Introduction
Further to my previous post (Ref.1), I was hoping to receive a DRM transmission on the 31m band at 1900DST/2300UTC. I used the same equipment: SDR-IQ with HF Loop antenna tuned for 9.5MHz. There were several very powerful signals but no DRM. I did receive a strong USB signal on 8764KHz which turned out to be a USCG Marine Weather voice broadcast. In previous posts I looked at receiving NOAA Weather Fax, NAVTEX & SITOR transmissions (Ref.2/5).
Equipment Setup
Figure 1 shows the HF equipment setup. First I tune the HF Loop antenna to the band I want to listen to. In the case of the 31m band, I use a small Sony ICF7600 portable shortwave receiver to do this. I connect the centre pin of the PL-259 antenna connector with an alligator clip to the Sony whip antenna. Then I set the frequency to 9.5MHz/USB and tune the loop for maximum noise. I use the SDR-IQ receiver (14bit ADC!!) with Spectravue software.
Transmission Schedule
I managed to receive the weather broadcast during the 2315Z transmission time from 2319/2320UTC (Ref.6). The noise level was down at -130dB with the signal peaking from -120dB to -110dB. The frequency was exactly at 8364KHz_USB no tuning required. The voice was clear and discernible.
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References
#1. – “HF SDR-IQ on 19m VOACAP Prediction”
https://jeremyclark.ca/wp/telecom/hf-sdr-iq-on-19m-voacap-prediction/
#2. – “OpenPlotter3 Marine NAVTEX”
https://jeremyclark.ca/wp/telecom/openplotter3-marine-navtex/
#3. – OpenPlotter3 HF Marine Weather Fax”
https://jeremyclark.ca/wp/telecom/openplotter3-marine-hf-weather-fax/
#4. – “Marine HF Weather Fax on SDR-IQ”
https://jeremyclark.ca/wp/telecom/marine-hf-weather-fax-on-sdr-iq/
#5. -RTL-SDR for Marine Weather on HF SITOR”
https://jeremyclark.ca/wp/telecom/rtl-sdr-for-marine-weather-on-hf-sitor/
#6. – “NOAA National Weather Service”
https://www.weather.gov/marine/uscg_broadcasts
