Australia(?) on 1548

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Australia(?) on 1548

Postby Toomas Losin » Sun Dec 29, 2013 4:30 pm

Yesterday's stormy ionosphere may have stirred things up so that some Australian signals made it to the Lower Mainland. In the interference from KRPI 1550, I heard a carrier on 1548 that was almost strong enough for audio at 14:40 UTC (06:40 PST). Ten minutes later there were some faint Australian-accented voices. By the TOH the signal had faded out, so no pips or ABC fanfare were heard. If 1550 had been silent then the presumed-Australian signal would have been listenable for a minute or two.

Earlier in the evening at midnight PST I was able to hear KICY 850 as it began its Russian broadcast with some interference from a presumed KOA which was fading in and out occasionally. The Asian signals were weaker than normal, probably from the stormy ionosphere, but the South Pacific opening didn't happen until closer to morning.
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Re: Australia(?) on 1548

Postby Tape Splicer » Sun Dec 29, 2013 5:52 pm

Toomas; Listening through the static and other QRM can be quite a challenge. I heard stuff I could not Identify while I was sitting on the side of the mountain outside of Chilliwack during our Christmas getaway.

What type of radio and antenna are you using to pick up those "exotic" signals? Living in a small apartment I don't have much room so I use a Grundig G8 as my radio of choice with the little Nexxtech as a back up. The Grundig continues to amaze me each time I use it.
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Re: Australia(?) on 1548

Postby Toomas Losin » Sun Dec 29, 2013 9:06 pm

My good catches are being made with an Icom R71a and an 8x4 metre Pennant antenna. It's the antenna that has made a huge difference — with it I began to receive trans-Pacific signals similar to what is reported in other forums. Similar but still not as many signals.

For example, Japan and Korea are frequently heard but Australia is not and I have yet to hear New Zealand or Tahiti. However, other West Coast DXers are not reporting the South Pacific much at all this year. To improve reception I'm not sure if I would need to turn the antenna further South (difficult) or if I need a better antenna like a Beverage (not practical in a city), or if it's the location. It's an open question to me how much of a problem Vancouver Island is for South Pacific signals.

I have a G8 too and I also bought a Tecsun PL-390. I have heard reports of good reception from people using them barefoot but I've never had steller trans-Pacific performance from either. The best I've heard is Japan, faintly indoors but somewhat better outdoors. I've tried coupling the Pennant to them but that won't work without a preselector as the strong locals drive the radios into blocking. Perhaps they perform better away from the 50 kW blowtorches in the Lower Mainland with a lower noise floor. If you're away from the city can you hear Japan on 774, 747, or 828, or Korea on 1566? KICY 850 or the aviation weather from Level Island on 529 can be hints that conditions are good.

The R71a has a large dynamic range that can handle the 50 kW locals without blocking and it has single sideband modes which make it easy to spot a carrier or listen to the cleanest sideband.

It's the SSB modes that let one listen for carriers; faint ones, presumably from the Australian and other South Pacific stations are frequently heard but voice is rare. The strength of a carrier tells me when something interesting is happening. That's how I spotted 1548 early this morning. SSB is the most important feature missing from the G8 or PL-390 style radios, as it's no fun listening for something exotic when one doesn't even know there's nothing there at the moment!
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Re: Australia(?) on 1548

Postby jon » Mon Dec 30, 2013 1:43 pm

I really appreciated your comments on the Icom R71a. Somehow, from your past comments, I had assumed you were getting all this on a Software-Defined Radio, i.e. - something you have to attach to a computer before it will work. And I wasn't prepared to "go there" at this point anyway.

The R71 was replaced by the R72, but both are no longer in production. Fortunately, the R75 replaces both, is still being made, and highly recommended by medium wave DX'ers as the best receiver under $1000. Careful shopping will usually turn up a used one for $400 including shipping to a U.S. address. On the other hand, a fully functioning R71 is harder to find.
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Re: Australia(?) on 1548

Postby Toomas Losin » Mon Dec 30, 2013 6:39 pm

No SDR yet. I want one, just haven't done the research to pick one. The front end would need to work in this RF battleground and the software would need to run under Linux. While the R71a doesn't block with a broadband antenna there are faint intermodulation products in a half-dozen places. Fortunately those mostly disappear after sunset.

Further to SSB: On an AM-only rig one can still spot a trans-Pacific signal by listening for the het against a local station if there is one near the frequency. So 1548 would produce a 2 kHz het with KRPI (and KKOV) if there's a signal at all. However, AM will combine audio from 1548 and 1550 clearly so one can't be sure that 1548 is producing audio unless it's strong enough to hear the accent or something identifiable. That's why I'm almost always using SSB: LSB on 1548 will give clear audio from 1548 while 1550 produces SSB squawks.

There was a carrier on 1548 again this morning which strengthened to weak audio for half a minute, so not as good as yesterday and KRPI was all over it.
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Re: Australia(?) on 1548

Postby jon » Mon Dec 30, 2013 7:05 pm

For what it is worth, here is the SDR that my long-time DX friend in Seattle currently uses:
http://www.winradio.com/home/g31ddc.htm

As you might guess from the name, it runs on Windows.

Current price, from the factory, is just over $1000 U.S., including shipping to your door in Canada. Same price as U.S. shipping address, which is unusual.

If you weren't aware of it, there are upgrades available to the Icom R-71:
http://www.kiwa.com/r71audio.html
Greatest interest is one or two that could fix an otherwise dead receiver.

The same folks have some really useful upgrades to the newer Icom R75, most notably the "AM BCB RF Attenuator Disable", which can increase broadcast band sensitivity by 3dB.

Finally, although there may well be better receivers if all you need is 500KHz-1710KHz, this one is fun to look at:
http://icomcanada.com/products/receiver ... r9500.html
I can think of better uses for $13,300. Not including a downpayment on the $150,000 110 inch TV that Samsung released recently:
http://www.ctvnews.ca/sci-tech/samsung- ... -1.1611437
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