SWLs of the U.S.S.R. before the Second World War used call signs of the RK-[number] series, regardless of which of the republics they were from.

As for the pre-war call signs of individual and club stations, then, using Georgia (Georgian Soviet Socialist Republic) as an example, it looked like this:

In October 1926, the first legal HAM radio operators appeared on the air in the territory of the USSR, which was legalized by the decision of the People's Commissariat of Posts and Telegraphs of the U.S.S.R.

Until the end of October 1928, HAMs received individual call signs of the so-called "digital series" (their prefixes consisted of numbers - from 01 to 99, with the corresponding suffix RA). After the issuance of the call sign 99RA, from 1928, HAMs began to be issued the RB series, and then the RW series.

The first HAMs in Georgia in 1928 were:

05RB - Aghamalyan M.T. (Tiflis, now Tbilisi, later - au7AB)

69RB - Akimov Sergey Yakovlevich (Tiflis; later - eu7AE)

10RW - Zelik Ya.M. (Poti; later - au7AH)

33RW - Barbaumov F.P. (Tiflis; later - au7AN)

41RW - Gupenets A.G. (Sagarejo city; later - au7AO)

59RW - Kvernadze A.D. (Tiflis; until 1929 illegal - RTRL; later - au7AR)

69RW - Zakharov M.L. (Tiflis; later: au7AR, U6SF)

70RW - Bering V.E. (Tiflis; later: au7AT)

76RW - Osepyan (Tiflis; later: au7AU)

Club stations were also opened:

RB14 - Tiflis (central club station of Georgian SKW - Short Wave Section, in Russian: Секция Коротких Волн; later - au7KAD)

RB26 - Manglisi settlement (Regiment Club; later - au7KAE)

RB27 - Tiflis (Polytechnic Institute; later - au7KAF)

RB54 - Tiflis (later - au7KAH)

It should be noted that at that time, Soviet HAMs signed their QSLs not with their first name, but with their last name. After World War II, this practice continued for some time, but by the 1960s, everyone began signing with their first name.

On October 20, 1928, the People's Commissariat of the U.S.S.R. introduced a new call sign system. The territory of the USSR was conditionally divided into 9 regions (the European part received the prefix "eu", and the Asian part - "au"):

Central Industrial Region of the Russian Soviet Socialist Republic - eu2
North-Western Region of the Russian Soviet Socialist Republic - eu3
Volga Region of the Russian Soviet Socialist Republic - eu4
Ukrainian Soviet Socialist Republic; Moldavian Soviet Socialist Republic, and Crimean Autonomous Soviet Socialist Republic - eu5
North Caucasus, Russian Soviet Socialist Republic - eu6
Bryansk and Smolensk regions of the Russian Soviet Socialist Republic, and the Belorussian Soviet Socialist Republic - eu9
Siberia and the Far East of the Russian Soviet Socialist Republic - au1 and au4 respectively
Republics of Transcaucasia - au7
Central Asian republics - au8

The two letters of the prefix were printed on QSLs in both upper and lower case (most often lower case), or not printed at all.

Here is a list of individual HAMs of Georgia in the period 1928-33:

au7AB - Aghamalyan M.T. (Tbilisi; earlier - 05RB)

au7AD - Molchanov M.A. (Tbilisi; later - U6SH)

au7AE - Akimov Sergey Yakovlevich (Tbilisi; earlier - 69RB)

au7AF - Paparidze (Tbilisi)

au7AH - Zelik Ya.M. (Poti; earlier - 10RW)

au7AN - Barbaumov F.P. (Tbilisi; earlier - 33RW)

au7AO - Gupenets A.G. (Sagarejo city; earlier - 41RW)

au7AR - Kvernadze A.D. (Tbilisi; earlier - 59RW)

au7AS - Zakharov M.L. (Tiflis; earlier - 69RW; later - U6SF)

au7AT - Bering V.E. (Tiflis; earlier - 70RW)

au7AU - Osepyan (Tiflis; earlier - 76RW)

au7AV - Bartyshevsky Nikolay (Tiflis; later - U6SJ)

au7AX - Glukharev (Tiflis)

au7AY - Aleksandrov (Tiflis)

au7AZ - Kharatov (Tiflis)

