High Sierra Alert/IFlows VHF Data Receiver Benutzerhandbuch

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float charger will keep the battery charged.  NOTE: it is important not to reverse 
polarity when connecting power to the Model 4500 Receiver. 
In areas subject to electrical storms it is advisable to use a lightning protection 
device in the antenna transmission cable to protect the receiver from damage due to 
"near hits".  During periods of electrical activity the receiver may present a shock 
hazard should the antenna be struck by lightning.  During these periods it is 
recommended that personnel stay clear of the receiver and associated equipment to 
reduce the chance of injury due to this hazard. 
3.0 OPERATION 
The Model 4500 receives frequency modulated RF signals from remote 
transmitters and repeaters.  These signals are then amplified, demodulated and the 
resultant audio signal is sent to the decoder.  The audio signal consists of tones having a 
frequency of either 2133 Hz or 1920 Hz. 
The Green LED on the front panel indicates if power is being supplied to the 
receiver and should always be on. 
The speaker On-Off switch on the front panel of the Model 4500 allows audio 
monitoring of the received signals.  
4.0 RADIO 
4.1 Frequencies 
available 
If the systems operating frequency is specified, then the radio is preset at the 
factory with the selected channel highlighted on the cover.  To change or select a 
frequency, remove the four screws that secure the transceiver cover.  Using the channel 
selection guide on the inside of the receiver cover, set the 4-position dip switch to the 
required frequency. 
Frequency between 148.000 and 174.000 MHz can be programmed into these 
radios.  The 16-channels factory defaults are commonly used frequencies.  UHF 
frequencies between 406 - 470MHz are available on request. 
 
 
 
Model 4500     April 2004