Re: RF Clipper Diode Design


jdow
 

They are all pretty close in frequency. Exotic resonators might be needed. And even the 100 W signal would need to be attenuated somewhat. These babies do not have a 120 dB plus instantaneous dynamic range meaning weakest detectable signal at the same time the very strong signal is present within the RF passband of the front end.

{^_^}

On 20200203 01:30:54, Allan Isaacs wrote:
If you get 30 to 40dB skirts from a tuneable bandpass filter wouldn't that
do the job re 100W versus 120KW? You may need a 3-gang tuning 500pF
capacitor and a set of carefully matched coils.
Allan G3PIY
-----Original Message-----
From: main@SDR-Radio.groups.io [mailto:main@SDR-Radio.groups.io] On Behalf
Of jdow
Sent: 03 February 2020 09:07
To: main@SDR-Radio.groups.io
Subject: Re: [SDR-Radio] RF Clipper Diode Design
In his particular case replacing the antenna with a paperclip, bent or
unbent,
would probably work. A large attenuator in the antenna lead would also do
the
trick. He's not exactly trying to receive a weak signal. It's simply weak
compared to what is around it.
He needs the band stop filter if he wants to wander out to OTHER weak
signals.
But 100 W next to 120 kW at 3 km distance is one bodacious humongous
whomping
big signal.
{o.o}
On 20200203 00:48:02, Allan Isaacs wrote:
Back in the 1920s and 30s a common problem was reception of weak signals
in the
presence of strong local broadcasts (not that I remember.. I just read
about it).

The answer was to design a proper RF front end with bandpass tuning etc.

There's nothing wrong with constructing a tuneable front end for an SDR.
In fact
the graphical presentation of the spectrum makes it easy to align such a
tuner.

Combine this with a directional loop antenna and you have a perfect
general
solution.

Allan G3PIY

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