Outernet 3.0: 30kbps now, 100kbps eventually - even smaller antenna


#162

Konrad,
“Disclosure” day by the end of the year is almost here. Standby for the “On The Air” frequency.


#163

@donde @Syed
I’m standing by… I can’t wait for the next lesson.

–Konrad, WA4OSH


#164

Of course when you are hunting for a signal you should use a dish at first. Trying with a bare LNB is done only after you have positively identified and demodulated the signal using the dish.
Normally (at least here in Europe) the satellites these days transmit mainly multiplexes that take up a full transponder and are at a symbolrate around 27.5 Msps. Selected transponders are used for narrower signals containing only a single programme and some of them may be used for temporary links for newsgathering etc.
So indeed you should start looking at Lyngsat to find the transponder layout on the satellite you want to try.
No need to look at the transponders sending a multiplex at high rate. Look for transponders that have some different, narrower, signals or are labeled “FEEDS”. Or those that are not listed on Lyngsat at all.


#165

@pe1chl @donde @Syed
So retrofitting my 18 inch (45 cm) dish for Ku FTA reception and getting a sattellite finder (or tuner) would be the priority.

I would imagine the tuner would help align the dish on to known satellite(s) and a splitter between the dish and the satellite tuner, with a DC block, would allow me to look at the down converted L-Band with the RTL-SDR.

I looked at some other projects. The LNB gain when combined with a dish might be too strong for the RTL-SDR dongle. I might need some attenuation when using the dish. Also, there were a couple of instances where a VHF-3500 MHz high pass filter was necessary to keep from overloading the RTL-SDR from TV Stations, Cell towers, radars, etc.

–Konrad, WA4OSH


#166

If RTL-SDR has a built-in LNA like my FunCube, you could disable it. For now, I’m also using a 1065 MHz Flightradar 24 bandpass filter. Does help a bit. Won’t be useful if Syed gets a frequency 100 MHz above. I think it will be in High band: 12 Gig


#167

I have several SDRs 1) several RTL-SDR with different chipsets 2) AirSpy+Spyverter 3) HackRF, 4) SDRx (which has a L-Band LNA and SAW filter, and a broken 5) DreamChaser 2.03.

I thought ADSB was at 1090 MHz.

I’m sure that a VHF-3.5GHz high-pass filter will help.

–Konrad, WA4OSH


#168

I am also considering the freesat satellite v8 finder, What are peoples thoughts on the need to worry about vert/horz polarization when just pointing the lnb just at the az / elev. I figure the 3db loss would really be negated by atmospheric scattering of the signal path and probably with a accuracy never reaching 2 degree spacing between the adjacent geosatellites… I expect to see multiple birds simultaneously.

Speaking about the FreeSat V8 Satellite Finder, I read somewhere that it uses a channel seaching database… Since we are not really looking for something in the scheduled or predefined database, is this going to be a problem?


#169

You of course are only interested in finding and properly identifying the satellite. The SCPC channels will not be listed as video or radio channels.

Check out the Freesat Download Center

Then look at the Freesat V8 Finder NA Sat List

The DreamCatcher 3 will decode the SCPC stream out of the down-converted Ku -> L-Band block.

–Konrad, WA4OSH


#170

Yes, you are correct about ADS-B frequency at 1090. 1065 was the closest I could find at the time from Mini-Circuits. The interference dropped from -60 to -80 dBm


#171

The enthusiasm here is great. I just wanted to reiterate that we are using a non-standard carrier (not DVB-S), so any hardware that is acquired now won’t be particularly useful.


#172

[quote=“myself, post:110, topic:4395”]
Okay, so from the reading I’ve done, there seem to be two types of Ku linear LNB’s, called Standard and Universal. The Standard type covers 11.7-12.2GHz, and the Universal covers 10.7-11.7 as the “low band” and 11.7-12.75 as the “high band”.
[/quote]There is also wideband which covers entire range with single 10.4GHz local oscillator and two ports for horizontal and vertical.


