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[[File:РАДИСТАНЦИЯ А-7.jpg|thumb| A7 VHF transceiver]]
{{Short description|Portable military VHF radio transceiver}}
{{redirect2|A7a|A7b|the aircraft (A-7A and A-7B)|LTV A-7 Corsair II}}
⚫
The Soviet '''A7''' VHF transceiver (later models include the '''A7a''' and '''A7b''') was developed during [[World War II]] and used for communication in rifle brigades and regiments. The complete station was designed to be transported by an individual soldier.
{{moresources|date=September 2019}}
{{Use dmy dates|date=September 2019}}
[[File:Радиостанция А-7.jpg|thumb|A-7 VHF transceiver]]
⚫
The Soviet '''A-7''' VHF radio transceiver (later models include the '''A-7a''' and '''A-7b''') was developed during [[World War II]] and used for communication in rifle brigades and regiments. The complete station was designed to be transported by an individual soldier.


==Design and features==
==Design and features==
===A7===
===A-7===
The A7 is a portable man-pack, radio transceiver with narrow-band frequency modulation. The set can be used as a radio telephone in a wired network and managed remotely. Setting the frequency of the receiver and transmitter is adjusted in tandem by one handle, in fact the receiver and the transmitter are separate. The antenna and buffer oscillator circuits are common for the receiving and transmitting circuits.
The A-7 is a portable man-pack, radio transceiver with narrow-band frequency modulation. The set can be used as a radio telephone in a wired network and managed remotely. Setting the frequency of the receiver and transmitter circuits is adjusted in tandem by one control handle. The antenna and buffer oscillator circuits are common for the receiving and transmitting circuits.


The receiver section is a [[superheterodyne]] design with a single frequency conversion, consisting of 8 identical 2K2M [[Vacuum tubes|valves]]. A regenerative detector with adjustable feedback is used. The transmitter section includes a 2K2M modulator valve, a CO-257 buffer amplifier valve, and a CO-257 power amplifier valve. Switching from reception to transmission is achieved by switching the power from the heater circuits of the receiver and transmitter valves, alternately.
The receiver section is a [[superheterodyne]] design with a single frequency conversion, consisting of 8 identical 2K2M [[Vacuum tubes|valves]]. A regenerative detector with adjustable feedback is used. The transmitter section includes a 2K2M modulator valve, a CO-257 buffer amplifier valve, and a CO-257 power amplifier valve. Switching from reception to transmission is achieved by switching the power from the heater circuits of the receiver and transmitter valves, alternately.<ref name = "User manual">http://www.rkk-museum.ru/documents/archives/images/2-43-01.pdf User manual. Retrieved 15 July 2018.</ref>


The transceiver with power supplies and accessories is housed in a wooden box with shoulder straps for carrying as a backpack. For long distances, the set is carried by two soldiers. The set only requires one radio operator. The deployment time is typically not more than 5 minutes.
The transceiver with power supplies and accessories is housed in a wooden box with shoulder straps for carrying as a backpack. For long distances, the set is carried by two soldiers. The set only requires one radio operator. The deployment time is typically not more than five minutes.


*Frequency range: 27-32 MHz.
*Frequency range: 27-32&nbsp;MHz.
*Number of frequency channels: 101.
*Number of frequency channels: 101.
*Transmitter output power: 1W.
*Transmitter output power: 1W.
*Sensitivity of the receiver: 1-1.5 μV.
*Sensitivity of the receiver: 1-1.5 μV.<ref name = "User manual"/>
*Intermediate frequency: 1100 kHz.
*Intermediate frequency: 1100&nbsp;kHz.<ref name = "User manual"/>
*Antennas: a whip with a height of 2.5 m and a beam length of 6.4 m with a three-beam counterweight (for operation from buildings).
*Antennas: a whip with a height of 2.5 m or a flexible wire 6.4 m long.<ref name = "User manual"/>
*Range of action:
*Range of action:
**On rough terrain - up to 7-8 km.
**On rough terrain - up to 7–8&nbsp;km.
**On urban conditions - 3-4 km.
**On urban conditions - 3–4&nbsp;km.
**On slightly cross-country terrain outside of buildings - 10 km and more.
**On slightly cross-country terrain outside of buildings - 10&nbsp;km and more.
*Power source - two dry anode batteries BAS-80 with a total voltage of 160 V and two 2 NKN-10 nickel-cadmium batteries. The time of continuous operation from one set is 35-40 hours.
*Power source: two dry anode batteries BAS-80 with a total voltage of 160 V and two 2 NKN-10 nickel-cadmium batteries. The time of continuous operation from one set is 35–40 hours.<ref name = "User manual"/>
*Dimensions of the transceiver (without protruding parts): 285 × 135 × 165 mm.
*Dimensions of the transceiver (without protruding parts): 285 × 135 × 165&nbsp;mm.
*Dimensions of the packing box: 210 × 385 × 330 mm.
*Dimensions of the packing box: 210 × 385 × 330&nbsp;mm.
*Mass of the radio station: 15.5 kg, the battery weighs 6 kg.
*Mass of the radio station: 15.5&nbsp;kg, the battery weighs 6&nbsp;kg.


