Hi
still experimenting with frame antenna for 136kHz. The attached drawing (20kB)
shows almost how it would have been made today, somewhat different from
the actual antenna.
Experienced that it was no need for amplifier for a loop for 80m reception
(used to avoid electrical noise from the open power lines),
and now also experienced that an amplifier did not improve reception for my
136kHz aerial,
the coupling has 1/100 area of the whole frame, seems to work for 50 ohm,
the tuning range seems to be somewhat too small, need somewhat increased
capacitance in cold weather, but it is low enough for rain.
The S/N ratio is almost the same with the coupling loop as for high impedance
amplifier connected to the end of capacitance.
The aerial has been tested in +10°C....-2°C
Signal strength last night for DCF39 was 80-150µV (-75...-80dBU)
Not sure if it is still a point to ground the center of the tuned loop.
73
Jan_Martin
[email protected] (WW.Loc: JO38XC)
N4623-Kristiansand (tel.: +47-380-87178)
http://www.laud.no/la6nca/la8ak/
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