Відео

I learn something eminently practical from every one of your videos. I’m taking my vertical out for POTA this weekend and will definitely try my hand at gating some directional gain.

Thank you for posting Jim! Rocking on !!!

Outstanding presentation. I have an FT-891 with a ATBK-120 counterpoise on a ATAS-120. Here in ABQ, we have rocky/stony soil. I have this attached to a GRA-ULT01 MK3 Tripod. Beneath it I have the Faraday fabric. Terrible reception. I then attached two 32 ft 20 Ga wires w/ banana clips, to the tripod, for radials. I have a 2 ft copper coated ground rod attached to the tripods so239. I still have terrible reception at my apartment. Any suggestions?

Thanks for posting this video! It is greatly appreciated!

I've always been told that the self resonant frequency is when the amplitude is at its highest peak, not the lowest. Can you please explain this?

Great content Jim! Thank you for putting this together for us.

cool vid thx!

I love the Easy Radial. So the coiled part of the wire does not account for the length of the radial, only the extended part of the wire?

Hi Jim, great video, I learned a lot. Honest question would a mag mount have given you similar results?

Good evening, if I want to put a vertical antenna 40m at the rooftoop, which is the best & most suitable counterpoises? Thank you

Put a shunt coil from feedpoint to ground inside the box to perform final impednce match.

Thank you for your excellent work. Makes one want to reconsider transformer-less resonant center fed dipoles.

Thank you very much for sharing, Jim.

Excellent presentation Jim. Clear, concise, helpful. You have a new fan/subscriber. W6BOW

These are good if you’re pairing them with Mylar bags of whatever size is best for you. To me the Gamma lids are just for ease of access and basic protection.

How much improvement is gained by elevating both the feedpoint and the end of the radial? If these figures are at 1ft, how much of an improvement would be seen at 10ft? 20ft?

Thanks Jim, for sharing your time and knowledge with us Beginner question: I can see the common mode choke (coax/ft-240-43?), but where's the balun? impedance at the feeding point is ~75ohm? Sorry if it is explained in the previous videos. I need to watch them again. Now I got the transceiver (I'm a "practical learner" if the term is correct) 73 de PU5MFH

Thank you for this excellent field work. In my exploration I've come across data that the length of individual radials on the ground doesn't matter as much as the amount of wire on the ground. Four wavelengths of wire on the ground reaches the point of diminishing returns roughly equivalent to two elevated 1/4 wave radials (which also matches my experience). I've used 3 bundles of six 14' radials on the ground with excellent results on 20m and above. Using silicone insulated wire they resist tangling and are easy to toss out with a clip on the end and then separate by running your fingers through them. Elevated radials are usually quicker to setup, but not always a practical option.

Turban is a hat beanie

That's a neat and very interesting idea!

Thanks for the demonstration of the changes' effect and for the good explanation. 🙂 This is in fact the kind of information I am interested in as a newbie in the ham radio hobby. I cannot put up a suitable antenna at the apartment and therefore depend on using wire antennas when operating from top of nearby hills. So far, I am interested merely in 15/17/20m, and my question refers to these upper bands that allow for using a vertical dipole (half wave): If the gain that can be achieved by adding such elevated radials to an end fed is in the range of up to 2 dB, am I then correct that when using a conventional vertical half wave dipole I will anyway have a gain of 2.15 dBi and thus have a better gain than what can be achieved with an end fed with radials? 🤔 (Please note that I am referring to the bands that have half wave length dipoles of a "manageable" length. I understand that with >20m wave length it is a different story.) 73 de DL1HNR, Henner

最好用场强表 进行测试来验证一下真实性

I wonder if there would be a difference in resistance in the SS antenna if it was measured vertical versus laying flat? Maybe the slip connections on the antenna would be tighter or have more surface touching in the joints when vertical.

I use elevated radials all the time. 2 sloping down at roughly 45 degrees at a 90 degree angle to each other. Noticeable improvement over other configurations like the magic carpet.

Will adding a second radial help to lower SWR. Also, would a second radial make the antenna even more directional. I have recently seen several videos using 2 raised radials and they claim it helps by increasing the dbi. Some videos are claiming 4 - 5 dbi increase. Curious to hear your thoughts. Thanks Terry

Thanks Jim!! Excellent video!!

