Jim Silly-Balls posted:

This isn’t specifically radio related but radio adjacent. I picked up this oscilloscope. It’s a 2 channel 100mhz Instek from the early 00’s

It’s in sort of a weird position where it’s straddling the older school design and the modern design for oscilloscopes. It has a CRT, but a really nice crisp late-era CRT, but it also has onboard compute capabilities, onboard storage, serial communications, video-out over VGA and stuff like that.



On the subject of serial communications it apparently speaks SCPI, which is a standard protocol for lab equipment like this. Is there any sort of software that will talk with this over SCPI, or am I stuck rolling my own?

I received the manual with it and it lays out all of the SCPI commands that will work with it and I can slowly peck them into putty, but if there was some sort of graphical front end to make it easier that would be nice

thehustler posted:

More firsts: borrowed some gear and made my first HF contacts today. That is really addictive Vs tuning around on VHF and getting nothing at all. God, this is a whole new world! I worked North Carolina, Italy, and Russia on 50W with an 857 and a Buddipole knock-off.

I need my own gear, pronto.

Also worked another satellite today, managed to get into AO-91 really well and SO-50 again so this crappy antenna definitely isn’t a fluke. Surprised how simple it was to get into. Hand-aiming definitely not easy though.

What’s the best iOS app for live tracking with azimuth/elev etc? Maybe tape my phone to the boom or make a little cradle for it.

thehustler posted:

857

Motronic posted:

Switching power supply, USB3 device, etc. come to mind first as "things around my radio that I'd be looking at". Have you put ferrite cores on all the cables in/out around whatever that is that's producing the waterfall to see if you can lower your noise floor?

Helianthus Annuus posted:

i haven't tried the ferrite cable chokes yet... the RFI situation in my shack is hardly ideal! It's on the 2nd floor, and I'm not permitted to punch holes in the walls or run cables out the window. So, the radio and antenna are completely ungrounded.

The antenna is a telescopic whip, extended to its full length of about 116 cm. It's indoors, and very close to all kinds of noisy stuff: computers, speakers, computer monitors, laptops, cell phones, etc.

I know there are many things I need to do before I can eliminate the noise. The ferrite chokes are a good suggestion, because I don't have to put holes in the walls or relocate my shack. But for the moment, I'm more interested in studying the noise than eliminating it!

I know that there are different kinds of noise, and I'm hoping someone can identify this stuff based on the screenshot. Switching power supplies around the house would be my guess too. But, if that's right, what could cause them to change the frequencies of their emissions like that? Something happening with the electrical utility's equipment -- maybe a transformer?

thehustler posted:

Do they go if you disconnect the whip?

Helianthus Annuus posted:

I know that there are different kinds of noise, and I'm hoping someone can identify this stuff based on the screenshot. Switching power supplies around the house would be my guess too. But, if that's right, what could cause them to change the frequencies of their emissions like that? Something happening with the electrical utility's equipment -- maybe a transformer?

Jonny 290 posted:

switching power supplies have notoriously unstable oscillators and you'll see shifts like that whenever something gets plugged into or disconnected from them, they heat up, they cool down, a stray neutron hits them, butterfly flaps its wings in Tibet...the list goes on. They suck real bad.

Tommah posted:

Those vertical lines could theoretically be generated by something plugged in your house, even if it's far from the radio itself. My uneducated understanding is that sometimes the rfi can travel across building wiring. Possibly it could be generated by something in your neighbor's (if you have one) apartment or even from a neighboring building through the outside power lines since the wiring is close/actually connected somewhere.

The best thing would be to turn off all power to the building and then turn breakers on one-by-one and check the waterfall each time. But it sounds like you probably don't have good access to that, so you could unplug everything in your apartment and then plug them back in one-by-one to see what generates which lines and also which lines are gone when everything's unplugged. If you have lines but nothing plugged in, then you can rule out stuff in your apartment causing it and your options to fix them start narrowing.

One thing that's killing my noise floor right now are christmas lights -- ones on my house as well as neighbors'.

It helps to have an external battery when testing this stuff so you can completely eliminate interference to the transceiver coming through the power lines.

Buy yourself a big bag of ferrites/chokes because once you start hunting RFI and noticing improvements, you'll never stop seeking the interference.

Motronic posted:

Voltage changes from the utility, voltage sags in your house (i.e., fridge, oven, other high current devices turning on), the equipment on the load side of the switching supply changing loads, pretty much anything like that. I would expect it to be close to your receiver if it's coming through that way.

