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Sure, no problem. If you want to be an eagle scout about it, bury some 2" or so PVC with a couple drain holes facing downward every few feet, run a stringer line (hint: fishing line, ping pong ball and a vacuum cleaner) and pull it through. Or you can just direct bury and accept that you may need to replace it in 4-5 years. I've had buried runs for that long with no problems at all. I swear by Shireen coax; their RFC400 stuff is really good and half the price of Times Microwave LMR400. I bought a 1000 foot spool from them for $400 years ago and still have a couple hundred feet left, and i use it eeeeverywhere. My current dipole is at the end of 80-ish feet of RFC400 transitioned into about 60 feet of RFC240 (lighter for the suspended run up to the feedpoint) and it works absolutely great. Here's who heard me after two contacts on 40m, on 5 watts of FT8 this sundown, and what the waterfall was looking like across 40. Coax loss isnt a huge thing down on HF.   Get the apex 25-35 feet up and you too can pull in the continent, if not the globe
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Oct 19, 2022 04:08
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If the apex height off the ground is less than the total length of the ladder line, what do I do with the extra? Also, would I need to buy a tuner for this setup? I'm not against getting a tuner, i'm just trying to figure out what I do and don't need before i buy a bunch of poo poo i don't have immediate use for.
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Oct 19, 2022 06:16
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Jonny 290 posted:Sure, no problem. If you want to be an eagle scout about it, bury some 2" or so PVC with a couple drain holes facing downward every few feet, run a stringer line (hint: fishing line, ping pong ball and a vacuum cleaner) and pull it through. Or you can just direct bury and accept that you may need to replace it in 4-5 years. I've had buried runs for that long with no problems at all. I swear by Shireen coax; their RFC400 stuff is really good and half the price of Times Microwave LMR400. I bought a 1000 foot spool from them for $400 years ago and still have a couple hundred feet left, and i use it eeeeverywhere. fuckin sick as hell man
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Oct 19, 2022 12:28
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Jonny 290 posted:how much land and trees do u have?  the noise...  which is why i am looking at common mode chokes. i am also borrowing/soon buying a ft8900 for vhf packet use (digirig mobile), its nice finally having more than 6-7 watts from a handheld. Big Mackson fucked around with this message at 14:37 on Oct 19, 2022 |
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Oct 19, 2022 14:32
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andrew smash posted:If the apex height off the ground is less than the total length of the ladder line, what do I do with the extra? Also, would I need to buy a tuner for this setup? I'm not against getting a tuner, i'm just trying to figure out what I do and don't need before i buy a bunch of poo poo i don't have immediate use for. It needs to be uncoiled and away from big metal objects and the earth - that's the tricky part. Generally people in that situation will have a tie-off point 6-10 feet off the ground and pull the ladder line out horizontally to the coax transition after which you can do Whatever, but in your situation if you're going for superstealth you're going to have to be....creative. If you definitely can't do something like that you may want to look at something like an OCFD or fan dipole, which can be fed with coax the whole way. As far as tuners go, yes, you'll want one. It will be useful for your whole rear end ham career. Big Mackson posted:
Common mode will cut down the noise buuuut it's now also hamstringing the coax shield's use as a counterpoise. With a situation like that, i often suggest a variant of the off center fed dipole. a 'standard OCFD' has a 1/3 - 2/3 split; meaning that say with mine, it's 66 feet total length and the legs are 22 and 44. Fed with a 4:1 balun into coax. The advantage of this is that you can get pretty close to no-tune on a few bands. However somebody figured out a while ago that you can do a 1/6 - 5/6 split and the SWR isn't really close to 1:1 on any band, but it's low enough that any tuner can handle it with few losses, and it's now usable on the third harmonic. Mine, for example, is cut for 40m and is not usable on 15m. the 1/6 setup solves that at the expense of always needing a tuner. so say you wanna play on 40m and up, you'd have 11 foot and 55 foot elements, and that's pretty doable with the layout you have there. The balun will be only 11ft +insulator distance from the house and you can just kind of let the coax droop a few feet down from that and then bring it towards the house.
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Oct 19, 2022 18:49
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I may be able to convince the wife that a 40 odd foot pole guyed into the trees isn't a big deal. Jonny 290 posted:As far as tuners go, yes, you'll want one. It will be useful for your whole rear end ham career. is it better to use one that connects at the transmitter or one of the automatic weatherproof ones that connects at the feed point? are they each good with different use cases?
