I would recommend a SAW filter that has a pass band of 1525 - 1559 MHz. TawSaw has something that is a known good, but I’m not sure you can buy this retail anywhere: http://www.taisaw.com/upload/product/TA1405A%20_Rev.1.0_.pdf
I would suggest the MAX12000 from Maxim Integrated as the LNA module.
You can place the SAW in between the two stages of the MAX12000.
If you want to email me, I can send you a pre-release version of the demod.
Have recompiled the Outernet L-Band decoder library for Oarange Pi Armbian OS.
All working now.
Have not received any data yet, just using a simple antenna with NO Low noise amplifier.
Will set up patch antenna and LNA today.
Thanks for this. Very exciting.
Seasalt.
In Philippines I have set up the Home made Patch Antenna pointing approximately at Elevation angle: 22.2° True azimuth: 262.6° and have connected and powered my Low Noise Amplifier (20db) It has made a big improvement…
I see no signal at Outernet frequency 1539.8725 MHz… with the Outernet software or with GQRX.
I have the Elonics 4000 dongle attached to a Orange Pi and am using rtl_tcp -a 192.168.6.51 to send the dongle raw data over wifi to GQRX on my Ubuntu Laptop and using GQRX to decode the waveform information.
But with GQRX at 1542.8725 I see a very strong signal. (Does any one know what these signals are?
PS ( I have not calibrated my E4000 dongle) I assume it is very close in Frequency error.
It’s odd that you are not seeing our channel at all. Where did you obtain the E4000? The ones from NooElec have very little drift, so you should not be looking that far away from 1539 MHz. However, just a few minutes ago the frequency for IOR-64E was changed to 1545.525 MHz. This is a 10kHz channel that has 2dB more power.
Can you doublecheck GQRX? One other point: You may need to cascade two of those LNAs, since our LNA provides 34 dB of gain (and we have a SAW filter between them).
OK I changed my dongle to the RTL-SDR with a TCXO and it seems to work much better. on 1545,525 with GQRX but the Outernet decoder still wont permanently connect.
Here is a snapshot of GQRX.
Here is a zoomed in GQRX.
Can you highlight just 10 kHz?
Are you receiving code lock on the demod? I don’t expect frame lock right now, but you should be seeing code lock on the debug screen.
Here is a picture of the Outernet Demodulator trying to get a signal.
Sometimes it gets a signal and then after a second or two it looses it.
Something is wrong. It’s not getting a signal at all. It should be on code lock right away. In GQRX what is the SNR of the channel?
By the way, I think it’s going to be very difficult to receive the signal with only 20dB. We have not been able to close the link with less than 30dB from an LNA.
I agree I think the single LNA has improved reception but I think I will need two Low noise amplifiers to get enough signal boost to decode the information. I have another LNA coming at the end of the month.
Has any one else managed to get the L-Band decoder working in the field?
I am not sure how you use GQRX to show the signal to noise ratio.
Seasalt.
To obtain SNR, you are really just eyeballing the noise floor figure and the top of the channel. This is the new channel on IOR-64E viewed through SDR#. You can see a nice clean channel that should be very easy to lock on to.
Syed,
Is it possible the Polarity of my Antenna is wrong. Ie right hand versus left hand?
Yes, it’s possible, but didn’t you copy Adam’s design? Our requirement is for RHCP. If I had to guess the problem I would say it’s lack of sufficient amplifier gain. But if you made a left hand antenna, that will also be the problem.
Syed you suggested
“I would recommend a SAW filter that has a pass band of 1525 - 1559 MHz. TawSaw has something that is a known good, but I’m not sure you can buy this retail anywhere: http://www.taisaw.com/upload/product/TA1405A%20_Rev.1.0_.pdf”
I realize that Outernet is incredibly busy on the L-Band project but, could Outernet please start selling the appropriate LNA’s and a built version of the L-Band 1520 - 1560 SAW band pass filter in the Outernet shop.
I have looked everywhere on the internet and they are either very expensive or they want me to buy 5 chips etc.
I think L-Band Outernet will be a huge success and create a lot of interest from hobbyists who will use a RTL Dongle, SAW filter, LNA and a Arm linux mini computer fo decode your data.
Seasalt.
Syed said.
“If I had to guess the problem I would say it’s lack of sufficient amplifier gain”
I agree Syed the problem appears to be lack of amplification. I am close to getting a signal. I have ordered another $12.00 40db LNA and should have it by the end of the month. http://www.ebay.com/itm/182191602094?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
The cheapest Inmarsat SAW / band-pass filter that I could find on the internet was 25 Euro and I think that is getting too expensive.
( ADS-B filter 1090 MHz: L-band (Inmarsat, Thuraya, Iridium, GPS) filter )
They look like great filters but I am hoping that if all Outernet hobbyists get involved and collectively buy a simpler SAW filter in bulk, maybe we can hopefully get the price down to $10 .
We definitely intend to start selling components, such as an LNA module. I don’t have many to spare right now, but I could sell one for $19. Unfortunately we don’t have the manufacturing scale just yet for a $10 price.
We do have a radio coming out with an integrated LNA and SAW, as well as TCXO. That will retail for about $40. The patch antenna will initially be $29, though we also hope to bring that price down with volume manufacturing.
We will support the Raspberry Pi 3 and CHIP computer from NTC. Naturally we will support the RTLSDR. We are finishing support for one more radio type (SDR Play) before releasing the demod and our decoder as freeware.
."We do have a radio coming out with an integrated LNA and SAW, as well as TCXO. That will retail for about $40. The patch antenna will initially be $29, though we also hope to bring that price down with volume manufacturing. "
Syed that sounds fantastic. I think for early adopters and DIY people a $40 Radio will be excellent.
Seasalt
Syed I would be grateful if I could buy a made up SAW filter and / or, a whole radio. I am happy to be a Beta tester here in the Philippines and already have the demodulate software set up on a Orange Pi
. I have a USA postal address I get stuff shipped through.
Regards’
Seasalt
Sure thing. Please email me directly again. We can work out the details.
