Register a SA Forums Account here!
JOINING THE SA FORUMS WILL REMOVE THIS BIG AD, THE ANNOYING UNDERLINED ADS, AND STUPID INTERSTITIAL ADS!!!

You can: log in, read the tech support FAQ, or request your lost password. This dumb message (and those ads) will appear on every screen until you register! Get rid of this crap by registering your own SA Forums Account and joining roughly 150,000 Goons, for the one-time price of $9.95! We charge money because it costs us money per month for bills, and since we don't believe in showing ads to our users, we try to make the money back through forum registrations.
 
  • Post
  • Reply
CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer
Joining SDR chat, I took my Technician test earlier this week and am now to be globally known as KN1UIW (I'm just happy I got a whiskey in my assigned callsign). I've got multiple RTL-SDRs and I've camped out on 146.520MHz and never heard a thing. I've also tried to tune into some repeaters in my area and never picked anything up either. Is there a better frequency in the cheapie SDR's range I should sit on to hear people? My antenna is just a 510mm piece of solid core 20AWG jammed into a Type N connector with another 510mm piece of that same wire crushed under a nut on the barrel of that connector so I don't have a ton of range either.

Adbot
ADBOT LOVES YOU

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Partycat posted:

The thing with analog FM call is you need to be sitting on it to hear anything and people don’t chat there normally. More than once I’ve driven from NY through Chicago on the 90, or cutting through Canada, and I haven’t heard jack poo poo.
Huh I did not know that. I'm surprised because there's so many amateur radio clubs and resources out there that I expected I'd be able to wander around the dial and pick up conversations happening at any time.

This is the first time I've started in earnest to try to pick up VHF since I've usually only worked with decoding digital stuff in the 915MHz ISM band and building my own transmitters for talking on that. Thanks for the info, I'll keep poking around and set up a scanner myself to hop around the frequencies and hopefully catch someone making a call. It's more of just a personal goal to be able to pull a conversation from the air like magic more than a desire to chat with people.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer
Hey guys am I doing Amateur Radio right?


I was able to receive my first transmission on HF today! I have my technician's license but still haven't bought a transmitter since I am still exploring what's out there and I don't have much money so I can't afford to buy equipment I might not use. That's a USB battery pack -> Raspberry Pi 3A+ -> rtl-sdr.com v3 -> sma to type-F -> piece of old cable tv cable -> salvaged power supply choke with wire salvaged from something else (a terrible 9:1 unun) -> screwed to a wooden garden stake, clamped to a ladder -> hookup wire (29ft) -> broom attached to the fence with clamps. The Pi runs rtl_tcp doing direct sampling, to which I connect over wifi with SDR#. I had tried it with just the wire stuck into the SMA jack on the rtlsdr but got nothing so this was going to be my last effort before I gave up. I'm super pumped when I was able to pick up CW on 40m, and then people started talking on 40m. I heard it all. Almost could understand the majority of it too.


I'm super pumped I was able to hear something for a change. I pick up a lot of DMR on 70cm, some regular nets on 2m, but never really hear people chattin' it up so I've been kinda lukewarm on jumping in, especially considering that I live in a pretty restrictive HOA. "An antenna?! What are we, a bunch of poor people?!" It really gets exciting when there's stuff to hear and soon people will be hearing about how *my* weather is.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Progressive JPEG posted:

That rules and I'm kinda jealous because all my radio equipment is still in boxes from a move. You're effectively getting 100% more done with your ladder and RTL-SDR than I am with a couple grand of equipment and parts!
Thanks! But now I am kinda jealous of you having boxes of radio equipment. I have piles handmade antennas made from old RG6 or other bits of wire I had lying around. Today I'm spending the day trying to decide if I should get a cheap Baofeng or save up and get a more powerful mobile station instead of an HT. I already spent :10bux: on some SO-239 connectors and type 2 toroids to upgrade my random wire to something more effective and robust.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer
Ah see now this is good advice. When I google for people talking about those Baofengs, there are tons of people using them and seem to be really keen on owning multiple of them. I hear about the good bits and not as much about the bad. I was considering waiting a bit and getting a mobile station instead and it sounds like that's what I should be doing. I've got a couple scrounged 12V power supplies that should be able to run one and my 2m/70cm antenna-in-a-pvc-pipe would probably be a better match for that instead of a HT. There's also a hamfest in the next county over in a couple weeks so I'll probably go see if someone's unloading something.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Pimblor posted:

Who needs to read hamsexy, just go to your local small town hamfest, better than the county fair.
I am going to hamfest, my first, on Saturday. Oh boy oh boy I am going to get all the old crusty stuff.

