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Re: ON4BCB's L/S filters for dualband feeds



Simon,

Did some field testing during the weekend. I constructed a dual band
patch antenna, L/S. This patch has an isolation of around 40 dB between
L and S. With the two filters ( see Walters website ), i could not measure
the isolation, due to the fact my tracking generator gives - 10 dBm out.
the isolation was + 100 dB. Also, the returning signal from the reflector
is the opposite polarization from the patch element ( RHCP)

I tested on a 1.2 m antenna transmitting 10 W to the L band patch, and
receive on the same S band patch. NO desence at all ! works great.

Best 73,
Eddy ON7UN

----- Original Message -----
From: "Walter Crauwels" <walter.crauwels@skynet.be>
To: "Amsat BB listserver" <Amsat-bb@amsat.org>; "Simon Lewis"
<simon@creoch.freeserve.co.uk>
Cc: "ON7UN QTH" <ejespers@wanadoo.be>
Sent: Monday, November 12, 2001 10:15 PM
Subject: Re: [amsat-bb] ON4BCB's L/S filters for dualband feeds


> Hi
>
> Well there is still extra loss on the dualband feed which give us more
than
> 100db in total.
> Further these filters are Free, the G3WDG's ones NOT
>
> We like to keep the HAM spirit in mind
>
> See also ON7UN's measurements
>
> 73
>
> ----- Original Message -----
> From: "Simon Lewis" <simon@creoch.freeserve.co.uk>
> To: <amsat-bb@AMSAT.Org>
> Sent: Monday, November 12, 2001 9:59 PM
> Subject: RE: [amsat-bb] ON4BCB's L/S filters for dualband feeds
>
>
> > Hmmmmmmm!
> >
> > These look similar to ones ones I saw posted a month or so ago -
> > Interesting - I have been playing with ones that came from G3WDG's web
> > site (www.g3wdg.free-online.co.uk) but they have a very bigger notch and
> > work very well.
> >
> > This design look very similar but from my experience the notch needs to
> > be deeper - closer to 100 dB
> > I think 50-60 dB is not near enough. Still too much signal given that
> > the dual band helicals type feeds are so close. Receive performance will
> > be noisy.
> >
> > For anyone interested take a look at G3WDG's website at the address
> > above.
> >
> > Regards
> >
> > Simon GM4PLM
> >
> >
> >
> >
> >
> >
> >
> > -----Original Message-----
> > From: owner-AMSAT-BB@AMSAT.Org [mailto:owner-AMSAT-BB@AMSAT.Org] On
> > Behalf Of Walter Crauwels
> > Sent: 11 November 2001 14:28
> > To: Amsat BB listserver
> > Subject: [amsat-bb] ON4BCB's L/S filters for dualband feeds
> >
> >
> > Hi all,
> >
> > Just to inform you that we are near to some working results Here is my
> > URL if you need a source for filters in order to operate mode L/S full
> > duplex with a dual helical or patch feed.
> >
> > http://users.skynet.be/on4bcb/l_s_filters_for_dualband_l_s_feed.htm
> >
> > Please send comments by email or on this reflector
> >
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA. To
> > unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
>
>

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