The base of this article has been written from MARIO GATICCI ( SWL I0-14.179) after the arrival in the italian surplus market a big lot of IRET radio sets. Me with the cooperation of the portuguese friend Joao Freitas added some additional details and pictures. I hope the work will be appreciated.
Mario Galasso - IK0MOZ
The IRET sets had built with a standard not compatible with the NATO
systems, employing loudspeakers, microphones, and connectors totally different
from the models to us generally known. Perhaps this industrial strategy
finds motive in the fact that almost the totality of IRET production had
destined to no NATO nations and specially to South America and Arabic countries.
For instance in the middle of the years 80 the IRET furnished to the IRAQ
a large quantity of VHF sets used from Iraqi army during the Gulf war.
A quality test of the IRET sets made from the Americans on captured sets to the iraqis troups gave a negative evaluation.
Surely the quality it is not comparable to the USA production, but probably the negative sentence has been too exagerate.
Beyond to the IRET trade-mark there are present models marked BERO, ELECTRA or ISKRA, firms that probably for commercial reasons were tied up with the IRET.
Some years ago, the IRET (Industria Radio Elettrica e Telecomunicazioni) closed for financial problems the productive activity in his Trieste city plant.
The sets below briefly described are the material available on the surplus market (mainly italian and portuguese), so must be not taken like a catalog of the IRET production.
COMMANDO: Transceiver, portable, Hand held, VHF.
NA-21: Transceiver. Manpack. VHF. Six channels crystral controlled. Frequency coverage from 156 to 174 MHz. Power around 1 watt. Supply by a package of rechargeable batteries. The apparatus also having the IRET constructive characteristics is marked: BERO - TRIESTE.
PA-21 : LinearAmplifier: VHF Low. Used in combination with PRC-239. Include an audio frequency amplifier and loudspeaker. RF Power 20 W
PA-72: Linear Amplifier. HF. Power 100 watt. Used in combination with the PRC-247A and VRC-247 sets. Power supply to 24 volt or 220 volt with external PSU.
PAL-30: Linear Amplifier. RF. VHF
LOW. Output power 20 watt used with the PRC-638 set series. Include
also an audio frequency amplifier with 2 watt output.
PSU type PU-64 for12 Volt or type PU-66 for 24 Volt.
PR-39: Receiver. It works in VHF from 40 to 56 MHz. Frequency indication on LCD display. Loudspeaker or earphone output..
PRC-116 : Transceiver. Portable
Hand held. VHF.
Late '60s to early '70s. They all work on 18volt D.C. from batteries or
factory acu. . Frequencie ranges varie from 47Mc to 56.9Mc FM. 5 channels.
PRC119 : Transceiver portable. Manpack VHF Low. Frequency range 47 to 56.9 MHz. 6 channels crystal controlled. Power supply battery pack Cd/Ni acu. (type AL18/1) or four 4,5volt batteries. Tape antenna. Battery charger type CA-29
PRC-216 : Transceiver.
Portable Hand held VHF Low Frequency range 47 to 56.9 MHz..
6 channels crystal controlled.
PRC-236 : Transceiver.
Portable Hand held. VHF Low. Similar to PRC216 but with 100
channels 100 KHz steps.. Back side, antenna accessories are
the same as the PRC216's.
PRC-238: Transceiver. VHF LOW. Manpack. Working from 38 to 56 MHz. Supply by batteries contained in a compartment part of the set.
PRC-239: Transceiver. Very small size. Operational frequency from 47 to 56 MHz with steep of 100 KHz. The power output is around 1 watt. Supply from 4 flat 4.5 V batteries.
Can be used in combination with linear PA-21 (see below)
PRC-247 A: Transceiver. HF. Portable.
Frequency range from 2 to 30 MHz in 100 Hz steps, Modes: SSB (A3J), compatible AM (A3H), CW (A1). Possibility of FSK with auxiliary adapter. Power switchable 2 and 20 Watt. Built in antenna tuner. Supply to 24 volt through a NiCd batteries package or external PSU. Whip ( AT-30) or wire antennas.
PRC-247: Transceiver. HF-VHF. Portable. Frequency range from 20 to 69.750 MHz. Sizes equal to the HF model PRC247A. Built in ATU. The power output is selectable from 4 Watt (low power) to 20 Watt. The supply is furnished from a package of NI.Cd batteries. Fairly curious are the initials, that are identical to that of the preceding HF model.
