The PERFECT DIY antenna for EMERGENCY Comms??
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- Опубликовано: 6 май 2022
- In this video, we build and test a 2m / 70cm dual band roll-up portable antenna.
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Again, I don't apologize for the crappy jokes. I would, however, highly recommend you research and build (or buy) your own Ed Fong J-pole - these are great antennas!
Great video. Don't sweat the people who cut their ladder line to 42".
By the way, I always enjoyed what happened right after Deep Thought said the answer was 42. The next chapter starts:
> Out of the corner of his eye Phouchg could see the sea of tense expectant faces down in the square outside.
> "We're going to get lynched aren't we?" he whispered.
@@m_a_s6069 If only our politicians would read it.
The humor is fine, love to hear a hitchhikers guide reference 😀 😄. Keep up the experiments. 73's from Bergen op Zoom the Netherlands
The guitar explanation really spoke my language. Thank you, sir!
Cheap connectors are a pain. Glad you fixed it! Good diagnosis! Glad to see the issue present itself so easily!
Thanks for all the fish...
Thanks for all the fish. And a great video. As Jesse and Marvin said Ed recommends the thinner wall PVC. It’s not always easy to find though. Incidentally, Ed is very approachable and helpful if you have questions. Also the antennas Ed sells are made by his EE students and the proceeds go back to the class to acquire equipment and materials for the classroom and lab.
The crane's cries went with the mellow jazz, Nice
Great video! I need to build one of those for portable ops.
I see a lot of hams build these, and no one seems to tests their antenna with an SWR meter, to tune it. And when they did, they were in their home's ham shack, which is the worst place to tune any antenna. I recently built mine, and have been testing and tuning it, outdoors, away from any electronics, or metal. Hanging 20 feet up a tree.
Even though I followed the instructions, the SWR is way the hell off, on 2M. I have learned that the point where you solder, the feed line coax on, can greatly effect the SWR, more than the length of the antenna. Just by moving those 2 connections up or down the ladder line, can re-tune the SWR. My antenna is still not tuned yet!
Great points! I lucked out with this antenna and it 'just worked', but I went back and built another one (off camera) more recently with the help of a VNA. For a Saturday project, I'd highly recommend people listen to one of Ed Fong's presentations on the roll-up J-pole here on RUclips, and then try to make one, testing with the VNA as they go!
For the SO239 just solder the braid, crimp on a connector and nut and bolt it to the chassis. Better still, get more pipe and encase the pole as a radome, fix the SO239 to an end cap and rivet the ring terminal through the cap for a good fit so it is air tight. Also depressure the radome by a quick squirt of body spray into the pipe, light it and seal the end. The gas will burn out inside creating a vacuum and lower the atmosphere in the radome. It will make it less susceptible to bending over time and survive wind storms as well.
Also, nice video. de 2M0WHN
I learned a long time ago that stripping coax with a knife sucks I use a soldering iron to thermally strip coax and a precision mechanical stripper for thin strands so I don’t cut strands.
sounds like an interesting method...! 73,
Great video, subbed. I've actually built several of these. I do have a tip though, use the thinner wall PVC, the schedule 40 is thick enough that it will actually slightly degrade the radiation pattern. 73's
Awesome, thanks for that! 73,
Life is too short to mess with cheap underpowered soldering irons.
Groovy music dude
Andy UK.
I get it... 'Don't Panic.' and 'Don't forget your towel!' (Damn Vogons...) 😏
I spit my pan-galactic gargle blaster out all over my screen when you said that.
Really good video Lots of things can be learned from watching it.
The soldering iron looks like the one I have from RS and it is a 25 watt. I could be wrong though as most RS irons look a lot alike. The wattage should be printed on the label near the bottom of the irons handle. I use a 100 watt Weller iron for when I have to do heavy work like that and a 40 watt Weller iron when installing PL-259's on coax.
On the soldering to the case/mount of the SO-239 I always use a small machine screw, inside star washer and a nylon lock nut with an appropriate ring lug (non-insulated) crimped and soldered to the shield of the coax and insulated with marine heat shrink tubing. I have never had a problem using this method.