I got my toroid and upgraded my garbage random wire antenna with a proper 9:1 unun with a counterpoise and everything. I'm really confused after hanging it up this morning. I'm on 20m and hearing a guy in Kansas talking to guys in Quebec and Alabama and Connecticut then someone in Florida. I can only hear him but I can hear him STRONG. I can also hear a guy in Georgia talking to someone in Florida. According to HAM Universe I should only be hearing people from 20-75 miles or "up to a few hundred miles". Are there HF repeaters or something that I am unaware of, or is it possible to hear people a thousand miles away on 20m?

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Pham Nuwen posted:

What it's saying is that 20m is good for long range contacts during the day, and that if you end up talking to someone who's only a few hundred miles away it's probably because your signal went around the other side of the world. The bit about ground wave signals means you may also pick up people who are within line-of-sight, but that's not the primary method by which contacts are made.
Ohhhhhhhhh you're right I did misread it. I think my eyes must have just skimmed it looking for numbers. Wow that is very exciting! We gotta work out some upgrades now so we can more reliably pick up both halves of conversations and also so I don't have to carry the ladder out every day to hold up the other side of the antenna. Man this is so boggling to me that it is possible. I have listened so intensely to so much static over the past few days I swear I can hear voices in any random noise now.

Thanks for setting me straight, I just thought there was no possible way a RTLSDR operating in a direct sample mode attached to a piece of drat wire could pick up anything from more than a few dozen miles away.

CapnBry fucked around with this message at 16:34 on Sep 26, 2019

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Jonny 290 posted:

20 meters is just kind of notorious for that. There's a big "no coverage" donut hole for a few hundred miles around you, after that the signals boom in.

You seek 40 meters. It's more of an evening/morning band but has a much smaller coverage hole around you and you have a higher chance of hearing both sides of a conversation.
Oh man that's cool to hear. My random wire is only 24ft until the spool of wire comes in tomorrow so my 40m reception currently is good enough to decode CW but pretty difficult to hear phone clear enough to understand most of what is going on. Tomorrow I'll have enough wire to do 41ft or maybe more which should improve my reception on the longer wavelengths. I need to measure across the yard to the tree to see how much space I have. (God I hate that so many resources online measure antenna lengths in feet)

I'm like the guy that d0s expects to find on amateur radio. Building stuff from the 3D printer and scrap bits and whatever wire I can scrape together and being just amazed at the possibilities and how ingenious people are to create antennas.

Note kickin' rad 3D printed wingnuts too, although I am a bit upset I didn't do them in different colors but not enough to actually change the spool just to print 0.1g of plastic.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer
Oh I am happy to have contributed something to this thread then: increased desire to buy more gear. Whenever I see 3D printers, I mostly see people posting photos of some random useless plastic knick-knack or lovely vase / pencil holder. My printer prints only functional equipment, with project enclosures being the top use. The only problem is that I spend way longer than I should iterating on the design after it is functional. Last Saturday I said "Let me just throw this together" and 3 hours later the best and most overdesigned 8mm mini T-handle socket rolled off the printer. That's right, three hours to make a cylinder with a toggle on top... but there's not another one on the planet that fits my hand exactly as well as this one.

Speaking of which I realized last night that there's a huge flaw in my unun enclosure design in that the wire wrapper bits block access to the little handle on top I use to hang it from a hook on my patio. If I rotate them 90 degrees they block the wingnuts rotation. If I turn them into an X then the wires will wrap over each other and I wanted to keep them separate so I can only deploy the counterpoise when I feel like it. I might have to reimagine the whole thing into more of a kite spool shape now but then I'd need two spools and now this is spinning out of control.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Jim Silly-Balls posted:

What’s your favorite way of scanning the whole (RTL-SDR usable) spectrum for signals? The SDR# frequency scanner never seems to work for me, but maybe I’m doing it wrong?
As far as I know the SDR# frequency scanner "SpectrumSpy" only works with Airspy devices and not generic RTLSDR. I use rtlpan.exe that just runs rtl_power in the background and displays the results. As eddiewalker said, it is sllllowwww. A scan of 100MHz to 1100MHz takes over a minute and because the RTLs reception rolls off toward the edge of the ~2.4MHz bandwidth, you'll want to discard like 30-50% of the data to get it closer to accurate so it is even slower. It isn't good for driving around scanning for whatever you can find, or even really seeing what's broadcasting in your house due to how short it is tuned to any frequency. What are the odds of catching that thing that transmits every minute if you only look at the window for less than a second and only rescan every couple of minutes. rtl_power can be told to sit on each window for a long time and get averages or peaks which is helpful in this regard to get a bigger picture.

