Project Cohiradia

Recordings

Download of recordings.

Report 2023

Cohiradia report 2023.

Documentations

Download of documentations.

Software

Software download.

Introduction

Imagine that you could tune through and listen to all the stations of the medium wave band, which were active on a certain day in 2006, on your historical radio receiver at any time. You could then get the feeling as if all these stations were broadcasting right now. Of course the playback should not be based on an artificial montage, but on an authentic historical recording. This scenario probably represents a dream of many collectors, whose beautiful and valuable devices will remain increasingly 'mute' due to the rapidly progressing final shutdown of AM transmitters. Exactly this dream is fulfilled by the COHIRADIA project, as this demo video shows.

COHIRADIA is an acronym for COnservation of HIstorical RAdiofrequency bands by DIgital Archiving.

Goals

COHIRADIA has two main goals:

  1. to give interested radio enthusiasts and collectors the opportunity to play back original radio signals recorded in the past on historical radio receivers. These signals should not contain only a single station, but a whole frequency band (e.g. medium wave) with all radio stations contained therein on the correct carrier frequencies existing at the time of recording. This allows all stations to be tuned-trough on the radio receiver.
  2. to record currently broadcast radiofrequency bands, especially in the AM range, at various locations around the world. The goal is to map the still existing landscape of active stations in the form of archive files in time before the technology finally will die out.

Technical Solution

COHIRADIA is made possible by recording and playing back digitized radio frequency signals using software-defined radios (SDRs). Wideband recording directly from an antenna is now relatively easy with several SDRs on the market, while playback requires more advanced SDRs with transmit output. The initiator of COHIRADIA uses the STEMLAB125-14 from RedPitaya, which offers a high quality for recording and playback with 14 bit ADC resolution and 125MS/s sampling rate. Alternative TX-capable SDRS with similar or better performance specifications also exist.

The recordings can be played back by anyone who also possesses a STEMLAB125-14 or a suitable TX-capable SDR. The use of a uniform data format guarantees interchangeability between different platforms.

In order to build up a rich archive in as short a time as possible, interested amateurs are invited to make their own recordings and to make the data available to the Radio Museum and/or to report on the successful playback of files on historical radio equipment. Creative ideas for other applications (activities, museums, ...) are also very welcome.

If you are interested, more details on the technology, software and quality criteria used can be found in the report 2023.

The oldest existing recordings on MW and KW were made by the initiator in the years 2006 - 2009 in analog form on a video recorder and digitized in 2021 with a STEMLAB125-14. All further datasets, especially from 2015 on, were produced directly digitally by various radio amateurs participating in COHIRADIA, mainly on long, medium and short wave up to 30 MHz. On these recordings there are still many European stations which have been switched off in the meantime.

For the playback of the data files as well as for the creation of own recordings on the STEMLAB125-14 a first software version was created in Python and is available for Windows10 as exe program. The author has already created a GITHub repository for the sources, a release as an open source project is planned for the near future.

Hermann Scharfetter initiated and drives the project COHIRADIA. You can contact him as member of rmorg via his profile or as a guest via email to further develop the project.

Other Archives

Besides COHIRADIA, the following archives are known to contain interesting wideband material as well:

Recordings (78)

