NOAA WX decoding issue

[aarongriffin81]

I am new to wx satellite monitoring and setting up a station using a homemade double cross dipole antenna and uv5r HT. I made an audio output cable using the earpiece that came with the radio and cut the end and ran that to 'line in' on my desktop pc. I have about 25 feet of headphone cable between the pc and the outside radio/antenna and about 2 ft of coax between antenna and radio. I am getting good signals I think but when wxtoimg processes it the results are not what others are getting. I can see bits of color and no overlays. wxtoimg says something about volume too high or bandwidth too narrow, etc. I ordered an rtl-sdr and waiting for delivery. Besides the rtl-sdr, what else can I do to get the color/map overlay to work?

 

[Freemor]

I am new to wx satellite monitoring and setting up a station using a homemade double cross dipole antenna and uv5r HT. I made an audio output cable using the earpiece that came with the radio and cut the end and ran that to 'line in' on my desktop pc. I have about 25 feet of headphone cable between the pc and the outside radio/antenna and about 2 ft of coax between antenna and radio. I am getting good signals I think but when wxtoimg processes it the results are not what others are getting. I can see bits of color and no overlays. wxtoimg says something about volume too high or bandwidth too narrow, etc. I ordered an rtl-sdr and waiting for delivery. Besides the rtl-sdr, what else can I do to get the color/map overlay to work?

The raw images from the satellites are greyscale. Colour and map overlay come from using file -> auto process option on the captured RAW image. For the map overlay to work you need up to date Keplers. I wrote a 2 line script that grabs them and moves the file into the right directory as the softwares auto-update/ manual update of the keplers no longer works.

You can get the up-to-date Keplers here: http://celestrak.org/NORAD/elements/weather.txt
The just move the weather.txt into the right folder. $HOME/.wxtoimg not sure what it would be on windows.

 

[aarongriffin81]

I copied the text into the weather.txt fileI had inmy installation directory and autoprocessed it again and played with overlays and this is the best I got so far. I'm not sure the overlay is accurate, I am in north Missouri and the signal was almost flawless far into the south, better south than north. Why is the second half of the pass(south) worse than the north? Also, how do I confirm the map overlay is true? I cannot make out water to confirm it in the greyscale.

 

[aarongriffin81]

I just got another good pass with lots of improvements after editing the weather.txt file. Here are my results, I'm pretty excited and impressed so far since I don't even have an rtl-sdr yet. This is only the uv5r audio jack fed into the pc, I raised the double cross dipole about 10 feet total for this pass, previous tests were 3 ft height. I have one more question regarding the map overlay, I can see that it is pretty close now withthis latest pass but along the Baja of California it is noticeably off. Is there a way to adjust the map overlay in wxtoimg?
Thanks for helping me improve my setup!

 

[Freemor]

I copied the text into the weather.txt fileI had inmy installation directory and autoprocessed it again and played with overlays and this is the best I got so far. I'm not sure the overlay is accurate, I am in north Missouri and the signal was almost flawless far into the south, better south than north. Why is the second half of the pass(south) worse than the north? Also, how do I confirm the map overlay is true? I cannot make out water to confirm it in the greyscale.

be sure to set your station location under Options -> ground station location

 

[Freemor]

Also now that you have the updated Keplers and set your ground station loacation you can use file -> Satellite Pass list to get a list of passes that will be received well. There are many passes that are very low on the horizon and this do not recieve well. I know because I kept trying for ones not on the list and they generally turned out badly.

 

[ArloG]

Also to get good images the FM IF bandwidth needs to be in the 38-40 kHz range.
The easiest way to get updated keps is to use the wxtoproxy application. Launch it first and just update from the wxtimg program.
Don't overload the HT volume into your pc. And wxtoimg should show an audio level of around 50%.

In your settings if you know that your reception is weak at extreme N-S, E-W. You can change settings to record only when the sat. is above a certain elevation. For me it happens to be 10 degrees.

