Active Antennas for Radiomonitoring

Application Note

Products:

Generally applicable to all active antennas from Rohde & Schwarz,

in particular this Application Note covers the following products:

ı R&S

HE600

ı R&S

HE010E

ı R&S

HE010D

ı R&S

HE016

ı R&S

HK014E

ı R&S

HL033

ı R&S

IN600

The fundamental working principles of active antennas are asserted and it is described what makes them

different compared to passive antennas. Furthermore the important parameters relating to active antennas

are explained and typical system applications are discussed - including a comparison with passive antenna

solutions and a chapter explicitly dealing with radio monitoring in the HF frequency range.

Note:

Please find the most up-to-date document on our homepage

http:\\www.rohde-schwarz.com/appnote/8GE02

Application Note

Maik Reckeweg

2.2016 – 8GE02_0e

Introduction

8GE02_0e

Rohde & Schwarz Active Antennas for Radiomonitoring

Table of Contents

1 Introduction ......................................................................................... 3

2 Working principles.............................................................................. 4

3 Characteristics of active antennas .................................................... 6

3.1 Antenna Impedance ..................................................................................................... 6

3.2 Antenna factor .............................................................................................................. 7

3.3 Antenna noise .............................................................................................................. 8

3.4 Sensitivity ...................................................................................................................10

3.5 Gain .............................................................................................................................11

3.6 Non-linear distortion..................................................................................................12

3.7 Dynamic range ...........................................................................................................13

4 Application examples ....................................................................... 15

4.1 Calculation of field strength in the far field ............................................................15

4.2 VHF example scenario ..............................................................................................16

4.2.1 Scenario 1 - Reception of a weak signal .....................................................................16

4.2.2 Scenario 2 - Reception of a weak signal in the presence of strong interference ........20

4.2.3 Other measures to reduce or avoid intermodulation ...................................................25

4.3 HF example scenario .................................................................................................26

4.3.1 Effects on polarization caused by the ionosphere .......................................................26

4.3.2 Field strength measurement at HF using different types of antennas .........................26

4.3.3 Selecting an appropriate HF antenna ..........................................................................29

4.3.4 Active HF monitoring antennas summarized ...............................................................32

5 Literature ........................................................................................... 33

6 Glossary ............................................................................................ 34