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A week into my ham license and I just scored a good deal on an FT-891. While I wait for that to ship and arrive, I'm looking into the hows and whats and whys of setting things up in the space I have available. Got a lot of thinking to do about antennas, but I spent some time last night thinking about equipment grounding, since I'll be on an HF-only radio. Any RF ground line I run from the shack will likely have to travel 15-20 feet to the ground rod already installed in the back yard. I'm understanding that this is just about the length where it could start resonating and causing some problems. So, because I'm a complete noob, I have a couple questions for anyone with more experience: - If I run 10-15 feet of flat copper strap for the majority of the run, can I attach standard copper wire to each end to make it easier both to connect to equipment and route out of the house, respectively? The ~1-3 foot runs of wire at each end should still be better than an entire 20 foot run, right? Or is there a reason it'd need to be strap the entire way? - I ran across this "RF Suppressor Ground System" article online (Alternative 2 at the bottom of this page) that implies you can use coax and an HV capacitor to get to ground at any line length without worrying about RFI. If this were true, seems like everyone would be using this method and it'd be plastered all over books and the Internet. Has anyone used this, or seen this used? Or am I worrying too much about RF grounding in general?
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Nov 22, 2020 16:05
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Sir Bobert Fishbone posted:Or am I worrying too much about RF grounding in general? Most likely. Get your gear set up first and see if you actually have a problem that needs solving. I've had those problems, and I've also run (and am currently running) with a bare minimum and have zero issues at all.
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Nov 22, 2020 16:20
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Motronic posted:Most likely. Exactly what I wanted to hear. Thanks!
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Nov 22, 2020 16:32
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Jonny 290 posted: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. I feel this, but I've got gazebos and driveways, no coops or cabins. I'll probably setup some logging about the RF links (prometheus + grafana) but quickly not sure where to go. If the network grows might be able to do interesting stuff, may as well leave it up.
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Nov 22, 2020 18:17
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anybody have any experience with VOXing on Anytone dmr handhelds?
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Nov 27, 2020 11:48
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Random question, would it have been illegal when this guy turned on this Vietnam-era emergency beacon that transmitted on 282.0 MHz? https://www.youtube.com/watch?v=2Zjv1u9GOs8&t=155s its cool, Im not a narc
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Nov 28, 2020 08:10
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The Scientist posted:Random question, would it have been illegal when this guy turned on this Vietnam-era emergency beacon that transmitted on 282.0 MHz? Pretty sure that's still Coast Guard Operations so yeah......if it's not an emergency you're not authorized to transmit on it. Depending on where he is and the building construction absolutely nobody noticed.
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Nov 28, 2020 17:54
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It sorta pains me as a licensed ham but I am looking at buying a pair of FRS walkie talkies, to keep in contact with non-ham family members while out in the mountains but within a mile of each other. I figured this thread would be a good place to ask. Any recommendations? Or is it simple enough that selection doesn't matter much? The Bi-Mart by me carries several tiers of Midland brand FRS radios, so if those are considered decent I will probably get those. Also these Midland ones don't list actually the transmission power on the package, just some lovely overly optimistic maximum range estimate! 
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Dec 1, 2020 01:19
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alnilam posted:It sorta pains me as a licensed ham but I am looking at buying a pair of FRS walkie talkies, to keep in contact with non-ham family members while out in the mountains but within a mile of each other. I figured this thread would be a good place to ask. Any recommendations? Or is it simple enough that selection doesn't matter much? The Bi-Mart by me carries several tiers of Midland brand FRS radios, so if those are considered decent I will probably get those. if it doesnt list the power then its 500mw (if not less) and old-rules FRS you probably would be best suited just paying the fee for the no-test GMRS license (covers whole family) and looking specifically for new-rules (post 2017) radios that claim to be GMRS and do list the power (which should be like 2 watts?)
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Dec 1, 2020 01:24
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Wait so they changed the rules 3 years ago but still nobody makes a 2W FRS radio?
