Bowman - H4855 - PRC-343 - Personal Role Radio

Made by SELEX Communications (Marconi is on the label) and used mainly in the UK and by U.S. Marines. Also by Australia.

There's a need for a short range radio for individual soldiers (intra squad). There have been a number of different ones (PRC-68 Family) and this is yet another. This radio appears to have been designed starting with a clean sheet of paper, a luxury that's not often available when the new radio needs to be compatible with all the older radios going back to the time of the gladiators. This radio probably will not communicate with any other radio either military or civilian.

Antenna

The radio is designed to be worn on the non shooting shoulder and placed so that the antenna is above the top of the shoulder, thus giving it a good field of view. This is why the audio cord on the headset is much shorter than those on older larger radios. The radio uses the very common SMA female panel jack that will mate with SMA male cable ends or the stubby 2.4 GHz antenna. At 2.4 GHz antenna height is everything. The best place would be on top of the helmet of a standing soldier.

Frequency

Instead of operating in one of the standard military frequency bands this radio operates (2.4 - 2.483) in the 2.4 Ghz Industrial Scientific & Medical (ISM) bands where no license is needed for secondary users. This particular band has a Wi-Fi specification, IEEE 802.11, that's commonly used for linking laptops and PDAs to a network. The 802.11 protocol is used by this radio. I think that means that no license is required to use this radio in the U.S. If you know one way or the other please let me know.

The 16 position channel knob on top of the radio combines with the 16 position rotary switch on the 12 contact face to allow for a total of 256 channels. No programming of the radio is required.

Low Probability of Intercept (LPI), Low Probability of Detection (LPD)?

When PTT is first pressed a sequence of tones is heard in the earphone and a WFS-1 Wi-Fi detector shows activity. But in a few seconds the activity stops (just one radio being used) and the side tone in the headphone no longer matches the spoken voice. I think this means that the radio was unable to link to another radio and has quit transmitting. It appears that no linking occurs until the PTT is pressed, which is a good way of doing it. That way you are not carrying around a beacon to let others know you are around.

At about 100 feet the WFS-1 is still has one LED on so the actual range is probably much more. The output power is specified as 50 mW. This means that there's a 100% chance of detection at 100 Feet and maybe longer ranges depending on what's between the transmitting PRR and the WFS-1 Wi-Fi detector.

Carry Pouch

The snap that secures the narrow bungie cords over the top of the radio has a projection that's the tool needed to set the Group number 16 position switch when the PTT is removed. But how do you loosen the screw holding the PTT to the radio?

DC Power

Instead of using a military battery it uses a couple of the very common "AA" batteries that are available about anywhere in the world. The down side to that is most AA batteries do not work at or near freezing temperatures. Is there a provision for external DC power to the radio? This would be good for retransmission use.

There may be a reverse connected diode across the battery contacts so if both batteries are installed backwards they will get very hot but the radio will be protected. A better way is to use a FET switch (see Analog Troubleshooting by Bob A. Pease of National Semi).

Audio Connection

LEMO I think the 5 pin headset plug is the FGG.1B.305.KLAD62. This plug supports: Ground, Mike input, Headphone output and retransmission. For retransmission all that's needed is a special cable to interconnect the two radios (this is very similar to the PRC-68 family and other mil radios).

Lemo has a USA site. A mating receptacle might be the EGG.1B.305.KLL (rear nut) or EEG.1B.305.KLL (front nut)
A strain relief for the headset plug might be the FFM.1B.130.LC nut plus GMA.1B strain sleeve (both of which are not on the stock headset plug but should be.)

The audio connection is on the PTT switch pack, not on the radio proper. So the 12 contacts on the side carry the aduio connections.

There is a collett on the back of the LEMO connector that needs to match the diameter of the cable. So when making up LEMO plugs you need to know your cable diameter prior to ordering the connectors. I'm working on making an audio test box for the 5 pin connector. I have a query into Belden, but it's being delayed by the Thanksgiving holidays.

Tones

Power on: three short tones.
Power off: four medium length tones and one long tone.
Battery Low: four tones alternating in frequency.
Combat Net Radio call waiting: Three medium tones and one long tone repeated every five seconds.
Wireless PTT affiliation: stair step of eight tones upward in frequency. Repeated if successful. Downward sequence of eight tones if failed.
Volume and Channel changes: one beep per step

Headset

The headset has a single ear piece and attached to it are the 20" cord that connects to the radio and the mike on a flexible boom. The ear piece has open holes surrounding the speaker element so that you can also hear any ambient sounds. The mike is of the noise canceling type and so needs to be placed so it touches you lips. Is is worn with the speaker on the left ear.

Data Connection

One of the PTT switch packs supports data by means of a connector on the attached cable end. But I now think the Dual PTT U-229 connector also supports data coms. The sales brochure implies low data rates, not 802.11 Wi-Fi rates. There's a cable to connect the data port to a PDA. If you know about this please let me know. I'm guessing that it's the standard U-229 Data protocol.

There may be a special cable to interface to a Personal Digital Assistant (PDA).

The Bowman radio can be connected to a PLGR or DAGR GPS receiver using the data interface. A simple application of this would be to send your position either in absolute coordinates or relative to some bulseye location. A more advanced application would involve sending targer or close air support data messages.

