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|Radio Set AN/PRC-521 (RT-5113)
The purpose of this documentation is to explore the undocumented modified installations possible for use with the Canadian Forces radio set AN/PRC-521 (RT-5113). Please note that the information presented in these pages concerning these modified installations are unauthorized modifications and unauthorized installations. There are no advantages of using a PRC-521 in a vehicular installation other than to make use of the embedded COMSEC in the PRC-521. Since the PRC-521 does not provide any ECCM capabilities, compatibility with field deployed PRC-521 can be achieved with the use of an RT-524 or a PRC-25/77 set.
The first possibility is the integration of the AN/PRC-521 in a vehicular installation. A vehicular installation can be accomplished with minimum efforts. With a few simple adapters and some extra parts, the AN/PRC-521 can be employed in a radio station vehicle and achieve an acceptable transmission range.
In the first example, we will look at a basic configuration employing existing equipment that is specified in the ECL for a VHF radio station vehicle.
The parts required are:
|Figure 1. Block diagram of installations.|
In this second example, we will substitute the ground plane antenna in configuration #1 for a broadband vehicular antenna system.
The parts required are:
As most users will not be familiar with the 4242-MK2 antenna, now is a good time for some background information on it. The 4242-MK2 is a broadband, centre-fed, dipole antenna. The antenna base is physically identical to that of the MX-6707 for the exception that it utilizes broadband circuitry that does not require any mechanical nor electrical tuning mechanisms. The frequency coverage of the 4242-MK2 is from 30 MHz to 88 MHz. This antenna offers no relative gain. For the most part, it is -1 to -3 dB below reference for the exception of the band area between 74 MHz and 84 MHz where the antenna exhibits a 0 to +1.8 dB gain with the peek being at 80 MHz. Despite this, tests with this antenna has yielded excellent results with the added advantage of not having any requirements for electrical "tuner" connections and making the antenna fully compatible with the AN/PRC-25/77, the RT-524 and the AN/PRC-521 radio sets. Furthermore, its broadband design and its power handling capabilities of 100 watts also makes it compatible with ECCM radio system such as the AN/PRC-116 (JAGUAR-V). Other enhancements include EMP protection, the upper section of antenna affords protection from electrocution in the event of powerline contact and, the overall design of the antenna makes it suitable for shipboard, shelter and fixed-station applications with no requirements for a ground plane. The only recommendation that I make is that the user physically mark the lower and upper fiberglass antenna elements of the 4242-MK2 as they closely resemble and can be confused with those of the AS-1729/VRC (MX-6707) antenna elements (AS-1730/VRC and AT-1095/VRC) but are not interchangeable.
In this third example, we will explore the "ultimate" installation.
The parts required are:
In this configuration, we will add to the basic AN/PRC-521 installations mentioned
above the capability for an operator to have an amplified audio output to a loudspeaker
and the ability to connect standard North American audio accessories to the radio
set. Since the radio set utilizes U.K. Clansman Standard audio connectors it is
necessary for the user to fabricate an adapter cable that will convert the Clansman audio
connector on the AN/PRC-521 to one that can be utilized with North American Standard
military audio connectors (U-183/U and U-229/U).
You will require the following parts to manufacture the audio cable adapter.
Assemble the cable as follows:
|Figure 2. Audio connector adapter assembly.|
Now that you have an adapter cable, you can connect any standard audio accessories to
Since the PRC-521 only has about 400 mWatts of audio output, which is unsuitable for use with the LS-454/U loudspeaker, we will use the AM-6747/V audio amplifier/loudspeaker to boost the output of the radio set to an audible level. Connect a suitable cable from the audio connector (J2) of the AM-6747/V to the locally manufactured PRC-521 audio adapter. Then, connect either a H-250/U handset or M-80C/U microphone to the AM-6747/V's handset connector (J1). Apply power to AM-6747/V from the vehicular system's 24 VDC supply.
|5935-00-701-2215||Adapter, BNC jack to TNC plug|
|5935-99-721-6448||Connector, 7 pins, (RACAL Audio)|
|5935-00-929-7082||Connector U-228/U (5 pin in-line jack)|
|5985-01-431-1468||Antenna, Broadband, Centre Fed, 30 - 88 MHz, Model 4242-MK2-N|
|5935-00-259-0205||Adapter, BNC jack to N plug, UG-201A/U|
|5895-01-056-4553||Amplifier, Audio Frequency, AM-6747/V|
|6145-00-484-8981||Cable, Electrical, 5 conductors w/shield (audio)|
|5995-21-913-2633||DC Power Adapter Cable, AN/PRC-521|
Revised: June 08 2017
(C) 1998-2022, Richard Lacroix. All rights reserved.