Satillite Decoding

[DXJR]

Hello.

I have setup SDR# and WXtoImg and did receive one image from NOAA 18 yesterday. Now I am not quite sure i have this setup right and would like someone to take a peek.

I setup SDR# to pipe the audio to vac2 then i use WXtoImg to receive the audio and decode.
Screenshot by Lightshot

I set my location in the WX client and believe i set up the audio correctly.

Where should my sample rate be? 2.4msps?

I only have a clear line of site to the eastern sky my western view is totally blocked. Is there a way to force WX to record and decode regardless of pass times?

Are there any other pieces of software that can decode satellite images and such? I tested out multipsk and i just cant wrap my head around teh staggering list of potions and things you need to set up to receive and decode proper like.

Thoughts ideas hints?

Since you brilliant people over here were able to get me trunking i figured i would bring this here for you to mull over.

 

[rbm]

I've had good luck with the settings shown in the first image below. (Click on the magnifying glass to see the details)

Using VB-Virtual Audio Cable for the audio output. (I've also used VAC but prefer VB cable.)

I get the best decodes using WFM, no filtering, and 36,000 bandwidth.

Set the SDR audio level near maximum and try to keep it in the green, around 60%-65% or so in WXtoImg.

Edit: That's using an ST-2 antenna with a preamp right at the base of the antenna and feeding a number of radios.

Rich

The settings:



The results:

 

[rbm]

In addition, make sure you have your dongle calibrated correctly.

I set my bandwidth a little wider than needed to account for some doppler shift.

Even with that, if I'm sitting at the computer during the pass, I'll 'tweak' the frequency up or down to keep it centered.

I've used all of the sample rates at one time or another and it hasn't made much difference if any in the decodes.
With digital modes I usually set it narrower just so it's easier to see the signal without zooming the FFT display.

Rich

 

[DXJR]

I thought about adding a preamp but i didnt want the noise level to get to out of control. I have a ramsey pa-10 and the adjustment pot is broken off wide open. I was also a little hesitant because of the the weak protection my dongles have.

I have about 75% level in WX when its receiving.

Is there any other software like this? I only have an eastern view and this tries to receive from any orientation. I have roughly 180 degree view of the sky.

 

[rbm]

I don't think a preamp will damage your dongle.
In more than 30 years of using them, I've never had a problem.

I have preamps on all of my antennas except for one.
I also have 12 dongles that I've been using for years and never had one fail yet.

You may already have this link. It's a good site to see where the satellites are.

Just go to the right side and change the custom location to your own.
And it will track the satellites for you.
Since you can only see to the East, you can see which passes will work for you.

LIVE REAL TIME SATELLITE TRACKING AND PREDICTIONS: NOAA 19 NOAA 18 NOAA 15 NOAA 17

Rich

Edit: By the way ...................
The Ramsey PA-10 may not be the best amplifier for that band but .......
This.............
"I thought about adding a preamp but i didnt want the noise level to get to out of control. "
You'll never know unless you try it. You may be pleasantly surprised.

 

[dragonball]

i use FLDIGI

 

[DXJR]

Rick,

I took your suggestion and hooked it up. I have a mixed bag of results. Local FM broadcasting stations are crossing all the way up to 137 mhz. It did boost my signal up a bit and not as much noise as i would have imagined.

I dont know if i will be able to decode with it hooked up now. Too much interference on 137.100 mhz from that broadcast site.

I narrowed the bandwidth to 36,000 and am going to give it a shot when i get an opening.

Dragonball,

I played with FLDIGI but had the same success as with MULTIPSK. I found it overwhelming. I guess ill give it another go and see if i can sort it out.

 

[DXJR]

Screenshot by Lightshot
Screenshot by Lightshot

I dont seem to be getting anything useful out of this. I have seen tons of stations setup and they work.

Why is it that its showing NOAA 19 around the tip of South America but its trying to record it?
APTDecoder seems to be the msot accurate as far as predicting the satellites but its not showing correctly on the map. However recording starts then right after i see the data stream in SDR#

With PreAmp
http://prntscr.com/5nbgk4
Without
http://prntscr.com/5nbh3n

Guess im going to keep on trying without it for now.


Question, how important is a tuned antenna for reception?

http://prntscr.com/5nbi7m
That is the results from the last pass with the PreAmp. Not sure if it was a bad pass or too much qrm for a good decode. Probably both.

 

[rbm]

One other thing I forgot to mention.

Do NOT use AGC for either the RTL or Tuner.

Uncheck both of them and adjust your gain manually.

I never use the AGC function in SDR# because it always sets the gain way too high.

I looked at your screen capture above and it appears that your gain is set quite high.
Notice in my screen capture the noise is down around -45 to -50. In yours it's up around -30.

Once you start decoding, slowly adjust your manual gain up or down and you'll see where the image will clear up.

Rich

 

[DXJR]

One other thing I forgot to mention.

Do NOT use AGC for either the RTL or Tuner.

Uncheck both of them and adjust your gain manually.

I never use the AGC function in SDR# because it always sets the gain way too high.

I looked at your screen capture above and it appears that your gain is set quite high.
Notice in my screen capture the noise is down around -45 to -50. In yours it's up around -30.

Once you start decoding, slowly adjust your manual gain up or down and you'll see where the image will clear up.

