Thanks for the very interesting report on the untuned FSL and preamp.
You didn't say but apparently you parked so the FSL was peaked/pointed
for maximum pickup toward the North Pacific. You might have had better
DU reception if it had been pointed the DU direction. Looking at your
pictures, your transformer would work better as a broadband
transformer if the windings were overlapping instead of side by side.
The impedance matching transformer articles by Nick Hall-Patch and
John Bryant at dxing.info explain this. I've done my own tests and
overlapping windings always work better for broadband toroid
transformers. (It's possible the small impedance transformation
doesn't do much too, but it probably doesn't hurt much either, if at
all.)
73 and hope you continue to have good coastal vacation DXing.
Steve
NE Oregon
On 9/10/2012 6:00 PM, Guy Atkins wrote:
Yesterday morning before sunrise I sought out the Cape Perpetua, Oregon
cliff that has served Gary DeBock so well with a flood of DU DX with his
Ferrite Sleeve Loop (FSL) antenna.
With Gary's encouragement and supply of a regular tuned FSL, and Chuck
Hutton's help with electrical formulas and initial impedance
measurements,
I was able to convert the FSL into a broadband (non-tuned) loop for
capturing the entire band with Perseus SDR recordins. The antenna
accompanied me to Oregon, secured inside a container strapped to the
roof
of our family's vacation vehicle.
The 7-inch FSL was converted to broadband use by the removal of the
tuning
capacitor and the addition of a homebrew 1.6 to 1 turns ratio
transformer
and a Wellbrook FLG100LN amplified Flag antenna module. (FSL >> 26/15
turns
on Amidon FT140A-J core >> input of FLG100LN >> receiver. Chuck
calculated
the FSL's impedance as 3K ohms at 1.7 MHz; the Wellbrook's input
impedance
is 1200 ohms.)
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