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Paul MaudDib posted:My house is a ranch box that lays at roughly a SSE azimuth on the long side, let’s say heading 150. I’d like more like a heading 210 or 240 azimuth. 180-240 would be great. You could run copper radials around it/across the roof to the ground and attempt to tune up your whole house. A friends father (SK who I got a lot of gear from) was doing that with a fiberglass antenna from a boat as his vertical rather than a metal chimney, but it's the same concept. He was tuning it with an SG-230 (https://www.sgcworld.com/230ProductPage.html) which as I understand it is made to tune up various parts of a boat for whatever HF boat people happen to need.
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Apr 15, 2023 15:31
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Motronic posted:You could run copper radials around it/across the roof to the ground and attempt to tune up your whole house. Is this the 2m antenna SK?
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Apr 16, 2023 04:18
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drunk mutt posted:Is this the 2m antenna SK? Yes, the same.
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Apr 16, 2023 15:02
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Happy world amateur radio day
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Apr 18, 2023 13:04
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Finally put together the (tr)uSDX and rigged it up with a 20m EFHW sloper run up a flagpole, configured it for digital modes, and made some QSOs last night for the first time after being licensed for like five years but never doing anything with it. Some PSK31, mostly FT8, got all the way out to Ukraine (over 4000 nm away) with 3W transmit, which is pretty cool/insane. Now even when the Internet infrastructure here gets ripped apart by a tornado or hurricane I never have to log off, which of course is the real goal of all radio amateurs.
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Apr 19, 2023 14:55
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E4C85D38 posted:Finally put together the (tr)uSDX and rigged it up with a 20m EFHW sloper run up a flagpole, configured it for digital modes, and made some QSOs last night for the first time after being licensed for like five years but never doing anything with it. Some PSK31, mostly FT8, got all the way out to Ukraine (over 4000 nm away) with 3W transmit, which is pretty cool/insane. You're 4 microns away from Ukraine?
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Apr 19, 2023 15:56
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mycomancy posted:You're 4 microns away from Ukraine? No, no, he's 2950 ft/lbs away.
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Apr 19, 2023 16:33
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nautical miles, I may have mixed up the units from something else I'm doing since I estimated by degrees of longitude
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Apr 19, 2023 16:57
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Time to make a 144 mhz yagi antenna. 1.  2.  3. Improved 
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Apr 28, 2023 14:37
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I am very much just dipping my toes into this hobby and only in the last few weeks started reading up on antenna theory and design. The active element is really just a half wave dipole, yes? What's that black bridge between the two poles? So far I've got a Baofeng UV-5R and an RTL-SDR + Dipole Antenna, HAM is fun! Managed to decode some APRS signals this weekend... Too bad I have no idea what any of the output meant!
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Apr 28, 2023 19:13
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that's a hairpin match. a dipole in a yagi antenna generally has pretty low impedance. that adds an inductor between the two halves to bring it back to a decent match. there are a lot of ways to match a yagi's driven element - hairpin matches, gamma matches, and even just adding a carefully spaced element ("OWA" designs)
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Apr 28, 2023 19:15
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Big Mackson posted:3. Improved You might run into issues with the alu/galv steel/copper/tin joints over time, suggest greasing that poo poo up (Biltema low temperature grease is pretty good and cheap). Maybe get some ring crimp terminals (cable shoes!) too. And like ideally get some taps and machine screws, or maybe a rivnut set would be mechanically better.
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Apr 28, 2023 20:35
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longview posted:Those Clas Ohlson big head screws are ridiculously handy (but omg you need a better PH2 screwdriver, those heads are murdered). This antenna is a test antenna to see if i can even receive and send signals so far up north that i live. If it works then i will modify it so its more rigid and weatherproof etc. Yeah, i am working on buying more tools so i can do things the right way. Biltema is a pretty noice place for radio amateurs. The masts sections (1.5 meter) from biltema are BASED.
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Apr 29, 2023 18:18
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I found a thing at the thrift shop:  A handheld emergency radio telephone. Between 5 and 2w of AM power on 2182kHz. It has a huge 2m long whip antenna, and a reel of wire you drop into the water as a ground. Range quoted varies between 40 and 80 nautical miles. It generates a carrier, and the receiver board works. However, the audio amplifier is dead so no modulation and no received sound through the earpiece. I'm thinking about what to do with it. I think it should be doable to tune it down to something like 1850kHz, that's only a 10% down tuning step. However, both TX and RX are crystal controlled. Contemplating what's the easiest way to go. I'm considering a mixer to mix 1850 to 2182 for the receiver, so i don't have to change anything on that board and perhaps even be able to tune the RX. The TX just needs a stable oscillator, which isn't too critical for 160m AM. But if i make it a VFO, then i also have to be able to tune all the resonant circuits. A fixed frequency makes for harder operating. I can't choose another frequency if it's busy, after all, or respond to people calling unless i'm within their filter. The internals are pretty crude (but very sturdy - the TX board is 2 or 3 times the thickness of a conventional circuit board) with (for transistor equipment) uncommonly huge AF transformers: 
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May 3, 2023 13:12
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When you see a good wax thread wrap job like that, you know its built to take a beating
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May 3, 2023 13:53
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I still keep a roll of waxed cotton line around and do old school cable lacing when i can. e: Were it me, i'd try to get it on the WSPR frequency and get one of those little si5351 boards that can transmit wspr running as the oscillator. dont even need the audio modulator then.
