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Jonny 290
May 5, 2005



[ASK] me about OS/2 Warp
I rambled about a couple of my late 80s / early 90s handheld radios itt

https://twitter.com/jonny290/status/1353793922322100224

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croup coughfield
Apr 8, 2020
Probation
Can't post for 130 days!
that handset looks fukken badass

net work error
Feb 26, 2011

The fact it's still usable today rocks.

Achmed Jones
Oct 16, 2004



finally got to play with my nanovna. i learned two things

1. this thing is pretty cool
2. my na-771 kinda sucks :(

also, im kind of confused - the ic-705 has a bnc connector, and it's almost certainly female. but when i look at pictures, it looks like there's a post sticking out there. is there a plug in there or something?

Eeyo
Aug 29, 2004

what do you mean post sticking out? like in the insulator/conductor part in the middle, or an extra knob on the ground?

that's definitely a bnc female, it has an insulator with a cylindrical hollow conductor in the middle. the conductor doesn't really go 'in' like in a lot of other female connectors, the insulator/conductor has some prominence from the base of the connector, but is shorter than the grounding around it.

Jonny 290
May 5, 2005



[ASK] me about OS/2 Warp
yeah its a regular BNC. the thing i think you're seeing is the pair of spring terminals that form the center pin socket.

Still want one but i have a 703 which is one of god's own finest creations, and I don't use it enough as is. maybe when, you know, traveling is a thing again.

Achmed Jones
Oct 16, 2004



ah cool, that solves it. thanks y'all!

minidracula
Dec 22, 2007

boo woo boo

Jonny 290 posted:

same idea, different values. you need much bigger capacitors and inductors down at HF for the same effect. ill post some pics of my little sdr setup this weekend
JPEGs plz. Curious to see your setup.

AveMachina
Aug 30, 2008

God knows what COVIDs you people have



Hello hamthread. I just got my Technician license two weeks ago, a Yaesu FT-4x, an NA-771 antenna. Local listenings around Christmastime was an audibly-ancient gentleman talking about cleaning candy machines for 60 years and how "you have to heat them up real good to get all the stuff out" and the sheer :wtc: factor has me absolutely in love with keying into the invisible world.

I don't know what broke in my brain, I think I just wanted to listen to P25 phase II in the area, saw how much digital transceivers cost and their limitations, couldn't decide if I wanted to use a mobile or handheld transciever, and here I am now, but let me introduce you to a project I'm calling Vine Room. Basically a low-cost portable SDR transceiver receiver.

I have okay knowledge of wiring electronics, soldering, etc. I bought a Raspberry pi, touchscreen, and RTL dongle and in the works are an RTC (CMOS battery), audio board, battery/charging board, speakers, and fans.

I know fuckall about Python but I'm learning, and it seems that things that already exist like RTL-SDR Scanner, OP25, and Gqrx are good things to piggyback off of and frankenstein together to get the functionality I want--portable, Rx-only scanner that goes from 26-470mHz (the frequencies my antennas catch) and plays whatever it stops on. Maybe add FM2TXT for fun?

The UI design is the easiest part since that's what I partially do for a living, but learning Python, debian-based linux, SDR, breaking apart code, wiring stuff up, is really invigorating. I really miss the non-SMD days of electronics where soldering didn't involve a jeweler's loupe.

I got RTL-SDR scanner working on the Pi already, which is super promising. I'm brand new at this so anything working at all is a huge win.

Thank you for coming to my TED talk.

Captain Foo
May 11, 2004

we vibin'
we slidin'
we breathin'
we dyin'

is ham software with a ui that involves actual thought processes even legal

Achmed Jones
Oct 16, 2004



Captain Foo posted:

is ham software with a ui that involves actual thought processes even legal

the fcc technically allows it but bandcops will ride your rear end about it

spankmeister
Jun 15, 2008






I'm sure those interfaces all make perfect sense if you were huffing lead fumes in the 70's

AveMachina
Aug 30, 2008

God knows what COVIDs you people have



spankmeister posted:

I'm sure those interfaces all make perfect sense if you were huffing lead fumes in the 70's

Or were frozen in amber in 2002

champagne posting
Apr 5, 2006

YOU ARE A BRAIN
IN A BUNKER

Captain Foo posted:

is ham software with a ui that involves actual thought processes even legal

Which of the 800 variants of sdr software are you thinking of?