Date/Time Content Band Country
2024-02-20 LW band including Helissandur (Iceland) in audible quality LW Kangasala, Sahalahti, FI, FI
2024-02-19 LW band including Helissandur (Iceland) in audible quality LW Kangasala, Sahalahti, FI, FI
2024-02-19 LW band including Helissandur (Iceland) in audible quality LW Kangasala, Sahalahti, FI, FI
2024-02-06 LasPalmas_Canarias_MW, Las Canteras, night MW Las Palmas, CNR
2024-02-05 GranCanaria_MW_daytime MW Puerto de Sardina, CNR
2024-01-01 MW New Year's day, QTH: Perfugas(Sardinia). Special: New year's concert 2024 of the Vienna Philharmonic Orchestra on RNE MW Perfugas, Sassari Province, I, IT
2023-12-31 New Years eve 31-12-2023, MW, rec. Neunkirchen-Seelscheid MW Neunkirchen-Seelscheid, DE
2023-12-31 New Years eve 31-12-2023, LW, rec. Graz, Midnight sequence LW Graz, AT
2023-12-31 LW Band with New Year's speech of Queen Margrethe II at the last transmission of Kalundborg, 243kHz, rec. by Jorma Mantyla in Finland LW Kangasala, Sahalahti, FI , FI
2023-12-31 LW: Kalundborg 243kHz last transmission, QTH: Kungsbacka, B. Madeberg LW Kungsbacka, SE
2023-12-31 LW: Kalundborg 243kHz last transmission, QTH: Haderslev, C. Nielsen LW Haderslev, DNK
2023-12-24 VLF and LW 10 -260kHz: Grimeton SAQ Christmas transmission 23 and Kalundborg Morning gymnastics on Christmas Eve 2023 VLF,LW Graz, AT
2023-12-24 SAQ Grimeton Christmas Eve 2024, rec. Neunkirchen VLF Neunkirchen-Seelscheid, DE
2023-10-29 Welle 370, 100 Jahre Rundfunk in Deutschland, rec. Neunkirchen KW_49m Neunkirchen-Seelscheid, DE
2023-10-24 SAQ Grimeton on UN-Day 24.10.2023, rec. Neunkirchen VLF Neunkirchen-Seelscheid, DE
2023-09-28 The last hour of Gold London on 1548kHz, MW Graz MW Graz, AT
2023-09-27 MW band with the first evening of Country Radio on 639kHz (CZE, Liblice) MW Graz, AT
2023-09-24 MW Perfugas, past midnight MW Perfugas, I, IT
2023-09-24 LW Perfugas, past midnight LW Perfugas, I, IT
2023-09-24 MW Recording in Perfugas (Sardegna) MW Perfugas, I, Italia, Regione Autonoma della Sardegna
2023-09-24 LW Recording in Perfugas, Sardegna LW Perfugas, I, Italia, Regione Autonoma della Sardegna
2023-09-23 MW, Sedini during daytime MW Sedini, I, IT
2023-09-23 LW, Sedini during daytime LW Sedini, I, IT
2023-09-21 MW Perfugas, at night MW Perfugas, I, I
2023-09-21 LW Perfugas, at night LW Perfugas, I, I
2023-09-21 MW Sunset at the beach of Badesi al Mare MW Badesi, I, ITA
2023-09-21 LW Sunset at the beach of Badesi al Mare LW Badesi, I, IT
2023-08-12 MW night spectrum in Gothenborg (Sweden) MW Gothenborg, SE
2023-08-06 New Zealand North 2023-A, part 2, recorded by Christian Holme MW Robert Findlay Wildlife Reserve, near Pukorokoro / Miranda, NZL
2023-08-06 New Zealand North 2023-A, part 1, recorded by Christian Holme MW Robert Findlay Wildlife Reserve, near Pukorokoro / Miranda, NZL
2023-05-18 Radio Dechovka from Zbraslav, 100 years anniversary of Czech Radio, RX Neunkirchen/Seelscheid MW Neunkirchen-Seelscheid, DE
2023-05-18 Radio Dechovka last time from from Zbraslav, 100 years anniversary of Czech Radio, RX Graz MW Graz, AT
2023-05-06 Coronation ceremony of Charles III, full transmission on BBC4 on LW, RX Neunkirchen LW Neunkirchen/Seelscheid, DE
2023-04-14 Last transmission of RTE on 252kHz: Last 15min, RX Luzern LW Luzern, CH
2023-04-14 Last transmission of RTE on 252kHz: Last hour. RX Neunkirchen-Seelscheid LW Neunkirchen-Seelscheid, DE
2023-02-13 SAQ Grimeton on World Radio Day 2023 13.02.2023, rec. Neunkirchen VLF Neunkirchen-Seelscheid, DE
2023-01-19 Last transmissions of Absolute Radio on MW, RX Luzern MW Luzern, CH
2023-01-19 Last transmission of Absolute Radio, rec. Neunkirchen MW Neunkirchen-Seelscheid, DE
2023-01-19 Last transmissions of Absolute Radio, RX Graz MW Graz, AT
