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Not much. The vertical bars will add a shitload of capacitance, which makes it electrically longer. I really like this experiment. Proceed! (also if you need to lengthen the elements a bit, you can just attach bits of wire to the end and let them hang down. Won't mess up the pattern or whatever. A common trick with hamsticks is to tune them high on the band, then add a little alligator clip wire to the end of the whip if you want to go lower.)
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May 16, 2024 07:43
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Before i raise my big mast and finalize my creations i would like to build a good enough cross yagi for sats. I am using the 1/4 wavelength offset placement method and 1/4 or 3/4 wavelength 75 ohm coax feed method for cross yagi. calculator for single yagi gives me this result for a relatively small yagi. https://www.changpuak.ch/electronics/yagi_uda_antenna.php Javascript Version 12.01.2014, based on Rothammel / DL6WU ------------------------------------------------------------- Frequency : 145 MHz, (useful from 142.1 to 147.9) Wavelength : 2069 mm Rod Diameter : 10 mm Boom Diameter : 20 mm Boom Length : 3206 mm d/lambda : 0.005 ( min.: 0.002 , max.: 0.01 ) D/lambda : 0.010 ( min.: 0.01 , max.: 0.05 ) Elements : 8 Gain : 10.61 dBd (approx.) ------------------------------------------------------------- Reflector Length : 997 mm Reflector Position : 0 mm ------------------------------------------------------------- Dipole Position : 497 mm ------------------------------------------------------------- Director #1 Position : 652 mm , Length : 941 mm Distance Dipole - Dir. #1 : 155 mm ------------------------------------------------------------- Director #2 Position : 1024 mm , Length : 932 mm Distance Dir. #1 - Dir. #2 : 372 mm ------------------------------------------------------------- Director #3 Position : 1469 mm , Length : 924 mm Distance Dir. #2 - Dir. #3 : 445 mm ------------------------------------------------------------- Director #4 Position : 1986 mm , Length : 916 mm Distance Dir. #3 - Dir. #4 : 517 mm ------------------------------------------------------------- Director #5 Position : 2566 mm , Length : 909 mm Distance Dir. #4 - Dir. #5 : 579 mm ------------------------------------------------------------- Director #6 Position : 3186 mm , Length : 903 mm Distance Dir. #5 - Dir. #6 : 621 mm ------------------------------------------------------------- Directors / Parasitics are isolated. Please choose an isolater thicker than : 10 mm Should i use a folded dipole or straight dipole as driven element? with straight dipole isnt it just solder on direct feed and with folded dipole it is complicated matching systems? or is there advantages to folded dipole that make it worth it? Not using a 1:1 transformer with straight dipole is not that critical in real life application right? edit: is there any way to weatherproof feed to yagi without building a box around the feedpoint? trying to keep everything as simple as possible. Big Mackson fucked around with this message at 15:54 on May 16, 2024 |
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May 16, 2024 15:21
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Can't say either way on the dipole question without knowing the feedpoint impedance. Your first director is pretty close to the driven, so i'd imagine this is a 50 ohm design? if so you don't want to use a folded setup. as far as feedpoint goes, i treat feed and phasing lines as consumables and just put ring terminals on the shield/center after stripping back a couple of cm. Then i bomb the whole thing with a ton of silicone sealant. Seems to keep them in good shape for a few years at least. You don't need a balun or transformer for this stuff if you build it all balanced enough. if you can get things to millimeter accuracy, things will be fine.
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May 16, 2024 19:47
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Coxswain Balls posted:Searching through the thread to get ideas for balcony antenna setups, but unfortunately the MFJ Big Stick that gets recommended a lot is out of stock everywhere, and with them going out of business the odds of finding one seem slim. Have you tried DX Engineering? They still have them in stock and I’m thinking of getting one along with an FT-710 since those are on sale for nearly $300 off today it seems, probably for Hamvention. https://www.dxengineering.com/parts/mfj-2286
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May 16, 2024 22:52
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Big Mackson posted:Boom Diameter : 20 mm excuse my ignorance (i keep procrastinating on actually getting my license and finally trying tx'ing) but what material will you use to make a 3.2m boom with a diameter of only 20mm? where do you keep something this size once it's done? always up on a tower?