Captain Foo
May 11, 2004

we vibin'
we slidin'
we breathin'
we dyin'

Boiled Water posted:

Which of the 800 variants of sdr software are you thinking of?

yes,

Achmed Jones
Oct 16, 2004



i was trying to check out the ISS flyover and the lovely app i was using completely poo poo the bed. i'm really salty about it, cause it maxed out at 54 degrees. there'll be another one on monday but it'll only be 19 degrees so might not be visible behind buildings

i mean, we didn't see it anyway, but it would've been nice to have had a better chance

drunk mutt
Jul 5, 2011

I just think they're neat

Achmed Jones posted:

i was trying to check out the ISS flyover and the lovely app i was using completely poo poo the bed. i'm really salty about it, cause it maxed out at 54 degrees. there'll be another one on monday but it'll only be 19 degrees so might not be visible behind buildings

i mean, we didn't see it anyway, but it would've been nice to have had a better chance

The rig is still down unless it's a scheduled thing and they use the Russian radio. At least, I haven't seen any repairs on the cable in the last few EVAs.

horse_ebookmarklet
Oct 6, 2003

can I play too?
When I use a VNA, am I essentially radiating a CW signal at my sample points and measuring various parameters of the reflection, right?
And I am probably sweeping outside of my specific band(/license) I want, because I want to see where it is tuned.

So essentially the VNA is unintentionally radiating and this is bad. ?

My nanoVNA2 is prolly pretty low power (how much??), but sometimes I use the work $$$$$ VNA at like -10dB....

horse_ebookmarklet fucked around with this message at 06:17 on Feb 7, 2021

drunk mutt
Jul 5, 2011

I just think they're neat

horse_ebookmarklet posted:

When I use a VNA, am I essentially radiating a CW signal at my sample points and measuring various parameters of the reflection, right?
And I am probably sweeping outside of my specific band(/license) I want, because I want to see where it is tuned.

So essentially the VNA is unintentionally radiating and this is bad. ?

My nanoVNA2 is prolly pretty low power, but sometimes I use the work $$$$$ VNA at like -10dB....

I'm guessing you'd be using a dummy load, so not really sure if there is concern there.

horse_ebookmarklet
Oct 6, 2003

can I play too?

drunk mutt posted:

I'm guessing you'd be using a dummy load, so not really sure if there is concern there.

no like doing an s11 of an antenna

Achmed Jones
Oct 16, 2004



drunk mutt posted:

The rig is still down unless it's a scheduled thing and they use the Russian radio. At least, I haven't seen any repairs on the cable in the last few EVAs.

we weren't trying to talk to it, just see it

Stack Machine
Mar 6, 2016

I can see through time!
Fun Shoe

horse_ebookmarklet posted:

When I use a VNA, am I essentially radiating a CW signal at my sample points and measuring various parameters of the reflection, right?
And I am probably sweeping outside of my specific band(/license) I want, because I want to see where it is tuned.

Yep. The nanovna just generates a stepped sweep, with one step for each frequency point you're measuring. It's not a nice sine wave either, so if you're trying to use it to check the SWR of a run of coax looking into a power amp driving an antenna or something, it could be radiating at multiples or fractions of the sweep frequencies too.

horse_ebookmarklet posted:

So essentially the VNA is unintentionally radiating and this is bad. ?

My nanoVNA2 is prolly pretty low power (how much??), but sometimes I use the work $$$$$ VNA at like -10dB....

Well the nanovna drives its load with a 3.3V logic-level clock generator IC with a 50Ω output impedance through a bunch of resistors that work out to dividing that supply by around 6 so the most power it could get out (peak-to-peak voltage of 0.55V on a 50Ω load) is going to be like, maybe -1dBm max? Above 200MHz it's going to be less because it relies on the harmonics and those are going to be lower-power than the fundamental. That doesn't seem all that bad, but I don't really have an intuition for how much power that is for a transmitter. Significantly less than a milliwatt seems like "who cares" territory though, but I'm not certain the answer isn't "the FCC".