2023-01-01 New Year's Memories 22/23: Last transmission from RTL on LW, RX Luzern by Gianni Müller LW Luzern, CH
2023-01-01 New Year's Memories 22/23: Last transmission from RTL on LW, RX Graz LW Graz, AT
2023-01-01 New Year's Memories 22/23: Last transmission from RTL on LW, RX Neunkirchen LW Neunkirchen-Seelscheid, DE
2022-12-31 New Year's Memories 22/23: Afternoon in CA synchronized with Europe's last hour of New Year's Eve MW Los Gatos (CA), US
2022-12-31 New Year's Memories 22/23: New Year's Eve on LW, RX Luzern LW Luzern, CH
2022-12-31 New Year's Memories 22/23: Last transmission from SVK on 702 and 1098 kHz, RX Luzern MW Luzern, CH
2022-12-31 New Year's Memories 22/23: New Year's Eve on LW, RX Graz LW Graz, AT
2022-12-31 New Year's Memories 22/23: Last transmission from SVK on 702 and 1098 kHz, RX Graz MW Graz, AT
2022-12-31 New Year's Memories 22/23: Last transmission from SVK on 702 and 1098 kHz, RX Neunkirchen-Seelscheid LW/MW Neunkirchen-Seelscheid, DE
2022-11-16 VLF/LW: Grimeton SAQ on UNESCO 50th anniversary day ULW/LW Graz, AT
2022-09-10 14min recording with the last 5 minutes before all RAI MW transmitters closed MW Graz, AT
2022-09-10 Shutdown of all RAI MW transmitters, last hour MW Graz, AT
2022-08-18 MW in northern Greece, summer evening MW close to Parga, GRC
2022-08-10 MW band, recorded in summer on a Ferry in the Adriatic Sea, part2 MW Adriatic Sea
2022-08-10 MW band, recorded in summer on a Ferry in the Adriatic Sea, part1 MW Adriatic Sea
2022-07-18 LW, strong Luxembourg effect on 162kHz/198kHz LW Lossburg, DE
2022-06-11 Luxembourg effect with RTL modulated onto 162kHz Allouis, sample 1 LW Graz, AT
2022-06-11 Luxembourg effect with RTL modulated onto 162kHz Allouis, part1 LW Graz, AT
2022-05-13 LW 13-05-2022 morning LW Neunkirchen-Seelscheid, DE
2022-05-13 LW recording with Luxembourg effect on 162kHz LW Neunkirchen-Seelscheid, DE
2022-05-02 wideband recording including LW and MW in one LW&MW Neunkirchen-Seelscheid, DE
2022-05-01 LW 01-05-2022 morning LW Neunkirchen-Seelscheid, DE
2022-04-27 MW California 27-04-2022, evening MW Los Gatos (CA), US
2022-04-19 MW California 19-04-2022, morning MW Los Gatos (CA), US
2022-04-15 MW 15-04-2022 evening MW Neunkirchen-Seelscheid, DE
2022-02-27 MW 27-02-2022 incl. reactivated Ukrainian Station on 549kHz after Russian invasion MW Graz, AT
2021-12-31 Shutdown of MW transmitters in CZE 23:00 UTC: Liblice 2 and Ostrava MW Graz, AT
2021-12-31 Details... MW Graz, AT
2021-12-31 LW band with shutdown of the LW transmitter Topolna in CZE at 23:00 UTC LW Graz, AT
2019-12-31 Silvester 2019 on MW, midnight sequence, RX Hildisrieden bei Luzern MW Hildisrieden, CH
2019-12-31 Silvester 2019 on LW, sequence 3, RX Hildisrieden bei Luzern LW Hildisrieden, CH
2019-12-31 Silvester 2019 on LW, sequence 2, RX Hildisrieden bei Luzern LW Hildisrieden, CH
2015-07-20 MW midsummernight 2015: 4 min around CEST midnight; RX Luzern MW Luzern, CH
2009-01-01 KW, 49m band, analogue recording on VR KW 49m Graz, AT
2006-12-31 MW, 30/31-12-2006 short clip MW Graz, AT
2006-12-31 MW, 30-12-2006, part2 midnight MW Graz, AT
2006-12-30 MW, 30-12-2006, part1 midnight MW Graz, AT
2006-12-07 MW, 07-12-2006, part2, analogue VR MW Graz, AT
2006-12-07 MW, 07-12-2006, part1, analogue VR MW Graz, AT

Discussion

Date/Time Title Author
2022-04-03 Software for COHIRADIA: Details and problem-solving Hermann Scharfetter
2022-04-03 Software für COHIRADIA: Details und Problemlösungen Hermann Scharfetter
2022-04-02 Wideband recording of historical AM radiofrequency bands Hermann Scharfetter
2021-12-19 Breitbandaufzeichnungen von historischen AM-Bändern Hermann Scharfetter
2022-04-03 Hardware for COHIRADIA: Details and problems/solutions Hermann Scharfetter
2022-04-03 Hardware für COHIRADIA: Details und Problemlösungen Hermann Scharfetter