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Re: WEFAX Info (OT)



OK, I'll measure the dimensions of the patch and post them to the amsat-bb 
this weekend.

The patch is tuned w/a spectrum analyzer but until I finish my move to the 
country I am not in the position to setup the dish, preamp and downconverter 
to try it out.

To the group:  Has anyone thought about modifying a MMDS downconverter  for 
1691 MHz?  It should at least be possible to use one of these $30 specials 
as an LO anyway.  (With modified scanners or ham gear, the IF need not 
necessarly be 137.5 MHz) It's just a thought for those out there who'd like 
to try GOES/Meteosat reception without great expense.

Fred W0FMS


>From: "Gerald Payton" <n5gpc@earthlink.net>
>To: "Frederick M. Spinner" <fspinner@hotmail.com>
>Subject: Re: [amsat-bb] WEFAX Info (OT)
>Date: Wed, 19 Jun 2002 13:29:53 -0500
>
>Absolutely!  It would be a great help if you sent it.  Others have sent me
>emails voicing WX Sat interest too.
>Thanks,
>Jerry  N5GPC
>
>
>----- Original Message -----
>From: "Frederick M. Spinner" <fspinner@hotmail.com>
>To: <n5gpc@earthlink.net>
>Cc: <amsat-bb@amsat.org>
>Sent: Wednesday, June 19, 2002 1:08 PM
>Subject: Re: [amsat-bb] WEFAX Info (OT)
>
>
> > To AMSAT-BBers:  I'm sending this slightly off topic reply to see if 
>there
> > is interest in me "web-publishing" the dimensions of my (untested on an
> > actual dish) 1691 MHz patch feed.  Please ignore and accept my 
>condolences
> > if you are not interested.
> >
> >
> > The WXSATS are linear polarization.  I've used the ubiquitous "coffee 
>can
> > feed" and even three element "loop yagis" as feeds.
> >
> > I've recently built a linear square patch antenna, tuned it up on a
>network
> > analyzer, but have yet to hook it to the preamp/downconverter for 1691
>MHz.
> > I used to really be into WEFAX, but my interest wained a bit now that 
>all
> > that data is available on the Internet.  Still have the equipment and 
>will
> > eventually try it.  (OK, covenants have also killed off my permanent 
>WEFAX
> > setup.-- but not for much longer!)
> >
> > If you really are interested I'll measure the dimensions of my square
>patch
> > (a little rectangular after tuning) feed.  I used to use 4-5 foot dishes
> > with a system of about 1 dB NF for really good WEFAX. Note: you will 
>need
>to
> > physically rotate either the feed or the entire dish to get the 
>strongest
> > signals on the WEFAX birds.  They are linear polarized and neither
> > Horizontal nor Vertical in my experience.
> >
> > Note: with the launch of the next gen GOES, the WEFAX is going to go
>away--
> > become all digital, anyway.  The specs are supposedly going to be public
>and
> > the signals are to be unencrypted so this could be a cool new project in 
>a
> > couple of years.
> >
> > There is already a 9600 GMSK subcarrier on the 1691 MHz transponder for
> > EMWIN transmissions.  This too will go away.  All the data will be muxed
>on
> > a higher speed FEC'ed data stream.  But this will likely take two-three
>more
> > years.
> >
> > Second note:  The WEFAX 2400 Hz AM Audio subcarrier is modulated on an 
>FM
> > carrier at about 50 KHz bandwidth.  A standard ham rig is too narrow on
>NBFM
> > and too wide on WBFM settings to receive this signal.  So a cheap,
> > appropriate reciever for this can be made by removing the second IF (455
> > KHz) filter in a "Bearcat-like" scanner (replace with a 0.01-0.1 uf 
>cap).
> > This has worked in almost all cases and still allows the scanner to be
>used
> > for other things (albeit at a wider bandwidth).
> >
> > I'm assuming that you are going to use the WXSAT soundcard software to
> > demod.  I played with it and it seems to work just fine given good IF
> > bandwidth.
> >
> > Hope this helps you, Jerry, and others on the amsat-bb list.
> >
> > Fred Spinner, W0FMS
> >
> > >From: "Gerald Payton" <n5gpc@earthlink.net>
> > >To: "AMSAT-BB" <amsat-bb@AMSAT.Org>
> > >Subject: [amsat-bb] WEFAX Info
> > >Date: Tue, 18 Jun 2002 23:12:18 -0500
> > >
> > >I apologize to the group for asking about weather satellite info, but 
>my
> > >searching on the net has been non-productive.
> > >
> > >Specifically, I am looking for URLs or info on Geosats 1691 MHz 
>antennas,
> > >feeds and such.  I have everything but the antenna.  I have an extra 
>dish
> > >and would like to use it.
> > >
> > >Any help would be appreciated.
> > >
> > >Jerry  N5GPC
> > >
> > >
> > >----
> > >Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > >To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> >
> >
> >
> >
> > <html></html>
> >
> >
> > _________________________________________________________________
> > Chat with friends online, try MSN Messenger: http://messenger.msn.com
> >
> >




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