I also use a very small amount of Penatrox "A" on this connection. It is a water proofing, anti-seize, and electrically conductive compound sold in marine supply stores and online at some electronics and ham radio sites.
Penatrox "A" can also be used on the threads of the SO-239 to water proof the connection as well as prevent seizing up of the PL-259/SO-239 and it makes for a better electrical connection between the shield side of the connection.
Do Not use it on the center pin as it can very easily ooze out and create a dead short between the center conductor and the shield.
Great advice here! Thanks! 73,
@@hamradioexperience You also need to be careful when laying the heat gun down as the nozzle gets very, very hot and it will melt anything plastic rather quickly! At 20:44 you lay the gun down and it looks like you laid the nozzle right on it's power cord.
Okay, while I am at it, 300 and 450 Ohm twin lead (I make all of my Slim Jim's out of 450 ohm feedline) is called window line, not ladder line.
300 ohm twin lead is only called window line when it has the "windows" cut in the separating insulation, other wise it is just twin lead.
The windows are there to lessen the strain of snow and ice that may accumulate in the winter months.
Ladder line is a 600 Ohm impedance feedline and is usually a DIY project constructed of 14 to 10 AWG wire with insulators spaced equidistant apart.and actually looks like a rope and slat ladder, just on a smaller scale.
Instead of the SO-239, try a PL-259 and a barrel connector covered in Marine heat shrink, that way you can use any length of coax that you need to to feed the antenna and get it up really high for the best coverage. Alternately, you can get inline SO-239 connectors that install similar to a PL-259.
73,
de N1WOM
KD2SML here. I have found you need a lot more heat to solder to a mass of Brass that large, but alternatively, you can just use a spade or ring connector and screw it to the mounting holes on the panel mount. Electrically it'll be fine. I've made many antennas like that.
Slim Jim antenna, i build it for backpacking purposes, easy to carry, you can just roll. Hand when you need it.
Ah, The ham radio experience. Now theres a hoopy frood who really knows where his towel is.
When Soldering to your coax connector ruffing up the metal is good. I would suggest try using some extra flux to the job. Nice job. 73 k9zl
Thumbs up for the "42" reference.
I like the video. It's Mostly Harmless.
Big dollop of Rosin flux usually does it for me with those hard to solder bits
The answer is .... 42! Deep thought
Here is a suggestion. For soldering connectors like the ground or center conductor of a SO239 or a PL259 try using a "jet" type butain lighter they are usually about 5 or 6 bucks at most convince stores. They will heat up the connector very quickly for soldering. I have one that works well on even 2 inch hardline.
Funny thing, I've got one of those, but it doesn't work well. What I ended up doing (VERY carefully) off-camera is using a MAPP-gas torch. Time for an actual soldering station lol...73!
I have two Ed Fong J-poles. He says to use the thin wall PVC pipe as the schedule 40 detunes the antenna.
Yes, I need to try that. I think I got the Sch40 stuff...73,
Hitchhiker's Guide to the Galaxy...
Guess with solder goes to clean your tip prior and retin it before use, having some scrubing brass or a wet sponch to clean in between joints. Clean the spot before you solder, apply a flux, preferable the right one (pine rosin, paraffin oil, Vaseline are the basic). Having fume extraction is another and holding tools of some sort - crocodile clips on some stiff wire stuck into a board.
So long, and thanks for all the fish.
"which is Infinitely long, due to the view of the camera..." That's funny! Life is often based on perspective.
No antenna can put out more power than put in unless it is an active one. If a gain is apparently being seen something else is being sacrificed, probably directionality.
Right. In this case, what's being 'sacrificed' is a bunch of radiation that would otherwise get directed skyward is instead directed outward. Think beach ball vs. donut. A dipole would be more similar to the beach ball; the Ed Fong antenna makes the radiation pattern look more like a donut. 73!
So ham radio is kind of like life, universe, and everything?😂
Don’t forget your towel.
A little late (ok alot late) to the party, but on the use of your heat gun, watch the top (metal ring) of the gun with the power cord for the gun, I have melted a few cords with accidentally laying the tip of the gun on the cord. Oh, and your "crappy joke" was not crappy, it made this old hitchhiker laugh. Thanks for the Video
If you make another or for anyone else the correct PVC pipe is 3/4 inch pr 200 psi . That is what Ed Fong specs as well designed this antenna to use. The schedule 40 pvc pipe is twice as thick as pr 200.
