No capturing data.

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No capturing data.

Postby vk2byf » Sun Dec 21, 2014 7:30 am

Hi I'm new to this so I need some help please.

Ok I can find the satellite and I receive signal with Yaesu FT-817 S4 on home-brew Eggbeater antenna pair, UHF and VHF with preamp.

I seem to have +/- 10kHz of Doppler shift and have to follow the signal to keep audio in the receiver passband.
I am not using a dongle, Does autotune only work for Dongle?
I hear the signal, sounds like pink noise and I can hear and see the characteristic dual tones every 10 seconds or so on the tuning spectrum display.
Sounds exactly like recorded wave file samples on the web site.

It's 1200baud BPSK, right. Is the data in the noise or in the tone pair, which seems to short to carry much data?

Nothing shows on the status bar at the bottom, no sat ID no frame numbers, nothing.
Should Dashboard work with an ordinary SSB receiver? I use Dig mode or USB.

As far as I know I have it set up as per the FUNcube manual but I end up with a captured file with 0kb of data

I'm able to hear other Sats ok with this setup AO-07 SO-50, Fo-29

Much obliged for any help. Yes I have read the manuals dashboard and FUNcube

Regards Bob VK2BYF
Last edited by vk2byf on Thu Jan 29, 2015 3:32 am, edited 1 time in total.
Posts: 7
Joined: Thu Dec 18, 2014 6:51 am

Re: No capturing data.

Postby AL0I » Tue Dec 23, 2014 3:55 am

vk2byf wrote:Does autotune only work for Dongle?

No, it should work for any audio source, but in my experience, it seems optimized for IQ signals provided by an SDR device. If you are manually tuning, then you will probably get best results for the first few minutes and the last few minutes of a high elevation pass since Doppler shift will be minimal during that period, and you won't have to shift tuning very much or very often to keep the signal within the passband.

vk2byf wrote:Is the data in the noise or in the tone pair, which seems to short to carry much data?

It's in the "noise". You should be able to tell that the autotune is using the dual-tone periods for tracking in the passband

vk2byf wrote:Should Dashboard work with an ordinary SSB receiver?

Yes, but you will only see an effective passband that matches the bandwidth of your receiver, so you will only be using about 2.4-3.0 kHz on the left side of the Dashboard display at the bottom of the screen if you use USB mode. I'm not familiar with the FT-817, so I can't say anything about the Dig mode.

I will add a couple of comments on relevant issues that might be causing you grief.

First, the type and capability of your computer processor(s) and the load on that processor can have a significant effect on your ability to use the Dashboard software. So using a faster, more capable processor (or a processor with more cores) and reducing the number of additional processes or programs that are running at the same time as the Dashboard can improve your decoding prospects.

Second, noise/interference sources within the frequency range spanned by the FUNcube signal during a pass can cause you to be unable to decode the signal if the noise/interference signal overlaps at all with the FUNcube signal for some or all of the pass. Best decoding results will be when the signal-to-noise ratio is greatest, and that doesn't necessarily correspond to when the FUNcube absolute signal strength is greatest. You may have to do some detective work and determine what noise sources are present and take steps to mitigate the ones you have some control over.

As an example, I have interference spikes and signals due to several reasons and sources. Computer equipment in general and networking equipment in particular generates fixed frequency spikes at my location, and these signals are strong enough that, if they overlap with the FUNcube signal at all, I am able to decode few (if any) frames. I also have a variety of RF emitters in fairly close proximity (some quite strong) that I have no control over, and these can also have an adverse effect depending on which direction I am pointing my antenna and the time of day. Also, because I use a wideband receiver (Alinco DJ-X11T), I suffer from sporadic image signals that can completely obliterate the FUNcube signal for up to several seconds at a time.

Good luck on resolving your issues, and welcome to the forum.
Posts: 7
Joined: Fri Nov 15, 2013 12:16 am

Re: No capturing data.

Postby vk2byf » Fri Jan 16, 2015 4:51 am

Hi Aloi

Thanks for taking the trouble to respond to my post.

I have successfully decoded and forwarded data to the warehouse as VK2BYF.

My entire problem was simply that I had my sound-card configured for the default 48k sampling rate.
Once I changed that to 96k, I could decode 100 frames on a single pass. I'm happy with that.
Now to make sense of the data. I need to know which axis is which on the bird.
It looks like the home-brew 146MHz eggbeater antenna is doing a great job almost horizon to horizon.
for 6 degrees and above. I can even see the typical eggbeater notches in the radiation pattern,
as the footprint moves over my QTH. Manually tuning to keep the signal in the passband of my receiver
is no problem. I don't loose frames as I move the dial slowly from about 145,9375 to 145,9310 over the pass.

Next I plan to use one of those cheapy USB dongles and automate the process.

I't all good fun and slows down dementia.

Thanks again Phil, Regards Bob VK2BYF
Posts: 7
Joined: Thu Dec 18, 2014 6:51 am

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