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I don’t think there’s a limit, but 10 contacts have to be in a midnight-midnight UTC window. If you camped in one spot for 3 days, I’m pretty sure you could get credit for 3 consecutive activations.
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Oct 19, 2020 22:16
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What's a decent base station/mobile that will be good for someone who only has their tech that isn't some crazy 1,500$ USD thing? Like, something I can hook up to a better antenna and get some range and more than 2m/440 without droping a half month's salary?
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Oct 20, 2020 03:39
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Neito posted:What's a decent base station/mobile that will be good for someone who only has their tech that isn't some crazy 1,500$ USD thing? Like, something I can hook up to a better antenna and get some range and more than 2m/440 without droping a half month's salary? Your confusion here is that you think it's about the radio rather than the antenna. What kind of space do you have?
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Oct 20, 2020 04:08
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Neito posted:What's a decent base station/mobile that will be good for someone who only has their tech that isn't some crazy 1,500$ USD thing? Like, something I can hook up to a better antenna and get some range and more than 2m/440 without droping a half month's salary? Can you actually spend $1500 on a dual band mobile radio? The most expensive options I can find on HRO are $550.
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Oct 20, 2020 04:55
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poeticoddity posted:Can you actually spend $1500 on a dual band mobile radio? I’m guessing OP was looking at an ic-9700.
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Oct 20, 2020 14:20
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Motronic posted:Your confusion here is that you think it's about the radio rather than the antenna. What kind of space do you have? I'm only asking because right now all I have is an HT. I'm living middle floor in a triple decker, so I've got some windows and, if I can convince my room mates, a porch on the other side of the house I could run a feedline through, but no roof access and it's a shared backyard so I can't do any sort of perminent installs there.
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Oct 20, 2020 18:31
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Neito posted:I'm only asking because right now all I have is an HT. Your HT, attached to an appropriate antenna, will do a lot more than this "$1500 thing". So what it comes down to is figure out how to set up a temporary or permanent antenna as best you can. You're not going to be able to make up for lack of that with a more expensive radio/more power/etc. So again, worry about the "not fun" part of figuring out an antenna for the band(s) you want to operate on. Even a dual band vehicle antenna stuck out on a porch or out a window is going to do more for you than replacing your ht.
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Oct 20, 2020 18:44
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Stream comin' back. https://twitter.com/KC4YLV/status/1318660512087900160
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Oct 21, 2020 00:04
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Finally made my Slim Jim. Didn’t have the right tools so snapped the ladder line on both sides while stripping the feed line point. Soldered it back on, bit weak now when I roll it up now but it’ll do. This thing isn’t even tuned yet and a guy across town said I went up 3 S points with him vs a 5/8 whip on my HT. Unreal. It isn’t even much higher up. Just make stuff and stop worrying about it, that’s what I’ve learnt. Edit: gently caress the flower pot, and I just used a kit but I checked all the dimensions first and I’m getting a NanoVNA next week so we’ll see how much I can improve it. thehustler fucked around with this message at 23:48 on Oct 22, 2020 |
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Oct 22, 2020 23:42
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There are changes coming to the DMR net. We will maintain a bi-weekly schedule, however, the times will be flipped. So, the new times are Tuesdays 01:00 UTC (6pm PT) and Fridays 03:00 UTC (8pm PT). Additionally, since there has been interests from over the pond, we're going to hold a Saturday rag chew at 18:00 UTC (11:00am PT). If there are suggestions for a better time, just say something and if there are no objections that will be it; unless it's just really dumb. The current talk group is still on BrandMeister network ID 3163563 Also, make sure you do the following if it pertains to you: quote:WHEN CREATING THE CONTACT MAKE SURE TO SELECT GROUP AND NOT PRIVATE
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Oct 24, 2020 01:38
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I’ve come up with a silly 433 MHz 3 element yagi handheld design which absolutely doesn’t have a 50 ohm feedpoint impedance (will find out on Monday when my nanoVNA arrives), and it’s not really the kind of construction where I can make some complex adjustable metal bar system thing, given that it’s very thin wood and just strands of wire for elements. I used hot glue gun to secure everything. I’ve been told the yagi impedance can be adjusted by using folded dipoles for driven elements, but I can’t really do that due to the construction method. Another method is to move the director and reflector elements towards the driven elements. Is this all I need to do? Will I get close to a useable SWR such that I can just solder the coax on to the elements? Or is there a hairpin match calculator somewhere I can use to match the (apparently) 20-ish ohm with a short length of wire? I couldn’t find one. Assuming moving the elements is a goer i did have the idea to use velcro for everything so I can adjust it and see the results in real time. Everything at 70cms is so small that experimentation is really fun!