Can I get the final numbers 🤔
could you just soldier to a eye connector and bolt it with a star washer to the base?
I've heard these antenna's need to be 20ft or more up to work well, what do you think?
Thanks for the video.
Yes, soldering to an eye connector would work, except I wanted the antenna to be really low profile, so I couldn't use bolts. Regarding height, a VHF/UHF antenna will get out further the higher you can mount it. When you're within a couple feet of the ground, things start getting really weird. So yes, 20ft is better than 10ft, but 10ft gets out! 73,
Okay just out chillin with my ohmies. So the coax was RG 174? Haven't built mine yet but have everything except bottom connector. Attaching to top of buddy pole mast once completed. Good video. 73
I'd have to run out and look, but I'm pretty sure I used RG-8X. 73!
you really need to do a test simplex not repeater. you can open a repeater with a coat hanger.
The answer to the ultimate question 42
Is a ham radio kosher?
Please make 2meter gamma match anteena
Requst
Can you make a video showing how to build the Ed Fong GMRS antenna?
Short answer, no, but because I don't have a GMRS license. I've thought about getting one at some point. If I do, it might be fun to build it (and make a video).
If you want to build your own sooner, I'd research the dimensions, and then buy an NanoVNA to test and tune the antenna.
73!
@@hamradioexperience thanks for the advise.
Don't Panic ... I didn't cut too soon 🙂
But a regular j pole made for vhf also works good on uhf it's a hormonic to vhf just check the swr if you can see the frq you using is 50 ohms a antenna analyzers will show if it's 50 ohm's
very true! 70cm turns out to be a harmonic of 2m! 73,
Just a stupid question....the so239 has screw holes in the ground flange....why would you not just put a ring terminal on the coax ground braid and attach it with a screw, rather than heat it with a map gas torch in an attempt to solder (which would likely also require additional solder flux)?
Not stupid. Ring terminal would definitely be easier. The reason I soldered it was because I was going for a super-low profile, so I glued the SO-239 into the pipe. That made it so I couldn't use the ring terminals and screws. 73,
I like the trash can joke. Hey thanks for the post 📯
I'm studying for the technicians license and watching videos to learn all kinds of stuff. A lot of people refer to the bands in meters and others in MHz. Its the same right?
Yup, it's the same. frequency [MHz] = 300/wavelength [m]. Some people rather talk in frequency; others rather talk in wavelength. So you have to know both :D
Good luck studying! Post up how it goes! 73,
the answer is 42. You are showing your age with that quote LOL :) Do you have your bag of fluff or your clear plastic bag containing a microscopic battle fleet?
I get 42
It was 42, it's not 42 anymore.
i think you soldered your braid on the wrong side of the laDDER LINE - switch those and everything should work correctly
"*"
42 😀
So I can pick up 2 meters and 70 cm… but can I have a QSO with a restaurant at the end of the universe? Asking for a friend!
Maybe if the right tropospheric phenomena are at play.... :D
1/137
I've seen that number. What is it?
The primary issue with soldering a Panel Socket is that it's not designed to take solder !
PL259 plug and socket @ 144 MHz is -3dbi.
Read a book ! Like W. I. Orr for an example.
;)
SO-239 for 2M /70cm? Are you mad?
Thanks for commenting! It helps grow the channel!
Could you please reduce the background noise, aka music? I don't understand the need of everyone on YT to use competing audio to get a point across? Your audience is listening intently, have you spent an hour straight listening to it? Do so before choosing the 4 second loop. I want to hear what you have to say, not wannabe composers. I'll check back. I appreciate those who wish to teach. I've taught a lot of professionals, and don't remember needing background, unless it was a damage control exercise, then the fires and flooding weren't actually simulated. People glean an awful lot aurally. Unrelated background is a hindrance to learning. Good luck.
Just subscribed. Looking forward to more videos. Especially since I'm 30 miles south of you. 73. Kd9qlk