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Daniele
I would expect to Receive virtually no signal using an
optical cable, because one of the dipole elements would be missing and you would
only have the small probe element doing all the work and capturing little or no
signal. The probe element has to be tuned against something and if you take away
the coax feed cable the only thing left is the small cct board that might act as
the second element but this again is so small that signal pickup would be very
low ie very little signal capture area.
This type of antenna does not sound attractive to
me.
I have a commercial LF ships probe type antenna about
1 metre long as one element and a wire hanging down as the Second element, the
assembly has a preamplifier and coax feed to the RX.
mal/g3kev
----- Original Message -----
Sent: Thursday, August 11, 2011 3:03
PM
Subject: Re: LF: Re: HB9ASB...
Yes I'm sure it works. BTW,
I work in the optical networks area of a well-known (swedish) company of
telecom equipments, so I really trust optical comms ;-)
The interesting thing would
be to compare in a very quiet location an active,
optically-coupled E-probe, with very short copper leads, just for the
battery; and another identical E-probe, installed at the same height, on a
similar pole, etc. with "conventional" feeder through a coax cable. Just to
see what changes.
I mean, if the cable
actually is an integral part of such an antenna ("the cable is the real
antenna", as I read sometimes in comments about the MiniWhip), I would expect
a significant improvement from using a coax rather than fiber. It would
be necessary to find a very quiet location for such test, to prevent
local hum from giving an obvious advantage to the fiber solution.
Regards
D.
From:
Stefan Schäfer <[email protected]>
To:
[email protected]
Sent: Thursday, August 11, 2011 2:46
PM
Subject: Re: LF: Re:
HB9ASB...
Hello Roelof, Daniele, LF, Yes, it
works. Before i started with the VLF stuff in February 2010 i did tests
with LF active antennas, battery supplied, and signal transfer by fiber optic
cables. Actually it worked well with a single BF862 with the TX LED in the
drain-to-plus stage and a 9V battery. This was an interesting
alternative. But later i started with the LF grabber and so it becomes
inpractical since i don't want to replace a battery all the time and thought a
solar module might be covered by snow in winther and so on... Nice
stuff to experiment. Anyway you have to be in a quiet location but noise
transfer on a coax screen was history... It also worked on a multi turn loop
which i used in France last year... 73, Stefan/DK7FC Am
11.08.2011 14:33, schrieb Roelof Bakker: > Hello Daniele, >
> I have the parts on hands, but house restoration has prevented tests
so far. > I will report in due time. > > However Stefan has
used an optical link with a 30 cm active whip. > So, it certainly will
work. > > 73, >
Roelof
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