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Oct 31, 2020 23:51
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Probably of interest here is the Amateur Radio Emergency Data Network that basically works as a LAN for any nodes in the region, and it’s been thoroughly stress tested with mobile nodes using VOIP. There’s a few totally solar nodes running livestreams of video in remote locations. You basically run one medium range radio with a connection to a WiFi router, and then host a server for the LAN or connect to other services on the network. https://www.arednmesh.org/ https://youtube.com/watch?v=SQIFJe3rmZ0
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Nov 1, 2020 21:01
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Anyone wanna buy a shitload of ladder line? Turns out making antennas is for chumps and is best avoided and you should just buy one. Who knew? I threw my wire cutters across the room after accidentally severing one side and just realised it was time to give up.
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Nov 6, 2020 16:46
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thehustler posted:Anyone wanna buy a shitload of ladder line? Turns out making antennas is for chumps and is best avoided and you should just buy one. this hobby is totally pay to win >:[
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Nov 6, 2020 23:38
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thehustler posted:Anyone wanna buy a shitload of ladder line? Turns out making antennas is for chumps and is best avoided and you should just buy one. What? Just do a Western Union Splice and cover it up with some weatherpoof goop.
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Nov 6, 2020 23:51
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i recently received one of those new model nanovna v2 in the mail and used it against every antenna i already had and learned a lot. it also showed me i can basically make a resonant antenna out of anything that has coax and some wire at the end of it. not bad for the price. i figure any antenna analyzer will do the same thing for teaching. before that the swr meter in my hf rig wasn’t really doing it for me
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Nov 6, 2020 23:53
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manero posted:What? Just do a Western Union Splice and cover it up with some weatherpoof goop. Problem is that you're shortening your already-cut-antenna then. I had a decent ish 2M one and snapped it too many times and ended up cutting it in half and making two 70cms versions. One turned out OK, the other turned out poo poo, but now I've overcut them both during tuning and they're resonate at 446MHz so that may be a happy accident. But I have a 2M 300 Ohm one that I've just made according to yet another random page of dimensions online and I know it won't work right. I'm getting to the stage where I am genuinely considering paying somebody to make me one resonate for the UK 2M band for SOTA use. I just want something that works, I can't be arsed loving about anymore. I have a NanoVNA, I just wasn't prepared for how much literally moving the unit with cable attached would change the properties. I am trying to tune antennas on the shortest length of coax I can and then I plug my 5 metre length in and the VNA reads totally different - expected, perhaps, but your numbers go all to cock and you aren't sure what is true anymore. Edit: followed dimensions perfectly on that 300 ohm version and got 140mhz. I can just shorten the top a bit and resolder the ends together I guess? Will that bring it up? thehustler fucked around with this message at 17:25 on Nov 7, 2020 |
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Nov 7, 2020 02:26
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Oh you're trying to do J poles with ladder line. Yeah, dimensions are important there  I'll be honest i'm very experienced with a lot of builds and have never built a functioning ladder line j-pole, so you're already way ahead on the last one. Agree that you should shorten the end by a few mm and see if it creeps up. Also be aware that you'll need some sort of choke (either air core or ferrite) where the coax joins it, otherwise there's a high chance your coax shield is going to act as part of the antenna, and will be detuned by various objects and generally not work the same in two different setups. The choke is key.
