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AMPKT – Amateur radio packet explorer

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Re: AMPKT – Amateur radio packet explorer

#21

Post by kunwon1 »

kunwon1 wrote: post #18
JKCalhoun wrote: post #15

Earlier quoted context omitted.

Interesting. Also interested in getting into this. I have played with SDR, not FT8 though. Maybe you can point to a site that helped get you started with FT8.

I don't recall any specific how-to sites, I was all over a lot of them. There are three applications in my 'pipeline': SDR++ (a standard SDR client, any should work as long as you can choose your audio output device), WSJT-X [1], and GridTracker [2] I'm on Linux, and I'm using PulseAudio. I need to route audio output from SDR++ to WSJT-X. I do this using these commands, which I found somewhere online that I can't rec…

Also, a few more items that I recall being difficult to figure out-

1. FT8 uses a standard frequency setting on each band. The presets are built-in to WSJT-X, or you can find them online. WSJT-X and your SDR client should be set to the same frequency.

2. To decode FT8, your radio should be in USB mode, and your system clock needs to be very accurate (By which I mean, you need NTP)

3. FT8 signals are practically invisible on a normal waterfall display

I had everything hooked up for a few days of head scratching before I realized that I hadn't setup NTP on my PC for reasons that escape me. As soon as my clock was synchronized, messages started pouring in. I have the most luck on the 20 and 40 meter bands.

Re: AMPKT – Amateur radio packet explorer

#22

Post by kunwon1 »

wkat4242 wrote: post #19
kunwon1 wrote: post #17

Earlier quoted context omitted.

This is the antenna: https://www.amazon.com/dp/B08LVYTL5V I doubt that I could transmit with this, but I could be wrong. It's not something I've investigated.

It says maximum power 250mW so it looks like you could do really low QRP with it. I do wonder if you'd get a signal out from your apartment though.

Wow! That surprises me, and I probably never would have checked, so thanks. I think of FT8 as deep magic at this point, so it wouldn't surprise me if that's enough to reach pretty far

Re: AMPKT – Amateur radio packet explorer

#23

Post by bmitch2112 »

lhamil64 wrote: post #12
bmitch2112 wrote: post #11

Earlier quoted context omitted.

FT8 is lots of fun. Even more fun when you go to a park or up a summit and see how far you can get out and how far you can hear. You don't need very expensive radio equipment to transmit FT8 so if you do get your licence back it is worth looking into. http://qrp-labs.com/qdx.html

I got my license about a month ago and ordered a QDX to try FT8, but they're super back-ordered. The orders page shows that they're just now fulfilling orders from May.

Do you have another radio to try it with?

Another cheap option is the truSDX https://dl2man.de/

I have it working with my Android Phone using https://github.com/N0BOY/FT8CN

It makes for a super lightweight pack. I usually bring a 17foot whip antenna to a park or summit and get contacts all over the world.

Re: AMPKT – Amateur radio packet explorer

#24

Post by bmitch2112 »

nvy wrote: post #13
kunwon1 wrote: post #10

I recently got back into amateur radio with an SDR (listening only, my license has lapsed and I need to renew it) I found that using the FT8 protocol, I can pick up transmissions from up to ~6000 miles away, using a very cheap magnetic loop antenna mounted indoors in my apartment. My building is made of concrete slabs and I was pretty shocked that I was able to receive such distant transmissions. I think I've investe…

Wow. Can you link to the antenna you use? Could you achieve those distances transmitting with the same antenna, assuming you renewed your license?

You basically just need any sort of wire to receive. FT8 is a very weak signal mode so I wouldn't be surprised if you string up some speaker wire inside and still hear signals.

Re: AMPKT – Amateur radio packet explorer

#25

Post by lhamil64 »

bmitch2112 wrote: post #23
lhamil64 wrote: post #12

Earlier quoted context omitted.

I got my license about a month ago and ordered a QDX to try FT8, but they're super back-ordered. The orders page shows that they're just now fulfilling orders from May.

