Very Lazy Edition: Coil-Shortened Dipole Antenna Calculatorhttps://www.66pacific.com/calculators/coil-shortened-dipole-antenna-calculator.aspxPrevious Thread: >>2974159>New to /ham/? Read this shit!http://www.arrl.org/what-is-ham-radiohttps://www.fcc.gov/wireless/bureau-divisions/mobility-division/amateur-radio-service>Your search engine of choice works well too!>The wiki is down but is archivedhttps://archive.is/PjR5s>NEW FAQ is updated to preview 15https://files.catbox.moe/aftx43.htm>Idiot's Guide to Coax Cablehttps://www.pcs-electronics.com/guide_coax.php>Looking for frequencies to monitor near you?http://www.radioreference.com>Random Wireshttps://udel.edu/~mm/ham/randomWire/>Basic Rx loop fundamentalshttps://www.w8ji.com/magnetic_receiving_loops.htm>DIY SWL Mag. Loophttp://www.kr1st.com/swlloop.htm>Small Tx Loophttp://webclass.org/k5ijb/antennas/Small-magnetic-loops.htm>In Depth Loop articleshttp://www.kk5jy.net/magloop/>Homebrew RF Circuitshttps://www.qsl.net/va3iul/Homebrew_RF_Circuit_Design_Ideas/Homebrew_RF_Circuit_Design_Ideas.htm>NEW Libraryhttps://mega.nz/file/UCgEGAjb#rwNcnMAQCUUbSp8supsFvn9QEHCWUW86eLcZa16ZG4Y>Online Practice Tests:http://aa9pw.com/https://hamstudy.org/https://hamexam.org/> Real-Time Propagation Datahttp://prop.kc2g.com/https://www.ham-stream.com/>Space Weatherhttps://www.swpc.noaa.gov/communities/radio-communicationshttps://www.solarham.com/>point to point predictions, its free and will give you an idea of how much power/ what frequencies to use to reliably talk to your friendhttps://www.voacap.com/hf/>WSJT-X Home Pagehttps://wsjt.sourceforge.io/wsjtx.html>Homosexual (ft8) guidehttps://www.g4ifb.com/FT8_Hinson_tips_for_HF_DXers.pdf>APRShttp://www.aprs.org/>Weather Fax resourceshttps://www.weather.gov/media/marine/rfax.pdfhttps://weatherfax.com/stations/>how do I into Morse code in a good way?https://pastebin.com/HByjfN4F>Shortwave radio schedulehttps://shortwave.live/
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breaker 19 this here's the swollen prostate you got your ears on?
Stand-by, I have to QSY. Comms are being interferred with by the incessant, non-stop digital drone of %&*@! computers slowly texting “599” to each other.
>still wasting money by buying from the antenna jews
how is activity on some of the other hf freebands? 6600khz, 13790khz.also, anyone with any experience in the ISM band of 13mhz?
>local fire>major damage>fire still spreading>ARES activates>gets in the way just to make themselves seem releventI wouldn't be surprised if they started the fire.
>>2987893where did the ares man touch you anon?
>>2987901Right in my repeater.
>>2987813I want a QSL card from H0MER.
What are your preferred news sites for /ham/ news? I used to watch Techminds on YouTube but he seems to have fallen off the net.
>>2987833
>>2987941I don't. I got tired of them parroting the same exact stuff as if every single one of them got the same script to read from.
is it worth it saving up for one of the more expensive radios like icom 7300 or something second hand?i see that they have unlockable vfo. do most other radios have that too?also, having a built in antenna tuner is very good.thats just an examplewhat is the cheapest radio that has built in antenna tuner and unlockable vfo?i mean using 22m or 45m or 11m + the standard ham bands.
any opinions on xiegu g90?i see one second hand for 200
>>2987996>what is the cheapest radio that has built in antenna tuner and unlockable vfo?
>>2988026i think xiegu g90 fits the bill.it also has an swr scan which is handy.the one for 200 is gone. it was cheap.
could some kind anon post a problem for me, I have with a hermes lite 2 sdr, on the support google group? I managed to never have had such an account and they offer no other option. It would be much appreciated and I offer one or two internets as a thankyou gift.