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May 16, 2024 23:04
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Supersonic posted:Have you tried DX Engineering? They still have them in stock and I’m thinking of getting one along with an FT-710 since those are on sale for nearly $300 off today it seems, probably for Hamvention. Oh nice! No I didn't, I was mainly looking at Canadian sites but their shipping prices are pretty reasonable. I'm also headed across the border to pick some stuff up soon anyways, so I might be able to save even more money by sending it to a parcel service. We'll see how the silly dipole works this weekend before I consider grabbing one. I'll also go over their site for other stuff I'll eventually need like power supplies and dummy loads. I just got back from checking out the radio stuff and while there wasn't much else (guy passed away two years ago), god that Kenwood is so nice. It's just the right size for both a bench station and also just lugging around. At $425 I'll probably end up being over budget after taking accessories into account, but I was still tempted. Took some better pictures of it for her ad.   
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May 17, 2024 00:39
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Will I run into much loss if I’m running a 25ft length of RG-8x cable from an antenna to a transceiver? Realistically I only need about 10-15 ft but I’d like to go for a 25’ length for times when I’m somewhere else which requires a longer cable. Also, for VHF/UHF is there a recommended handheld which isn’t too expensive? I wouldn’t mind trying to hit a local repeater but don’t want to spend too much given the cost of HF stuff. But if I can find something decent on DX Engineering for around $100 I might add it to my HF order. Lastly, is this a good power supply to get for an FT-710? It seems to be good and apparently Samlex makes whitelabel power supplies for Yaesu so I think it should work well but just want to confirm: https://www.dxengineering.com/parts/sxa-03436 Supersonic fucked around with this message at 04:23 on May 17, 2024 |
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May 17, 2024 04:20
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1: Loss is frequency dependent. at HF, 25 feet of 8x is basically perfect. At 2 meters, you'll lose a db or so, but not a big deal. At 70cm, it's definitely non optimal and you're losing a bit of reach. FWIW I have been buying LMR240 for all my short/flex runs and it's not that much more in small quantities, and it's _great_. 2: Yaesu FT-60R. It's the preferred HT of the YOSPOS ham contingent, and we're notoriously picky about gear. Will run until the year 3000, been in production for 15ish years, accessories are everywhere. Get a AA battery pack and run nimh cells in it, you're good. 3: Samlex is solid, that's a good buy that will last a long time and not poo poo up your airwaves with broadband RF.
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May 17, 2024 04:34
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Boy is there a big difference between how I had my weather satellite antenna set up and the two meters this experiment would use. Would it be fine to use metal eyelets on the boom past the railing for the drop rigging in case anything breaks? I was originally thinking of drilling holes to run safety line through but I don't want to compromise its strength more than necessary. Just playing around with designs now. I'm starting to get the appeal of using something like fishing rods instead. If I chicken out at least I'm only out five bucks.
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May 17, 2024 05:28
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It would be fine, but also lol i'd just be tying the 550 cord around the 1x2 at that point. and yeah the fiberglass angle is seriously worth considering. Tenkara poles are floppy as poo poo, to be sure, but it doesn't matter that much in your case except at the feedpoint; coax is relatively heavy and the center would sag a bit. No real performance change, just aesthetics. But! Also! I want to encourage you to not overthink this. the difference between a hyper engineered oxygen-free-copper wire and analyzer-balanced-balun setup and a bunch of fence wire hooked to CB coax thats wrapped around pvc for a choke is like 0.1 db and is never the make/break between landing a contact and not.
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May 17, 2024 06:26
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Jonny 290 posted:1: Loss is frequency dependent. at HF, 25 feet of 8x is basically perfect. At 2 meters, you'll lose a db or so, but not a big deal. At 70cm, it's definitely non optimal and you're losing a bit of reach. Will the FT-60 be able to hit a repeater about 15 miles away using the stock antenna?