#173

No DVB-S2(X)? I hope you won’t regret that later… DVB-S2 NIMs are of course mass produced at very low price, and the only problem I can see is that their lowest symbolrate is above what you are currently planning.
Official spec is usually 1 Msps but that is only because the specsheet conveniently lists “symbolrate: 1-45 Msps”.
TV amateurs use them at symbolrates as low as 300ksps and I read that the achievable minimum setting in one of the chipsets would be 105ksps. At a bandwith of about 1.4*symbolrate that would be around 150kHz of bandwidth, clearly a bit more than you are planning, but the advantage of bog-standard NIM modules that are L-band in demodulated data out at around $15/piece is not to be overlooked to easily…


#174

There are no low-cost S2X ICs that support the Very Low SNR mode of the S2X standard. At this time, there is one commercially available chip that does support VLSNR, but it is obscenely expensive. VLSNR was important because it demodulates down to -11dB SNR, whereas S2 is limited to -2dB SNR with QPSK 1/4. S2 ICs are plentiful, of course, though they tend to require a TS-interface, which further restricts the types of compute IC we can use.

ST does have a demodulator that can go really, really low (symbol rate), but they shut down their STB business unit last year, so selecting that part would have been a very risky choice.

At volume, we should be able to get 100kbps out of our own NIM for less than $15.


#175

Wooow…that is really impressive for that little bit of money! Awesome work Syed :slight_smile:


#176

That is down the line, not right away.


#177

Actually, there are countless applications that can benefit from a low-cost NIM for SCPC data.

Of course the big talk is the Bitcoin Block Chain broadcast.

We’ve seen Amber Alert (missing children) and Silver Alert (missing old people) signs on the freeway, variable speed limits, closed lane indications, etc.

If you have seen satellite dishes on top of gas stations, I think there are several things that are being sent down by satellite. 1) Bad credit card numbers 2) The gas prices 3) Entertainment programming at the gas pump. The video loop appears to get updated by satellite.

In rural areas, I can imagine that the current market price for various commodity items can be very useful.

I’ve seen satellite dishes on top of grocery stores. Certainly the in-store entertainment audio, sales prices for the tens of thousands of items come to mind. LCD displays are cheap enough that the prices on the shelves could be updated by satellite. Traditionally, grocery stores had 3-5 T1 lines running to them.

The Internet of Things concentrates on sensing things from a remote source and bringing that data to a centralized cloud server. But I can also see information being disseminated from a centralized cloud server to small satellite receivers.

Eg. turning on and off irrigation systems based on weather predictions.

Eg. Severe weather, tsunami, earthquake, wildfire warnings.

Finding the applications can increase the number of NIMs demanded and bring down the price.

–Konrad, WA4OSH


#178

Syed, When you release frequency and polarity, would I and others be able to see a carrier? Simple setup for me is MK-1 LNBF powered by 20 volts on a photo tripod pointing at correct satellite. And Using SDR# into Windows 10 laptop. If true it would put smiles on many faces, and more importantly help us learn how to point a dish-less LNB well before we see a DC3 board.


#179

I’m not entirely sure you’ll be able to see the carrier, but it’s worth a shot. It will be on the high-side of RTLSDR bandwidth. It looks like we are on the verge of finalizing something on EchoStar-9, which is at 121W.

Pointing a dishless LNB is exceptionally easy. I just eyeball it and twist my wrist until I see the packets-LED blink.


Aiming my receiver
#180

Can’t seem to find EchoStar-9 on N2YO. Maybe, it’s really GALAXY 23 (TELSTAR 13)? I see 22 other EchoStar’s listed, but not EchoStar-9.


#181

Yes, it’s EchoStar 9 / Galaxy 23

Thanks @Syed I can now try to find a clearing through the trees to see it.

–Konrad, WA4OSH