Minto, Daniele,
@Daniele: Nice to read you also want to join in on LF! BTW VLF is not
forgotten here, i want to come back in September. But want to have the
LF system ready for the DX season and wat for lower QRN on the Dreamers
Band...
You don't have a licence and cannot TX? Wouldn't it be worth to learn
for a licence for that reason? :-)
And have you done further tests on sferics and so on your remote VLF
QTH? Any news?
Just got re-fascinated by John/F5VLF about the earth antenna stuff and
want to do more experiments on that antenna again but LF improvements
are very time consuming! But i have holidays now :-))) I am curious how
the earth antenna performs as a RX antenna on 137 kHz (directional
pattern and gain and noise). As a TX antenna i will be to lossy i think
and its not worth the effort carrying 100s of kg of batteries on the
hill for doing some CQ calls that are not answered....
@Minto:
Am 14.08.2011 19:33, schrieb Minto Witteveen:
Above 10 MHz the gain drops off rapidly, it is nearly
useless at 14 MHz. a -77 type would be much worse there I think.
Sure. I just talked about LF now. I read the -43 type is suitable for
40...400 MHz, at least this is said in the catalog...
As for the Q: I did a comparison between an FT50-43 and
a 14 mm 4C6 (for my 137 KHz low-pass filter, see my website). The Q of
the FT50-43 coil was abt 50, the 4C6 – with a lower Al - was 140 !!
Interesting! 140 at which L? I am searching for ferrite cores to
achieve a high Q on LF, in the range of 100...1000uH. Where can i get
these cores? At RS? Where do you buy them? They are usually samller,
cheaper and easier to handle than pot cores.
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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