User's Manual

VHF Headstation & In-Line Amplifiers
User Handbook
Handbook Nō.-50-127201FCC Issue No:-A
Date:-14/06/2005
Page:-
24 of 45
4.3 ¼Watt 0- -30dB Switched Attenuator (10-000701)
4.3.1 Switched Attenuators
The AFL switched attenuators are available in two different types; 0 – 30dB in 2 dB steps (as
in this case), or 0 – 15dB in 1 dB steps. The attenuation is simply set using the four miniature
toggle switches on the top of each unit. Each switch is clearly marked with the attenuation it
provides, and the total attenuation in line is the sum of the values switched in. They are
designed to maintain an accurate 50Ω impedance over their operating frequency at both input
and output.
4.3.2 Remote Attenuators (10-001201)
The remote attenuators perform exactly the same RF function as the manually switched
version. The only difference being, in the remote version, binary signals from the
controller/monitor PCB are fed to the attenuator via a multi-wire (4-bit) digital signal to
relays that control which attenuator network to switch into circuit. The remote attenuators
are entirely passive devices and should need no regular maintenance.