Re: Most Distant Nightly MW Received At Home


Gary DeBock
 

Hi Todd,

<<<   Have you ever used a Tecsun PL-380's digital signal strength to determine the lowest ambient RF noise sweet spot, either in the home backyard, or when listening away from home?    >>>

No, to be honest, I've never really attempted to use the PL-380's digital signal strength readout to measure anything other than signal strength on a DX station. Part of this is related to the fact that by 2015 the Tecsun PL-380 was somewhat superseded by the C.Crane Skywave in RF design (which eliminated the PL-380's internally generated heterodynes), and around that time I switched over to the Skywave portables (which lack a digital signal strength readout) for my own personal DXing. An additional issue here was the neighbor's deployment of a plasma TV around 2016, which generates S9 noise on most MW frequencies across the band. The noise can be nulled down to S7 with a sharp-nulling FSL antenna, but of course that null bearing isn't necessarily favorable for the DXing signal that you are chasing. All is not lost, however-- the noise issues at home were the primary motivation for development of the "Frequent Flyer" FSL antennas :-)

<<<   I am in the process of finding out if 1580 KHz KBLA Santa Monica, USA at 7,499 miles is a nightly AM signal at my Sydney house. 1580 KBLA was heard this week inside the house at signal levels just strong enough to be heard in wide AM. In order to increase KBLA S/N ratio, I used the Tecsun to survey inside every room inside the house. The next step is to check noise levels in the backyard by tuning to 1580 KHz during the evening when KBLA is not present.    >>>

You certainly must have some salt water enhancement in the local area, Todd. It's not very often that I hear of routine reception of any USA station in Oz! Certain Victoria, B.C. DXers report somewhat routine reception of 612-4QR during our summer season here, but they are using table receivers which large external antennas. On the Oregon state coast there is a plunging ocean side cliff which offers freakish reception of New Zealand signals in August, so that a 7.5" loopstick Ultralight can routinely come away with good reception of 531-PI, 657-Star and 1017-Tonga around sunrise. But these signals completely disappear only a couple of km inland.

<<<   In the house, ambient noise on 1580 KHz typically reads 27 to 32 dBu. The major noise contribution is assumed to be 50 Hz power noise. I will eventually turn off the master power switch to see if the Tecsun dBu reading drops further.
There is further scope positioning the 40 inch PVC loop on an outside table well removed from the house. This small ground elevation, antenna clear of the home noise field and attenuation effect, should bring KBLA up out of the noise.
It's likely that 1580 KBLA would be a relatively strong signal at an elevated east Australia coastal listening site overlooking the ocean towards North America.   >>>

It would be a fascinating experience if an Oz DXer could actually set up a portable PVC loop or FSL antenna on such an elevated east Australia coastal listening site, and document the difference in 1580-KBLA's signal strength compared to a sea level site. Local DXer (well, semi-local, because he lives in B.C.) Nick Hall-Patch has been doing this at the Rockwork cliff in Oregon for the past couple of years, documenting the enhanced propagation at the Rockwork ocean cliff site near Manzanita. Shortly after Nick first reported solid evidence that the cliff was indeed boosting the transoceanic DX propagation from New Zealand, the number of DXers showing up for our annual August DXpeditions got a nice boost :-)

73, Gary

            

      


-----Original Message-----
From: Todd via Groups.Io <toddemslie@...>
To: main <main@UltralightDX.groups.io>
Sent: Sat, Feb 2, 2019 11:45 pm
Subject: Re: [UltralightDX] Most Distant Nightly MW Received At Home

Hi Gary,

Have you ever used a Tecsun PL-380's digital signal strength to determine the lowest ambient RF noise sweet spot, either in the home backyard, or when listening away from home? I am in the process of finding out if 1580 KHz KBLA Santa Monica, USA at 7,499 miles is a nightly AM signal at my Sydney house. 1580 KBLA was heard this week inside the house at signal levels just strong enough to be heard in wide AM. In order to increase KBLA S/N ratio, I used the Tecsun to survey inside every room inside the house. The next step is to check noise levels in the backyard by tuning to 1580 KHz during the evening when KBLA is not present.

In the house, ambient noise on 1580 KHz typically reads 27 to 32 dBu. The major noise contribution is assumed to be 50 Hz power noise. I will eventually turn off the master power switch to see if the Tecsun dBu reading drops further.

There is further scope positioning the 40 inch PVC loop on an outside table well removed from the house. This small ground elevation, antenna clear of the home noise field and attenuation effect, should bring KBLA up out of the noise.

It's likely that 1580 KBLA would be a relatively strong signal at an elevated east Australia coastal listening site overlooking the ocean towards North America.  

Regards,

Todd.
 

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