background image

MHX2421 Operating Manual:Glossary

 

5

 

Figure 1  Gain Calculation 

The power level has been set to 30dBm (1W) on the transmitter, and the 
receiver sensitivity for the MHX2421 is -108dBm.   

System gain would be calculated to be: 

30 - 2 + 6 + 3 - 2 + 108 = 143 dB. 

 

Figure 2 System Deploying 

When deploying your system, care must be taken to ensure the 

path loss 

(reduction of signal strength from transmitter to receiver in dB)

 

between 

equipment does not exceed the system gain (140 dB in the above example).  
It is recommended to design for a 

gain margin 

of at least 20 dB to ensure 

reliable communication.  Gain margin is the difference between system gain 
and path loss.  Referring to the same example, suppose the path loss is 100 
dB, the gain margin would be 40 dB, which is more than adequate for 
reliable communication. 

Path loss is a very complicated calculation which mainly depends on the 
terrain profile, and the height of the antennas off the ground.  

The following table provides path loss numbers for varying antenna heights 
and antenna separation:  These numbers are real averages taken from rural 
environments.  They do not apply to urban, non-line-of-sight environments. 

Table 2 Path Loss 

Distance 

(km) 

Base Height 

(m) 

Mobile Height 

(m) 

Path Loss 

(dB) 

5 15  2.5 116.5 

5 30  2.5 110.9 

8 15  2.5 124.1 

8 15  5 117.7 

8 15  10  105 

16 15  2.5 135.3 

16 15 

5  128.9 

16 15  10 116.2 

16 30  10 109.6 

16 30 

5  122.4 

16 30  2.5 128.8 

 

Base Height (m)

Mobile

Height

(m)

Distance (km)

Summary of Contents for MHX2421

Page 1: ...MHX2421 2400 MHz Spread Spectrum OEM Transceiver Revision 0 30 March 5 2007 17 2135 32nd Ave N E Calgary Alberta T3K 4Z4 Phone 403 248 0028 Fax 403 248 2762 www microhardcorp com Model MHX2421 Microh...

Page 2: ...TIONAL WARRANTY Indemnification The Purchaser shall indemnify Microhard Systems Inc and its respective directors officers employees successors and assigns including any subsidiaries related corporatio...

Page 3: ...ntennas Antennas not listed in the tables must be tested to comply with FCC Section 15 203 unique antenna connectors and Section 15 247 emissions WARNING MAXIMUM EIRP FCC Regulations allow up to 36 dB...

Page 4: ...ights ii MHX2421 Regulatory Requirements iii CONTENTS IV 2 GENERAL 1 2 0 PRODUCT OVERVIEW 1 2 1 OUTPUT POWER LEVEL 2 3 INSTALLATION 4 3 0 OVERVIEW 4 3 1 ESTIMATING THE GAIN MARGIN 4 3 2 ANTENNAS AND C...

Page 5: ...pectrum1 this means that it can be used without access fees such as those incurred by cellular airtime a serial I O data port with handshaking and hardware flow control allowing the MHX2421 to interfa...

Page 6: ...power levels so it is recommended that the lowest power necessary is used using excessive power contributes to unnecessary RF pollution Ideally you should test the communications performance between...

Page 7: ...MHX2421 Operating Manual Chapter2 General 3...

Page 8: ...between a transmitter receiver pair The number can be calculated based on knowledge of the equipment being deployed The following four factors make up a system gain calculation 1 Transmitter power use...

Page 9: ...ween system gain and path loss Referring to the same example suppose the path loss is 100 dB the gain margin would be 40 dB which is more than adequate for reliable communication Path loss is a very c...

Page 10: ...procedure for installing cabling and antennas for use with the MHX2421 module 3 2 1 Internal Cabling The most common method for installing the module is to run a cable from the module s MCX connector...

Page 11: ...stors The most effective protection against lightning is to install two lightning surge arrestors one at the antenna the other one at the interface with the equipment The surge arrestor grounding syst...

Page 12: ...uipment If the equipment is in a fixed location and is to communicate with only one other unit also in a fixed location then a Yagi antenna is suitable Choose a Yagi with enough gain to ensure adequat...

Page 13: ...m to the maximum power setting of 30dBm Example 2 What is the maximum power the MHX2421 can be set to comply with FCC and IC given the following equipment given a Yagi Ant Gain 12dBd and cable and con...

Page 14: ...ni Directional Antenna RPTNC Pigtail MHS034020 10 5 dBi 2 4GHz Omni Directional Antenna RPTNC Pigtail MHS034030 12 dBi 2 4GHz Omni Directional Antenna RPTNC Pigtail MHS034040 15 dBi 2 4GHz Omni Direct...

Reviews: