Help with WEFAX 1.691 Mhz
Michael
--
Respectfully,
Northern NJ
R75 w/DSP, Kiwa agc/sync & audio mods
G5RV & 400ft longwire w/ICE-180
MFJ-1048 preselector
SoundBlstr Live PC card w/five piece Cambridge
speakers & full software mixer/eq.
craigm
Radioman390
>that transmit on 1.691 ???
Is this MHz or GHz?
Michael
Michael
"craigm" <camenRE...@charter.net> wrote in message
news:3E4FBBFA...@charter.net...
> What radio and antenna are you using?
I have a 400ft longwire and a G5RV
Bob Liesenfeld
>
> > >Has anyone ever decoded images from the geosyncronous weather satellites
> =
> > >that transmit on 1.691 ???
> >
> > Is this MHz or GHz?
>
> Mhz
Really? 1.691MHz is at the top end of the AMBC band. I could very well be
mistaken, but I don't think there is any satellite transmission that takes
place there. It sounds like you may be mistaking the baseband frequency
(around 1.6KHz) for the RF carrier frequency.
Here is a good site that covers some of the basics:
http://www.nottingham.ac.uk/meteosat/wefax.html
Again, I could be mistaken, and stand ready to be corrected. Good luck with
your weather endeavors.
72
Bob WB0POQ
Michael
"Bob Liesenfeld" <wb0...@visi.com> wrote in message
news:3E4FC155...@visi.com...
>
>
>
> >
> > > >Has anyone ever decoded images from the geosyncronous weather
satellites
> > =
> > > >that transmit on 1.691 ???
> > >
> > > Is this MHz or GHz?
> >
> > Mhz
>
> Really? 1.691MHz is at the top end of the AMBC band. I could very
well be
> mistaken, but I don't think there is any satellite transmission that takes
> place there. It sounds like you may be mistaking the baseband frequency
> (around 1.6KHz) for the RF carrier frequency.
> Here is a good site that covers some of the basics:
Hiya... There are stilettos that transmit on 1.691 I think I'm hearing one
now. They are the geosyncronous sats. All others, I think are above
130.000mhz. See the COPY/PASTE I made below from this link.
http://www.hffax.de/WX_Satellite/wxsatellite.html
Geostationary Satalites
==============
GOES-2 78 degrees long WEFAX 1691 Mhz
GOES-6 135 degrees long WEFAX 1691 Mhz
GOES-7 112 degrees long WEFAX 1691 Mhz
Meteosat-3 75 degrees long WEFAX 1691 Mhz
craigm
The geostationary ones are at 1691 MHz. (Not 1961 kHz.)
Try a google search on "wefax 1691".
You'll need different hardware.
Craig
Michael
> The low earth orbit satellite are at ~137 MHz.
> The geostationary ones are at 1691 MHz. (Not 1961 kHz.)
>
> Try a google search on "wefax 1691".
>
> You'll need different hardware.
What hardware ???
Also.. If I get a HF scanner that goes up to 13GHz, will I need anything
additional to get the low orbit sats ???
Will a sound card and PC software work to get the images ????
Thanx in advance.
Michael
Dale Parfitt
Michael wrote:
> "craigm" <camenRE...@charter.net> wrote in message
> news:3E4FCB3...@charter.net...
> > The low earth orbit satellite are at ~137 MHz.
> > The geostationary ones are at 1691 MHz. (Not 1961 kHz.)
> >
> > Try a google search on "wefax 1691".
> >
> > You'll need different hardware.
>
> What hardware ???
>
> Also.. If I get a HF scanner that goes up to 13GHz, will I need anything
> additional to get the low orbit sats ???
>
> Will a sound card and PC software work to get the images ????
>
> Thanx in advance.
>
> Michael
1.691 GHz not MHz. You will need a small dish, feed and Low Noise Amplifier.
I used seperate software and interface 20 some years back- but today probably
all the interface is handled via the sound card.
Dale W4OP
Bob Liesenfeld
>
> Hiya... There are stilettos that transmit on 1.691 I think I'm hearing one
> now. They are the geosyncronous sats. All others, I think are above
> 130.000mhz. See the COPY/PASTE I made below from this link.
>
> http://www.hffax.de/WX_Satellite/wxsatellite.html
>
> Geostationary Satalites
> ==============
> GOES-2 78 degrees long WEFAX 1691 Mhz
> GOES-6 135 degrees long WEFAX 1691 Mhz
> GOES-7 112 degrees long WEFAX 1691 Mhz
> Meteosat-3 75 degrees long WEFAX 1691 Mhz
Yes I see that information at that site. However, "1691 MHz" is one thousand
six hundred and ninety one Mega Hertz, or 1.6GHz (G=1 billion). Your posts have
stated "1.691 MHz" which is one (decimal point) six hundred and ninety one
hundredths MHz, or a factor of 10 to the power of 3 times smaller.
1.691 MHz is within what is called the low frequency band. Propagation from
space vehecials in this frequency range would be very poor. 1691MHz on the
other hand is in what is called the ultra high frequency band. This range is
widely used for space communications.
The site you quoted has some good information on the hardware needed for this
kind of work. I hope this helps.
72
Bob L.
Michael
YES GHz....
Sorry..... I didn't even think about the decimal ... Grrrrrrr
Michael
Grrrrrrr......
I have been copy/pasting that darn decimal over and over again...
Sorry...
"Bob Liesenfeld" <wb0...@visi.com> wrote in message
news:3E4FC155...@visi.com...
>
>
>
> >
Michael
> What radio and antenna are you using?
I'm using an Yaesu VR-5000 with my 400ft longwire. This is the first time
I'm using this receiver. A friend lent it to me to evaluate for a few weeks
while he's on vacation. I'm considering buying one.
One of the things I've been trying to do is get satellite images.
I've had no luck doing so. After looking at some web pages, I see I need
some additional equipment to do anything with the geosyncronous sats up high
at 1691Mhz, including scrounging up a dish antenna and a downconverter.
I'm going to take a crack at the low orbiting sats around 137 Mhz (that's
137 Mhz) :-)
I've already gotten some good info on tracking them for optimum receiving
times in my area, but I have no idea if a PC card and WXSat is good enough.
I think I might need a weatherfax PC card or a demodulator. Not sure...
Michael
Albert P. Belle Isle
wrote:
>
>
>I'm using an Yaesu VR-5000 with my 400ft longwire. This is the first time
>I'm using this receiver. A friend lent it to me to evaluate for a few weeks
>while he's on vacation. I'm considering buying one.
>
================== snip ----------------------------
>
>I'm going to take a crack at the low orbiting sats around 137 Mhz (that's
>137 Mhz) :-)
>
>I've already gotten some good info on tracking them for optimum receiving
>times in my area, but I have no idea if a PC card and WXSat is good enough.
>I think I might need a weatherfax PC card or a demodulator. Not sure...
>
>Michael
>
Michael:
WxSat and your soundcard will do an _excellent_ job of decoding, but
you have to feed it demodulated FM that carries the AM Fax modulation.
The bandwidth of the 137MHz APT signals is over 30kHz, and a 40kHz IF
bandwidth is required. If you use the typical NBFM bandwidth of 15kHz,
you'll get muddy images. If you open it up to the 150kHz used for FM
broadcast stations, the signal-to-noise ratio will be terrible and the
pictures full of white noise.
Consequently, you may have to trade your VR5000 for one of the (not
very expensive) APT receivers with 40kHz bandwidth, or modify the IF
filter bandwidth of your receiver.
Furthermore, the polar orbiters are spin-stabilized and use their
twice-per-scond spinning about the trajectory axis as the way they
scan each line of the imagery.
The APT signal their spinning antennas emit is thus circularly
polarized, so your linear wire will sense large variations in signal
strength between the time the signal polarity is horizontal like your
wire and the time when it's vertical. These variations will be
synchronous with the twice-per-second spin/fax-scanning rate.
Consequently, you'll need a circularly polarized 137MHz antenna, such
as a turnstyle or a Lyndenblad array (what I use). Either type is
fairly simple to build, and turnstyles are sold ready-made. However,
the antenna should be mounted outside with a mast-mounted pre-amp to
keep your coax from losing all the signal on the way down to you.
You have everything you need to decode and display the imagery, but
you'll have to invest a little time/money in getting it a decent
signal.
Try it with what you have, however, at the time NOAA12 or NOAA15 (on
137.5MHz) or NOAA17 (137.625MHz) comes over your location with a
strong signal.
If you use NBFM mode on your very sensitive VR5000 with an outside
antenna (of no more than 1/2 wavelength at 137MHz - NOT a 400 foot
wire with its extremely complex pattern of nulls from its 17
wavelengths) you should still be able to see an image of sorts.