Yesterday morning I set up my longer (41ft) wire and was able to get tons of 40m traffic, as far away as California and New York (from Florida) and even a guy in Dallas who said he was only 150W, clear as a bell. Today my reception is garbage and even the signals I can get fade out entirely. I also picked up some people on 80m. I didn't end up buying anything at the hamfest yesterday-- I just didn't know enough about what I was looking. Some people were nice though and willing to just chat about what they've got and why they're getting rid of whatever they had to sell, so it was an enjoyable morning.

My favorite thing I heard yesterday was some guy on the 15m band who was going on about how in the 50s the US and the communists had a plan for world peace and were working toward merging and they just needed a war to get everyone on the side of peace, so they planned to sink the Lusitania together and put ads in the newspaper to tell people to not go on it and oh man my head was just spinning.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Jim Silly-Balls posted:

Where do you guys find is the best frequency to hear actual voice? Or maybe I should be asking where is the best place to go to find out for your location? 99% of the spectrum is tones and digital data these days it seems
I think I asked the same thing a few pages back since I had a hard time finding people talking as well. I tried looking up repeater lists and scrolling endlessly around only to hear the (blaring low baudrate sound) of DMR everywhere I went. I even installed DSDPlus and Virtual Audio Cable to decode it only to find it was just the repeater letting me know it was out there.

Then I jumped on my club's weekly net and hooray people! That's when I also found that there's a buncha nets going on on Tuesday night, including one that takes them like 20 minutes just to check everyone in. Listening to the nets from the repeater and switching over to the repeater inbound frequency to hear the station's actual transmission gave me a lot of experience in messing with my setup and getting the antenna in the right place to get good reception.

So I guess my answer is to look for clubs in your area, see if they have a website, then check out their net. It is a good time to find other people too-- when a lot of people are idling around waiting for their nets. Other than that, I have a hard time finding people talking on 2m/70cm but other than net o'clock the highest traffic I see is during morning commutes and Saturday morning. 70cm being more active. I've never heard anyone on 146.520 and I sat on that frequency for days after my Technician's class told me that's where conversations start. The other option if you have transmit ability is to just call CQ and see if anyone answers.

HF is full of life if you can get down there. There's always a few people talking on 40m although my reception is still pretty hit or miss. I'm not sure how people find other people to talk to without an SDR or some sort of waterfall though.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer
Wardriving! I used to do that with my laptop and a bluetooth GPS that was wired into the 12V supply in the back of my old 4Runner that I think cost like $70 at the time. I haven't done that in a long long time and I kinda want to now that we have Raspberry Pis and 2.4GHz yagi that cost like $8. I already have a USB GPS and a wifi dongle with an RP-SMA jack... great now you've just put another shovelful of project in my project pile.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer
Actually the hardware designer is just being contracted to make a new version that is almost completely redesigned from scratch with the commonality being that it can run the same firmware and is about the same size. They're giving away the schematics and gerbers for free as soon as it is done. The original creator of the NanoVNA simply asked for a name change to differentiate it from his design, which seems fair enough, but they're not in charge of naming whatever product comes out because they're just designing the hardware. Seems fair enough. :shrug:

For those that don't know, the NanoVNA is a $40 VNA with a (lovely) touchscreen and lipo battery that does S11 and S21 measurements from 50KHz - 300MHz and can measure up to 900MHz with reduced accuracy. It is pretty OK tool, but pretty amazing for its price point. You can't even get a low end VNA for 10x that price. The "V2" is redesigned to go up to 3GHz with increased accuracy across the board, targeting the same price, so I'd say hardly lol-worthy. Sure going to beat my setup with an RTLSDR, broadband noise source, RF bridge, and rtl_power doing sweeps to just get reflected power for the same price.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

longview posted:

Below the antenna is a stack of circuit boards:

That's mother-flippin' awesome is what that is. Kudos to you for being so clever.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

rdb posted:

Thanks. I ordered one from nooelec directly. Amazon went from 1 week delivery to over a month overnight despite the item being in stock. No luck getting a raspberry pi anytime soon either. I am going to go ahead and just put linux on a spare external ssd for my mac. Lets just hope it gets here before whatever is about to happen does happen.
If it doesn't look like Amazon can get it out to you, I have an old NooElec SDR that was my main SDR for years I can send you along with a Raspberry Pi 2B and a wifi adapter to borrow until the supply chain gets back to normal. It can't do direct sampling for doing <28MHz but it does have a temperature-compensated oscillator and a pretty blue aluminum case. All you gotta do is pay to ship it back when we're all healthy again. My city goes on lockdown tomorrow at midnight so PM me your address if you need any of this. You'll need a power supply (5V/2A micro USB or any 7-24VDC power supply with a 5.5x2.1mm barrel jack) and a microSD card.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Terminal posted:

Also found out very quickly how insular and toxic the local GMRS & 2M repeaters are.
I get a real kick out of listening to some of the crazies out there on 40m. There's one guy I hear from Georgia who will just say the most batshit insane stuff about like how Mexico did Vietnam and that's how Obama (if that is even his name) turned the interstate system into a death trap. He goes on and on for 5-10 minutes at a time and almost interrupts himself mid-sentence to say "come back" and then pauses so his buddy can just get "mmhmm" in, and then goes on for another 5-10 minutes. I love sharing his accusations with my best friend. There's plenty of terrible people out there but it seems less awful and hateful than many gaming Discords!

I've got a dumb dumb question. I'm trying to throw together a quick 20m spiral loop antenna and I have never used a variable capacitor before. As you can see here I turned my L-C resonating bit into just a wire by soldering the loop to the solder lugs on both sides.


Soooo where does one solder the other wire? To the clippy wire bit in the center? To the case somewhere? Sorry about the lovely lighting it was impossible to get enough light on it.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer
If I have a Random Wire Antenna with a 9:1 unun feeding it, do I need to design an antenna tuner for matching the 50ohm to 450ohm impedance of the antenna or is it supposed to be virtually a 50ohm load already? I'm looking to pick up another variable capacitor to play with matching and I'm trying to determine how big it needs to be at max. Does the imaginary part of the impedance dominate the calculation when the unun is already trying to match the feed impedance? All of this is really low stakes just messing around experimenting and learning for fun on receive-only or lower power TX (10W max).

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Jonny 290 posted:

It's supposed to be 50 ohms on the coax side of the unun, yeah.

Build yourself a simple LC tuner and goof with it!


That's exactly what I was doing yeah! Building the coil is easy enough with just some winds of wire and a few taps, but I was going to order a capacitor and I didn't know how big it would need on the top end to tune 80, 40, and 20 meters. I guess it doesn't make all that much difference since even at 450 ohms it doesn't look like I'd ever need more than 500pF. I'm trying to find a nice two gang version with like 250pF each so I can mess with switching them in and out and hopefully doesn't look like it spent half a century at the bottom of a lake. Also for not a lot of money because I am cheap as hell and not from overseas because I am impatient. Oop found one on eBay finally, 30-300pF and 30-500pF sections with a 4:1 knob and hard stops on either end for just $14 shipped woohoo tuner baby.

CapnBry fucked around with this message at 20:08 on May 3, 2020

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Jonny 290 posted:

I'll mail you one for the cost of shipping if you like, I just gotta figure out how to do curbside UPS/USPS pickup.
Oh man that's awesome of you! I had browsed like 15 pages of them on eBay this morning and gave up but I was reinvigorated by your post and managed to pick one up already. I appreciate the offer, that was super nice of you. Size doesn't really matter to me at this point, I'l just loving around, but I'm definitely keeping my eyes peeled for a vacuum variable capacitor that someone is unloading because at some point I'm going to want to try to put 100W or more into these things for funsies.