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May 17, 2024 06:45
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Jonny 290 posted:But! Also! I want to encourage you to not overthink this. the difference between a hyper engineered oxygen-free-copper wire and analyzer-balanced-balun setup and a bunch of fence wire hooked to CB coax thats wrapped around pvc for a choke is like 0.1 db and is never the make/break between landing a contact and not. Hahahah, the wire I'm using is actually from a block heater cord I got off the road that someone forgot to unplug. They drive off with them still hooked up and best case they're usable, worst case they're destroyed with just three twisted conductors ripped from a sheath. I always make a habit of picking it up when I see it because "hey, free wire!". Each conductor in this set is exactly the right length to cut in half and make my two elements (calculated the ideal element length at 5.075±0.063m). I have my pick of 5.06, 5.08, and 5.09m element pairs., and I'm definitely keeping at least one uncut to do the end fed option you suggested earlier. The original plan was to just hitch the cord to the wood but my mind keeps thinking of failure states and how to prevent the worst case scenarios from happening. The radio part is pretty much done, so now I get to focus entirely on the safety aspects and coming up with a checklist for the proper order to do all the setup in to help things go smoothly and safely. Extending the booms with another four feet helps a lot, since it lets you keep it under you arm while doing the clamping. Opens up a lot of additional options for safety rigging, too. 
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May 17, 2024 07:11
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Supersonic posted:Will the FT-60 be able to hit a repeater about 15 miles away using the stock antenna? Most handhelds (including the ft60) have a 5w output, so they're all going to perform similarly in that regard. I've hit repeaters 50+ miles away with an ft-70 and the stock antenna, but I was on top of a mountain at the time-line of sight is much more important than type of radio when it comes to repeaters. I also find that a nice inexpensive upgrade for handhelds is the Super Elastic Signal Stick which gives a nice boost to performance while still being bendy for easy stowing Walrusmaster fucked around with this message at 14:26 on May 17, 2024 |
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May 17, 2024 14:22
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I'll second the signalstick, it's an incredible choice for any HT and hits the sweet spot of cheap and effective. If you can fit it on your radio, an SMA to BNC adaptor will help if you plan on changing antennas alot (for example, a J-pole at home and a SESS on the go); SMA is only built to hit a certain number of usages.
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May 17, 2024 19:57
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 Feels way better with an extension and more safety line. I don't have any 50 ohm coax that's long enough, but I might have a run of 75 ohm TV coax that's long enough I could use with a couple of adapters if having the SDR on the boom isn't a good idea. edit: 
Coxswain Balls fucked around with this message at 01:45 on May 18, 2024 |
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May 18, 2024 01:25
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the milk machine posted:excuse my ignorance (i keep procrastinating on actually getting my license and finally trying tx'ing) but what material will you use to make a 3.2m boom with a diameter of only 20mm? Buying several of these today https://www.obsbygg.no/bad-og-kjokken/ror-og-avlopsdeler/2323103?v=ObsBygg-8711283027050 and then cutting and using these https://www.obsbygg.no/trelast-og-tyngre-byggevarer/treverk/listverk/dekor-og-overgangslister/2323064?v=ObsBygg-8711283026947 to connect the square booms so the boom is 4 meter long. It is a cross yagi so the horizontal and vertikal elements are offset by 1/4 wavelength. True length of antenna will be around 3.7ish meter i guess. Ordered these https://www.pneumabeam.no/products/antenne-bygging and i am going to cut and place elements with SUB MICRON precision  so i think i can get away with not using a balun.It will be on a yaesu g-5500 rotator setup and a 7-8 meter fiberglass mast. It will be made for longtime installation so i dont have to rent a lift to fix things all the time. Big Mackson fucked around with this message at 12:59 on May 18, 2024 |
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May 18, 2024 12:55
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Even with just the balun on the end the boom is disconcertingly wobbly. I might be able to stabilize it a bit by playing with the guy wires, but I'm definitely going to minimize what I put up there. I'm going to put in an order for some RG-316 to use as transmission line, so while I wait on that I can focus on the structural part.