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Dec 1, 2020 05:27
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https://www.google.com/search?q=%222+watt%22+%22frs%22+%22radio%22+-gmrs+-dmr+-ham&ie=UTF-8&oe=UTF-8&hl=en-us&client=safari I found the search link from here, where stackexchange is being stackexchange but some helpful posts managed to make it through
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Dec 1, 2020 05:51
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I've just picked up a DMR radio on test (MD-390) and it's loving weird. I have a UHF repeater near me that I can open fairly well on analogue. It's only a mile away. But on DMR I am just not getting in to another repeater at the same QTH. I'm using a 70 Slim Jim with an SWR around 1.1 on the input frequency of 438MHz, and I've also tried a couple of 1/4 wave HT antennas too. I get a full signal on Rx from the repeater and it decodes with no audible errors. But my input just isn't getting in at all. That same Slim Jim (or the 1/4 wave antennas really) has zero issues working the other repeater on analogue at all. One thing I have noticed is that when I hit PTT the red light sometimes flashes 3-4 times and then stops. There's no signal coming out of the repeater at the time so I'm not blocking someone. But there's no connection at all made. I also noticed that my clock on the display is in no way correct. Does this have an effect on your outgoing signal at all? Does it need to be accurate? Not liking this at all, it's very weird. I don't want to plug the hotspot in because I feel it defeats the point, but I will to make this test fun if I have to.
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Dec 1, 2020 11:49
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It seems my radio may be hosed so I’m getting it swapped for an MD-380. We’ll see how it goes.
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Dec 1, 2020 18:24
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Achmed Jones posted:https://www.google.com/search?q=%222+watt%22+%22frs%22+%22radio%22+-gmrs+-dmr+-ham&ie=UTF-8&oe=UTF-8&hl=en-us&client=safari This is maddening, almost nobody lists their Tx power so even that google link misses a bunch of potentially good choices. It seems if you go to amazon product Q&A, inevitably someone asks the power and in the case of Midland radios, the manufacturer actually responds with the ERP. The highest end FRS radio with a "range" of 38 miles transmits 1.5W, which is kind of strange - it's above the old rules limit but below the new rules limit, it seems strange they wouldn't make one that does exactly 2W. Check out this bewildering answer from amazon Q&A for the T290VP4 GMRS radio with a quoted 40 mile range: Haha, you have entered the wormhole. These radios are 2.85W according to the FCC filing for the radio FCC ID MMAT295. (Both T290 and T295 have the same ID). Watts can be misleading though, because this radio has a longer internal antenna than the popular GXT1000 and therefore performs a bit better. And to add to your confusion, there are 3 (yes 3) different FCC filing for the GXT1000. The newest GXT1000 radios made after Sept 2018 under FCC ID MMAGXT1050G are now only 2.5w. These radios are junk. If you can find GXT1000s a bit older before 2018 under the FCC ID MMAGXT1050P, those are a bit better at 3.07w. Then there's the totally discontinued GXT1000s manufactured before 2015 that have FCC ID MMAGXT950 that have the full advertised 5.33w. If you can get your hands on these older radios, they are amazing. Also the answers in that stack exchange link recommend looking for hybrid FRS/GMRS radios, but most manufacturers seem to have since changed their marketing and no longer use that designation, they just call everything 2W and below FRS now.
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Dec 1, 2020 20:29
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Got my replacement test radio and now DMR is cool and I am starting to like it. I do definitely think the hotspot stuff doesn't interest me, but I don't mind internet-connected "proper" repeaters. Getting the same signal in to it as I did with my analogue TXing to the same RX site now. How much do people use DMR simplex? Is it very geographic in its use, does nobody really use it, or do people actually give it a go vs analogue FM? I am tempted for SOTA use, but I guess for remote activations it may be better to pull a voice out of static instead. Depends how much is around you. In other news I have no idea why 2m Slim Jims resonate so high up in the 70cm band - can anyone explain that? They *work* on 433 FM but the trough is more towards 438 - perfect for 7.6MHz split repeaters, but not really for analogue FM. It's not like other antennas where if it works on 145 it works on 433, etc. Edit: ignore me, the resonance seems to only changes with coax attached so something must be up. thehustler fucked around with this message at 18:39 on Dec 2, 2020 |
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Dec 2, 2020 16:39
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alnilam posted:This is maddening... mycrimes.txt and all but i simply gave up on correct radios and use a bank of CP200d's for GMRS/FRS use these days
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Dec 2, 2020 19:30
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why is it so difficult to get audio in / audio out over bluetooth to pc/laptop? i guess ill have to buy tsa6015 to get bluetooth.