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Oct 19, 2022 18:54
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I need to find a way to get an inconspicuous antenna set up on my apartment balcony. technically my lease agreement only says no satellite dishes so I bet I could disguise it as christmas lights or something and put it along my railing but that does leave the question of how to get the lead to it actually inside I don't have a license yet so I'm not going to be keying up or anything but I wouldn't mind listening to the aether from time to time
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Oct 19, 2022 18:55
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Kazinsal posted:I need to find a way to get an inconspicuous antenna set up on my apartment balcony. technically my lease agreement only says no satellite dishes so I bet I could disguise it as christmas lights or something and put it along my railing but that does leave the question of how to get the lead to it actually inside 
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Oct 19, 2022 19:00
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andrew smash posted:I may be able to convince the wife that a 40 odd foot pole guyed into the trees isn't a big deal. It's best to minimize the length of feedline that is on the 'high swr' side of the setup. Shack tuner setups will always be a bit lower performance than a tuner at the antenna; the flip side is that outdoor remote tuners are expensive, need to be weatherproof, and generally can only be used for one antenna, versus the shack tuner that can be used with many. You dont even need the tall pole for this setup if you have a limb 40 feet up that you can get a rope over. hanging the feedline is fine as long as the ladder line section stays clear.
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Oct 19, 2022 19:17
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Jonny 290 posted:Common mode will cut down the noise buuuut it's now also hamstringing the coax shield's use as a counterpoise. Hmm, i have added a wire to the coax shield (right before it goes inside) and it leads to a ground rod, is the counterpoise already messed up?
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Oct 20, 2022 16:05
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Big Mackson posted:Hmm, i have added a wire to the coax shield (right before it goes inside) and it leads to a ground rod, is the counterpoise already messed up? A counterpoise is an alternative to ground. Unless your ground is really bad, it should be better than a counterpoise from what I understand.
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Oct 20, 2022 16:26
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DevNull posted:A counterpoise is an alternative to ground. Unless your ground is really bad, it should be better than a counterpoise from what I understand. it goes to a 1 meter ground rod and that ground rod is connected to another ground rod 1 meter from the first ground rod but i can also connect to a third ground rod 5 meters away if i i need more ground rod. ground rod.
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Oct 20, 2022 17:33
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Big Mackson posted:it goes to a 1 meter ground rod and that ground rod is connected to another ground rod 1 meter from the first ground rod but i can also connect to a third ground rod 5 meters away if i i need more ground rod. I think you are probably fine, it is also a matter of ground composition. That said, I think a lightning arrester would be better. That should ground the shield, and will also ground the center if there is a close by lightning strike.
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Oct 20, 2022 19:26
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https://twitter.com/xssfox/status/1578690753131581441
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Oct 20, 2022 19:28
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Big Mackson posted:it goes to a 1 meter ground rod and that ground rod is connected to another ground rod 1 meter from the first ground rod but i can also connect to a third ground rod 5 meters away if i i need more ground rod. ok! you are on the right track and doing the right thing. However, you're also running up against one of the reasons i hate end feds. The impedance by the balun/transformer box is insanely high. like 3200 ohms. what this means in reality is that signals do not need to generate much current in the wire at those points. any old fuckin' noise can worm its way in there. so, even though your counterpoise/ground is lightning-solid, we'll say, the noise signals still have a chance to make it into your coax and to the radio even if - and sometimes especially if - your counterpoise is anywhere near 1/4 wavelength to ground. This sounds wild, but you might want to experiment with a short counterpoise rather than the big long one. If you do get reduced noise, what you can do is to add a big fat rear end inductor on your 'long' counterpoise at approximately that far down. That way you still have lightning protection but the long tail and ground rod will be decoupled from the antenna proper.
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Oct 20, 2022 19:48
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Thanks obama!
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Oct 20, 2022 21:38
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got all the parts i need to build a new, oh, lets say 3-5 kW rated 1:1 balun for my doublet i wanna put up 240 size (2.4" OD) type 43 ferrite cores. 8 bucks each and worth erry penny. also got 16 gauge magnet wire and a coil of PTFE tubing to insulate the wires (they sell it in all sizes for 3d printer folks now) will probably build it up tomorrow. oh also got a relatively gray/brown spraypaint that im gonna hit the ladder line with to kind of make it blend in to the tree a bit.
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Oct 21, 2022 04:03
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it begins that ptfe tubing is super slippery! (duh) but didnt kink once. good poo poo also i have the ladder line stretched out and just hit it with some of that earth tone spray paint, drying now. Hopefully will help with the stealth angle!
