Author Topic: 2130 kHz - 2.130 MHz FM Russian Railroad Dispatcher Radio Traffic 15 JUL 17  (Read 691 times)

R4002

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I did a quick 2-4 MHz band scan on one of the Russian remote SDRs and the band was pretty quiet except for the very active frequency of 2130.  At first I thought it was distorted AM but flipped over to FM (narrow FM, NBFM, NFM, narrowband FM...roughly 9.5 kHz bandwidth) and the voices came in nearly full quieting.  I know secretsquirrel mentioned use of NBFM in addition to regular old AM and SSB for village radio...but this is the first time I've come across it.

Roundtable "net" like communications style, hearing lots of different voices chattering with each other, both OMs and YLs.  Seems like pretty informal two-way communications.  Some of the transmissions have a 1000Hz / 1kHz tone transmitted with the audio.  I'm not sure if this is part of some weird selective calling system or simply an malfunction.  Some of the transmitters have the tone, others don't.  Several times, there was no voice traffic on the channel, but the tone was there.  Almost like its serving as a "channel marker" (we know the Russians are fond of those...).

Never seen FM used in the 2 MHz band before.  There's got to be at least 8-10 different stations chatting right now, some of them are weak and others are nearly full scale and full quieting.  Anybody speak Russian?  This is the SDR I'm listening to these stations on:

http://nsk.swl.su:8073/

---

Also,

Does anybody know the history of Russian / Soviet military radio design development?  I've stumbled upon some bits and pieces of information.  For example, discussions of the Red Army using British and US gear in WWII under Lend-Lease, including the famous English W.S. 19 Wireless Set No. 19 with Cyrillic labels and the American BC-348 series of HF receivers with Cyrillic labelling (called the US-9 or YC-9 in Russia) but information on Russian made radios is a little harder to find (doesn't help that I don't speak Russian).  There are some obvious nods to US, British, Australian and Italian tactical radio design in several Russian/Soviet bloc radios I've seen...for example the use of switches for 10 MHz, 1 MHz, 100 kHz, 10 kHz and 1 kHz steps for HF radios, and the use of 1 MHz steps,  100 kHz steps, and a 00/25/50/75 kHz switch for 30-76 MHz (or 20-70 MHz) FM tactical radios.  

I know about their tank and mobile command radio equipment, mirroring the WWII and Korea-era US military frequency plan of 20-59 MHz, FM mode, often adding AM, USB and CW to FM capability.  Of course, there's provision for MF/HF portable and mobile radios, and I found a Russian defense contractor's website advertising an aircraft radio that covers 30-174 MHz and 200-400 MHz AM/FM with various encryption and frequency hopping ECCM capabilities.  Doesn't explain the use of FM on the 2-3 MHz band though!  

There are lots of articles talking about Soviet-era receivers covering the frequency range in question...but I can't find much of anything on transmitters and/or transceivers.  
« Last Edit: July 17, 2017, 1423 UTC by R4002 »

ulx2

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Hello! 2130 and 2150 KHz are the ex-USSR railway dispatch channels. Also 2444 and 2464 kHz FM are still being used for subway communications in some places.
« Last Edit: July 15, 2017, 1523 UTC by ulx2 »
LOC: Kyiv, Ukraine
RX: Degen DE-1103 portable
ANT1: Two phased external wires (2x10 meters approx.)
ANT2: Long wire (25 meters)
ANT3: Homemade M0AYF wide bandwidth active loop
ACC: Homemade passive preselector, homemade phasing device

http://ulx2.byethost24.com/

R4002

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Interesting.  So chances are they're using former USSR railroad radio equipment? 

2130 kHz, 2150 kHz, both FM?  2444 kHz and 2464 kHz are closer to the other "village radio" communications that have been heard too.

ulx2

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Yes, these frequencies are still widely in use by railroad dispatchers. 2130 kHz is the most active channel. And I think, you have heard dispatchers' QSOs there. They are using old Soviet (42РТМ-А2-ЧМ, 43РТС-А2-ЧМ) and modern (РВ-1М, РВ-1.1М, РС-46МЦ, РВС-1, Орион РВ-4, Орион РВ-4М, Оріон РС-4, Оріон РС-6, etc.) equipment for simplex group call communication with engine drivers, duty yardmasters, etc.:

http://www.orion.te.ua/index.php/en/products/for-railways
http://scbist.com/aza-stan-tem-r-zholy/12148-poezdnaya-radio-svyaz.html
https://www.youtube.com/watch?v=GEsjgryPp7M
https://www.youtube.com/watch?v=1hzcH7QLaes
https://www.youtube.com/watch?v=xflY1dieU5s


And this has nothing to do with music broadcasts/QSOs of radio hooligans (unlicensed freebanders) on 2900 - 3300 kHz frequency range ("village radio" as you called it).

The modulation on all four frequencies is rather phase one (PM). As I know, typical 2130 kHz transmitter includes: 118.3 kHz driving oscillator, phase modulator, 18x multiplier (3x + 3x + 2x)...

Typical antennas are guide wires (bimetallic waveguides) dangling along railway.


« Last Edit: July 16, 2017, 0313 UTC by ulx2 »
LOC: Kyiv, Ukraine
RX: Degen DE-1103 portable
ANT1: Two phased external wires (2x10 meters approx.)
ANT2: Long wire (25 meters)
ANT3: Homemade M0AYF wide bandwidth active loop
ACC: Homemade passive preselector, homemade phasing device

http://ulx2.byethost24.com/

skeezix

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This is great info.

I tuned into http://msk.swl.su:8073 and hear clearly something on 2130 NBFM.


ulx2, do you happen to know what 1765 and 1820 USB are/were for? I have a НЕДРА-П & A Карат-M and both came on those frequencies. I think the НЕДРА-П from 1964 and the Карат-M is from the 1980's.




Minneapolis, MN

R4002

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Very interesting indeed.  I'm actually listening to a QSO on 2130 kHz FM (PM) right now [1422 UTC].  I've changed the title of the thread to reflect that these are legit users and not 'village radio' or freebanders/outbanders or bootleggers. 

ulx2

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ulx2, do you happen to know what 1765 and 1820 USB are/were for? I have a НЕДРА-П & A Карат-M and both came on those frequencies. I think the НЕДРА-П from 1964 and the Карат-M is from the 1980's.

skeezix, НЕДРА-П & Карат-M were being used for SSB radio communication in geological survey, agriculture, forestry and some other non-military spheres of national economy in USSR. And these frequencies are the channels for this communication. НЕДРА-П was initially developed for geological survey and Карат-M for agriculture was.
« Last Edit: July 22, 2017, 2356 UTC by ulx2 »
LOC: Kyiv, Ukraine
RX: Degen DE-1103 portable
ANT1: Two phased external wires (2x10 meters approx.)
ANT2: Long wire (25 meters)
ANT3: Homemade M0AYF wide bandwidth active loop
ACC: Homemade passive preselector, homemade phasing device

http://ulx2.byethost24.com/

skeezix

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ulx2 - Thank you! That's great information.

I bought them off of eBay some time ago from a guy in Ukraine and ever since then, keep looking for more of their type. Oddly, for the years I've been looking, they're the only ones that have shown up.

Minneapolis, MN