 

[aarongriffin81]

Thanks everyone for helping me! I had already set my location but I only used 1 decimal digit on my coords because I didn't think it would matter when I first set it up. Now it has 6 decimal points. Example, I had 39.7 but now I have 39.790588, This should help alot.
Arlo, my cheap uv5r doesn't have that ability as far as I know. The UV-5R is able to Transmit on Narrowband (12.5kHz) and Wideband (25kHz). I assume that is for tx and rx but I can't find much documentation for that. Either way it is no more than 25kHz. I'm actually surprised I am getting as good of results as this with such little and cheap equipment. It took me a few days to figure out the double cross dipole antenna wiring and I have nanovna to help. The instructions I followed lacked clear polarizations for each dipole as well as lacked compensation for velocity factor for the phase coax. I almost gave up on it because until it was right I could hear NOAA sats better on a wet noodle stuck in the antenna port than with the faulty dbl X dipole.

I also raised the antenna for the upcoming pass and may post the results if they turn out good.
Thanks again!

 

[Freemor]

I just got another good pass with lots of improvements after editing the weather.txt file. Here are my results, I'm pretty excited and impressed so far since I don't even have an rtl-sdr yet. This is only the uv5r audio jack fed into the pc, I raised the double cross dipole about 10 feet total for this pass, previous tests were 3 ft height. I have one more question regarding the map overlay, I can see that it is pretty close now withthis latest pass but along the Baja of California it is noticeably off. Is there a way to adjust the map overlay in wxtoimg?
Thanks for helping me improve my setup!

Nice captures. I'm not seeing your station marker on the map so either you have the option to show you location off or you haven't set your Lat and Lon yet as mentioned above. Doing so will help with map accury. and you can turn off displaying your location if there is some concern about that under map overly options.

Under Image there is "shift image" that might be what you are looking for.

 

[aarongriffin81]

Here is my recent pass but it is not as clear. Also, my coords didn't change yet. I've had the program running the whole time so maybe it needs to close and open to update my coords? Baja of California makes it easy to see the overlay is off. I set the auto record and it worked great! It started and ended around 7 degrees. I was hearing it around 3 degrees and got impatient wondering if it would begin recording or not.

 

[aarongriffin81]

Thanks, I found the 'move map overlay' under images. You hold the mouse on a distinct spot and drag a straight line to where it should be and let the mouse button go and it adjusts it. However, I closed and re-opened wxtoimg and it always processes it inaccurately. I wonder if I should move my coords in the same direction that I need to shift the overlay and make it draw the map where it belongs? The possible issue is that the next satellite pass may overlay it differently. I also checked the box to show my location marker and it looks very accurate so it seems to know my precise location now even though the overlay is off by at least 100 miles.

 

[Freemor]

have you done the slant correction / dsp calibration. I assumed yes because the first pic you posted was vertical. if not that might be part of the problem. if not check under help and it'll walk you through the process

 

[ArloG]

Google Earth your exact location. Convert it to decimals. Enter your altitude also. Longitude West of Greenwich will be negtive.
2 decimal places will be good enough. Not sure if it likes more.
Close and reopen the program and make sure it stuck.
Wxtoimg settings are located in:
C:\Users\<your pc login name>\AppData\Roaming\WXtoImg\WXTOIMG.CFG
Are you using the Kevin Schuman version?

As a noob, you're doing well. If you're really into it a quadrifiler helix antenna with plans from J Coppens will really help a lot.
Also a preamplifier located as close to the antenna as possible helps signal strength a lot.
I use a nooelec LANA. Depending on if you have very strong FM broadcast stations and 2 meter, public service transmissions.
You may consider one that has bandpass filters. But where I live, the LANA works very well.
Also. Unless your antenna is very close to the radio. You can never go wrong with high quality 50 ohm coax. LMR-400 it is for me.
Look at other designs. An "ugly choke" with 4 or 5 turns of coax a few inches in diameter close to the antenna can help a bit.
I use a 1/4 wave sleeve, or bazooka, balun on mine.