*All practical tests of ground-based small wind turbines show the same thing: 1) They hardly produce any electricity. 2) They don't last long!* Solar panels generate at least 10 times as much electricity for the same investment of money and time. And maintenance-free for at least 25 years!* Wind/electricity yield increases with the third power of the wind speed.+ 100%wind = +800% electricity. But close to the ground, however, 0 constant wind, but gusts.

What about those with flat spiral secondary coils? They seem to be a lot more compact.. Does this still work with the S. Exciter type?

so with a poor ground, radials laying on the surface of the ground are acting as if they were elevated

Best video I’ve seen yet on this topic. Thank you so much!!!!

Awesome stuff!! Thank you! That snubber circuit is clever! I've never seen anything like that before.

I use 3 sets of 3 10 ft long 20 gauge radials with my MFJ 1898 on a spike in the ground to get the best SWR readings on 10, 12 ,15 & 20 meters on 40 meters I need to remove one set of radials to get the SWR where I want., the antenna is tuned at 40 meters but SWR is high until I remove the radial, i will try lifting the radials off the ground. Thanks for the research

Whoops. That hurt. :D Been there.

Ciekawe 👍Wszystkiego dobrego

Thanks for a great video Jim. I have just installed a 9 band vertical made here in Western Australia and your video made setting up the counterpoise so easy. I used two 2.75 metre lengths of 300mm wide aluminium flashing, and earthed the sheets and the antenna with a copper earth rod. This reduced the SWR on the 10, 11 and 15m bands to very low levels. As this is a semi-permanent installation, I buried the sheeting just under the lawn grass. I still have higher levels on the 40 and 80 metre bands, but I will work on this over time. Once again thanks for your help.

This was 2018; I hope they've changed the design and it's now airtight.

Excellent! Thank you Jim! I think the acid test would be to run power into two transformers back to back into a dummy load and look at the harmonics with a spectrum analyzer.

Always great to see more videos from you, Jim. You provide a lot of food for thought and contribution to our greater understanding of the various, nuanced phenomena that make up our hobby. :)

Excellent video! Jim, you do nice work. One thing I'd like to mention.... The impedance of a loaded vertical may not be 50 ohms - usually it is not. For example, a 1/4 wave vertical over perfect ground has an impedance of about 35 ohms. A loaded vertical is usually less. This is with perfectly conducting ground as a counterpoise. 35 ohms would be an SWR of 1.4:1. So if we measure an SWR lower than 1.4 in this case it would mean that the ground is providing resistance (loss). Improving the counterpoise with more radials (for example) may make the SWR get higher. This is actually a good thing. Moral of the story... SWR is not a reliable indicator of antenna performance.

The radiation resistance?

RF is a surface phenomenon.

Cool stuff Jim! I learned this from a radio man, for locating intermittent wiring, and had forgotten about it. RIP K5DLE……

This is very intetesting and a bit surprising too. How would the high resistance of the stainless steel whip affect RF performance and efficiency? Thanks, Mike.

Can you repeat this using an RF source?

Suspicion confirmed. Some whips appear to have a tight connection between the sections, which eventually become looser as time passes. You have to wonder what's going on when a considerable amount of power is transferred into the antenna, and the multitude of potential outcomes. Heat at specific points which results in metal expansion and the possibility of arcing, and a poor-quality radiated signal for instance.

Wow!

Maybe I missed it, what brand is the stainless whip?

This is quite eye opening... it goes to show not all telescoping antennas will perform the same and not to assume their performance! Thank you for the video!

Very well done Jim. Thank you. ---- You got me very interested in mag-loops. When I try to measure resistance on various loops I'm testing, I always get .1 ohms. That's of no help to me. ---- It would be very interesting to see tests on your various loops as my understanding is how critical it is to have very low resistance on the loop. Also........is it necessary for those leads for your testing to be that long? You mentioned a loop and I was just wondering if there is something to that. ------ I'm a truck driver Jim, so I need everything in baby steps. Ha. ---- Your presentations are first class. Thank you Jim. 73.

Impresionado!!! La práctica puede reescribir la teoría. Muchas gracias. Gran trabajo!!!