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Dec 2, 2020 19:46
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I went to a local store and by total coincidence found the strongest Midland FRS-only one (that is either 1.5 or 2 watts) on a one-day sale for $50 instead of $80 a pair. They only had the T75, the camo print version of the T71, so now my FRS radios are camo lol  but hey lucky find on the sale. It will probably serve our purposes fine and if not I'll sell it and go GMRSSniep posted:mycrimes.txt and all but i simply gave up on correct radios and use a bank of CP200d's for GMRS/FRS use these days i'm telling
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Dec 2, 2020 19:48
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Just moved into a townhouse in the SF Bay Area (big mistake, I know) and I'm looking at my HF antenna options. I've set up my office on the second floor and had hoped to just run a stealthy random wire out to a tree behind the building, but the windows are metal-framed casements. I think penetrating the wall is probably out of the question. Is there any sort of trick to getting an antenna feed through a casement window without just leaving a big open gap at all times? Otherwise, I have a 20m hamstick I could clamp to the window frame as needed... or I guess I could try running some sort of loop around the ceiling of my 10'x10' office.
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Dec 7, 2020 17:05
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Why is penetrating the wall out of the question? How about penetrating the window frame or even casing? Is this because you're renting? I get it if that's the case. But if you're not there are options. Including coming out of the soffit if there is a roof above this second floor office.
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Dec 7, 2020 17:22
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Motronic posted:Why is penetrating the wall out of the question? How about penetrating the window frame or even casing? Yeah, it's a rental, forgot to mention. The office is on the top floor and the roof is indeed right there, and with some slightly dangerous stretching I could reach out the window and touch the soffit, but if there is access to the attic from inside the building, I haven't found it yet.
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Dec 7, 2020 17:36
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Pham Nuwen posted:Yeah, it's a rental, forgot to mention. The office is on the top floor and the roof is indeed right there, and with some slightly dangerous stretching I could reach out the window and touch the soffit, but if there is access to the attic from inside the building, I haven't found it yet. For a rental you're probably down to getting creative with making a wedge that fits the casement window when slightly open that both seals it and leaves you room to run wire through.
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Dec 7, 2020 17:48
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Pham Nuwen posted:Yeah, it's a rental, forgot to mention. The office is on the top floor and the roof is indeed right there, and with some slightly dangerous stretching I could reach out the window and touch the soffit, but if there is access to the attic from inside the building, I haven't found it yet. At one point I used something like the Comet CTC-50M to get though a window with something without making holes. It is essentially a short flat transmission line with connectors on each end. https://www.dxengineering.com/parts/cma-ctc-50m
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Dec 7, 2020 17:57
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Here’s some good nautical radio nerdery
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Dec 7, 2020 18:31
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I wondered what the heck happened to ya pham. Hope you are enjoying SF! https://mfjenterprises.com/products/mfj-1622 would be my first suggestion. They suck at 40m, don't believe that, but on 20 and up they're alright. Otherwise just cut a piece of pine 1x3 or something to fit the window width, put a 1/4x20 long bolt through it with wing nuts and run your hot wire through there, use the window frame for ground and maybe add a couple counterpoises.
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Dec 7, 2020 19:35
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Jim Silly-Balls posted:Here’s some good nautical radio nerdery Never seen that for anything marine, but keying your mic is pretty common in aviation to enable/dim runway lights, etc.
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Dec 7, 2020 20:08
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The thing I don’t understand is how on earth you would see that sign when you really need it. In order to read that sign from a boat you would need to be dangerously close to the lighthouse on a clear day during the day time. Exactly the time that you don’t need a lighthouse Hell I had to get closer than I wanted to with my drone to see the drat thing. Unless keying the mic 5 times is just standard lighthouse activation throughout the boating world.
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Dec 7, 2020 20:13
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chrisgt posted:Never seen that for anything marine, but keying your mic is pretty common in aviation to enable/dim runway lights, etc. The USCG has been rolling it out for a while now. Getting rid of the fog detectors that didn't always work right... Plus less noise for rich people to complain about. quote:The Coast Guard is replacing many fog detectors with mariner radio activated
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Dec 7, 2020 20:15
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razak posted:The USCG has been rolling it out for a while now. Getting rid of the fog detectors that didn't always work right... Plus less noise for rich people to complain about. Huh, cool! learn something new every day.
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Dec 7, 2020 20:56
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My father was a private amateur pilot in his day and would tell a cool story of the visual effect of flying in a small plane in the middle of the night over a rural area with like 0 light pollution and keying the mic 6 times on the grass mountain airstrip frequency to have runway/landing lights just emerge before you from the black abyss of what was the cockpit windows and it’s apparently a sight.