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May 18, 2024 15:30
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Learning structure and material engineering is a part of amateur radio. Radio amateur only survivor on earth? Society rebuilt. Perfect Sphere* Society. *may or may not be perfect
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May 18, 2024 15:45
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I'm doing so many knots and hitches right now while experimenting with rigging. My childhood in the sea cadets continues to pay off.
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May 18, 2024 15:54
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Add a brace lengthwise to make it a T shape (viewed down its length), that will get rid of the wobble.
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May 19, 2024 03:34
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M_Gargantua posted:Add a brace lengthwise to make it a T shape (viewed down its length), that will get rid of the wobble. How far down its length? I'm wary of adding any more weight than is strictly necessary, although if the rigging pans out I'm open to adding stuff to reduce harmonic vibrations. Here's what I've got planned out so far. The static lines and pulleys are rated for around 200kg which should give enough safety factor. I didn't add it to the plan to keep things clean, but the near end of each boom is also hitched to the rail for additional redundancy. Won't be able to do any testing until the weather gets better though. 
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May 19, 2024 05:44
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Jonny 290 posted:https://www.aliexpress.us/item/3256806627252168.html?spm=a2g0o.cart.0.0.429438daFIXWme&mp=1&gatewayAdapt=glo2usa First one has arrived!  It's cute as hell. The whip feels as good as, or perhaps better, than the $70 MFJ whip. The radials are cute - lil' bit of DIY there  I vote this one thumbs up if you want a little porta-whip. Granted this is 10mm metric, not 3/8x24, but all the same, a great deal. Gonna see if i can piece together a tapped loading coil for it next.
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May 19, 2024 21:44
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Can't wait to see how those go so I have backup options if this experiment doesn't work out. I was able to do some testing today and the 2-meter booms are just too gnarly for my taste. 1-meter seems fine so far at least, we'll see how it fares once I install the elements.
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May 20, 2024 04:33
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Jonny 290 posted:First one has arrived! You can get nice coils on Aliexpress, too: https://www.aliexpress.com/item/1005005812936449.html This coil is actually a part of JPC-12/PAC-12 antenna (it goes under both names it looks like), also sold on Aliexpress: https://www.aliexpress.com/item/1005005002239701.html I bought it last year, and it's an amazing little thing. Centre-lodaded (or bottom-loaded, if you so desire) vertical ground spike for 40 and 20-meter bands, or a quarter wave for 15 and up. With some practice and soft ground takes about 60 seconds to set up. All the sections are M10 threads, but eh, I live in a metric country so no big deal. You can also buy the individual parts. Need more aluminium sections? Extra loading coil? You're covered. You can even get it in JPC-7 variant, which is a dipole. Yes this whole thing is a copy of Buddipole and Buddistick It too comes with a ribbon cable to use as radials, which I have to say, is a genius cost-saving measure. Works quite alright, even though the durability is questionable. So I replaced the radials with this nifty British army thing: https://www.youtube.com/watch?v=KRCTu3yyakc Edit: while posting this I wound that there's even capacitive hats for the whip: https://www.aliexpress.com/item/1005004243833410.html Aliexpress antenna parts rabbit hole runs deep. The Claptain fucked around with this message at 09:16 on May 20, 2024 |
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May 20, 2024 09:13
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NOW we're talking. Heck yeah thanks for the great info.
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May 20, 2024 18:38
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This is the third or fourth time in the last few years that something has reminded me Dayton exists in late May and I think to myself "Isn't Hamvention soon?" and it turns out I just missed it. Doesn't seem like there was really any discussion here either, has it just lost relevance? At least in the generally younger, more tech-savvy part of the ham community represented here, of course...
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May 20, 2024 22:22
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ever since even a couple years before covid, every hamfest i have gone to has either been NO LOWBALLERS selling dead tech trash at a huge markup, or they buy a couple Yaesu HF rigs from HRO and tack 30% markup as a convenience fee. I haven't found a good deal at one since 2019 at the latest. The days of $20 2-meter mobile rigs are long gone
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May 20, 2024 22:46
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Getting my license has lit a fire under my friends' asses to finally get theirs too. One of them has a bunch of stuff that was given to him when one of his friends' dad passed away. The VHF/UHF stations already look like they could be some fun, and one of those power supplies might work with that Kenwood transceiver if I end up caving and picking it up. Not sure what that ICOM antenna is, and neither of us know anything about digital modes for the other stuff.       