I was wondering if the antenna you took a picture of with your (original) DJI Mini was your antenna or your neighbor's, but now I guess we've answered that question too.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Jonny 290 posted:

The big tall one with the cross pieces and all the wires is a full size 40 meter 'folded monopole'. It's by far the best antenna I've ever built, the thing is an absolute rock star on 40 meters. 2:1 SWR curve is between 6900 and 7350 kHz.
I love messing with antennas and building them just seems like magic. I'm very excited to get my NanoVNA V2 to put some numbers to the things that I can only see as "well this sucks" or "oh man really good" currently. I built a 40m spiral loop antenna that just doesn't work very well but the bright side was that it had a 8-25pF variable capacitor and after 3D printing a little knob for it, I could SEE the bandwidth and tune of the antenna in the waterfall. It made me giddy with delight to see physics working and I am excited to improve and build more.

So am I looking at this diagram correctly that in like the 5-wire, all 5 wires are active elements? How long (wavelength-wise) is each section? It is too big to fit in the area I have but I'd be interested to know more about it.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Pardot posted:

Not sure if this is the right thread but I just got my first rtl-sdr thing. It works, and I was able to tune into some radio stations which was kind of neat. I first wanted to read my power meter and https://github.com/bemasher/rtlamr all running, maybe, but it's not seeing any packets at all :/ Has anyone tried that before and know of any common problem spots?
Are you sure your power meters are sending those types of messages? I tried running rtlaml a couple of years ago and saw nothing, but my local utility just recently came by and upgraded my meter so I just tried it again and now I see a buncha meters. You could try adding -msgtype=all to the command line, but that actually reduced the sensitivity significantly for me. I'd see very few messages with that set compared to the default (which is just SCM). Also make sure you're using an appropriate antenna length for 915MHz, around 78mm long.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Nitrousoxide posted:

I see some online study aids and courses. Any recommended ones?
Not really online, but I read this book when I was worried about passing my Technician's exam. I read it over the course of two evenings in just a few hours and got 100% on the test. It's not very long and really tries to just give you the answers in long form instead of being real lessons about the subject. The Tech exam is really easy but there's a lot of things I would have had to guess at if I hadn't read it ahead of time.

I got one of them-there NanoVNA V2 deals (back in April but it just came Saturday) and was able to tune my random wire antenna like a "Pro" instead of just listening for louder static. And 1.18 SWR and 49.4ohms impedance? C'maaaahhhn!


Even more of a miracle because it is this pile of junk on a patio. Look, Ma, no inductance needed on 20m!

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer
I've been messing with my NanoVNA and I was really disappointed with some of the numbers I was seeing all of a sudden on 20m, then I moved another piece of coax out of the way and everything got much better. I've got two antennas on my roof, a 41-ft random wire with a 9:1 unun for HF, and a VHF/UHF antenna. The antennas are at least 10ft apart from each other. Each is connected with a separate length of RG-8X with PL-259 connectors on each end and I connect the one I want to use to the RTL-SDR. I notice (now that I can see it) that moving the unconnected VHF/UHF antenna's wire around greatly affects the SWR on the HF. The coax cables run somewhat close together for half their length. Am I supposed to ground out the unused antenna somehow to prevent it from being a passive element in the other? The SWR jumps from about 1.30 to over 2.5 just moving the disconnected antenna's coax end near the HF coax.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

manero posted:

Try adding a counterpoise wire to the ground on the 9:1 unun, they can be kind of touchy with respect to SWR and feedline length, and chances are the antenna is looking for something to couple to the other "half" of the antenna.
Oh I should have mentioned that. I have a 10m length of wire for a counterpoise on the unun, however in my testing I had it sort of laying mostly in a pile a foot away from all the coax. I have to keep it stored most of the time because I never know when the lawn guy is going to show up and chop up my wire laying across the lawn. I will test again with it extended and out of the way to see if the VHF/UHF antenna is somehow becoming a better ground due to the proximity, and also go up on the roof to check the connections because it is just wrapped around a screw sticking out of the unun case, forming a real quality connection no doubt.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer
Can someone tell me if what I've got here is actually present or is some sort of harmonic artifact that comes from using a cheap SDR radio?


It is some Spanish-language shortwave radio stations that come in incredibly well here in Tampa, but scrolling around I hear the same broadcast at a lot of places across many bands, and sometimes coming in right in the middle of my 20m (which is the same broadcast as what is just above 40m). I'm contemplating buying a more expensive SDR like an RSP1A or maybe cheap out and get an MSI.SDR, but don't know if it will eliminate receiving this in a place where I don't think it actually is. Right now I am getting it on 7.33500MHz, 7.365000MHz, 14.069800MHz, 14.100000MHz, 14.13000MHz, all the exact same stream.