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May 3, 2023 17:13
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My Technician license had long-since expired and been purged from the ULS database. When I was thinking of New Years resolutions around the start of this year, I decided that I should study for another Technician license for some mental exercise and to see how things have changed over the years. Everything came back to me fairly quickly, which is good, and I passed my Technician element exam at the beginning of March. I decided that I should challenge myself and keep going. I ordered the ARRL General and Extra license manuals and got to work. Last night, I received this: I owe much of my success to the training videos from NRHARC on Youtube (which I highly recommend). General: https://www.youtube.com/playlist?list=PLs_Ab58w9LI9T0qCOsOD25KKTCAV92L5W Extra: https://www.youtube.com/playlist?list=PLs_Ab58w9LI_6ENIq9q8geKXTrtHDT6ns I watched both playlists at 1.5x speed and still understood it all (the instructors speak very, very slowly), so the 7 hours for the General playlist and 20+ hours for the Extra playlist aren't as bad as you would think. You also shave off a lot of time if you skip ahead 30 seconds here and there through material you may already know, questions, introductions, etc. The ARRL Extra Class license manual was much easier to understand after watching the videos, and I took a bunch of sample tests using https://www.aa9pw.com/ for practice.
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May 3, 2023 17:25
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Heck yeah, congrats! Now you don't have to worry about those pesky General class band limits
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May 3, 2023 18:40
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Jonny 290 posted:I still keep a roll of waxed cotton line around and do old school cable lacing when i can. This is kinda what i was thinking about. What i expect to run into when using a tunable oscillator, is that i need to figure out a way to tune the output stage too. I have no idea yet if the antenna tuning and output filter setup is 'coarse' enough to cover 1810-1890kHz (my country's band limits for 160m). I think it might just work. Being able to do digital modes also extends range a bit. On sea water, the expected range is 40-60 mile, but on land the range will probably one tenth of that in AM voice. LimaBiker fucked around with this message at 11:29 on May 4, 2023 |
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May 4, 2023 11:27
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why are used vhf ssb transceivieiversiverts selling out before i can buy one and why are the y so expensive? 
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May 5, 2023 14:51
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Got my General and the VEs encouraged me to get me Extra soon!
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May 10, 2023 00:49
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hell yeah, congrats
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May 11, 2023 23:25
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my attempt at uhf cross yagi.   took the feeding design from this but i had only 50 omh coax so i made the coax longer. idk if that works lol. 
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May 13, 2023 14:41
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100 ohm coax hack: take two 50 ohm runs, cut to length per velocity factor calculations and such at each end, connect the shields together, but insulate them the two center conductors are now a 100 ohm balanced feedline. use that for the phasing piece
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May 13, 2023 17:42
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Jonny 290 posted:100 ohm coax hack: my brain almost got scannered by how easy solution this was.
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May 14, 2023 18:07
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You can do it the other way around, too! Connect both the shields at both ends, connect both the centers at both ends. You now have a 25 ohm coax section The most interesting application i've thought of for this hack is the series setup (first config i explained) with that twin run RG6 quad stuff. 150 ohm balanced, shielded feedline with pretty low loss. Could be handy in some random wire / ladder line type setups.
