX Repeater even down to.10 Watt! That is not shown to be true from the tests conducted on February 14th, 2009, see below. 5.0 N6BOX Repeater Test, Saturday February 14th, 2009 Atmospheric conditions on the day of the test were ideal. Temperature around 64 degrees F, clear skies, Humidity around 40%, it had just rained the day before, no smog. Equipment Consisted of a Yaesu FT-736R transceiver, a Yaesu Power/SWR Meter,102 feet of new LMR-400 Coax, four (4) N connectors, a Hustler G6-440 Antenna (6 dbd Gain) and a portable Tripod for mounting the Antenna. The Antenna and Tripod were set on the Roof of the Boeing Building at approximately 130 Feet above sea level. Here are the results: 9:43 AM down 5 Mhz with a pl, antenna vertical Watts Report 4.0 Full Quieting Full Quieting 2.0 Minor white noise 1.0 White noise up a little 0.5 White noise at 4% 0.25 White noise at 50% 9:45 AM down 5 Mhz with a pl, antenna with downtilt Watts Report 1.0 Fair mmount of white noise % white noise 9.51 AM down 5 Mhz with no pl, antenna with downtilt, QSO with Alan Watts Report 4.0 Heard on input Heard on input 2.0 Heard on input File: RacesRepDsgnDoc.pdf Page 6 of 14

7 5.0 Continued 9:58 AM simplex, no pl, antenna with downtilt, N6BOX QSO with ham at Pomona Swap Meet Watts Report 4.0 No Interference 10.0 No Interference 20.0 No Interference No Interference 10:04 AM Test Complete 6.0 Modify Path loss numbers to reasonably match the test above For reliable communications (99%) the ARRL Antenna Book, Chapter 23, Figure 9, shows a free space terrestrial path loss of -178 db from Boeing Seal Beach to N6BOX Moreno Valley vs the db calculated from the above formula. We first heard white noise at about 2 watts out. Lets run the numbers again with a -150 db Path Loss Path loss= db at: 449 Mhz at: 48.3 miles Transmitter Output (PEP) PEP = 15 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm File: RacesRepDsgnDoc.pdf Page 7 of 14

8 6.0 Continued Transmitter Output (PEP) PEP = 10 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Path loss= db at: 449 Mhz at: 48.3 miles Transmitter Output (PEP) PEP = 9 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 8 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 7 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 6 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Multiplying factor M= 10^ G/10 M = Dimensionless Transmitter Output (PEP) PEP = 5 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 4 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 3 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Path loss= db at: 449 Mhz at: 48.3 miles Transmitter Output (PEP) PEP = 2 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm File: RacesRepDsgnDoc.pdf Page 8 of 14

9 6.0 Continued Transmitter Output (PEP) PEP = 1 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Path loss= db at: 449 Mhz at: 48.3 miles Transmitter Output (PEP) PEP = 0.5 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 0.25 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm Transmitter Output (PEP) PEP = 0.10 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at N6BOX is EIRP-Path Loss+N6BOX Ant Sys Signal Level= dbm > dbm This path loss, -150db, seems about right for the conditions at the Test. It is also about 1/2 way between the free space Path Loss of db and the ARRL number of db. 7.0 Calculate Signal levels from N6BOX at various distances toward Boeing Building Use the modified path loss numbers based on -150 db at 48.3 miles N6BOX Transmitter Calculations Coax Loss: 7/8" Hardline.74db/100 ft at 450 Mhz : 120 feet loss = db Connector loss: Assume all Type"N" 4 at.1 db/ea = 0.4 db Duplexer Loss: 1.5 db Total loss (L)= db Antenna System Gain in db, G = Antenna Gain - (L) Antenna Gain = 7.2 dbi (Diamond X50NA) Antenna System Gain (G)= db Gain Path loss= db at: 449 Mhz at: 5 miles Signal Level is EIRP-Path Loss Signal Level= dbm Path loss= db at: 449 Mhz at: 10 miles Signal Level is EIRP-Path Loss Signal Level= dbm File: RacesRepDsgnDoc.pdf Page 9 of 14

