[amsat-bb] Lindenblads

[Robin Midgett]

Gentlemen,
Perhaps I didn't phrase my question plainly enough. Doug is correct; my
question centers around the perceived benefit of having both LHCP & RHCP
Lindenblads with a switch to select between the two...is there a real
benefit?

Having recently been part of an ARRISS event, I witnessed the benefit of
being able to reverse the sense of the cross-polarized Yagi we were using
for the QSO, so it seems to carry forward that having that agility would be
beneficial for Lindenblad antennas, which is why I asked for input from
experienced Lindenblad users.

And yes, the sense of a single Lindy can be changed if the elements are
mechanically rotated in phase with one another about the Z axis. Saying
that it can't be done is akin to saying a Yagi can only be used in one
direction, and none of us accept that as truth.

Again, I appreciate the input from experienced users of this antenna array.



On Wed, Sep 17, 2014 at 4:39 AM, Francesco Messineo <
francesco.messineo at gmail.com> wrote:

> >
> > -----Original Message-----
> > From: Robin Midgett <K4IDC at comcast.net>
> > To: AMSAT-BB <amsat-bb at amsat.org>
> > Sent: Mon, 15 Sep 2014 6:23
> > Subject: [amsat-bb] Lindenblads
> >
> >
> > Hello to the group,
> > I'd like to hear from any users of the Lindenblad antennas regarding
> > switching polarity & circularity.
> > Based on the article on the AMSAT web page by W6SHP at
> > http://www.amsat.org/amsat/articles/w6shp/lindy.html, I'm led to believe
> > that the maximum effect comes from having one Lindy for each of RHCP &
> LHCP
> > per band in addition to being able to invert the polarity of each.
> > I'd like to hear from users concerning how often switching between RH &
> LH
> > circularity yields benefits as compared to switching polarity on a single
> > Lindy.
>
> I have used for some time a small satellite station composed of two
> lindenblads, one for 145 MHz and the other for 435 MHz. The UHF one
> was a parasitic lindenblad from a well known project of some years ago
> that I think is still available on the web (I don't remember the
> details now). I have commented on my experience with lindenblads on
> this mailing list a few times in the past, so there might be my
> messages in the archives (if they exist at all).
> What I can say is: signals are nowhere near the ones you can have with
> even small yagis with azimuth and elevation controls, also adding two
> preamplfiers under the antennas greatly improved the chances to make
> QSOs.
> I was able to work many contacts with that setup (FT-847 as rtx),
> mostly CW on the linear sats, but also some FM contacts on all
> satellites available some years ago (2008-2010), and of course some
> SSB contacts on the linear sats.
> I assume that having switchable polarity can only make things better.
>
>
> HTH
> Frank  IZ8DWF
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