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Oct 21, 2022 17:18
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Jonny 290 posted:it begins so, this is a “Balun”, right? is there any defining characteristic that makes it distinct to an inductor? or even a transformer? ( I get that the second one is dumber since 1:1 isn’t transforming any voltages)
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Oct 21, 2022 17:29
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an excellent question! So, the goal is to ensure the 'output' (we'll strictly use transmitting as our framing, though almost all RF circuits are reciprocal) is balanced - one line is at -100V at the same time that the other is +100v, etc. A transformer would do this - they're defined as two disconnected windings coupled through induction:  However, the imbalance in current/voltage is probably fairly small compared to the power flowing all the way through. In a transformer setup, you do get perfect balance at the end, but the core has to inductively couple ALL the power from one winding to another. Baluns work a bit differently. The simplest 1:1 (which this is) is simply a transmission line wound around an inductor:  So, what happens here is: all of the 'real' signal just passes through, because the two lines cancel each other's magnetic field and none of that actually induces a flux in the core. The imbalanced part of the signal sees a very high impedance at the balun and sees it as a really large resistor, forcing it into balance. The only component that will be 'seen' by the core is the imbalanced current, if it exists. This means that instead of a transformer, which has to be rated and built to take 100% of your power, this design can be scaled to be able to dissipate only any unbalanced component, which with my planned antenna should be less than 1% of the total power. Hence why this bad boy could easily handle kilowatts of power with no ill effect - 1,485 watts would just yeet through with no problem, and that last fifteen watts would be easily dealt with. With a transformer you would want a very low loss inductive material; anything that doesn't make it from the primary to the secondary has to be dissipated as heat. With a balun, you actually want a really lossy core, as that more efficiently turns that imbalance into heat and makes it go away. I've built alternator whine chokes before using wire wrapped around a carbon steel head bolt from my scrap box - a very inductively lossy material - and they worked really well. Jonny 290 fucked around with this message at 17:56 on Oct 21, 2022 |
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Oct 21, 2022 17:53
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and just for more friday study sessions: i'm adding a MAGIC SWITCH. so what the f is going on here jonny? OK, so. One neat thing you can do with any sort of antenna with a long vertical feedline (as mine is) is to short both sides of the antenna feedline together, connect those to the coax hot, connect coax shield to ground (radials, a fence in my case, ground rod, whatever) and treat it like a big vertical antenna. If it has big long wires sticking out of each side of the top of that feedline, it's even better! they don't radiate much signal if they're balanced, but they add a shitload of capacitance to the circuit, lowering the resonant frequency and making it work like a bigger antenna than it really is. So what we've got here is a big DPDT switch to work the magic. The blue wires are the switch contacts in each position. In one position, it just runs each side of the balun output to one wire each of the final feedline and straps the shield of the input coax to ground.  In the other position, we tie the two conductors of the final feedline together and connect them to one side of the balun, disconnect the ground from the coax shield, and instead connect ground to the other conductor on the balun output. Exactly what we want!  I had a manual version of this with spade connectors in my last iteration of this antenna, and the general idea is that you run it in the 'straight through' mode during the day so you can work the high HF bands, and then when the sun sets you go out to the back yard and flip the switch to 'big vertical mode' and play down on 80/160 meters, listen to AM broadcast, whatever you like. Jonny 290 fucked around with this message at 18:40 on Oct 21, 2022 |
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Oct 21, 2022 18:36
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and the build is complete!    i dig the little weatherproof caps these switches come with - gasketed and everything. the big 1/4x20 on the bottom is the ground line for the fence.
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Oct 21, 2022 20:01
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Jonny 290 posted:ok! you are on the right track and doing the right thing. However, you're also running up against one of the reasons i hate end feds. i read basic noob information about how counterpoise in end fed antennas work and i now understand why i had to tune the radio when i used a ferrite ring or used a patch cable + filter. ground rod + common mode choke + inductor is probably the best cost/benefit i can do where i live. Too bad we dont live in a frictionless sphere world but have to deal with external factors 
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Oct 22, 2022 12:04
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Just an FYI, but digimodes like FT8 and JS8Call are becoming a big deal on 11 meters. There are CB operators making worldwide contacts using legal power (12W) on Channel 24 USB (27.235MHz) if you want to tune in on your SDRs.
MullardEL34 fucked around with this message at 09:28 on Oct 23, 2022 |
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Oct 23, 2022 09:11
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I know all about numbers stations but have you ever heard any people having encrypted chats, like with one time pads or codewords or anything like that? Is that something that people ever do for fun? When I first got into listening to webSDR stuff I sort of expected to find it often but never really have.