>>2988093no
>>2988098you must be some kind of a popular fellow ..
>>2988101do shit yourself. no one wants to be the middleman in this thread and another thread.what a stupid thing to ask.
>>2987996>what is the cheapest radio that has built in antenna tuner and unlockable vfo?The cheapest is the one you make yourself. Last thread had some practical links.>i mean using 22m or 45m or 11m + the standard ham bands.Those are some unusial bands, what are you planning?
>>2988590fishing vessels
>Very Lazy Edition: Coil-Shortened Dipole Antenna Calculator>https://www.66pacific.com/calculators/coil-shortened-dipole-antenna-calculator.aspxHey! An edition based upon my post!Btw, it didn't work. Instead, I just coiled so much on 4in diameter pipe 1ft long (R came out to be around 200), center placed the coil, the tuned at the last part. It's sweet spot is 1.945. Thamks to a tuner, the gentlemen's band is now covered. Even interrupted the only conversation on the band to ask for a signal report: around 55. Lol, as expected. 80m and 40m needs some tuning bit still work with an swr of around 3. 20m is spot on at 1.3.
What would a signal look like if you apply a sine audio into a SSB transmitter? The immediate answer would be that it looked like a sine shifted up, yet when you key the sighnal on/off, there is a transition. For an AM signal it would go either side of the carrier, but on a SSB it would be to one side only. So for USB it should be on the upper side of the sine signal, right? So for that reason the signal has to be a bit more involved. Anyone got a clue? The ham stackexchange was no help.
>>2989067maybe they would have been more helpful, if you'd be able to ask a proper question.
>>2989067Do you know what fourier and inverse fourier transforms look like? Or how sine waves multiply?If you have a 1kHz audio sine, modulating with a 1MHz carrier via AM, then you'll get a 1MHz sine wave that varies in amplitude at 1kHz, without crossing zero. The envelope will just be a 1kHz sine wave. Because of beat-frequencies. The keying on of this signal will look like two sidebands increasing in volume.output = (A*sine(1kHz) + C) * B*sine(1MHz) = A*B*sine(1MHz + 1kHz) + A*B*sine(1MHz - 1kHz) + B*C*sine(1MHz)If you remove the carrier wave so you have AM/double-sideband suppressed-carrier, you'll get a 1MHz sine wave that varies in amplitude at 1kHz crossing zero. The envelope will look like it's full-wave rectified 1kHz sine wave. output = A*sine(1kHz) * B*sine(1MHz) = A*B*sine(1MHz + 1kHz) + A*B*sine(1MHz - 1kHz)If you then remove the lower side-band so you just have the upper sideband, you'll be left with a 1.001MHz sine wave. The envelope will be flat, DC. In order to demodulate this, you need to know which frequency it's actually meant to be transmitting on. If you tune your radio to 1.0005MHz instead of 1MHz, you'll hear a 500Hz sine instead of 1kHz.output = A*B*sine(1MHz + 1kHz)For any suppressed-carrier AM modulation method, be that single or double-sideband, ideally no power is transmitted when no audio is being modulated. When A=0, output=0. This is one of the motivating factors behind suppressed-carrier transmission, to use less power to get the same signal across. So the keying on of any suppressed-carrier's audio waveform will just look like the sideband(s) rising from zero, not transitioning from any carrier.
Should you coil this dipole?
>>2989272>Do you know what fourier and inverse fourier transforms look like?Yes and yes>Or how sine waves multiply?Also yes.Yet that does not explain what the signal would look like in time domain when you key on/off a sine input to a SSB modulator.
>>2989338No, I'd rather use existing scaffolding for a full sized dipole:https://www.goldengate.org/exhibits/facts-and-figures-about-the-bridge/
>>2989527>what the signal would look like in time domainA quickly rising and falling amplitude of a sine wave. Be that at 1khz after being demodulated, or 1.001MHz before being demodulated. Pic related.