10 7.0 Continued Path loss= db at: 449 Mhz at: 20 miles Signal Level is EIRP-Path Loss Signal Level= dbm Path loss= db at: 449 Mhz at: 30 miles Signal Level is EIRP-Path Loss Signal Level= dbm Path loss= db at: 449 Mhz at: 38 miles Signal Level is EIRP-Path Loss Signal Level= dbm Path loss= db at: 449 Mhz at: 39 miles Signal Level is EIRP-Path Loss Signal Level= dbm Path loss= db at: 449 Mhz at: 40 miles Signal Level is EIRP-Path Loss Signal Level= dbm Path loss= db at: 449 Mhz at: 41 miles Signal Level is EIRP-Path Loss Signal Level= dbm Path loss= db at: 449 Mhz at: 42 miles Signal Level is EIRP-Path Loss Signal Level= dbm Path loss= db at: 449 Mhz at: 43 miles Signal Level is EIRP-Path Loss Signal Level= dbm Path loss= db at: 449 Mhz at: 44 miles Signal Level is EIRP-Path Loss Signal Level= dbm File: RacesRepDsgnDoc.pdf Page 10 of 14

11 7.0 Continued Path loss= db at: 449 Mhz at: 45 miles Signal Level is EIRP-Path Loss Signal Level= dbm Path loss= db at: 449 Mhz at: 46 miles Signal Level is EIRP-Path Loss Signal Level= dbm Path loss= db at: 449 Mhz at: 47 miles Signal Level is EIRP-Path Loss Signal Level= dbm Transmitter Output (PEP) PEP = Watts Signal Level is EIRP-Path Loss Signal Level= dbm 8.0 What output power will be required at Boeing to overpower N6BOX signal by 6 db at 10 miles from Boeing? From the above Calculations the N6BOX signal at 38 miles away, is dbm. The Seal Beach RACES Repeater must have 6dB more power than this at 10 miles out or dbm For the Seal Beach RACES Boeing Building Repeater Coax Loss: LMR 400 = 2.7 db/100 ft at 450 MHZ. At : 100 feet loss = 27dB 2.7 Connector loss: Assume all Type"N" 4 at.1 db/ea = 0.4 db Duplexer Loss: 1.5 db Total loss (L)= 4.6 db Antenna System Gain in db, G = Antenna Gain - (L) Antenna Gain = 6.0 dbd (Hustler G6-440) Gain in dbi = Gain in dbd = 8.2 dbi Antenna System Gain (G)= db Gain Path loss= db at: 449 Mhz at: 10 miles Transmitter Output (PEP) PEP = 9.5 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at 10 miles out is EIRP-Path Loss Signal Level= dbm> dbm +6 db 9.0 At 5 watts output power, at what distance will we overpower N6BOX from Boeing? Path loss= db at: 449 Mhz at: 8 miles Transmitter Output (PEP) PEP = 5 Watts EIRP (Watts) = transmitter output (PEP) x M EIRP= Watts dbm Signal Level at 8 miles out is EIRP-Path Loss Signal Level= dbm> dbm + 6db File: RacesRepDsgnDoc.pdf Page 11 of 14

12 10.0 What happens at Irvine Park? The path from Seal Beach to Irvine Park is: File: RacesRepDsgnDoc.pdf Page 12 of 14

13 The path from Irvine Park to N6BOX is: First of all, there should be no problem interfering with N6BOX at Irvine Park due to Terrain features. Secondly we know that we can communicate to Irvine Park from Boeing with 5 watts and a beam antenna on the CERT Trailer.We also can communicate from my car with the Diamond Vertical Antenna, the same one that is now on the CERT trailer, so we should be good here. It looks like Irvine Park is a non issue and no calculations are required. File: RacesRepDsgnDoc.pdf Page 13 of 14

14 11.0 Conclusions The N6BOX repeater operates on 50 watts on top of a 3000 foot mountain on Mhz transmit and Mhz receive with a pl of hz. From the Test which was done on February 14th, and the calculations above, we will not cause interference if we use a different pl to pick up our new repeater. We'll use hz as our encode pl. If our Repeater is not transmitting, we will hear the N6BOX Repeater id'ing and any conversation. If our Repeater is transmitting we will not hear N6BOX out to about 10 miles from Boeing, assuming we set output power at 10 Watts. If we set our output power at 5 watts, then we will not hear N6BOX out to about 8 miles from Boeing. I suggest we start out with no decode pl on our radios to enable us to hear whats happening on Mhz. We can always put the decode pl on if it becomes a problem, but N6BOX is a very low usage Repeater and we shouldn't have a problem. File: RacesRepDsgnDoc.pdf Page 14 of 14