CapnBry fucked around with this message at 14:12 on Aug 10, 2020

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

poeticoddity posted:

https://m.short-wave.info/index.php

If you're looking for strong shortwave signals in English or Spanish (that aren't just just the craziest of preachers) near you, Radio Havana has a few stations I used to be able to pick up at night in Georgia on a handheld receiver. I don't speak Spanish so I have no idea what content they played in Spanish (other than music) but their English station did news and even had a weekly segment about amateur radio which was neat.
Oh that site is great. I had googled looking for such a list but had a hard time finding a good site with that information.

I'm trying to go the other way though, NOT receive these signals. I don't think there should be a shortwave broadcast on 14.100MHz but I am getting one there. I'm trying to determine if that's a function of SDR in general, or my antenna, or if it is just specific to the model of SDR I am using. I don't want to spend $100 or more on a new SDR if it turns out I'll get the same signal all up in my FT8 or blasting over regular phone.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

poeticoddity posted:

Have you pulled up a receiver on websdr.org and compared the output there to yours?
Oh snap why didn't I think of that? Nope, a local websdr does not have the copies up in 20m but does show the multiple 40m signals so it is likely those are really there, but the 20m is something weird on my end.

ickna posted:

I would try reducing the sampling rate first to see if that gets rid of some of the images, and then try reducing the gain to see if any of the other ones go away.
Hey, dropping to 250kHz of bandwidth, the stuff in the middle of the 20m disappeared almost completely. The stuff in the 40m is still crazy loud so that backs up what the websdr in the area suggested as well. The adapter is a RTL-SDR.COM deal working in direct sampling mode so I have no gain control or preselectors or anything.

Uh oh looks like HRO has the RSP1A on sale right now for $99 whoops my money fell out, into their website.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer
I cleaned up my antenna tuner layout, replacing the air coil with a toroid, and 3D printed a box to put it all in. Six dang hours of messing with the box to get all the holes in the right place and make a pair of matching knobs that fit. Along the way, the capacitor's 4:1 knob mechanism just stopped working entirely. I'm not sure how that works (there's 0 exposed parts which reveal its clockwork) but I'm sure as heck not going to take it back out to fail to figure out how to fix it. I just clamped the knob onto the larger shaft and I find tuning with that easier anyway.


For reference, the setup that's been sitting on the porch for a month:


And my RSP1A comes today, yussssss.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Casual Encountess posted:

project update?
Sorry I haven't responded but I typed a whole giant message and hit Ctrl+R instead of Shift+R near the end and lost my post so I put off typing it again. It's been working great out on the porch. The completed tuner is so much more convenient. Set the dials to where it needs to be and no need to bust out the NanoVNA each time I change bands. Having the capacitor without the 4:1 gearing is so much better because there's no way to see the plates engagement from the outside and the dial is just a normal dial. I will probably put a label on the front with the various positions I discover but right now I can just eyeball it and get it right enough.

The RSP1A is great in that it has better sensitivity, and much finer gain control which means it isn't completely blown out by the shortwave stations on 40m. The echos of shortwave broadcast I was picking up in the middle of my 20m are also gone. Being able to grab large chunks of bandwdith at once is also great (up to 10MHz) which means I can get all of 2m or all of what I want to listen to in 70cm at once.

What does suck is that using it with my setup of a Raspberry Pi A+ that sits outside all the time and SDR-Console on my windows PC in the nice air conditioning and big monitor / speakers doesn't really work. You can use SDRUno in ExtIO mode along with rsp_tcp to stream it, but the wifi doesn't have enough bandwidth to send 16-bit I/Q 2MHz. I'm not even sure it is working properly in that mode because SDRUno is not my favorite receiver app. I can use rsp_tcp with SDR-Console through the RTL-TCP input by chopping the 16-bit I/Q down to 8-bit (drop the top 2 and bottom 6 bits), but also the gain control is lost almost completely. I asked the SDR-Console developer about it and typed out all the specs for the "enhanced mode" API (which just adds a few more commands) and he said to just put a Windows PC outside all the time instead, which I won't be doing. That's pretty disappointing because I'm not getting full use out of the RSP1A, and because it isn't an open source program I can't add it myself. I may try to come up with a workaround by reverse engineering their V3 Server streaming protocol and wrapping the sdrplay API on the other side to emulate it. I don't know if I have that kind of energy for that, or will be able to figure out how they compress the I/Q samples.