>>2989533It'd be easier to make the bridge an efhw. Hopefully you have a great atu because matching that is going to be a bitch.
just had my first brief and mostly one sided qso on 11m.some brit cqd on 27.555, said he would monitor 27.485.i went there and replied.he could barely hear my call sign but got the division prefix and the numeric part of the callsign.on receive it was much better though.i think its because the radio is in dire need of maintenance, probably some caps and alignment but regardless, i'm happy for the semblance of a qso.tonight i'm constantly hearing uk and ireland. some noticeable propagation is going on.
It’s time to start judging men by the *girth* of their antenna.Seriously… what’s in that thing?
>>2989753
I don't know if any of you /ham/planets use the ATS25, but I do DXing and I'm a lazy, impatient fuck, this shit is pretty goodhttps://golden-radio.com/
>>2989755Interesting. Looks a bit like one of those phased array antennas except with really complex “pads” I tried tracing their PCB design and came up with picrel.
>>2989802I try not to think about it, the demons can see you if you.think about them.too.mvuh
I am sitting in the dark listening to BPM China because my electricity is out. No hint of Jane Barbe tonight though.
i'm starting to narrow down my choice to the Kenwood TS450(S)anyone used these or similar models ts690 etc?
>>2989570The rising and falling parts are the ones that will cause sidebands, and on an upper sideband you will, strangely, get just get a sideband tail to the right on a waterfall diagram. And there is no way a sine wave will be able to do that.This is a hard question.
>>2989975The changing amplitude of a sine wave, when you take the fourier transform of it, will look like a collection of harmonics alongside the sine's main frequency spike. That's just how fourier transforms, and hence waterfalls, work. The slower the transition, the less significant those harmonics will look. With a really fast transition (significantly faster than the rise on an equivalent constant-amplitude sine), you get a bunch of higher harmonics going off by something like 20dB/dec. The fourier transform of a step response. With a slow transition, you'll get splitting of your 1.001MHz sine into miniature side-band-like things, and the slower the transition the closer these are together.Would be fairly easy to do in python or matlab or whatever, just generate a sine wave multiplied by some sort of keying function (e.g. atan(w*(t-t0))/pi + 0.5 ), and FFT it. You may want to add a windowing function if the beginning and end don't line up.
finally after 2 (two) months of monitoring the vhf repeaters by the 3-3 rule i heared two boomers talksomething happened, vhf is not dead
>>2990037>Would be fairly easy to do in python or matlab or whateverOK, please do.Say, a 1 kHz audio modulated to upper sudeband at 10 MHz, with a sinc shaped keying on/off, and then show the time domain signal.
>>2989722Nice. For a while when I first got on HF I could hear decently but couldn't be heard well. Turned out I needed a groundplane for my vertical I was using. After that it was much better.>>2989838>skree... skree... skree... skree..I spent friday night out in the boonies monitoring WxFax transmissions out of Alaska, Hawaii, and California plus some NAVTEX. Also a bit of listening to VLF and LF beacons and some AM BCB monitoring. Clear night, good conditions on the bands while nursing some beers with my Coleman lantern hissing away. Comfy.
>>2989956Yes. I bought my TS-690S new in '93. I still have it and it's still my No.1 favourite radio in my small collection. I've also played with a TS-850S and a TS-440S to a limited extent.
>>2990124i'm using a horizontally pol. full wave loop. dont think it needs a ground plane
>>2990127i see these going for 400-500 usd. they look interesting. with vox, it would be easier to do digimodes and 100w is perfect for most uses.
