Re: [IRCA] Oregon Cliff (Rockwork 4) Ultralight DU's for 7-23

[Guy Atkins <dx@xxxxxxxxxxxxx>]

Hi Gary,

Thanks for your excellent reports from the last two days.

I'm sorry to say that my Cape Perpetua cliff DXing was nowhere near the
quality and quantity you experienced with the air-cap tuned (single
frequency) Ferrite Sleeve Loop. Noise levels as expected were extremely low
and I heard tantalizing audio just above the minimal band noise using the
12-inch diameter broadband FSL into the Perseus SDR.

I had hints and snippets of many of the same Kiwis and a couple Aussies as
you did, plus two Japanese NHK stations. A definite peak was from 1250 to
1300, centered on local sunrise. I was getting bits of audio on
stations that barely registered on the signal meter, the noise was so low.
I was wishing the entire time for more gain... much more! The difference
between your results and mine at the cliffs this morning was so great that
it's not worth me sharing any MP3 recordings or greater detail.

Why the discrepancy from last September with the good Japanese and Asian DX
I heard from the same cliff location with the smaller 7-inch FSL, also in
broadband mode? It could be due to the typically stronger signal levels of
TPs. However, I now think that the very high "Q" or selectivity of single
frequency tuned FSLs trumps the performance of the broadband models.

After testing on USA/Canadian stations a few weeks ago while on a camping
trip, I thought I had verified that both types of connected FSLs "hear"
signals equally. I think the overall much weaker level of DUs is now
proving the difference-- your air-capacitor tuned model is simply superior,
and the broadband type cannot keep up. I'm open to other ideas, but it
appears it's back to the drawing board with the broadband FSL model.
Alternatively, some of the fellas on the Yachats DXpedition suggested using
a few coupling coil turns around the FSL's Litz wire coil, fed into a coax
cable, and then into Perseus. (Perhaps a matching transformer in between
would be needed.) Then, just use the FSL in single frequency mode but keep
recording Perseus WAV files while going from frequency to frequency,
lingering where there's DX activity. It's easy enough to know which
frequency was being peaked in the recording by just watching the spectrum
display. I guess this would be a hybrid mode of DXing with the FSL-- using
the SDR receiver but still tuning it one station at a time!

Despite this morning's disappointments at the Cape Perpetua cliff, our
revised, lengthy DKAZ antenna at the Deja Vu house is working extremely
well, and the eight of us are ready to capture a lot of DU signals tonight
on this "all Perseus" DXpedition.

73,

Guy Atkins
Puyallup, WA
DXing from Yachats, OR & Cape Perpetua, OR
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