Re: LF: Re: MiniWhip antenna, fiber optic TEST SIGNALS NEEDED on 630m WSPR

[Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>]

Hello all,

I'm continuing my monolog about my fiber optic tests :-)
Thanks to the active stations on MF this night. I got a useful set of data to compare the isolated active dipole to my grounded "usual" active antenna (coax cable), see attached.

First i must say that the antenna produces quite good results, although still not as good as the usual grounded mini whip. Apart from the fiber optic system (which produces some noise!) that is part of the whole RX system, the difference may be caused by the fact that:
-The /p MF converter (used as RX for the optical system) has a worse image frequency rejection then than the RX of the grounded whip.
-The height obove ground (and so the coupling to local noise sources) of the optical system is about 1.5m lower.

I'll stop this test now and will do further improvements to the electrical components.

All in all i must say that the chances look promising that such an optical system may become an alternative to the usual coax cable or STP solutions, at least for those who have to live without a clean RF ground!

73, Stefan/DK7FC


Am 11.07.2013 23:00, schrieb Stefan Schäfer:

Hello all,

Now i'm testing the fiber optic vertical short active dipole the first time during the night. A single decode of PA3ABK was possible so far. It would be nice to receive a few more stations there so i can compare the S/N reported by WSPR between my normal and the /p antenna. >From time to time i will also watch out for CW signals. This is the location: https://dl.dropboxusercontent.com/u/19882028/MF/20130711_202714.jpg
I'm watching on MF.

73, Stefan/DK7FC

MFtest.png
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