CapnBry fucked around with this message at 20:02 on Aug 21, 2020

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer
That is helpful, I didn't know that existed. I occasionally use SDR#, but this DLL doesn't work through the network either. I'm trying to avoid having a 50ft USB extension or running like 100ft of coax through the attic to use the device on the machine I want to listen from.

That said, it is nice that SDR# exposes their API so developers can write their own plugins to support things. I asked the SDR-Console dev for the DLL interface he uses for all his frontend plugins or any sort of information on the V3 Server protocol and he said no. It is a bit odd that it is free software but he really wants to lock it down.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Big Mackson posted:

we put a dll in your dll

Haha exactly, and this DLL only actually front ends another process running on another machine, which is in itself a front end to the sdrplay API service running on that machine, which talks to the hardware through a driver's service.

That' ExtIO dll is the one that worked in SDRUno, and thanks for pointing me to the URSP wrapper because SDR# I like a lot better than Uno. I just tried it and hooray you can get 16 bit samples into SDR#! Theoretically anyway, it definitely doubled the wifi bandwidth so I assume it doesn't get shrunk down going into SDR#, but I'll have to investigate. The RSPTCPServer is a bit wonky, I've already been hacking on it because it does all sorts of crazy stuff where it resets turning off AGC by mistake, and it is super puzzling why they went through all the trouble to make this EXTIO dll and then used this "gain index" thing instead of just exposing the actual separate gains used by the API. The Pi's network can't just barely keep up with 2MSPS at 16 bit as it is choppy and after some random amount of minutes I get a ton of kernel driver USB errors (from the sdrplay process) that requires me to reboot the Pi.

Still not ideal but this could work slightly better than using rtl_tcp emulation so I'm happy to have more options, thanks!

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

PhantomOfTheCopier posted:

I had to take my radio out of my Jeep, sigh years ago now, because of frequent vandalism.
As a TJ owner for 10 years, I sympathize with you. How many times have I come back to my Jeep to suddenly wonder "What. Why?! Why would someone take / break that?!" Bunch of savages in this town. With a Jeep, your stuff is everyone's stuff-- and they don't take good care of their stuff. :smith:

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

the milk machine posted:

i was fiddling around with a raspberry pi + sdr upstairs where i get better reception this summer; i think i was following along with this article: https://www.rtl-sdr.com/rtl-sdr-tutorial-setting-up-and-using-the-spyserver-remote-streaming-server-with-an-rtl-sdr/
I was not aware that spyserver would work with rtl-sdr, I might have to give this a try.

My primary radio is an SDR plugged into a Raspberry Pi 3A+ with rtl_tcp that sits out on the back porch and I connect over wifi from SDR Console or SDR#. It works great other than me having to go outside to switch the antenna from HF (random wire with 9:1 unun) to VHF/UHF. I used to have an SDRplay RSP1A but in this setup it couldn't run 16-bit samples or grab a lot of bandwidth without choking the network connection, so I went back to just the RTL-SDR.com dongle which gives me 90% of the signal for 20% of the cost.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Jonny 290 posted:

Yeah sounds like you're talkin about slow scan tv on 20 meters.
Never done this before so I gave it a try too! Hams doin' God's work out there

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer
I'll second getting an SDR. I've had a handful of them over the years and my current budget favorite is the RTL-SDR.com V3 along with the antenna kit for $35 (which Amazon is out of stock on currently). This is a device to allow you to listen to people and things on virtually any frequency 500 kHz to 1.7 GHz, and more importantly, *see* the signal and ~2.4Mhz of adjacent bandwidth. This is a lot easier than scanning the entire band looking for people talking and you can just click on their line in the SDR software on your computer to start listening to them.