Eeyo
Aug 29, 2004

just compiled the rtl_433 thing. i can see a bunch of random temp sensors, presumably just houses in the neighborhood or something?

i was loving around with the frequency and now im seeing a few tire pressure monitors. i uhh never thought about it but i guess you’d have to send out the data somehow if you’ve got an actual pressure sensor inside a wheel. wonder what kind of range those things have. i can see 2 unique ids, but i guess each tire could have a unique id so maybe im just picking up the closest front tires in my parking lot or something.

spankmeister
Jun 15, 2008






Been playing around with my LimeSDR mini and OsmoBTS, after many failed tries of getting any kind of BTS to run on a raspberry Pi 4.

Behold!


(I'm 001 01)


Protip: getting YateBTS to compile on a raspberry Pi isn't exactly trivial but when you finally do get it to work, it still doesn't work because even though they say they support UHD it only works with a BladeRF as far as I can tell.

The OsmoCom GSM stack has packages available for ubuntu and debian. I ended up installing the debian 10 packages on ubuntu 20.04 because the ubuntu repo doesn't have ARM packages.

(Went with ubuntu in the first place because of availability of LimeSDR packages, wasn't so successful before on Raspbian)

OsmoBTS is great but you need to configure and run all the parts of the GSM stack as a separate daemon, which ends up being like 12 different things. Still working on that.

I've also gotten srsLTE to work for 4G but haven't been able to get my phone to see the network yet. Possibly due to frequency stability of the LimeSDR, perhaps due to my writable SIMs not being good.

We'll see.

Jonny 290
May 5, 2005



[ASK] me about OS/2 Warp
don't worry about the nanovna emitting RF. it's a tiny whisper compared to the old men that spend four minutes key-down on 14.200 at 1350 watts while they 'tune up the amp' and fail to ID at the end, every time

spankmeister
Jun 15, 2008






I mean I'm over here setting up GSM towers illegally and I'm not too concerned about it tbh. I would be surprised if the signal even makes it out of my living room.

Jonny once I figure all this poo poo out I got you covered for cell service on rancho 290

Jimmy Carter
Nov 3, 2005

THIS MOTHERDUCKER
FLIES IN STYLE
yo does that setup work with CBRS? I've got a hankering to set up my own cellphone network and dual-sim my way to glory

spankmeister
Jun 15, 2008






Jimmy Carter posted:

yo does that setup work with CBRS? I've got a hankering to set up my own cellphone network and dual-sim my way to glory

I suppose the base station could work on any frequency but I don't think there are any handsets that can do that?

Project update: managed to get the phone registered to the base station and sent an SMS!

Jonny 290
May 5, 2005



[ASK] me about OS/2 Warp

spankmeister posted:

I mean I'm over here setting up GSM towers illegally and I'm not too concerned about it tbh. I would be surprised if the signal even makes it out of my living room.

Jonny once I figure all this poo poo out I got you covered for cell service on rancho 290

ho lee poo poo lmao YES

Jimmy Carter
Nov 3, 2005

THIS MOTHERDUCKER
FLIES IN STYLE
tonight's CBRS dive:

All the hotness is 3.5 ghz aka LTE Band 48, which is supported by pretty much every phone from the last 2 years. FB has dumped a bunch of money into a project called Magma to act as the backend to a network, which theoretically lets you plug an LTE base station into any internet connection and tunnel out to your own cloud, amongst many other things

If you want to do CBRS legit, you have to pay Google $2/phone/month to tell you what frequencies you can use at any given moment since it's shared with military radar and telcos who bought licenses (along with real-estate companies and John Deere).

You absolutely can run your own base station to cover your neighborhood, but that'll set you back at least $10k. Maybe $2-3k if you wanna do like, your house and your neighbors. Those power amps are spendy.

echinopsis
Apr 13, 2004

by Fluffdaddy
https://www.reddit.com/r/askscience...utm_name=iossmf


thought someone here might find this interesting 🤔

Jonny 290
May 5, 2005



[ASK] me about OS/2 Warp
thats a really good post and in particular the "how we can hear signals below the noise floor" part is a good primer on how we do that poo poo.

echinopsis
Apr 13, 2004

by Fluffdaddy
tbh all of this is super interesting to me.. right up until the talking to people part.

my exs dad has been doing it for years. was with tait radios from very early days, and never once took a payrise lol. he was too expensive to make redundant too becasue of his length of service so he just stuck around until he was mega old

electronics poo poo with him was the best part of being married to my ex lol. my kids dont seem interested when I rock up to pick them up and im asking about what he's doing this time but they dont care.

anyway. i just rememebr whenever id pick up my now ex when she was 17 i could hear noises from his garage, and it was because he never shut the radio off.

im sure if i made word of it to him all sorts of poo poo would come out of the woodwork and into my house for me and his grandkids to use..

