Hi Mauro !
The FZ_02 mechanical filter can be easily inserted into a 50 Ohm
receiving(!) system by the use of two 1:9 transformers (at Input and
Output of the FZ-02) to match the 500 Ohm Input/Output impedances of the
filter at the yellow wires! Use capacitors of the exact capacity [in pF]
as printed at both ends of the filter for compensation. (I soldered the
capacitors to the unused 18k-Ohm wires = red).
You will get a flat top of the attenuation curve and steep edges.
measured Attenuations at :
461.2 kHz -64.91dB
467.1 kHz -3.10dB
473.0 kHz -2.70dB
479.1 kHz -3.48dB
485.3 kHz -63.62dB
used 1:9 Transformer : FT50-43 toroid, 10 turns of (flat) trifilar
enamelled wire (AWG #26).
This filter is a good cure to all sorts of intermodulation and noise
caused by out-of-band signals.
73 de dg3lv Tobias
Am 16.02.2015 um 22:08 schrieb IK1WVQ Mauro:
this is the schematic of my stupid receiver..
today I bought from Ebay a mechanical filter FZ_02 to clean a bit the
coming soon: a 20W TX (mosfet IRF510) for tests with "earth_electrode
antenna" (impossible for me to build a Marconi)
73 de Mauro IK1WVQ
Very interesting... Do you have mord info Mauro?
Inviato da iPhone
> Il giorno 15/feb/2015, alle ore 22:28, IK1WVQ Mauro <[email protected]>
> Hi Luigi,
> your signal is ok here in JN44CB.
> my antenna is PA0RDT
> RX is a simple NE602 mixer with a MF 455kHz(yallow core) front end ..
> no RF preamplifier, no audio postamplifier . directly to the MIC
input of PC !!
> 73 de Mauro IK1WVQ
> At 13:40 15/02/2015, IZ7PDX Luigi D. wrote:
>> Gm Mf ...
>> I have the pleasure to introduce my new QRSS3 test beacon at
476.150 Khz in JN80PS.
>> 25 mt new Marconi antenna , 50 W.
>> Daily and night reports are welcome !
>> Thanks in advance.
>> Vy 73 de Luigi IZ7PDX
>> Inviato da iPhone