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Nov 8, 2020 20:28
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I have a clip on ferrite and the SWR is 1.12 with the antennas short coax of like 30 cms. As soon as I attach the 5 meter coax I want to use with a pole it goes up to 2:1. Is that a true measurement or is my NanoVNA lying? Snipping the matching stub made the frequency go up where I wanted it
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Nov 8, 2020 21:32
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I just wanted to report back and say that I finally got something working ok-ish 2M with my Slim Jim and managed to join my first ever net tonight (Edinburgh and District ARC)  there’s room for improvement but I don’t want to gently caress it up - it’s good enough. Time to order a fiberglass pole and see how much it breaks it and hoof the whole lot up a mountain for SOTA. Appreciate the help from folk here.I still haven’t had much luck with one for 70cms so I may have a crack tomorrow. 2M Slim Jims tend to be resonant at 440 which is way above U.K. 70cms allocation. I do have parts for a 1/4 ground plane on a socket type thing so I’ll give that a go. May be simpler. Still hampered by a crap QTH though. Edit: after I got a proper air choke on it the SWR came back down to like 1.3-1.4 ish. Edit 2: one other question, because nobody could hear me on 70 someone set up a rebroadcast to 70 of the channel we used on 2M. Is that... legal in the U.K.? It’s not a repeater, but it feels dodgy. thehustler fucked around with this message at 01:20 on Nov 10, 2020 |
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Nov 10, 2020 00:45
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Hey guys, can you teach me everything there is to know about antennas real quick?  I've done a bit of poking around and reading and just want to check if what I think I've learned is actually valid. Basically, I got a few ESP32-Cam modules a while ago and they come with a PCB antenna on the board and also an I think U.FL connector (one thing I'm not clear on is the difference between U.FL and W.FL, the wiki page says W.FL is even smaller but then lists the same diameter as U.FL? Is it just mated height that's different?). I have an box o' old computer crap that I grabbed an old busted TrendNet TES-637AP/A from, which is a 300Mbps WiFi N access point. I believe 300Mbps means it's MIMO but I'm not sure if that's actually part of the spec or just a common feature of access points for that spec. Here's what I've got:  I don't know anything about these antennas and have been trying to learn a bit. I've been mostly plating with the one that the plastic housing bit broke off and got lost from. Looking at it, I think the bit at the very end that is just the center connector with the shielding stripped away (but still enclosed in some sort of clear insulation) is effectively the antenna and it's a monopole with no ground plane. The rest of the wire which does have shielding around the center conductor functions as a transmission line so effectively just lets the antenna be located "far" from the coax connector on the PCB. As far as I can tell looking at the one that still has its plastic housing, there's nothing metal in there and it serves as a way to protect it, maybe keep it straight (not sure how big a difference that makes) and allows you to tilt and rotate it. The housing for the access point's PCB also seems to be just plastic so I think that these have no ground plane when used in their original position either. With no ground plane, I think the radiation pattern becomes more of a flashlight from the tip of the antenna whereas with a ground plane it would be a donut shape around the length of the antenna, assuming the antenna was perpendicular to it, but this is definitely one of the things I really don't know if I'm understanding correctly. I measured the stripped bit at the end at roughly 2.61cm which if it's behaving as a 1/4 wave monopole gives it a center frequency of 1/(2.61 cm * 4 / speed of light) =~ 2.87GHz which seems a little high for 2.4GHz wifi (center channel 6 is 2.437GHz) so I don't know if I'm wrong about what type of antenna it is, if that's a length that's a compromise and lets it be used well enough with all the global frequencies, or if it's just not that sensitive to that length so they don't bother making them super precisely. The access point obviously uses two of these antennas, not sure if the other one has the same amount of exposed conductor at the end or it's different. I'm also not so sure that they're used as monopoles in their original configuration on the access point or if they're hooked up in a way that makes it one dipole antenna, like a TV rabbit ears antenna, instead of two monopoles (or if that's even possible). I *think* WiFi MIMO is effectively two separate radios on adjacent channels and that they would both therefore be monopole antennas but I really don't know. I'm not totally sure how the PCB trace antenna works. I think this one is an inverted F type antenna that's folded a bit to save space. This type of antenna is also a monopole I think but the main advantage is that they can connect one leg of the F to ground and the relationship between this and the other leg allows them to impedance match this antenna with the output impedance of the SoC. I'm not sure if I need to impedance match the external antennas. I would think the output impedance at the U.FL connector is 50 ohms and that the external antenna would also be 50 ohms just because I'd expect them to have been designed to that standard but no idea how to check those assumptions. I guess my questions are, am I somewhat close to understanding this? If I am, I think the primary benefit to these particular external antennas is just simply to get the antenna away from the PCB, especially if you were going to put it in something like an Altoids tin and gives you a way to position it if you're using the one that still has its plastic part attached. Otherwise, I think they should have roughly the same performance so if you just have the PCB naked in the air, there's not really likely to be a benefit to these particular antennas? Appreciate any help you guys can give, hope I've explained my current "understanding" well enough.