>>2990201They're pretty decent radios and still hold their own today. If you do voice work, they're legendary for their audio. Unless you get an abused unit, I don't think you'll regret owning one.But they are getting up there in age so look out for leaking capacitors and the back-up battery. Not that it's common, but it does happen. Otherwise there are 2 weaknesses to be aware of. It's recommended that if C104 on the IF board is original (brown case) to change it out with a 25 V one, preferably with a Panasonic brand. They say if it hasn't leaked yet, it will. The originals are rated at 10 V but often get spiked at 14 V. It's easy to access so no fears about a complete radio tear-down. Flip the radio over and open the access panel, the capacitor is right there near the filter slots.The other thing to be aware of is that it uses proprietary DDS chips. The early chips were the 6631's and the later 66312's. The 6631's supposedly had a flaw and were prone to failure yet I don't know any 450S/690S owners that experienced that. My radio has the early DDS chips. Up to a few years ago you had to find a parts donor if you needed to replace it. I stumbled on a local parting a TS450S and I snagged the DDS board for cheap just in case. Regardless, there is an outfit in Italy called RF Systems that sells aftermarket boards.I did RTTY and PSK31 with mine. I recommend getting the CW filters for both IF's for narrow-band digital work. Inrad's if you can afford them. And finally, but not lastly, you can do computer control relatively easy if you are into that. I never did so I have no insight into that.Hope this helps.
>>2990308thanks for the tips, yeah i kind of expect to change a few caps in older electronics.in around 1990, the battery backed memory was pretty common in all kinds of electronics.i had to change the cr2033 on two synthesizers before.caps are no problem either.the worst problem would be that special chip youre referring to
>>2990308?did you have to align it?
>>2990382I've never done one to it yet. I lack a signal generator but am on the lookout for one. I'm also thinking about getting an aftermarket TCXO for it.
Hey guys, any ideas on how to use LoRa tech to help out campers near a national park? I read you could set up a "wifi" access point where people could send basic text messages that can bounce all the way to the city. Seems neat.
>>2987813Bump
>>2990900Can be done with a system like Meshtastic or Rnodes. But each user needs a LoRa terminal of their own. The common method is for the LoRa terminal to Bluetooth to your phone, and the app on your phone is used for interfacing with it to send and receive messages. But I believe you can also buy standalone terminals. A stand-alone terminal at each tramping hut might be sensible, assuming there isn’t already a method for emergency communication there. Lending terminals to trampers might be feasible, they come out to something in the ballpark of $20-40 for a Bluetooth model. Heltec and Lilygo make decent ones IIRC.LoRa terminals have decent range, but the real power is in their ability to hop from node to node. To properly take advantage of this you’d either need lots of spread out people with these at any time, or to set up repeater nodes, probably with solar and batteries, atop nearby hills.And then at the receiving end, back in civilisation, you’d need to figure out what to do with the messages. It’s not like they’re SMS texts sent via a SIM. Maybe you turn them into emails, or just use them for emergency comms.
>>2991101don't bump here, this thread will be around for months... unfortunately.
>Meshtastic
>>2991164What's wrong about it :(
>>2991180Nothing, actually. I like it along with the concept. I'm just making fun of the initial sojak reaction many had to it before it really took off.
>>2991127as much as i find meshnetworks cool and useful, their usability would go up 10 fold if the used hf frequencies.imagine a meshnet around 20 metres or even 40m.even on 11m! despite the patchy and random propagation it would still be better for mesh nets than uhf or morei understand meshtastic guys dont want big antennas but mesh on hf people dont care obviously.feels like hf is underrated among the younger crowd.
>>2991127i also read that hf is used for commercial fishing boat mesh nets and that some such nets exist happily outside of public knowledgein general, i've seen references to hf mesh in engineering articles about industrial mesh network use.uhf honestly looks like a toy in when comparing reliability
So I'm thinking about setting up a solar/battery powered FM radio station. A clandestine setup. A disposable one. I figure I'd be running around 1 watt so the costs of assembling everything won't be insane since I can't predict how long it's going to last. But that means I need to scout the perfect location. There is some mountainous terrain that's remote in my area that would be perfect to transmit from with a yagi but I'm not so sure 1 watt is enough for the kind of distance it would be from the town proper. I bet I'd fucking kill with 10 watts though going by my own observations of translator stations in the US that used that kind of power. Also that introduces other tradeoffs. I can get it up to a site where it is going to be hard for other humans to get up there and tamper with my shit but it also means I can't just walk up near the transmitter and access a hidden wifi access point to update the files on my audio source.Just a bunch of ideas but eventually when I have money to flush down the toilet I'll try to actually do this.