AveMachina
Aug 30, 2008

God knows what COVIDs you people have



echinopsis posted:

tbh all of this is super interesting to me.. right up until the talking to people part.

I have basically no intention to talk to anyone, I just like listening in on whatever random poo poo people are broadcasting. I'm the audio equivalent of a lookie-loo. A listen-loo.

During the power outages/snow in Texas where I'm at, I had finally gotten OP25 set up and running on my little project (yay!) and got a live stream of cops trying to move stuck vehicles, and linemen having frighteningly low awareness of where things were located at substations ("uh I'm on the uh east side and there's no transformers as drawn, uh, verify")

I had power the whole time so it was cool passing along intel on progress of power restoration to my coworkers during WFH time

hot dog event
Apr 17, 2002

i bought one of these HackRF units about two years ago after reading a bunch about the guy who made it and some of the videos he made. the maths go whoosh over my head though
https://cdn.sparkfun.com//assets/parts/9/9/5/3/13001-01.jpg

i toyed around picking up the FM band and was trying to find the ems channels to listen into but i just don't know enough about it. the waterfall graph is super pretty to watch though

are there other resources that any of you know to start messing around with it more
and i guess my other question is could i use something like this for like a home automation thing? maybe send signals to devices that use RF?

hot dog event
Apr 17, 2002

and question two is like more EE based but where is a good place to start learning more about radio from like a classroom setting? my library has access to Lynda and there's tons of stuff on there but i'd be willing to pay for udemy or even my local comm college to have something more test-oriented

champagne posting
Apr 5, 2006

YOU ARE A BRAIN
IN A BUNKER

aeflux posted:

i bought one of these HackRF units about two years ago after reading a bunch about the guy who made it and some of the videos he made. the maths go whoosh over my head though
https://cdn.sparkfun.com//assets/parts/9/9/5/3/13001-01.jpg

i toyed around picking up the FM band and was trying to find the ems channels to listen into but i just don't know enough about it. the waterfall graph is super pretty to watch though

are there other resources that any of you know to start messing around with it more
and i guess my other question is could i use something like this for like a home automation thing? maybe send signals to devices that use RF?

Jr pushed me over the edge and today I spent an hour fiddling with my shortwave radio with an extended antenna. The extended bit is a drain pipe on my apartment building.

edit: Drainpipe radio is currently bringing me some weird russian radio, and a ton of north african stations

champagne posting fucked around with this message at 19:39 on Mar 5, 2021

spankmeister
Jun 15, 2008






aeflux posted:

i bought one of these HackRF units about two years ago after reading a bunch about the guy who made it and some of the videos he made. the maths go whoosh over my head though
https://cdn.sparkfun.com//assets/parts/9/9/5/3/13001-01.jpg

i toyed around picking up the FM band and was trying to find the ems channels to listen into but i just don't know enough about it. the waterfall graph is super pretty to watch though

are there other resources that any of you know to start messing around with it more
and i guess my other question is could i use something like this for like a home automation thing? maybe send signals to devices that use RF?

There's many, many resources but these is a good place to start:

https://www.rtl-sdr.com/
https://www.sigidwiki.com/

echinopsis
Apr 13, 2004

by Fluffdaddy
idk how you mega nerds have done it but im finally
concede that the EM spectrum beyond visible light probably exists and make the first moves toward reviving radio signals with my metal teeth.

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champagne posting
Apr 5, 2006

YOU ARE A BRAIN
IN A BUNKER

echinopsis posted:

idk how you mega nerds have done it but im finally
concede that the EM spectrum beyond visible light probably exists and make the first moves toward reviving radio signals with my metal teeth.

careful not to listen too much to chinese radio , you might get activated

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