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Nov 13, 2020 19:47
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What are you trying to accomplish with all this?
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Nov 13, 2020 20:01
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it's a sort of quarter wave, but done to really inexpensive specs. It'll Radiate, basically, but that coax is radiating too, those are kind of a mess of a design but I don't expect manufacturers to put super high quality antennas in consumer gear. Those are almost assuredly u.fl connectors. i don't think i've come across w.fl before.
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Nov 13, 2020 20:13
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Just learning really. I got these boards to play with and saw the hookup for an external antenna and then had the thought of "hey! I have some antennas that I think I can hook up there!". So I'm playing with it to see if it's "better" in terms of range, but after trying to learn about the antennas I think these might be the same as the PCB antenna that they already had in ideal terms and thus they might not be expected to have better performance. So just trying to understand if that is the case, and if it is, why would you want these antennas vs a trace antenna? I think being able to enclose the PCB in a shielded box would be one benefit. Being able to position the antenna without repositioning the entire device would be another I could see, and I'm wondering if in practical terms that ability is actually a pretty large benefit over the trace antenna. I intend to collect some terrible data by writing a little program to log the wifi signal strength it's seeing but haven't done this part yet. Seat of the pants looking at my router's dashboard it seems that the antennas are indeed performing roughly the same. In both cases the ESP32 modules are just sitting naked in the air. I forgot to mention it above but my understanding is also that WiFi is pretty limited by regulation and that you can't just slap a high gain antenna on there because you're only allowed to output at a certain level and the amplifier can probably hit that level with a pretty basic antenna? Edit: ^^^ OK so it sounds like I'm on the right path in understanding here. So what could be the reason the AP manufacturer used marginal external antennas instead of PCB trace antennas since the housing is plastic anyway? Is the ability to position them independently a large benefit? Would having two antennas on the same PCB have caused problems? Is it just a marketing thing because having those antennas makes it look like a more serious piece of equipment to the average Joe? I'm thinking it's a combination of the above with heavy emphasis on the marketing one. Forseti fucked around with this message at 21:07 on Nov 13, 2020 |
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Nov 13, 2020 20:20
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They work a little better, and also manufacturers get charged by the square inch (cm, whatever) for board design. If the PCB size needs to be enlarged and it costs 10 cents more per board, but you can get those antennas for 8 cents, the choice is clear.
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Nov 14, 2020 19:33
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Thanks, that makes sense. Appreciate the input on stuff that's probably pretty basic and boring for this thread, very helpful when trying to learn about something to get confirmation that you're barking up the right tree!
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Nov 15, 2020 21:02
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Just passed the tech and general tests this morning. Time to read through the last 188 pages to see what I should focus on now!
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Nov 15, 2020 21:09
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Sir Bobert Fishbone posted:Just passed the tech and general tests this morning. Time to read through the last 188 pages to see what I should focus on now! Congrats!
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Nov 16, 2020 00:13
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Sir Bobert Fishbone posted:Just passed the tech and general tests this morning. Time to read through the last 188 pages to see what I should focus on now! protip: having lots of money solves a lot of problems.
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Nov 16, 2020 09:31
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https://v.redd.it/urjq94234jz51
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Nov 16, 2020 21:54
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My station wagon does that. Same antenna too. My favorite is when I go full speed under one particular bridge that's juuuust an inch too low. CLONK idk how it isn't bent yet.
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Nov 17, 2020 04:52
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My BMW does the same with its CB antenna. From the trunk lid it's just barely tall enough to hit every single beam in most parking garages.