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May 21, 2024 04:37
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Lots of good stuff. The old rat shack HTX-212 is a gem. I had one in my truck for a decade or more.
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May 21, 2024 05:44
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Jonny 290 posted:NOW we're talking. Heck yeah thanks for the great info. Glad to be of help! The whole JPC antenna system is great for experimenting, I already bought tripod adapter, and plan to order some clamps so I can see how well it works clamped to a balcony rail or something. There's so much weird ham radio stuff on Aliexpress, I wish I had unlimited time and money, lol. In other news, I think I may be developing a problem 
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May 21, 2024 13:03
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Finally got a day of good weather and low wind to test things out, and it seemed to be a success. I was able to hear tons of voices on the 20m band from all over the place covering most of North America west of here. I overheard one conversation in Japanese which got me super excited, but I'm pretty sure he was in California conversing with someone further west. I could faintly hear the person he was talking to, probably in Hawaii but it'd be wild if it was all the way from Japan. My SWR was absolute garbage though, which makes me curious about how much clearer/further I can go with some optimization. Would an antenna tuner be the easiest way to go about improving things? I might be able to experiment more with element length but I probably won't extend the booms any further until I find a more suitable material. I should also probably grab a manufactured antenna to compare against; I'll wait and see how those Ali Express antennas stack up against the MFJ 2286 (that's the big stick that's recommended, yeah?) before placing an order.  
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May 22, 2024 04:13
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Yeah, wire's too close to the rail and it's tanking your feedpoint impedance. OTOH it looks like it is almost a really good 15 meter match?
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May 22, 2024 04:48
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I cut the guy lines to work with 2m booms if I get more confident in my rigging capabilities. If only I lived somewhere that had readily available bamboo, that would probably work perfectly.
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May 22, 2024 05:27
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Garden shop probably has various lengths of bamboo stakes
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May 22, 2024 07:46
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Most of the ones I can find locally aren't long enough, sadly. Even if they were, their diameter is more on the thin side. This place has big girthy poles but the longer ones are too big to ship. I'm working on fixing that Mobile Authority power supply and man is there a lot of mouse poo poo in it. While I'm in there it wouldn't be a bad idea to replace the two-prong AC power cord with an IEC connector to ground the chassis, yeah?
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May 23, 2024 04:38
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Got back from the recycler expecting to just rip some power connectors from some trash. Found a couple of antennas that were destined for the crusher and grabbed them to play around with. Didn't cost a thing so if they don't work they'll go back anyways. Two PoE antennas and a whip with two of what I think are counterpoise elements broken off (seems like it should be six in total, alternating between long and short). One of the patch antennas has a port for a SIM card so it might be for cellular internet. It might be useful for a hotspot at a campsite or something. Progressive JPEG posted:Garden shop probably has various lengths of bamboo stakes Ended up finding 1"x8' poles at a cannabis supply store of all places. Now to figure out a way to attach them to the rail with clamps instead of lashing. A bunch of U-brackets might be the easiest way. Coxswain Balls fucked around with this message at 21:18 on May 23, 2024 |
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May 23, 2024 20:08
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Coxswain Balls posted:Ended up finding 1"x8' poles at a cannabis supply store of all places. Now to figure out a way to attach them to the rail with clamps instead of lashing. A bunch of U-brackets might be the easiest way. Honestly this find doesn't surprise me. What surprises me, is this doesn't seem like a normal convo for some stoner retail individual and want to hear more about this interaction.
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May 24, 2024 00:02
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I got it. clamp on fishing rod holders.
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May 24, 2024 00:31
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Jonny 290 posted:I got it. clamp on fishing rod holders. Like what you put on the side of your boat for trolling? Cus that actually is pretty loving great.
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May 24, 2024 00:59
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yep, exactly
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May 24, 2024 01:10
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