>>2991308>>2991309I suspect multipath propagation could cause even a single chirp-spread-spectrum signal to overlap itself and become incoherent. LoRa itself eats up tens of kHz bandwidth, not a big deal at 70cm but might not be welcome on 40m. And there isn't really a good way of controlling range, you might be trying to talk to a node 150km away, but you get a lucky bounce and happen to overlap with someone else's transmission in japan. Chirp-spread-spectrum is bad for coincident signals, neither of the original two signals can be extracted from the resultant overlapping RF from what I've read, at least if they're at the same frequency and spread factor. Hence the dead-time in the LoRa standard.>>2991318You can try to calculate your link budget to see what kind of signal you'd get. 1W continuous is doable, a 7.2Ah UPS battery has 86Wh of energy stored and would nominally last you 86h with no charging. I'd avoid such an extreme discharge of such a battery, but an 18-38 Ah lead-acid, or 12-26 Ah lithium would probably suit you fine with a ~15-30W solar panel, and appropriate charge controller. I figure you should be able to manage the power side of things in under 100USD, cheaper if you can use salvaged batteries (car or laptop or scooter). No clue about the transmitter, if there isn't anything off the shelf I'd attempt to use a cheap automotive FM transmitter, solder coax inside it, and feed that to a cheap aliexpress RF amplifier.If anything, it might be easier to make it an FM repeater, and beam audio at it with a highly directional antenna from somewhere more accessible. Having a wifi access point or whatever would be another thing to eat power.
>>2991320Well for the audio source I was thinking of using a Raspberry Pi Zero W. I can preprocess my audio and have the Pi acting as an AP I can connect to. Also I can have a script running that controls what's playing so there's some logic to my programming and it doesn't sound like some guy set up Winamp and turned on both shuffle and repeat all which is basically what every other pirate station I've ever encountered sounds like. I've explored lots of STL concepts in the past. From looking into the ways the pirates in London do it to the professional setups in the country where I live that I found with my SDRs. I guess that makes the most sense if I was going to go all out with the mountain site idea but I think it would increase the budget. Even if I could get much better results passing through MPX generated by gear in my house than aliexpress crap shoved into a box I'm not afraid to lose.
>>2991321>a Raspberry Pi Zero WThat will eat more watts than a cheap MP3 player or MP3 playback module, but it might be worth it for the extra features.
>>2991323Well it will be running headless and I can probably do a lot to get the load down. Start with a minimal distro and further debloat it. Everything can be managed carefully.
>>2991180NTA but for inexplicale reasons, mestastic is a bit cliched. I guess it will be hot the day it becomes prt of every mobile phone. Phone makes sure need something more distinguishing features than the sameness they have now.>>2991308>as much as i find meshnetworks cool and useful, their usability would go up 10 fold if the used hf frequencies.Can ISM bands be used? There is one on 13.56 MHz. Also check outhttps://www.lwca.net/sitepage/part15/index-what.htm>>2991318>So I'm thinking about setting up a solar/battery powered FM radio station.Bu why??
>>2991331I've always been interested in FM broadcasting so I'd like to mess around with it.
>>2991324More recent Pies(like 2040 and newer versions) may be better, that diagram must be super old. ESP chips are even more power efficient.>>2991333At least with meshtastic it would be legal and provide more enjoyment for more people.
>>2991345I might mess around with some legal stuff later too but I live in a rural area where there would be few other people interested in that. That's part of the reason why FM piracy seems like it could be a bit of fun. At this point there are basically zero stations that provide a reliable signal to my town. There were some before but they have since shut down. The terrain that surrounds the area makes it hard for signals from the closest cities with proper stations to make it in. TV is a different story with mountaintop sites serving us as well as the now gone FM ones used to.