If you really want to narrow things down run everything radio-related on battery and start turning thing on and off in your house. Or just start will being on battery and killing the main breaker. Then see what you have. Then start putting on ferrite chokes/rearranging cables to get your rig as quiet as possible. Then start turning things back on and see what's spewing what.

Helianthus Annuus posted:

do you suppose all these noise bands are coming from the same switching power supply? am i just seeing harmonics from some lower fundamental frequency? or is there some other reason why i see noise at multiple, separate frequencies?

Helianthus Annuus posted:

yes, thanks for asking! heres a screenshot of that happening.

you can see the noise floor come up when i first lay hands on the antenna. then it goes mostly dark when i actually unscrew it out of the magnetic mount. you can see it come back when i screw it back in.

Crusader posted:

just got this on the last iss pass:

yoloer420 posted:

I managed to get this with my baofeng held up to my mobile phone doing the decoding. I'm absolutely shocked it worked so well.

Helianthus Annuus posted:

drat, you really just put a speaker up to a mic, and it worked? i'm also shocked!

Jim Silly-Balls posted:

Is there a website that shows when the iss will be over your location? I’m down to stand in my yard with my phone smashed to my baofeng

yoloer420 posted:

I use Look4Sat or ISS Detector on Android. They're probably on iOS too.

Hurry though, SSTV broadcasts stop soon!

Helianthus Annuus posted:

Helianthus Annuus posted:

UPDATE: i was reading about digital SSTV today, and i saw a picture of a waterfall that looked just like the one I recorded! https://www.sigidwiki.com/wiki/WinDRM

Apparently, if i want to decode this, I'm supposed to downloaded a sketchy unsigned .exe for EasyPal from this extremely 90s website http://www.g0hwc.com/easypal_setup_help.html

I attempted to replay, demodulatem and decode this in EasyPal. I didn't get an image, but it did tell me the filename is supposed to be "de_W5NOW-18-new-jersey-picture-id622781084.jpg." Cool! But it told me the file was unrecoverable. It saved a 0 byte file to my drive, uselessly.

I wanted to see exactly what data I got, but i found EasyPal to be not-so-easy in this instance. After doing a little more research, I found this thing https://github.com/DazDSP/EasyDRF which appears to be a more modern and less feature-rich implementation.

EasyDRF also thinks the filename was supposed to be "de_W5NOW-18-new-jersey-picture-id622781084.jpg," but this time, it wrote 154 bytes to my drive. Well, here they are:

code:

00000000  02 93 01 40 02 af 01 44  02 ad 01 51 02 2f 01 3f  |...@...D...Q./.?|
00000010  02 2c 01 43 02 6b 01 4c  02 41 01 46 02 2f 01 3f  |.,.C.k.L.A.F./.?|
00000020  02 4b 01 43 02 a1 01 42  02 ad 01 51 02 2f 01 3f  |.K.C...B...Q./.?|
00000030  02 2c 01 43 02 6b 01 4c  02 41 01 46 02 2f 01 3f  |.,.C.k.L.A.F./.?|
00000040  02 4b 01 43 02 26 01 2c  02 59 01 45 02 3a 01 45  |.K.C.&.,.Y.E.:.E|
00000050  02 c2 01 54 02 ab 01 3f  02 ad 01 51 02 2f 01 3f  |...T...?...Q./.?|
00000060  02 2c 01 43 02 6b 01 4c  02 41 01 46 02 2f 01 3f  |.,.C.k.L.A.F./.?|
00000070  02 4b 01 43 02 ab 01 3f  02 41 01 46 02 44 01 42  |.K.C...?.A.F.D.B|
00000080  02 2f 01 3f 02 c2 01 54  02 ad 01 51 02 2c 01 43  |./.?...T...Q.,.C|
00000090  02 4f 01 48 02 b6 01 45  0d 0a                    |.O.H...E..|
0000009a

Well, thanks for reading my digital SSTV story.

ickna posted:

kind of a weird long shot, but the waterfall image looks like it is mirrored, like they transmitted it on LSB.. and the decoder is expecting the upper side band? I'm not sure how you would go about inverting the recording though.

quote:

The 2nd type of file to be sent with EasyPal is called Hybrid. This way of sending a file is much quicker but you are not receiving the image via the radio, you are only receiving a short header that tells EasyPal where to go and download the file and display it on your screen, This all goes on within the program. The sending station uploads "FTP" a file to a server then transmits its location and your program grabs it via the internet and displays it. This is nice when the bands are real busy as you have more chance of getting the short header than getting a 3 minute transmission. When receiving a Hybrid image there is no progress bar.