PRC-339/ 2: Man-pack of small dimensions, frequency of operation from 157 to 166 MHz, output power from 3 Watt to 300 mW, 12 Vdc supply by a batteries package.
PRC-416: Transceiver. Hand held type. Appearance similar to the COMMANDO, the frequency can be setted on six channels from 40 to 50 MHz.
PRC-436: Transceiver, portable hand held type, frequency range from 40 to 49 MHz with 25 kHz steps. Power 1 watt, Power supply by a battery block.
PRC-439: Portable Transceiver of
small dimensions (Same to PRC339). Working frequency from 40 to 49,975
with 25 kHz tuning step. Settable power between 3 watt and 300 mW. Supply
12 V dc. Of this model exist many versions with different color and
PRC-447: Transceiver. HF. Manpack. The frequency can be setted by six push-push switches. The range of frequency covered is from 1.6 to 30 MHz, with the possibility of 8 presetted channels. The operational modes are AM, CW, SSB, [cripto] and FSK with external adapters. By an external unit type DM1-DMT are possible digital communications. The power can be 4 or 20 Watt. For his operation it is necessary the ATU-447 that include the RF antenna group. The PRC-447 and l'ATU-447 are interconnected with two D connectors. The set is supplied by the PSU type PP-49, which furnishes the 13.6 volt, necessary to the operation of the whole complex, to its inside there is a package of rechargeable batteries
Many sets of this type are branded ELECTRA.
PRC-638: Transceiver. VHF LOW. Portable
manpack. Operational frequency from 30 to 79 MHz with adjustable steps
from 25 to 75 kHz. Output power can be selected from 300 mW and 3 Watt.
It is equipped with a VOX and TONE-SQUELCH circuits. It requires a supply
of 12 volt usually from a package of rechargeable batteries. Exists also
a battery box which contains the batteries and a suitable recharger. The
complete set of accessories include the handset, a three meters collapsable
antenna and a whip of one meter. All
the parts are contained 2 bags. Probably this set is the more diffused.
Different models of it has been producedt. The more exotic is the yellow-sand
colored with Arab front panel inscriptions.
PRC-650A : Transceiver.
portable small manpack. 6 channels crystral controlled. Frequency range
from 40 to 49 MKz.
PRC-677: Transceiver. VHF LOW. Manpack
type. Same performances of the model PRC-638. The
main differences are the lack of the squelch circuit and the switch for the modes control. In addition it has the possibility to preset 6 channels.. Through an additional unit it can operate in security-voice. The supply system is identical to PRC-638.
PRC-738: Transceiver. VHF LOW. Manpack.
Frequency range from 30 to 90 MHz. Former type had
the tuning controlled by rotary switches, in the last versions the reading of the frequency were legible on a display and the frequency setted with only two switchs (MHz-kHz). It can operate in simplex, duplex and semiduplex with the possibility of memorize six priority channels. Digital communications using the external unit type DM1-DMT is possible. The output power can be 0.3 to 5 watt. Supply to 12.5 volt (optimal 13 volt).
PRC-777: Transceiver similar for construction to the model NA-21. Of this model exist three variations working on different frequencies. The PRC-777/A from 68 to 78 MHz, the PRC-777/ B from 78 to 88 MHz, finally the PRC-777/C for the range from 115 to 137 MHz. Also these models are marked BERO-TRIESTE.
PRC-838: Transceiver more or less
similar to the series 638, the substantial difference it is in the Power
Amplifier that has a maximum output power of around 20 watt. The powers of transmission can be selected in three levels (20-3-0,3 watt). The RF power module of 20 watt is placed between the apparatus and the batteries compartment, accordingly the height and the weight is slightly bigger then 638, while the system of supply is the usual.
PRC-1216 : Transceiver. VHF LOW.
Hand held type almost similar to the known AN/ PRC-6.Range of
operation from 47 to 56 MHz, power 1 Watt. Suuply 18 volt by 4 flat batteries from 4.5 volt.
It uses a tape antenna one meter long. When not in use the antenna is wrapped around the set. A button switch adapts the circuit to the employment of an external antenna through a BNC connector.
RT1-F6: Transceiver similar to the COMMANDO. It doesn't have the output for an external handset. The antenna ( long and a short) has a screw type attack but with the set is supplied an adapter to connect the set to antenna using BNC connectors. Set built also with ISKRA brand.