Do you have another radio to try it with? Another cheap option is the truSDX https://dl2man.de/ I have it working with my Android Phone using https://github.com/N0BOY/FT8CN It makes for a super lightweight pack. I usually bring a 17foot whip antenna to a park or summit and get contacts all over the world.

No I don't, do you know if you can buy the truSDX pre-assembled, or does it just come in a kit? I'm visually impaired, so soldering is difficult for me. But I'd like to try getting on HF.

Re: AMPKT – Amateur radio packet explorer

#26

Post by sidewndr46 »

mzerod wrote: post #14

I have a QPSK & BPSK packet radio link to several other stations via the QO-100 satellite narrowband transponder, using a couple of Pluto SDRs and in some cases a mix/match of RTL SDR dongles and 70cm radios with transverters. Only a small group (4 so far) doing it, but we can be heard on the WEBSDR hosted at Goonhilly Earth station[1] Due to small dish sizes on RX (10GHz) we are keeping it simple and open at 1200 BP…

This is very cool. I wish those of us in North America had access to a satellite like this

Re: AMPKT – Amateur radio packet explorer

#27

Post by bmitch2112 »

lhamil64 wrote: post #25
bmitch2112 wrote: post #23

Earlier quoted context omitted.

Do you have another radio to try it with? Another cheap option is the truSDX https://dl2man.de/ I have it working with my Android Phone using https://github.com/N0BOY/FT8CN It makes for a super lightweight pack. I usually bring a 17foot whip antenna to a park or summit and get contacts all over the world.

No I don't, do you know if you can buy the truSDX pre-assembled, or does it just come in a kit? I'm visually impaired, so soldering is difficult for me. But I'd like to try getting on HF.

You can get it pre assembled. Here's a link to it on AliExpress: https://www.aliexpress.com/item/1005003908457475.html

The AliExpress link is one of the official suppliers listed on the site: https://dl2man.de/where-to-buy-trusdx/

Re: AMPKT – Amateur radio packet explorer

#28

Post by kwk1 »

jonah wrote: post #16

Note that you're not allowed to use encryption or engage in commercial activities on the amateur bands. (In the USA but probably in other countries as well.)

An important distinction is that what's not allowed is "messages encoded for the purpose of obscuring their meaning", not encryption altogether, which means things like digital signatures can be permissible, if the public key is available through well-known means or included as a separate part of the transmission.

https://www.ecfr.gov/current/title-47/part-97#p-97.113(a)(4)

Re: AMPKT – Amateur radio packet explorer

#29

Post by jonah »

kwk1 wrote: post #28
jonah wrote: post #16

Note that you're not allowed to use encryption or engage in commercial activities on the amateur bands. (In the USA but probably in other countries as well.)

An important distinction is that what's not allowed is "messages encoded for the purpose of obscuring their meaning", not encryption altogether, which means things like digital signatures can be permissible, if the public key is available through well-known means or included as a separate part of the transmission. https://www.ecfr.gov/current/title-47/part-97#p-97.113(a)(4)

I almost added that footnote. Thanks for the specific reference though!

Re: AMPKT – Amateur radio packet explorer

#30

Post by amatecha »

nvy wrote: post #13
kunwon1 wrote: post #10

I recently got back into amateur radio with an SDR (listening only, my license has lapsed and I need to renew it) I found that using the FT8 protocol, I can pick up transmissions from up to ~6000 miles away, using a very cheap magnetic loop antenna mounted indoors in my apartment. My building is made of concrete slabs and I was pretty shocked that I was able to receive such distant transmissions. I think I've investe…

Wow. Can you link to the antenna you use? Could you achieve those distances transmitting with the same antenna, assuming you renewed your license?

For listening, you can pretty much just throw some wire up and you'll hear stuff. When I first started, I got an RTL-SDR, and with alligator clips, added some random wire I had to the dipole antenna that came with the RTL-SDR. I was able to hear some FT8 signals from overseas. Helped that I lived in a top-floor apartment, but still :)
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