au7BA – Machutadze (Tiflis)

au7BB - Kutloev (Tiflis)

au7BC – Gusev (Tiflis)

au7BF - Gvishiani (Tiflis)

au7BG - Eramov G.N. (Tiflis; later - U6SG)

au7BH - Bakhtamyan P.Ya. (Tiflis)

au7BI - Japaridze M.I. (Tiflis)

au7BP - Malkov G.A. (Tiflis)

au7BQ - Martirosov S.M. (Tiflis; later - U6SC)

au7BT - Gabrielyan A.P. (Tiflis)

au7BV - Khazhaknyants (Tiflis)

au7BW - Kvitashvili (Tiflis)

au7BY – Chirkov

au7CE - Ermolov G.V. (Tiflis)

au7CF - Kandalaki (Tiflis)

au7CG - Gocheginadze G.Z. (Tiflis)

au7CH - Vichilyansky (Tiflis)

au7CM - Proletarsky K.A. (Sukhum)

au7CV - Efremidi L.F. (Tiflis; earlier - RK-1325; later - U6SB)

au7CW - Bagdavadze I.R. (Tiflis; later - U6SL)

au7CZ - Ozhogin Boris Mikhailovich (Tiflis; later - U6SE)

au7DB - Mühlman F.A. (Tiflis; later - U6SK)

au7DH - Sultanov G.M. (Tiflis; later - U6SN)

au7DW - Shishmonyan Artavaz H. (Tiflis; later - U6SD; after WWII in Kabardino-Balkarian ASSR – UA6XR, U6XR)

au7ED - Voitsik Nikolay Mikhailovich (Tiflis; later - U6SM)

Club stations (before 1930 the prefix was "ag"):

au7KAD - Tiflis (earlier - RB14)

au7KAE - settlement Manglisi (Regiment Club; earlier - RB26)

au7KAF - Tiflis (Polytechnic Institute; earlier - RB27)

au7KAH - Tiflis (earlier - RB54)

au7KAK – Tiflis

au7KAM - Tiflis (at the radio station of the Union of Soviet Trade Employees)

On June 1, 1933, the People's Commissariat of the Communist Party of the Soviet Union introduced a new (third) system of call signs: the U.S.S.R. territory was conditionally divided into ten regions (U1-U0), which existed until the beginning of the Great Patriotic War.

Individual call signs were given to:

U6SB - Efremidi L.F. (Tiflis, now Tbilisi; earlier: au7CV, RK-1325)

U6SC - Martirosov S.M. (Tiflis; earlier - au7BQ)

U6SD - Shishmonyan Artavaz H. (Tiflis; earlier - au7DW; after the World War II moved to Kabardino-Balkarian ASSR - UA6XR, later U6XR)

U6SE - Ozhogin Boris Mikhailovich (Tiflis; earlier - au7CZ)

U6SF - Zakharov M.L. (Tiflis; earlier - au7AS)

U6SG - Eramov G.N. (Tiflis; earlier - au7BG)

U6SH - Molchanov M.A. (Tiflis; earlier - au7AD)

U6SI - Parsadianov G.M. (Tiflis)

U6SJ - Bartyshevsky Nikolay (Tiflis; earlier - au7AV)

U6SK - Mühlmann Fedor A. (Tiflis; earlier - au7DB)

U6SL - Bagdavadze I.R. (Tiflis; earlier - au7CW)

U6SM - Voitsik Nikolay Mikhailovich (Tiflis; earlier - au7ED)

U6SN - Sultanov G.M. (Tiflis; earlier - au7DH)

U6SO - Lomidze D.K. (Tiflis; after World War II - UF6DL)

U6SP - Oganian G.Kh. (Tiflis)

U6SR - Oskuzov A.A. (Tiflis)

U6ST - Shishmanyan Zhirayr Khachaturovich (Batumi; after World War II moved to Yerevan, Armenia - UG6AW)

The only club stations of this period (according to surviving data) was UK6SU under the Batumi City Council of the USSR OSOAVIAKhIM).

That's roughly the story. Perhaps now it will become clearer how the pre-war callsign system in the USSR was arranged.

And, of course, a question for the group: I would be grateful if you shared scans of the QSLs of the above-mentioned callsigns.