VRC-247: Transceiver. HF. Vehicular version of the PRC-247A. The performances are similar to the portable model, the only differences are: no inside antenna tuner, the mechanical systems for the fixing on vehicle and the PSU system.
VRC-447: Transceiver. HF. Vehicular.
Similar to the manpack PRC-447. Frequency range from 1.6 to 30 MHz. CW,
compatible AM and SSB. The frequency tuning is possible through six switches.
Power HP 20 Watt, 4 W in LP.
Employs external antenna tuner and an external amplified loudspeaker.
VRC-512: Transceiver. VHF. Six channels.
It works on nautical frequencies.
The power of transmission is from 300 mW in LP and 3 Watt in HP.
It requires an external y 12 Volt dc supply .
VRC-517: Vehicular Transceiver for special employment. The frequency is legible directly on a dispay. Range from 156 to 174 MHz. It can operate in simplex, duplex and semi-duplex. The power is around 1 Watt. Supply 12 volt.
VRC-538: Transceiver. VHF LOW. Vehicular.
Operative frequrncy from 26 to 75.975 MHz. It has a built in antenna tuner. The output power can be selected from 30 Watt, 2.5 Watt and 400 mW. This set uses the same PRC247A cabinet.
VRQ-102: Vehicular radio set. HF.
Usable also like fixed station.
The major components are : Transceiver VRC-247 or the PRC-247A, Power amplifier PA-72 and antenna tuner type CU-5. Power output around 100 W
Supply 24 volt dc from the battery of the vehicle.
VRQ-106: Vehicular radio set for
special purpose. Composed by: HF transceiver VRC-247 plus VHF transceiver
PSU 28 volt or 12 volt. This set can be used also in fixed posting.
VRQ-109: Vehicular radio station,
usable also in fixed posting. The unit is composed from a PRC-638 and from
the linear amplifier PAL-30. Power supply 12 V dc. Output power 30 W
ATU CU: There are many antenna tuning units specially built for HF or VHF. Usually for HF are cabinet with inside a matching system while for VHF sometime it is only a connector adapter ( N to BNC ) with inside a coil or a capacitor.
Antenna: There are several types of antenna usually marked AT. Whips (short and long), tape, long wires, dipoles all for HF and VHF bands. Also in this case attention must be payed to the connections because usually are not standard.
A2-V : Loudspeaker for vehicular purpose
A49 : Amplified loudspeaker of small dimensions, used in the systems using two radio sets. Include interphone possibility.
AL18/1 : NiCd battery pack. 18 V. Used with small manpack and hand held sets (PRC-119, PRC-1216...)
BAGS : Usually in heavy cotton. There are bags for sets, for antenna and accessories.The bags for set sometime have lateral pockets to fit in handset or small accessories. These bags are available in two colors: Yellow sand or forest green.
CA-29 : Battery charger/PSU. Used with PRC-119
CA-65 : Battery compartment/PSU. Carries batteries for the sets PRC-447, PRC-638, PRC-677, PRC-738, PRC-838. In its inside there is a psu for the recharge of the batteries. The PSU has two separate entries on the input connector: the first to 220 CA volt for the recharge of the batteries from the mains, a second entry to 12 Volt dc used for the recharge through the storage battery of the car.
HR RT-F6: Battery charger for the hand held sets RT1-F6, COMMANDO and PRC-416. Input to 220 Vca v. Through a suitable adapter it can be also used directly in substitution of the batteries.
TS-1: Telegraphic key.
The mechanism is protected from a plastic cover. It has two straps to fix it on the leg. There are three different models, similar in the appearance but using different type of connector, (TS-1, TS-1A and TS-1MS).
HA-1: Headset / microphone assy. Different models of it, electrically similar but using different connectors type.
MT-4 : Microphone/Loudspeaker. Single
trasducer switchedby PTT.
: Handset for almost all PRC
series set. Built in several types all mechanically and electrically similar
but using different connectors type. Types known are the MT7, MT7-B,
MT7-D . In some case in the type name there is another letter probably
indicating the customer or the country. (MT7-DP = Portugal ).
MT-10 : Microphone. Dynamic. PTT button
SV-3: Scrambler for Security Voice communications. Usable with almost all PRC and VRC set series.
PP-49: Batteries container for the PRC VHF series.