>>2991346>At this point there are basically zero stations that provide a reliable signal to my town.Damn. I guess that if you build a repeater nearby and broadcast comfy music or podcast, no one would bat an eye. Just don't yell NIGGER 24/7, and I think your neighbours will appreciate you providing an FM station. Also, plan something in case of emergencies, your repeater could save lives.
welp i guess i'm going to now get into HFI picked up a yaesu something 100w for 20 meter for a decent price. How much will this thing fuck up other stuff, and how much will it get fucked up by other stuff? I have a mountain top stub tower that already has power and network, and also has some meshshit. It's a DC site, but obviously has a solar charge controller, just no inverters no AC. the tower is kinda full so I was going to go about 40ft away and put up a mast just for it for a full size half wave dipole and just run a coax over to the main cabinet and cram the radio there. Or should I move it further and just run power and network to a new cabinet for the radio?
>>2991345>More recent Pies(like 2040 and newer versions) may be betterThe RP2040 and its sucessor are microcontrollers, not SBCs. Same for the ESP32. Entirely different category of device with different use-cases.Now this anon may not need an SBC, depending on how the station needs to be run, but running a full linux distro with known good utils is probably a lot more flexible and reliable than programming your own code to run music to an FM transmitter. An MP3 player would be more reliable but even less flexible.>At least with meshtastic it would be legal and provide more enjoyment for more peopleMeshtastic cannot broadcast audio, full-stop. Maybe you can get 60kb/s bit rate out of LoRa, with continuous transmission (not allowed by LoRa), and even then you'd be getting worse than AM radio quality.Plus low-power FM is a thing, where I live you don't need a license for it at all, just to remain below the 1W power limit and broadcast your station name and contact details at least once per hour.
>>2991451>Maybe you can get 60kb/s bit rate out of LoRa, with continuous transmission (not allowed by LoRa), and even then you'd be getting worse than AM radio quality.At that kind of bitrate with modern codecs I could probably manage to put out audio, in stereo even, that sounds more pleasant than what most people hear on AM these days. That's not AM's fault at all. It's more down to how shitty most AM radios produced in the last 30 years are. Whenever I'm picked up by some ride service driver in the city and their Toyota has an AM talk station on it sounds like complete ass due to the filter width being too narrow. Meanwhile I hoarded Sony ICF-P36 units when they were finally discontinued because I like how it sounds on AM.That's not to mention all the electrical interference etc on the AM band that makes listening a shitty experience. But transmitting audio on LoRa would mean people would need specialized equipment to pick it up. Perhaps things like this are an interesting idea to explore but it would require hobbyists to come up with tooling and standardize it.
>>2991453Ok with compression you can get kinda crusty sounding MP3 at 64kbps, which is close to the 62.5kbps maximum bitrate of LoRa, definitely better than AM, but again LoRa is designed for short packet bursts with lots of dead time, allowing others to use the band when you're not transmitting. Unless you had an agreement that nobody would need to use a band of LoRa in a certain area, it would be a hard sell. Also that maximum bitrate means minimum range and maximum power consumption. You could maybe use it for short crusty voice messages if you really wanted.That said, there definitely is room for a low-power digital broadcast audio protocol to exist. Room for lots of Chirp Spread Spectrum and similar stuff, really. It's pretty cool technology. I imagine you can do something similar by using a sinusoidally varying frequency, and shifting its phase, though ramping chirps would likely be easier to demodulate.
>>2991454We have much better options than mp3 these days. Even a long time ago we had mp3pro. Digital Radio Mondiale uses xHE-AAC to achieve decent sound with very low bitrates but I believe it's heavily patent encumbered so opus is a better choice.
>>2991455Oh yeah, Opus goes to 6kbps for VHF radio bandwidth encoding. That might be doable for voicemails or short calls. But at 3-4000Hz it's recommending 15kbps for mono music. Interesting tech, this kind of audio compression is probably when you'd want a proper SBC instead of a dinky microcontroller.
>>2991456This is kinda making the wheels in my head start to turn. Could you imagine if an extremely efficient modulation scheme with a high degree of error correction existed that was open and patent/royalty free? To me DRM doesn't really seem to be good enough. Like if I have a marginal signal there's all kinds of dropouts etc. But if streams with these kinds of bitrates could be transmitted using less bandwidth and more error resilience it could be a big deal for pirates, or even legit broadcasters.