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Nov 17, 2020 16:52
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i've got an 8 foot HF whip on a spring and boy howdy when i find an untrimmed limb it's exciting
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Nov 18, 2020 01:22
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Due to COVID I'm going to be taking a lot more road trips over the next year or so, and will probably be moving between states in the same timeframe. So, I got a van. I was planning on putting a CB in it, because if I'll be on the road a lot, why the hell not. But I heard from a friend that, presumably, no one uses CB anymore; or at least not enough for it to be fun. He the said to get "a Boafeng setup for FRS/MURS." I've done a little research, and it seems like those aren't quite comparable in terms of use (like, FRS and MURS aren't really for tuning in and hearing a bunch of people bullshit with each other); is that accurate? Do they have any equivalent of CB channel 19? He also said that by going with a FRS/MURS unit I can possibly mess with CHUD militia comms, which sounds just delightful. I trust the goon radio hivemind more than I do this friend, so what do I do here? What do folks put in their cars these days? Honestly my experience with radio is basically just seeing the movie Breaker! Breaker!, and having a pocket shortwave receiver that I used to listen to random doomsday preachers. So I'm starting from square one here.
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Nov 20, 2020 07:02
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Capn Jobe posted:He the said to get "a Boafeng setup for FRS/MURS." Baofeng makes FRS/MURS legal radios but they also make radios that are capable of transmitting on FRS/MURS illegally. If you do go this route, make sure the Baofeng you buy is licensed for the frequencies you want to use. The chuds use these for their militia cosplays a lot. Some of them get ham licenses, some probably just operate illegally. I have a plain old CB radio with a big Wilson 1000 on the roof of my car, and I keep a lovely Baofeng HT tuned to the local repeater. I don't get much traffic on the CB out here in the mountains but a few families around here use the UHF ham repeater to cover for cell service gaps so occasionally you'll catch someone's dinner plans. CB's handy for long highway trips if you want to communicate with the trucks. Before Waze and before really-good-Google-maps-data it was still the best way to get live local traffic and speed trap alerts on major interstates. Now it's... well, 6 still lights up...
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Nov 20, 2020 07:34
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CB 19 was clutch when I drove down to ABQ in the middle of a snow storm on back roads. The semi leading the caravan and I chatted and I made sure to keep distance and he'd call out the sketchy curves and stuff. Great for road trips and there's a little Denver local chatter too. > What do folks put in their cars these days? My truck has a yaesu 8900 for 2m and 70cm (no lol i don't use the 10 or 6 bands, FM is dead-ish down there), a little uniden 510 CB and then my current HF rig is a Kenwood TS-50s with the autotuner in the back, right at the antenna feedpoint. It needs a capacitor job though and is getting a little long in the tooth, so I'm actually considering replacing it with a Yaesu 891. Remote head mountable and it's a very simple UI. The last thing you want on a mobile radio is fancy touchscreen poo poo.
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Nov 20, 2020 23:52
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Just joined my local AREDN ham mesh. 23 total nodes on the mesh. I'm the ONLY RF link, lol. All tunnels. Guess it has to start somewhere! The radio, CPE210, was like $25 used on ebay. noice.
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Nov 21, 2020 06:00
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hell yeah. I kept a 5.5-11mbps link up to a tower 7 miles away for a couple years with a bullet m2 up and a 14db patch antenna i bought at microcenter
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Nov 21, 2020 06:07
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Only got about 30-100KB/sec right now. A megabit would be cool. Need more height, like always. Text chat seems to work ok but drags clicking around multimegabyte webpages to get to. I was thinking of using a patch antenna and some ubiquity stuff but my local network is all mimo. The multipath performance is nuts, I was able to see the beacon from a node inside my stucco house via bouncing in a window. Crazy. Also! I am not the only RF Client! The tunnel is actually at someone's house I am hitting through the node. Seems a little more meshy! Jonny did you run any services? other than iperf
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Nov 21, 2020 17:45
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all i really did was throw up a proof of concept wiki and a little irc server but the only thing the locals seemed to care about was using it for free remote feeds to watch their cabins and chicken houses =/ so i kinda lost interest.
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Nov 21, 2020 22:49
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