WEAK SIGNAL DX - WHEN THE NOISE GOES AWAY

WEAK SIGNAL DX

.....WHEN THE NOISE GOES AWAY

Several days ago (Friday the 13th, no less!), everyone in our neighbourhood were notified that the electricity would be turned off off for a few hours to enable power line maintenance. I found that I was going to be home during the outage. GREAT!....I thought. Time to get out the 12v sealed lead acid battery, charge it up, bring it into the radio shack and connect up to the Yaesu FTDX3000 transceiver.

So when they finally turned off the power (for 2.5 hours as it turned out), I was seated at the radio READY FOR ACTION!!!!

Here's a summary of what happened during those hours, along with some YouTube observations.

Man-made noise levels can vary from day-to-day, especially during daylight hours. A few years ago, at my previous home QTH, local electrical noise was S9 for much of the time and effectively destroyed my shortwave listening hobby. Here at Mount Evelyn, being a semi-rural location, it's a lot quieter especially in the evenings.

I picked out a random frequency in the noisiest part of the shortwave spectrum that I could find on that day, and sat on it waiting for the power outage. I recorded a few seconds of video while the power was on, and then again as soon as the outage began. Watch the S-meter!......




BIG difference, huh? The noise floor drops to almost zero, except for the occasional atmospheric burst of static.

This left me with a few hours to search the bands for signals that are normally hard to hear at this time of day - 9:30am AEDT in late Spring. Firstly, I visited the 41mb to see if there were any signals still there - just two stations - Marti 7405 and RFA via Kuwait 7480. Both with very weak signals and the band had folded for around the next seven hours.

Then I moved to the other end of the dial and sought out the WWV time signal station on 25 mHz. There it was! Barely moving the meter, but certainly audible. OK! So the propagation gods are with us on this day! Good stuff! WWV is currently using only 2.5 kW into a vertical dipole, and reception on the 12 meter band is erratic and variable at best. Propagation conditions can change quickly from minute-to-minute.

Finally, I spent most of my time tuning the 31mb which, like the 41mb, is usually closed to all but the most powerful transmitters by mid morning at this time of year. There I found a bunch of stations scattered throughout the band, and nearly all were weak to very weak signals. Most were easy to identify as they are commonly heard in our winter months. But as we approach summer, they do their customary disappearing acts.

Below is a short video of just a few signals heard during the outage, starting off with WWV on 25000 kHz. Following that, I have listed all the stations heard during the outage.





7405   USA. R. Marti - Greenville NC. Very weak signal at 2240 with Spanish talks.

7480   KUWAIT. RFA - Kuwait. Tibetan service at 2245 with talks, a weak but clear signal and no sign of jamming.

9265   USA. WINB - Red Lion PA. American preaching at 2258, audible but not moving the meter.

9369.96   USA. WWRB - Morrison TN. American preaching at 2302, weak and not moving the meter.

9380   INDIA. AIR - Aligarth. The Vividh Bharati service in Hindi at 2306, barely audible.

9405   PHILIPPINES. FEBC -  Bocaue. Mandarin to EAs at 2309 with hymns and talk, very weak.

9415   CHINA. CRI - Beijing. Vietnamese to SEAs at 2311, news reports, weak signal.

9420   GREECE. Helliniki Radiophonia - Avlis. Traditional Greek children songs and anncts 2315.

9430   PHILIPPINES. FEBC - Bocaue. Beaming to SEAs in the In Mien language with talks and hymns at 2318, not moving the meter but audible.

9435   CHINA. CRI - Xian. Japanese service 2320, barely audible.

9445   D.P.R.KOREA. VoKorea - Kujang. Martial music at 2323, very weak in Mandarin.

9475   USA. WTWW - Lebanon TN. American preaching 2324, sounding quite loud at times but no meter movement. Still noted more than a hour later at 0035.

9490   IRAN. VOIRI - Kamalabad. The start of the Mandarin service at 2327, audible but no meter movement.

9500   CHINA. CNR 1 - Shijiazhuang. Very weak at 2330.

9505   USA. WHRI - Cypress Creek SC. Overcomer Ministry with the raspy sound of The Bro and another speaker, 2333, Barely moving the meter, but quite clear.

9535   KUWAIT. RFA - Kuwait. Tibetan service at 2340 with a long talk. No CNR 1 jammer heard at this time. Weak but clear signal.

9545   SOLOMON IS. SIBC - Honiara. Very weak signal at 2350 with chat show programming. Usually not heard at this time here but later after 0300, so a rare opportunity to catch it with the power outage.

9565   USA. R. Marti - Greenville NC. Fading in and out at 2352.

9570   ALBANIA. CRI - Cerrik. S/on in English at 0000 to NAm, barely audible.

9635.96   VIETNAM. VoVietnam - Son Tay. Network 1 National programming at 2357 with Vietnamese songs and anncts, ID at 0000. Still there at 0040 with a very weak signal and would not have been heard at all here at this time except for the power outage.

9690   INDIA. AIR - Bengaluru. English service to SEAs with a Bollywood music program at 0005, clearly heard but no meter movement.

9705   INDIA (Goa). AIR - Panaji. English to SEAs at 0010 with the same music programming and slightly better signal here than the // 9690 kHz.

9810   SRI LANKA. AWR - Trincomalee. Burmese service  to SEAs at 0015, weak signal.

9835   MALAYSIA. RTM - Kajang. Sarawak FM music programming at 0020. Rarely heard at this time 11:22am (AEDT), especially during the Spring season, very weak signal.

9860   CHINA. CRI - Jinhua. Hakka language service beamed to the Philippines at 0024, very weak.

9870   INDIA. AIR - Bengaluru. The Vividh Bhatati service in Hindi at 0026 to SEAs, weak signal but clear with Indian music programming.

9880   THAILAND. VOA - Ban Dung. Mandarin to EAs at 0031 with music programming and anncts. No CNR1 jamming heard.

11520   USA. WEWN - Vandiver AL. American preaching at 0045, not registering much strength on the meter but audio was clear and easily readable.

11580   USA. R. Slovakia Int'l - Okeechobee FL. English to ENAm 0050, very weak signal.

25000   USA. WWV - Fort Collins CO. Usual programming at 2253, weak and variable. Of my four antennas, the signal was strongest on the 7mHz double bazooka antenna.


At 0052 UTC, the mains power returned....and so did the noise. I went back to monitor 11580 and 11520 kHz  (the last two stations I tuned before just before the power came back on) and both had been submerged in the noise and totally unreadable.

I find it absolutely fascinating (and amusing!) how stations can still be heard, even when there is no movement being registered on the signal strength meter. But, don't expect hi-fi sound quality at armchair levels! That's not what this experiment is all about.

Moral of the story? If you can get away from an electrically noisy environment and off the power grid, you can hear some pretty exciting weak signal DX. This is the reason why I just love DXpeditions!

73 and best DX to you all.

Rob Wagner VK3BVW

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