LoRa RX

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Wellectric Mail

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Aug 21, 2023, 5:18:14 PM8/21/23
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Hi All ,

I have been interested in  HAB monitoring for some time  , so with the
help of the  PiInTheSky /lora-gateway instructions on Github I have
managed to put together a Pi 3B+ with a cheap LoRa card and it seems to
work !

Now I must apologise as I made a mistake with my location and after
correcting it I now appear twice on the SondeHub/Amateur map , will this
correct itself or is there something I need to to ?

Thanks Rich

73 G0RXH

Mark Jessop

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Aug 21, 2023, 5:42:44 PM8/21/23
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Nothing you need to do. The incorrect location will disappear from the map after a day or so.

73
Mark VK5QI

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Philip Day

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Aug 22, 2023, 2:00:19 AM8/22/23
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Hi Richard,

Thank you for contributing to the community in this way! Sounds like the whole thing might have cost you under £100!

With UKSA launching their badges for scouts, I wonder if simple version of this might help to get kids to 'listen' for both balloons, and LoRa enabled satellites? This could be super inspiring if it's in reach of family budgets!

John Laidler

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Aug 22, 2023, 2:22:40 AM8/22/23
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Rich,

I see you're not far from me, I live near Plymouth. I was interested to hear your gateway is showing on the Sondehub.amateur site. I dusted mine off recently to try and track a balloon but it didn't appear on the map. This was unsurprising as it was last used when habhub, the predecessor to sondehub, was in use so I guess it was trying to upload to the defunct site. 

The answer is probably just to rebuild the thing with the latest software. 

John
M0WIV 

On Mon, 21 Aug 2023, 22:18 Wellectric Mail, <richar...@wellectric.com> wrote:

David Akerman

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Aug 22, 2023, 2:25:07 AM8/22/23
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Yes, you need to update it.  You might want to wait a few days as there's an update coming out this week.

I forgot to update the gateways in my chase car before my last launch :/

John Laidler

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Aug 22, 2023, 2:26:54 AM8/22/23
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Ross G6GVI

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Aug 22, 2023, 3:47:42 AM8/22/23
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Well done Rich. A couple of us in Bolton built ours back in 2019, using a Pi2B and an Ra02 LoRa board, linked to the GPIO pins with DuPont jumper-wires.  They have worked well over the years - I have followed dozens of LoRa flights during that time (including Dave's "Apollo 50"). 
However I started having problems last week, which I hope I've sorted by simply removing and replacing the link-wires to wipe their contacts (Bill G4CFP had fixed a similar problem on the other unit by the same process last year).
I run my Pi via a VNC link and use Dave's excellent HAB Base Manager on my Windows desktop machine:

Many thanks to Dave for all the software and support - just remind me of the command to update the Gateway on the Pi: is it "git pull"?

Regards from Ross

P.S. there's another LoRa receiver in use locally, (operated by Jack G8HIK): that's a little TTGO-LoRa board (running Dave's software) plugged into his PC via USB and controlled by HAB Base. That works very well too.

David Akerman

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Aug 22, 2023, 3:54:24 AM8/22/23
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Yes git pull, but if you've not updated in a while there's an MQTT library to install too, because MQTT support was added a year or so ago.  RTFM applies here :D

I'm working on some minor changes to the error logging for Sondehub uploads, and there's a possible bug fix too (might be the user's setup, I'm not sure till I look into it later).

Dave

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Wellectric Mail

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Aug 22, 2023, 7:44:53 AM8/22/23
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Thanks to everyone for the kind support .

The module I used was the bare bones RFM98w unit , cost me less than
£5.00 and I placed it in a metal tin and used flying leads I soldered to
it with an SMC connector also soldered in for the ant connection . The
connections I just copied from the github instruction ,there are more
DuPont jumpers than needed as I took every connection out but found I
only needed the o/p pins 0 and 5 .

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Kind Regards
Richard G0RXH
pic1.jpg

David Akerman

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Aug 22, 2023, 7:51:06 AM8/22/23
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For anyone else doing this, some LoRa boards don't have DIO5 connected.  Not an issue; DIO5 is optional anyway for my LoRa HAB gateway program.  All you need to do is disable use of DIO5 but placing:

DIO5_0=-1

(for SPI channel 0, or)

DIO5_1=-1

for SPI channel 1.

Dave

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Ross G6GVI

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Aug 22, 2023, 8:43:56 AM8/22/23
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These low-cost LoRa boards often have poor frequency accuracy, which can make acquiring a weak signal difficult - although once acquired, the AFC will automatically track it.
However there is a facility within the Gateway.txt config file to compensate for an offset in the frequency reference:
PPM_<n>=<Parts per million offset of LoRa module.

To set mine, I set up a second LoRa module as a dummy HAB transmitter and measured its average frequency with a frequency-counter. Then I adjusted the PPM_0 parameter so that my receiver agreed with the counter (I think I ended up with PPM_0=-12 or something similar)

However, if you don't have a convenient local test-source, you could study the Receiver-reported frequencies on the Grafana chart for a flight you're following and see how your frequency compares. For example, looking at "ZURG" from last week:
ZURG_RRF.png
Here you can see that G8HIK-L (in dark red) is showing a few kilohertz lower than the others - that's because his TTGO receiver doesn't have a PPM adjustment facility (as far as I know). But knowing, this, he can manually set his frequency a few kHz higher than expected (although it's still reported to the Sondehub as his set frequency).

David Akerman

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Aug 22, 2023, 8:48:13 AM8/22/23
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That's how I calibrate my gateways too, with an accurate frequency counter.

I'll go through my other receiver programs to check which are missing the PPM facility, as that's important to make the uploaded frequency accurate.

Dave

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David Akerman

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Aug 22, 2023, 9:21:19 AM8/22/23
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Updated gateway now ready - see https://twitter.com/daveake/status/1693975593585394143

It now logs the response code and text from the Sondehub server should an upload fail.  This is in addition to the JSON that was already logged, in errors.txt

The user issue is unrelated (though would have been quicker to diagnose with the above changes) and appears to be because his Pi time is set to 2 hours ahead of reality.  The gateway uses the current UTC time from the O/S to timestamp uploads, so it's important for that to be (roughly) correct otherwise Sondehub can complain that the upload is too far in the future.

Dave

David Johnson

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Aug 22, 2023, 9:30:04 AM8/22/23
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For timekeeping on the pi, I use chrony and a Ublox GPS
Dave

Sent from my iPhone

On 22 Aug 2023, at 14:21, David Akerman <calt...@gmail.com> wrote:

Updated gateway now ready - see https://twitter.com/daveake/status/1693975593585394143

David Akerman

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Aug 22, 2023, 9:54:21 AM8/22/23
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Yes, on my primary gateway I do the same, but that's because (like yours) it needs accurate time for certain configurations of uplinking to the balloon.  For uploading to Sondehub it doesn't need to be at all precise.

Dave

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