Push To Talk

Instead of just using a common PTT switch there are a number of innovative options. The PTT module screws onto the narrow left side of the radio making contact with a 3 x 4 (12 contacts) array. There are a number of tone signals that let the radio operator know some key status situations. These can be turned off by holding PTT while turning on the radio. The tone signals are:
-- to be added --

The PTT modules are:

Single PTT button switch pack
Dual PTT button switch pack with cable for second radio. The UK Dual uses the 7 pin Clansman connector and the NATO version uses the 6 pin U-229 type connector for use with SINCGARS (RT-1439) or PRC-148 radios.
Data Interface Single button switch pack - supports combined voice and data although at low speeds (PDA cable?)
Wireless PTT switch - this is a small switch that can be affixed to the forearm of a rifle or anywhere that it would be convenient to have a PTT switch. It has it's own 3.6 V lithium battery that should last more than 10 years. 433 MHz 128 bit operation. If the PRR is turned off then turned on and before being used the Wireless PTT is pressed you will hear a series of ascending tones to indicate that the PTT has been affiliated with the radio. If the affiliation process fails you will hear a series of decreasing frequency tones.

I wonder if there is a garage door opener that would work? The frequency is the same as used with key fob car remotes and door openers and the "learning" process is the same.

NSNs

NSN	Prod #	Description
5820-99-721-8335	P21050000	PRR Body (Green) Complete – EnglishThe PRR body is complete with an antenna and an English user card. Must beused with single or dual push-to-talk (PTT) switch assembly. Requires two AA batteries (included).
5820-99-739-4033	P08130000	Single PTT Switch Assembly (Green) The single PTT switch assembly is for use with the PRR body.
5820-99-342-4097	P08120000	Remote Wireless PTT (Green)The wireless PTT remotely operates the PRR. Supplied with a black adjustable strap and buckle.
5820-99-127-2911	?	Dual PTT with 7 pin Clansman cable connector
?	?	Dual PTT with 6 pin NATO Audio connector
?	?	Single PTT with (detachable?) PDA cable
5820-99-280-7276	P14360408	CT/Light Patrol Headset (Green) – Noise-Canceling (NC) Electret MicrophoneThe vented, single-sided headset has an NC Electret microphone fitted to a flexibleboom arm. Fitted with an adjustable headband, the headset can be wornunderneath most passive ear defenders.
5965-99-664-9722	P07100000	Nuclear, Biological, or Chemical (NBC) Boom Microphone AdapterThe adapter is for use with most Davies headset models. One end fits over theheadset’s boom microphone and the other end plugs into the respirator’s speechmodule.
5820-99-425-3999	C410114	Carry Pouch (Green) – United Kingdom (UK) Pattern Disruptive PatternMaterial (DPM) The PRR fits inside a heavy-duty polyurethane, textured nylon pouch that attachesto webbing and helps protect the PRR from harsh conditions/impact.

12 Contact Radio interface

This 12 contact field contains the signals needed for the headset (mike, speaker and PTT) , for data coms (Tx data, Rx data and maybe Tx clock and Rx clock), for retransmission (PTT and Squelch) and probably some test modes and external DC power. If you have info please let me know.

Summary:

1	2	3	4	5	6	7	8	9	10	11	12
Mike	PTT	Spkr		Gnd

It sure would make it easier to have a pair of working radios.
Looking at the connector the top row (nearest the on-Vol control) is numbered left to right 1, 2, 3, 4 and the center row 5, 6, 7 ,8 and the bottom row 9, 10, 11 & 12.
First probing Voltage all combinations with the radio turned off.

B R->
V

1
M

2
P

3
S

5
G

1 mike

2 PTT

3 Spkr

5 Gnd

.044

x - no point in testing the same thing two times or the same contact.

Now probing with the On-Vol at full volume:

B R->
V

1
Mik

2
PTT

3
Spk

5
Gnd
Bat -

1 Mike

.040

0.3

cap

2 PTT

.054

.051.

.050

.051

.052

.05

cap

3 Spkr

2.2

.77

2.0

1.96

cap

1.9.

1.8

cap

-2.968

-.01

-2.915

-2.967

5 Bat-
GND

+2.594

.05

+2.963

+2.938

+2.963

-.006

-2.907

-2.959

-2.901

+2.910

+2.885

+2.91

-.048

-2.962

-2.936

-2.962

Note that a voltage of 2.9xxx volts is the full battery voltage from 2 Alkaline batteries or after a FET type switch.

Single PTT interface

Radio On max vol
Radio Audio Connector numbered 1 to 5 clockwise looking into the PTT jack with 1 at the notch.
The headset only has the noise canceling mike and earphone (no PTT switch)
The PTT button is between contact numbers 2 & 5
Ohms

B R-> V	1 Mike	2 Gnd	3 Gnd	4 Spkr	5 ?
1 Mike	0
2 PTT
3 Spkr				0
4
5 Gnd		0	0
6
7
8
9
10
11
12

Headset Interface

Shown above is the 5 pin LEMO headset connector. In normal operation this connector only carries mike and speaker audio. But when the retransmission cable is connected it also needs to carry a PTT signal to key the radio and a squelch signal. In the U-229 type connector this takes a total of 6 wires. So it's still a mystry how the retransmission works using only the 5 pin connector. Most likley pin 5 carries a digital signal as a bus. For example by using a pull up resistor the line is held high and when squelch closes (a signal is being received) that radio puls the line low, but that's just a guess.


1. Lid Removed	2. Connector lifted & Shield removed. Lines to tabs.	3. Tabs bent & Digital board top removed from radio	4. Remove SMA nut & can from chassis

4. Top of RF board	4. Bottom of RF board	3. Digital board bottom	5. Box & flex ckt w/ switches

Bowman - H4855 - PRC-343 - Personal Role Radio PRR

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