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May 14, 2023 18:22
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btw as far as cross/circular yagis go, i'm much more of a fan of feeding the driven elements in phase, and then offsetting the yagis by 1/4 wavelength in physical space. I did this for my 2m beam - bought two 5 element Hy-Gain yagis, extended the boom with a dowel and then reinstalled the second set of elements 18" offset on the first boom - and it worked gangbusters. The benefit is that you now don't have to do phase shifting AND impedance matching with that one section, and you can make the matching harness much more logical and balanced. yagi 1: tune it to 50 ohms yagi 2: tune it to 50 ohms Now run 3/4 wave of 75 ohm coax from each, and tee it the 75 ohm coax transforms them to 100 ohms at the far end. parallel both, boom there's your 50 ohm feed and the coax length is equal to each one, so you get good pattern and balance. if you're curious about the math words: a 1/4 wave matching section will transform the impedance such that the coax section is the geometric mean between the input and output impedance. So, 50 input, 75 coax, 100 output. (give or take, eh). Got a 20 ohm at resonance antenna and you want to match it to 300 ohms? 77 ohms geometric mean. I used this hack the other way around, where i had a ~120 ohm delta loop for 20m up and wanted to match it to my coax. I ran a 5/4 wave segment of 75 ohm coax, which is cheap and easy to find, to get it almost allll the way to the shack, and then fed 50 ohm coax to there. Bang on 1.1 match Jonny 290 fucked around with this message at 18:35 on May 14, 2023 |
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May 14, 2023 18:30
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i think i will buy something that is a better boom than i have and use the offsetting method. Then i can just connect 50 ohm coax from radio to 75 ohm coax near yagi that then splits into two separate equal length coax of specific length and they direct feed their own yagi. edit: then i can also buy materials to weatherproof everything. and use right length screws lol. Big Mackson fucked around with this message at 19:38 on May 14, 2023 |
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May 14, 2023 19:27
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And then, if you need to switch polarization from LHCP to RHCP or vice versa, you just reverse the polarity of the connections on one boom and you are d o n e. it's great
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May 14, 2023 19:54
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I was looking at this for my yagi that i am going to build (the same one as before just with more directors and a non-metallic boom) and i was wondering what it means with 150 ms delay? Do i have to manually tell the radio or soundcardmodemversionhere.exe to delay or else it will fry the LNA? https://antennas-amplifiers.com/product/low-noise-preamplifier/70cm-lna-bpf-split-rx-relay-eme3-432/ edit: also feedback regarding LNA's and satelllittteee work would be apprectieded. edti; i have not eeaten food todaus. Big Mackson fucked around with this message at 14:55 on May 18, 2023 |
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May 18, 2023 14:53
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that means it's designed to be run via a PTT sequencer. Common back in the day when there were high orbit satellites you needed an amplifier for Mic PTT into sequencer box Sequencer box has logic/enable triggers for your preamp, your t/r relay, your amp and your radio on Transmit (ptt down from mic:) power down preamp trigger t/r relay pause 150 ms power up amp pause 150 ms trigger radio transmit mode Receive mode is the same sequence in reverse Used to be you'd have to rig up a custom board with a bunch of 555 timers to delay things appropriately. These days you can probably do it with a $5 arduino and a few lines of code
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May 18, 2023 16:04
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Saw this and thought of this thread immediately. Thought I’d share https://youtu.be/DovunOxlY1k
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May 18, 2023 17:17
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Jonny 290 posted:that means it's designed to be run via a PTT sequencer. Maybe ill just make the bestest antenna ever so i dont need amping. simplify.
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May 20, 2023 14:12
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preamps can be nice but tbh the noise floor is so low on vhf and above that they aren't super necessary.
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May 21, 2023 18:04
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Hello Everyone, I just wrapped another semester of school, and decided on a whim to go to the Dayton HamVention this weekend. I came, I saw, I was surrounded by old, fat white dudes and was bored out of my mind by Noon. Buuuut I saw some cool stuff too and have decided to go for it and get licensed so I can do more than lurk on my Baofeng. I picked up the Ham Radio Prep courses for 75 bux, and they look all right. Has anyone done the online testing? They were doing free tests at Hamvention, but it was a mess and I wasn't going to wait 4 hours when I could look at the junk pile, I mean swap meet...
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May 21, 2023 19:45
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MrDesaude posted:I came, I saw, I was surrounded by old, fat white dudes and was bored out of my mind by Noon. Yeah, there's a pretty hard break between those hams and....well, ther rest of us. And it's more than refusing to use anything newer than windows 95. Glad you're still interested. There's a lot more to do and its fun. Just.....yeah, that's not so much fun unless you have a specific project or idea and run on through looking for deals on something while dodging wheelchairs and walkers.
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May 21, 2023 19:50
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made a better yagi. drivers not installed because i need to think how to isolate and weatherproof it.
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May 21, 2023 20:33
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MrDesaude posted:Hello Everyone, i dont know much about courses, but the technician test is very easy. read this free study guide (it'll take you a lunch break, maybe two) and then do some practice tests on hamstudy.org until you're consistently doing well (another lunch break or two). then schedule an online test and take it. i took my technician and general tests online, both went great. the strategy above worked great for them. the extra material is much more difficult (for me, at least - it might not be for you depending on your background), and i had to Actually Study, and ended up getting distracted by other stuff before taking the exam
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May 22, 2023 05:01
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I used HamStudy and did an online test; the Technician test is pretty easy and the General one didn’t take much more effort. In think most people could probably do both in the same session with some basic prep. I’m currently studying for the Extra exam and this one is taking significantly more effort (no background in circuits). phongn fucked around with this message at 23:05 on May 24, 2023 |
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May 23, 2023 03:30
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I recently got technician by literally memorizing the question pool on Hamstudy. It wasn't something I did intentionally; it just kind of happened over a few study sessions. Some of my friends were studying for Extra and I kinda got hyped up with them. I don't know how to actually use my cheapo HT and haven't done any transmitting at all. Listened to a couple of local nets with the HT and/or RTL-SDR. ps - my one friend did tech, general, and extra all in one session because he's crazy like that.
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May 23, 2023 04:12
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