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Dec 7, 2020 21:05
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Jonny 290 posted:I wondered what the heck happened to ya pham. Hope you are enjoying SF! Thanks, Jonny, I'll see if I can figure out a good way to mount that outside the window. There's a little lip under the window, so I could potentially attach to that. We just got to SF last week. When we decided to move a couple months ago, things were looking good, so it was, uh, interesting to watch the progression of poo poo as the move date approached. Hoping that the pandemic makes the biomedical industry take a look at itself and ask if it's a good idea to put essentially all west coast research in a few square miles of South San Francisco and San Diego...
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Dec 7, 2020 21:07
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RadioPassive posted:My father was a private amateur pilot in his day and would tell a cool story of the visual effect of flying in a small plane in the middle of the night over a rural area with like 0 light pollution and keying the mic 6 times on the grass mountain airstrip frequency to have runway/landing lights just emerge before you from the black abyss of what was the cockpit windows and it’s apparently a sight. It's very cool indeed! Can confirm that.
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Dec 7, 2020 21:58
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Found a remote root exploit (wormable - in true mesh style) in a popular 3rd party AREDN package. My entire mesh was vulnerable and the huge global AREDN network had probably over 50 nodes. I avoided the "Fuckery/exploits" and did responsible disclosure. Submitted a pull request with a fix, even. The people maintaining AREDN were super reasonable, had the fix posted, and forums cleaned of bad links in under 24 hours. Pretty good experience. And it wasn't even their package. The entire AREDN stack is CGI PERL!! in 2020. The 1st party packages seem to have been secured. Only took me around 5 beers to find my root RCE. Might take many more to find a second but smoke/fire.
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Dec 9, 2020 05:13
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Dang, nice hackin there. well done --- Actually threw my old Ringo up on a stick and ran coax back out to it (my landlord bitched 6mo ago so i ripped down my antenna farm in one night to keep them happy and have been 100% QRT since then). They're running a daily covid net where they talk about numbers and call out any new or lifted lockdowns or restrictions. Reasonably useful. Made a contact with a SOTA operation, not bad for being such a compromise setup compared to what I had up.
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Dec 10, 2020 19:04
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FT8 might be killing ham radio [citation needed], but it sure is a super fun way for a total noob to get confirmation that yes, in fact, your lil' backyard loaded vertical does have enough oomph to get you seen on every other continent on the planet.
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Dec 13, 2020 02:09
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Sir Bobert Fishbone posted:FT8 might be killing ham radio [citation needed], but it sure is a super fun way for a total noob to get confirmation that yes, in fact, your lil' backyard loaded vertical does have enough oomph to get you seen on every other continent on the planet. I have a hex beam, which gets me 6/10/12/15/17/20m really well. The fun part is watching for 6/10m to open up and start hitting Brazil with 5 or 10 watts. Some linked this guide a few weeks back on the Discord server: https://g4ifb.com/FT8_Hinson_tips_for_HF_DXers.pdf Read though that and you realize that it is a lot more complex than just some jack rear end in Missouri blasting 350W from his 80ft tower trying to rack up as many QSOs as possible.
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Dec 13, 2020 02:31
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DevNull posted:I have a hex beam, which gets me 6/10/12/15/17/20m really well. The fun part is watching for 6/10m to open up and start hitting Brazil with 5 or 10 watts. This looks like a good read; thanks! I threw together my eBay-special Easy Digi interface last night and hit Spain on 20 this morning from Colorado with my little antenna at 50W, which got me all kinds of riled up.
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Dec 13, 2020 02:43
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If I know my output power, height of antennas, and both locations, and I know that got a signal report from a certain distance of miles away to that second station, is there a way to take that S number and estimate how far that signal actually went? I know radiomobile does coverage maps, but this is me wanting to work with real world readings
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Dec 13, 2020 17:20
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for VHF/UHF? Honestly, you can do path loss calculations, but really the rule of thumb is horizon distance + a few percent (probably +3-5% for 2m and 1-3% for 70cm). This assumes totally flat terrain and no big buildings near the path - you can get either beneficial reflections off a warehouse or bad ones. Think about satellite work. It's no less than 600km away and five watts into a modest antenna gets you full quieting. And those birds have like 100 mW transmitters, i've often gotten s9+ levels off of them.
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Dec 13, 2020 18:06
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Thanks, that helps a lot, I can just calculate from there then.
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Dec 13, 2020 18:08
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