How Does That Work Crossband Repeating By Paul

How Does That Work? Crossband Repeating By Paul F. Ryan NØKIA 10 July 2003 © 2003

Purpose To describe crossband repeating in the context of pedestrian portable or emergency operations. 2

Serious Subject 3

What Is Crossband Repeating? l l l 4 Transmit on one band (i. e. 2 meters) Receive on another band (i. e. 440 MHZ) TX and RX done simultaneously in same unit Split frequencies may be used in one or both bands Usually split on VHF (repeater) side, simplex on UHF side.

Common Modes l l l 5 Simplex Split or Offset Semi-Duplex (Repeater) Crossband Repeat with a Repeater

Simplex HF – 14. XXX or VHF – 146. 565 6

Split or Offset Base Freq. +/- 5 KHz 7

Semi-Duplex (Repeater) 146. 940 146. 340 8

Crossband VHF – 146. 565 UHF – 446. 125 9

Crossband Repeat ICOM 2720 H VHF – 146. 565 UHF – 446. 125 10

Crossband Repeat w/Repeater (Active) ICOM 2720 H UHF – 446. 125 11 VHF Repeater

Another View 12 from March ’ 93 QST

Crossband Repeat w/Repeater (Passive) ICOM 2720 H UHF – 446. 125 TX VHF - 146. 94 RX 13 VHF Repeater

Issues l Identification l Power l Frequency l Procedure 14 selection

Issue - Identification Station in CBR must IDENTIFY per FCC rules l Usually only simplex side is involved in IDing l Unit may have CW ID option installed l IDing over the CBR may cause a “requirement loop” l “Site” requirement may be met by using HT? l 15

Crossband Repeating ICOM 2720 H UHF 16 VHF Repeater

Issue – Power 17 l Use lowest power setting to accomplish task l Cooling - CBR unit is in constant transmit l Unit may overheat in cramped locations l Make sure antenna/diplexer/duplexer can handle the load

Issue – Frequency Selection 18 l Use band plan for frequency selection l Usually one side will be simplex l Consider tone to reduce interference

Crossband Repeating ICOM 2720 H UHF 19 VHF Repeater

Issue – Procedure l l 20 Last heard input channel has control Cannot transmit while CBR is transmitting Squelch tail may be a problem Dropping tone on the tail may help

Demo 1 - Listen on 146. 94 (71. 9) 2 - Listen on 146. 34 (71. 9) 3 - Scan on UHF simplex. 21

Questions? 22