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Oct 23, 2022 17:46
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it's illegal to use encrypted communications over ham bands
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Oct 23, 2022 17:49
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"does this mean that digital modes can't use tls?" you ask yes, yes it does
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Oct 23, 2022 17:50
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Achmed Jones posted:it's illegal to use encrypted communications over ham bands  except when performing station control operations of an officially registered amateur satellite!its me, the Edge Case Knower
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Oct 23, 2022 17:56
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a couple other weird US carve-outs: * it is legal to play incidental music as part of manned operations from space. Exists because the Shuttle folks would sometimes get on the air and their wake-up song was playing in the background * also legal to be financially compensated while you are doing amateur contacts if you're a teacher. done so they could do ham classes on the clock
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Oct 23, 2022 17:59
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*RIAA hears faint sounds of notes in the background of the ISS* COPYRIGHT PROTOCOL ACTIVATED TARGET IS NOT EARTH BOUND ACTIVATING ICBM ATTACK SEQUENCE DESTRUCTION OF PIRATES IMMINENT
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Oct 23, 2022 18:25
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Achmed Jones posted:it's illegal to use encrypted communications over ham bands oh wth, ok. well that's no fun at all.
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Oct 23, 2022 18:38
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LifeSunDeath posted:oh wth, ok. well that's no fun at all. cold war era holdover tbh
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Oct 23, 2022 18:47
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it's also a transparency thing, i think. by which i mean, if encrypted comms were allowed it'd take precisely thirty seconds for companies (some big, some jerkface "disruptors") to start using those bands for whatever annoying middleman-injecting thing they're trying to do. iirc there's already HFT jerks using ham bands, i'd rather have a 'no encryption' rule than 'its technically ok as long as it isnt commercial, but also theres no way for us to tell what the actual message is cause its encrypted.'
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Oct 23, 2022 18:51
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Achmed Jones posted:it's also a transparency thing, i think. by which i mean, if encrypted comms were allowed it'd take precisely thirty seconds for companies (some big, some jerkface "disruptors") to start using those bands for whatever annoying middleman-injecting thing they're trying to do. iirc there's already HFT jerks using ham bands, i'd rather have a 'no encryption' rule than 'its technically ok as long as it isnt commercial, but also theres no way for us to tell what the actual message is cause its encrypted.' 2 bros coordinating a dead drop isn't imo a problem.
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Oct 23, 2022 18:57
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LifeSunDeath posted:2 bros coordinating a dead drop isn't imo a problem. i mean sure, but this also doesn't respond to the thing i just said in a meaningful way at all
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Oct 23, 2022 18:58
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How else are RIAA going to enforce its rules if the traffic is encrypted? Think Forums THINK
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Oct 23, 2022 19:01
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also it'd conceivably be fine to cryptographically sign messages without encrypting them since the meaning of the content isn't being obscured
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Oct 24, 2022 00:58
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Progressive JPEG posted:also it'd conceivably be fine to cryptographically sign messages without encrypting them since the meaning of the content isn't being obscured yeah a bunch of wifi mesh hams use ssh with cipher = plaintext just for session management and auth
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Oct 24, 2022 01:46
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I decided to go with the specific antenna you mentioned (ZS6BKW) and have been reading up on grounding and bonding but I feel like I'm falling down a rabbit hole. this seems like it's going to be way more work and expense than the antenna itself, lol. I'm looking through N0AX's book on the subject and every page is more stuff I had never considered before. oof.
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Oct 27, 2022 19:06
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<pours tea, puts on reading glasses> people freak out about grounding really hard. Yes, it is Best to have a fully NEC/FCC/NHTSA/DOE/whoever-compliant grounding system with 32 rods bonded by copper strap and welded together. I don't argue that. But for a lot of installs, you can get away with basic lightning protection for a lot less. Sink an 8' rod at the ladder line -> coax transition, attach a lightning arrestor to the coax side of the balun with a 1" jumper, bond it to the ground rod. That'll git r done. https://www.dxengineering.com/parts/alf-att3g50uhp I would not stray from Alpha Delta for this. Amazon has a shitload of $15 copies of this and I would not trust. These antennas are balanced so RF ground is not a concern or a need. All you gotta do is make sure there's a balun at the transition and sink a stake for lightning protection. This doesnt mean that you shouldn't unhook your coax in the shack during a lightning storm. but it will turn a strike from "burned the house down" to " guess i need a new antenna and coax". the thing about ground systems is you only gotta engineer and build em once.
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Oct 27, 2022 19:17
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