Ferrite RX antennas.. been there when 136 kHz started.
Not as good as a larger air-core loop, possibly noise caused by the
Barkhausen effect or similar effects, nonlinearities, etc.
Also beware the ferrite is a semiconductor so you will need some
E-field screening, otherwise the ferrite material will couple noise
into the windings. But it's not as bad as this may sound; actually I
used a ferrite antenna for reception for some years until I
discovered I had to disconnect the ...errr... RF counterpoise from
the main antenna from the mains "ground", and only use an earthstake
during receive, at DF0WD.
On the other hand, it's compact, relatively light-weight, and (in a
resonant configuration) gives a nice preselector.
I remember when I connected a ferrite antenna to a tiny receiver
with SA612 "gilbert cell mixer", the first signal I heard was G3KEV
calling cq in CW. Q5 in SSB bandwidth.
Such a receiver is extremely handy to go /p for reception, and
compare different sites.
73,
Wolf DL4YHF.
Am 14.08.2011 21:43, schrieb Minto Witteveen:
I haven’t thought about
ferrite RX antenna for LF….My guess is that it is not
going to work – not without an external antenna
coupled to the ferrite, and then what’s the point?
DCF77 clocks often have trouble locking indoors or in
the neighborhood of ‘QRM’ generators like PC’s, and
look what power DCF77 is using…
I could be entirely wrong of course…
73’ Minto pa3bca
Sent: Sunday, August 14, 2011 20:03
Subject: Re: LF: Re: 137 grabbers
<snip>
BTW what do you think about a ferrite RX antenna for LF? Now
i'm opening an older discussion i expect ;-)
73, Stefan/DK7FC
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