===A7a===
===A-7a===
A7a is a simplified version of the A7. The total number of valves was reduced to 9. In the transmitter section, the functions of the modulator and power amplifier were combined into one valve, and in the receiver section one valve was used to simultaneously perform the functions of a high-frequency and low-frequency amplifier (the so-called reflex circuit ). The ability to work by telegraph was removed. Energy consumption was decreased by about 30%, other main characteristics were not changed. The A7a set was manufactured by various factories in several different variants: with and without a tone button, with one or two measuring instruments, etc.
A-7a is a simplified version of the A-7. The total number of valves was reduced to 9. In the transmitter section, the functions of the modulator and power amplifier were combined into one valve, and in the receiver section one valve was used to simultaneously perform the functions of a high-frequency and low-frequency amplifier (the so-called [[Reflex receiver|reflex circuit]]). The ability to work by telegraph was removed. Energy consumption was decreased by about 30%, other main characteristics were not changed. The A-7a set was manufactured by various factories in several different variants: with and without a tone button, with one or two measuring instruments, etc.


===A7b===
===A-7b===
[[File:РАДИОСТАНЦИЯ А-7-Б.jpg|thumb|A7b]]
[[File:РАДИОСТАНЦИЯ А-7-Б.jpg|thumb|A-7b]]
A7b is a 10 valve version introduced in 1945. In the transmitter section two valves are used in parallel. The transmitting range was increased by around 50%. The frequency range is 24-28 MHz. There is no feedback adjustment in the detector circuit.
A-7b is a ten-valve version introduced in 1945. In the transmitter section two output valves are used in parallel. The transmitting range was increased by around 50%. The frequency range is 24-28&nbsp;MHz. There is no feedback adjustment in the detector circuit.


The A-7b was also manufactured from 1950 to 1956 in Pardubice, Czechoslovakia by the [[Tesla (Czechoslovak company)|Tesla]] company.
The A7b was produced locally in various satellite countries during the 1950s and early 1960s.


==References==
==References==
{{Reflist}}
[http://home.wxs.nl/~meuls003/gallery/a7a.html Personal website on wireless military technology]


==External links==
==External links==
Line 43: Line 47:
[[Category:Military electronics of Russia]]
[[Category:Military electronics of Russia]]
[[Category:Military radio systems]]
[[Category:Military radio systems]]
[[Category:Radio in the Soviet Union]]


{{comm-stub}}
{{Russia-mil-stub}}

Latest revision as of 12:00, 15 November 2023

"A7a" and "A7b" redirect here. For the aircraft (A-7A and A-7B), see LTV A-7 Corsair II.

A-7 VHF transceiver

The Soviet A-7 VHF radio transceiver (later models include the A-7a and A-7b) was developed during World War II and used for communication in rifle brigades and regiments. The complete station was designed to be transported by an individual soldier.

Design and features

[edit]

A-7

[edit]

The A-7 is a portable man-pack, radio transceiver with narrow-band frequency modulation. The set can be used as a radio telephone in a wired network and managed remotely. Setting the frequency of the receiver and transmitter circuits is adjusted in tandem by one control handle. The antenna and buffer oscillator circuits are common for the receiving and transmitting circuits.

The receiver section is a superheterodyne design with a single frequency conversion, consisting of 8 identical 2K2M valves. A regenerative detector with adjustable feedback is used. The transmitter section includes a 2K2M modulator valve, a CO-257 buffer amplifier valve, and a CO-257 power amplifier valve. Switching from reception to transmission is achieved by switching the power from the heater circuits of the receiver and transmitter valves, alternately.[1]

The transceiver with power supplies and accessories is housed in a wooden box with shoulder straps for carrying as a backpack. For long distances, the set is carried by two soldiers. The set only requires one radio operator. The deployment time is typically not more than five minutes.

  • Frequency range: 27-32 MHz.
  • Number of frequency channels: 101.
  • Transmitter output power: 1W.
  • Sensitivity of the receiver: 1-1.5 μV.[1]
  • Intermediate frequency: 1100 kHz.[1]
  • Antennas: a whip with a height of 2.5 m or a flexible wire 6.4 m long.[1]
  • Range of action:
    • On rough terrain - up to 7–8 km.
    • On urban conditions - 3–4 km.
    • On slightly cross-country terrain outside of buildings - 10 km and more.
  • Power source: two dry anode batteries BAS-80 with a total voltage of 160 V and two 2 NKN-10 nickel-cadmium batteries. The time of continuous operation from one set is 35–40 hours.[1]
  • Dimensions of the transceiver (without protruding parts): 285 × 135 × 165 mm.
  • Dimensions of the packing box: 210 × 385 × 330 mm.
  • Mass of the radio station: 15.5 kg, the battery weighs 6 kg.

A-7a

[edit]

A-7a is a simplified version of the A-7. The total number of valves was reduced to 9. In the transmitter section, the functions of the modulator and power amplifier were combined into one valve, and in the receiver section one valve was used to simultaneously perform the functions of a high-frequency and low-frequency amplifier (the so-called reflex circuit). The ability to work by telegraph was removed. Energy consumption was decreased by about 30%, other main characteristics were not changed. The A-7a set was manufactured by various factories in several different variants: with and without a tone button, with one or two measuring instruments, etc.

A-7b

[edit]
A-7b

A-7b is a ten-valve version introduced in 1945. In the transmitter section two output valves are used in parallel. The transmitting range was increased by around 50%. The frequency range is 24-28 MHz. There is no feedback adjustment in the detector circuit.

The A-7b was also manufactured from 1950 to 1956 in Pardubice, Czechoslovakia by the Tesla company.

References

[edit]
  1. ^ a b c d e http://www.rkk-museum.ru/documents/archives/images/2-43-01.pdf User manual. Retrieved 15 July 2018.
[edit]
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