Good listening,
Al
===============================================
Location: 42N39, 71W09
HF Antennas: 65ft TFD, 45ft T2FD, 28ft vertical, 65ft doublet
HF Receivers: Ten-Tec RX340, Ten-Tec RX320, Icom R71A
Decoders: Code300-32, Universal M-8000, PK-232MBX/DSP
===============================================
Michael
> Consequently, you may have to trade your VR5000 for one of the (not
> very expensive) APT receivers with 40kHz bandwidth, or modify the IF
> filter bandwidth of your receiver.
What APT receiver would you recommend ???
Michael
Radioman390
>The geostationary ones are at 1691 MHz. (Not 1961 kHz.)
Another complication:
In Europe they use the "period" and "comma" in numbers differently.
WTOP Washington we say operates on 1.5 Mhz (1500 Kc)
while in Europe it operates at 1,5 Mhz.
People average 18.000 dollars per year in salary over there.
Albert P. Belle Isle
wrote:
Michael,
I use a WEPIX 2000B from Vanguard Labs, but I don't even know if
they're still being made. You might run across a WEPIX on e-bay.
Hamtronics makes a kit about which I've heard good things.
http://www.hamtronics.com/r139.htm
It's not synthesized like the WEPIX, but uses crystals for each of the
APT channels. Since there are only 5 channels on which I've ever heard
anything, and only 3 active at the moment (2 NOAA and 1 Meteor),
that's a good design choice and saves a lot.
They also have good preamps - which I have used.
Swagur Enterprises used to sell a an APT receiver back-end that took
the 10.7MHz IF out of an Icom R7000 and provided the 40kHz IF
filtering, FM detection and audio amplification.
I suppose you could do the same with your VR5000's 10.7MHz IF output
into the back end of a Hamtronics APT receiver, also.
You will need a circularly polarized antenna, but once you have one
the receiver sensitivity doesn't need to be all that great.
It should have a front-end capable of blocking out strong local VHF
signals, however, if you're in an urban location. Oherwise things like
taxicab radios will occasionally add annoying "buzz lines" across your
otherwise handsome images.
Hamtronics also sells a preselctor to deal with such problems if you
run into them. They also sell turnstyle antennas and other APT
accessories.
http://www.hamtronics.com/r139_accys.htm
Ray Pfaff
wrote:
>Hiya....
>
>Has anyone ever decoded images from the geosyncronous weather satellites that transmit on 1.691 ???
>
>I have the PC software program "WXSat" and I use it to get the weatherfax images that are broadcast near me from Halifax and Boston. It works very well.
>
>This morning, I'm trying to figure out how to decode the actual satellite images on 1.691. I have 1.691 on now. I'm hearing something that sounds a bit like a NAVTEX signal. I gather it's the satellite, but I'm not sure.
>
>I've tried all sorts of settings on my WXSat software, but I can't seem to get anything. I have no idea if it's an 8 bit b/w image or a color image or what other additional settings I need to deal with when setting up WXSat for this.
>
>Does anyone have any experience with this ???? I'd love to get this to work. Raw satellite images would be great.
The reason that you're not getting anything is that HF Wefax and NOAA
images are AM, GOES is FM. If you can get the signal and change your
reception to FM, you can see something. Also, the GOES signal is
pretty wide band.
To reply to this message, replace "yar" with "ray"
Michael
> The reason that you're not getting anything is that HF Wefax and NOAA
> images are AM, GOES is FM. If you can get the signal and change your
> reception to FM, you can see something. Also, the GOES signal is
> pretty wide band.
Hiya... I know that now :-) I've been reading info on both low orbiting
NOAA and GEOS on 1691Mhz and other replies from ng members that know about
the subject. I'm gonna scrounge up a used dish antenna and get see about
getting some other items for little or no cost to rig up a groundstation.
I'm still not sure what to get and where to look for the stuff. I know
there are complete kits sold retail, but I wanna see if I can scrounge up
odds and ends and used stuff to get it done cheep. That's gonna be half the
fun once I learn a little more about what I'm doing/trying to do.
Michael
Ray Pfaff
wrote:
If you can find a copy, the New Weather Satellite Handbook by Taggert
has the info you need. I tried that route, but could never get the
feedhorn to work properly. I wouldn't make any major investments as
the analog stream from the GOES will be going away in 2-3 years.