 

[aarongriffin81]

have you done the slant correction / dsp calibration. I assumed yes because the first pic you posted was vertical. if not that might be part of the problem. if not check under help and it'll walk you through the process

No, I havn't. The slanted pics were just different 'projection' options and I picked some that I liked. I'll look for the

slant correction / dsp calibration

and report any improvements.

I just tried and get this error. what is PLL?

 

[aarongriffin81]

Are you using the Kevin Schuman version?

Yes, and its the pro version. I found the 'disable PLL' option but apparently it is too late to do so after the pass. I don't have an audio recording afterwards to try again until the next pass but I'm pretty happy with the results now. I'm sure it will be better when I use the rtl-sdr and wider bandwidth. Thanks everyone!

 

[Freemor]

Yes, and its the pro version. I found the 'disable PLL' option but apparently it is too late to do so after the pass. I don't have an audio recording afterwards to try again until the next pass but I'm pretty happy with the results now. I'm sure it will be better when I use the rtl-sdr and wider bandwidth. Thanks everyone!

The ones you posted here were different projections. but it is important to to the slant correction on a raw image to get the software set up.

My first pulls were very slanted so I have to work throught that before I could have other fun.

 

[aarongriffin81]

You guys have helped a bunch! Thank you. I wasn't expecting professional looking results with the absolute minimum equipment (uv5r, cut up headphone cord and a pc). I didn't use a cellphone, filter or pre-amp. Today, NOAA 19 was more than 80 degrees and here are some results. This far exceeds my expectations and I'm working on the next antenna to compare. Current antenna is a double crossed dipole that has 4 dipoles in total, two are fed out of phase. It seems to shine the best at 1 wavelength above the ground but I always want to try to raise it 7 or 8 feet to see over house roofs better.
My next antenna build is an Asymmetric turnstile antenna (ATA). It has 2 dipoles that are off-center fed and NOT crossed and each dipole is not split like usual. coax center feeds one dipole, off-center. Shield feeds the other dipole, off-center. The 2 dipoles are L shapes butted up near each other so the end result looks like a short dipole and a long dipole but they don't actually cross and both are the same length. It seems unorthodox....my kind of antenna! In fact. I can't find much info about it at all. Here is the link for the build...Asymmetric turnstile antenna (ATA).
73
KF0NKI

 

[Freemor]

You guys have helped a bunch! Thank you. I wasn't expecting professional looking results with the absolute minimum equipment (uv5r, cut up headphone cord and a pc). I didn't use a cellphone, filter or pre-amp. Today, NOAA 19 was more than 80 degrees and here are some results. This far exceeds my expectations and I'm working on the next antenna to compare. Current antenna is a double crossed dipole that has 4 dipoles in total, two are fed out of phase. It seems to shine the best at 1 wavelength above the ground but I always want to try to raise it 7 or 8 feet to see over house roofs better.
My next antenna build is an Asymmetric turnstile antenna (ATA). It has 2 dipoles that are off-center fed and NOT crossed and each dipole is not split like usual. coax center feeds one dipole, off-center. Shield feeds the other dipole, off-center. The 2 dipoles are L shapes butted up near each other so the end result looks like a short dipole and a long dipole but they don't actually cross and both are the same length. It seems unorthodox....my kind of antenna! In fact. I can't find much info about it at all. Here is the link for the build...Asymmetric turnstile antenna (ATA).
73
KF0NKI

Glad to see its all up and working for ya. If you capture multiple passes in a day the Composite processing feature of wxtoimg is very nice.
It'll let yo make bigger pics like this one. The second isa 3D anaglyph (anopther processing option that can be turned on)

 

[aarongriffin81]

Awesome, I did it! Thank you. There are 2 passes in this composite and they are very similar so it barely shows but it proves the concept perfectly for me. One of these passes adds the whole of Baja of California whereas one of the passes only showed a bit of it. It would be cool to have 30 degree passes to the west/east and compose them. Thanks again!
73
KF0NKI

 

[aarongriffin81]

Do you know if it possible to use your saved raw file and my raw files and compose them together? Here are my 2 good ones from today if you would try it and see if they compose. I zipped the 2 raw images and uploaded them here....2 raw files