APRS – Making it work

At the moment nothing at all apears to be coming down on Alphasat.

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yeah I just noticed :slight_smile:
This issue stared before 06:45 today though :slight_smile:

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Between 0100 and 1500 UTC I sent three APRS messages using my Baofeng HT, which were picked up by my iGate. None have downloaded from the Outernet on 4-F3 (98 W), but they showed up at aprs.fi

Richard
KE7KRF

Is APRS being sent thru Outernet now? I just got back from Hamvention 2017 and attended a forum by WB4APR where he talked about APRS and Outernet. I have had the Outernet receiver kit working for a few days now. I see some APRS packets but they are dated 2017-05-14(today is 2017-05-24) and looks like they are all APRSAT packets through the ISS.

I am using an RPI3 with rxos image.

Thanks,
Kevin

Yes, they should still be going out. Are you not seeing more recent messages?

Yes. I am seeing more recent messages since I posted. Thanks for follow-up.

Just saw your message arrive on “message” list as I was about to say only rs0iss messages were there LOL
73’s M0KNC

Dreamcatcher can run APRS iGate in RX mode (using the embedded rtlsdr chipset), check out the thread:
http://forums.outernet.is/t/armbian-for-dreamcatcher/3581/18

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It’s the future, July 11th, talking to you… but, yeah, all mine get thru quickly no problemo.

Hello future!!!
I see see big gaps when I have sent stuff that is on aprs.fi but NOT on outernet :slight_smile:

What server are you using? What medium are you sending APRS packets? VHF? HF? Android? Robust Packet?

I use a few differing methods but normally it is HF

a) i can use YAAC (Yet Another APRS Client) on my normal PC with “DireWolf” PC TNC, and a cheap VHF radio as described in the original post here to get onto VHF (YAAC can also connect directly to the APRS.IS backbone by internet, but where is the challenge in that LOL!)

b) my most common method is to run PSKmail ( http://pskmail.org/) and FLDigi in my “radio” computer connected to my FT450D on 10.147Mhz and beacon from there . PSKMail also can be used as an HF to internet mail system, but there are not enough servers, so can be a challenge!

c) I have experimented with “old fashioned” AX-25 unproto packets on HF ( normally 10.14760 USB DIAL freq) at 300 baud using CCW Messenger (Cross Country Wireless APRS Messenger program) and the UZ7HO Soundmodem (details of how to set this up to work are here Dual Mode Operation With APRS Messenger ) that works OK but the problem with AX-25 300 baud is that there is NO forward error correction ( FEC) so the entire packet must be perfectly received or nothing :slight_smile: The difference here is that on AX-25 there are LOTS of stations listening too, so it is more likely to be picked up and sent to the APRS.IS internet backbone, that is because the robust packet network is there are well, and the legacy AX-25 is often configured in the servers too! - Swings & round-abouts!

d) Recently I tried YACC on HF with the UZ7HO Soundmodem , to see if I could map the packets I received ( it worked!) and then I have also replaced the UZ7HO Soundmodem with DireWolf (with a 300baud configuration). It beacons well and seems to decode the RX packets well too.

You may note that I completely avoid “proprietary” systems like “robust packet”… That is a deliberate decision. :slight_smile:

Have a play, I have enjoyed making things work, even if only one out of a whole day’s beaconing on HF get there, I feel I have “made” it. Remember we are waaaaay down in the Solar Cycle, so unless the receiving server is pretty close it will be a challenge to get complex digital data through on HF (without resorting to commercial software and Kilowatt transmitters :slight_smile:
here is a screenshot of PSKMail receiving the response to a ping on 10.147Mkhz just so this post is not ALL writing :wink:

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Neil I appreciate this detailed explanation. Really interesting. I think PSKMail has so much potential but right now I am starting to get into WSPR and associated modes.

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@Seasalt
PSKmail is actually amazing when you can get a reliable connection to a server - we need more servers ( it is not so easy for a UK amateur to run a server on these networks for various reasons - so i have to rely upon European servers - I would love to run one myself, but…)
you may see me on jt-65 & /or JT-9 floating around :slight_smile:

Grab the beta version of WSJT-X and there is a new mode (FT-8) that is taking off big time on 40 & 20 mtrs

There is a an image of Lubuntu with the PSKMail server & client on it that can be burnt onto a 16Gb usb stick and then you just boot any old crappy computer from it and toy can be on the air it is here http://pskmail.org/downloads/lubuntuimage16-v1.1.img.gz the description of the older version of it is here Traveling a lot? Prepare for the next communication breakdown. | pa0r

Ok have grabbed the WSJTx beta 1.8 and have it receiving on Raspberry Pi 3 and a old IC -728 with a CIV Cable. It receives great. I do not have a transmit PTT to talk yet but am happy just receiving for now. Am picking Up mainly Japan and Taiwan to Philippines.

I also have it working in Ubuntu on my Icom 718 and Signalink sound modem but have not been able to get VOX transmit working.

It is truly amazing. Syed needs to get across this and possibly the 10 MHZ open to public band could be used by Outernet as a back channel.

Very cool. How about an upconverter to feed into the dreamcatcher, then have the “hf back channel” decoding added to the skylark software. I wouldn’t want to lug around one of my old hf rigs with all the associated extra power supplies and attachments. Don’t know who/what could be the transmitting station — one way xmit broadcasting is not allowed by US amateur license.

Great idea then every Dreamcatcher plugged into the internet could feed back channel commands from remote Outernet users by HF through to Outernet Head Quarters.

The 13.553 MHz to 13.567 MHz ISM Band might be perfect.

The new WSJTx JT 9, I believe use 16hz bandwidth so how many links could we have in 14khz of bandwidth?

“The industrial, scientific and medical (ISM) radio bands are radio bands (portions of the radio spectrum) reserved internationally for the use of radio frequency (RF) energy for industrial, scientific and medical purposes other than telecommunications”

I have been able to just use a RTL dongle with direct sampling turned on to receive WSPR Signals. It was one of the Armbian Dreamcatcher guides.

The ISM band is legal I believe for anybody to use. WiFi 2.4 g and 5 G uses the ISM band.

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Checking aprs with the ku version 3.02Q system. I notice that messages have major time gaps.
for example to: tests were received at
2018-3-19_14:02.txt but the next one is
2018-3-19_16:52.txt

I happened to be trying it out around 1400 and 1430 gmt however they were never received.

Does this mean messages received in aprs.fi or the “aprs IS” are not captured if they are outside of some timeframe ?

No - just seems like your receiver didn’t successfully receive the files. The APRS messages files go out of rotation within hours, so if you don’t have a good lock rate, theres a good chance some message files will not finish downloading before going out of rotation.

thats from my receiver.

Thanks, @Abhishek , Looking at my tuner status I have only a 19% valid packet
and corresponding PER of 0.814. So the issue is at my receiver. I am obviously
dropping a lot of the transmitted packets. Since the messages are not recycled and
retransmitted… I have to solve this at my end. thanks agiain