The antenna set is nice because it lets you pick up stuff your Baofeng will (local conversations on 2m ~144MHz and 70cm ~440MHz). You can pick up aircraft positions with ADSB (1090MHz) and hear them talking with air traffic control if that's nearby too (108-137MHz) . You can see wireless devices like weather stations and smart meters talking computer-talk (not wifi devices) on 915MHz and 433MHz. You can uhhhh listen to FM radio too. There's all sorts of data in the air around you at all times and an SDR lets you see it all. You can also attach a giant wire to it and listen to 20m, 40m, 80m people as well as AM radio and shortwave. I've just got a 40ft length of 20AWG wire hung up in the tree outside and I hear people from over a thousand miles away and have picked up FT8 digital messages from as far away as Japan and Slovakia from central Florida.

The only downside is you can't transmit, but it at least lets you see almost all of what is out there, and then you can get the equipment that lets you talk to who you want.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Pennywise the Frown posted:

Yeah that sounds pretty cool. Sucks that it's out of stock. Are there any other complete kits available out there?
The only other ones I've seen like the "Nooelec NESDR Smart v4 Bundle" don't really come with any good general purpose antennas. The SDR receiver is good, but the accessories are not. Amazon now shows the rtl-sdr bundle being back in stock on Feb 19th though.

Like poeticoddity said, you can really start racking up the price if you add on an upconverter, but I don't think that's necessary. I had an RSP1A ($120 sdr) and it had cleaner reception but it didn't blow my socks off in comparison with the cheaper dongle. It also didn't work remotely with most software without degrading its performance down to almost the same level as the cheapie. I have a Raspberry Pi Model A+ that I put outside connected to my antennas when I want to listen from my desktop PC. That solves the "drilling a hole in my house" problem you mentioned earlier, by just streaming the data to SDRSharp or SDR Console applications on my desktop but hardware compatibility is very basic.

When you start looking at high end SDRs, you might be in the $200 ballpark and while I'm sure their HF reception is top notch, I'd rather be looking at like an $999 ICOM IC-7300 which is a full 100W transceiver for HF.

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Pennywise the Frown posted:

Does the antenna require drilling from inside of my house to outside?
I picked up quite a bit VHF/UHF using the suction cup mount stuck to my window or sitting on my pot shelf with the bendy tripod, less with it on my desk with the bendy tripod. It is only (holds up 'I caught a fish this big' arms) at the most or hand-sized at the smallest so it's more of a put it in place when you need it thing than a permanent outdoor installation. The SMA extension it comes with has regular thin coax thinner than a USB cable wire, not like LMR-400 or something where the wire is so thick you can't just snug a window down on it.

For HF a super convenient way to hook up a Random Wire Antenna is to get a little 9:1 unun like this that has the push terminal block connector and stick a piece of wire in the RF port in one of the following lengths (feet): 29 35.5 41 58 71 84 107 119 148 203 347 407 423. I use 41ft (or maybe 35.5?) tossed up into a tree and can pick up 20m from thousands of miles away. EDIT: You can also just stuff that wire into the center of the SMA jack but there's an impedance mismatch so you lose some signal and also it falls out easily.

CapnBry fucked around with this message at 14:17 on Feb 18, 2021

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

horse_ebookmarklet posted:

Got a 3d printer and I'm goin WILD making brackets and learning fusion 360.
Or making protective caps for your PL-259 coax ends or making a box for a tuner?!

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

horse_ebookmarklet posted:

NICE! I'm at a basic "make a profile and extrude/sweep" level right now.
The caps sound like a fun idea, I wonder if I can model a thread into them...
That's probably better than I am with real CAD programs. I just sort of bumble along in OpenSCAD just getting by. I found that 6 turns of UNEF-5/8 thread seems to be about the perfect amount for enough to screw on and hold tight but not too much to sit there turning and turning and turning just to put the cap on.

Bonus Achievement: Emboss the text of which antenna they are in the cap. I have VHF and HF wires that look identical so I just look at the cap instead of staring up at the sky trying to figure out which gray coax is which.

Adbot
ADBOT LOVES YOU

CapnBry
Jul 15, 2002

I got this goin'
Grimey Drawer

Twerk from Home posted:

Does it actually look like DMR will be the standard that will be most popular with hams in a few years?
All I know is that 99% of all the traffic I pick up in UHF is DMR and I hate it. How am I supposed to listen in on everyone's conversations if I have to fire up the DMR decoder all the time and it is always so choppy if it decodes at all!

CapnBry fucked around with this message at 14:37 on Feb 23, 2021

  • 1
  • 2
  • 3
  • 4
  • 5
  • Post
  • Reply