Rich

Ahh so it should be more like this. Screenshot by Lightshot

Part of my problem is that i get really weak reception here and its quite one sided. I get some other satellites down links showing in SDR# but i think im receiving via multi path because its sporadic at best.

 

[rbm]

Ahh so it should be more like this. Screenshot by Lightshot

Yes ................ but,

Your gain is set so high that you will get a lot of false signals and overload.
Typically I run my gain around 29 dB or so for satellite reception. (Even the MilSats)
Any higher than that and I get a lot of garbage.

If you need to have your gain set that high to see the APT signals, only a better antenna will help you.

Also, with WXtoImg you should right click on FILE and UPDATE KEPLERS to get the latest data periodically.

For any tracking software or web site you need to make sure that it knows your correct Latitude/Longitude.

Rich

I'll try to catch one of the passes this afternoon so you can see all of my settings.

 

[DXJR]

I put in my location in both programs. You can see it on the map neighbor
Screenshot by Lightshot

I dont get why APT just tried to decode NOAA 17 when its on the other side of the world. Last time i checked, line of sight still is a factor.


I dont have money for gear unfortunately, or i would have a tower with a nice yagi or a dish Well that and the fact i live in an apartment and im not allowed to have an antenna technically.

Ok that would be awesome.

I havent tried setting the audio gain lower just the rf gain. I know it makes a difference with trunking but i wasnt sure with this being that its receiving several channels at once in WFM mode.

 

[rbm]

I was talking strictly RF gain.

It seems that when you entered your 'HOME' Latitude and Longitude you may have entered it wrong.

I'm in upstate NY and my Latitude is around 42.1000 and the longitude is around -75.9000
If you leave out the -, the site will think you're on the other side of the earth.

You need to have your audio gain almost at maximum when using WFM mode.

Rich

 

[DXJR]

Ahh that would be my issue for sure. Thanks for pointing that out to me, i would have been chasing my tail for days.

Screenshot by Lightshot

I put the preamp back inline and turned down the rf gain till the noise is around -35

Seemed to help cut back on that qrm from the broadcast station.

While the tracker software isnt quite right still it does start to record just before i receive in sdr#

 

[rbm]

Here are the settings and the resulting image from a NOAA-18 pass late this afternoon.

There's some noise streaking because I have a hill in that direction.

Rich


The settings:



The resulting image:

 

[DXJR]

I have come to the conclusion that its my location and antenna placement.

Its just a home brew ten meter half wave with four radials vertical in an X configuration, center fed. I threw two radials on it yesterday that are roughly two meter.

I swapped over the other antenna i have. This one is a half wave two meter made from rabbit ears style antenna whips isolated on plexiglass and tunable.

What do you recommend for my unique situation? I'm no stranger to a soldering iron and money is an object.

See i would be quite happy with that quality reception you achieved.

Your shack is awesome, i can only dream.

 

[rbm]

If you have room, this antenna will serve most of your needs.

AntennaCraft Scanner Antenna Kit with 50 Foot Cable (ST2)
Price: $36.99 plus $6.99 shipping.
AntennaCraft Scanner Antenna Kit with 50 Foot Cable (ST2) from Solid Signal

That's the one I was using for the NOAA image above. (But, I'm using a preamp)
I have 5 of them installed, feeding more than 40 scanners.

They're not very expensive and for the price, they work well.

Rich

 

[DXJR]

If you have room, this antenna will serve most of your needs.

They're not very expensive and for the price, they work well.

Rich

My question is, do you think this will provide improvement over my wire dipole even being that i only have 180 degree view of the sky horizontally and 90 degree vertical?

Literally my back is to the wall. I think i am pretty much doomed to the lousy reception because of my situation.

I could fit that antenna on my balcony like the others, and with 50 foot of coax well you really got me thinking now.

 

[rbm]

My question is, do you think this will provide improvement over my wire dipole even being that i only have 180 degree view of the sky horizontally and 90 degree vertical?

Literally my back is to the wall. I think i am pretty much doomed to the lousy reception because of my situation.

I could fit that antenna on my balcony like the others, and with 50 foot of coax well you really got me thinking now.

In my opinion, over a wire dipole, it would perform MUCH better.

Keep the coax as short as you can to reduce signal loss and you should be pleased with the results.

Obviously, it would be better up high and in the clear, but you gotta do what you gotta do.
The only way to find out is to give it a try. I think you'll see quite a bit of improvement.

For years I had to travel for business.
I was always able to find something that would work and be small enough to pack in a suitcase.
Including a long piece of wire with a fishing sinker dropped out of a hotel window to work the low bands.

Rich

By the way, a lot of years ago, a friend of mine told me that he was going to sell all of his radios.
He bought a house way out in the country and he didn't think he'd be able to hear anything after he moved.

I told him to hold off on selling his stuff until he tried it out.
We put up a Scantenna ST2 with a preamp and he heard more than he ever did before.
That was more than 20 years ago and he still jokes about it.

 

[DXJR]

Ok, ill give the antenna a try. Its cheap enough, and comparable to a discone. I was thinking about getting one a while ago.

Ever since i got the taste for contesting on eleven meter back a few years ago ive wanted more. Over fifty contacts on ssb in two mornings time in my log book really lit this fire.

I keep looking into all the cool things you can do with radio and its got me hooked. Well that and my dad was a ham so it kinda rubbed off on me.

One day i will get my license, until then ill just sit back and sandbag the waves.