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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!!!

Excellent! This validates my suspicion about SS telescopic whips. To overcome the SS whip's resistive loss and intermittent joints, clip a #18 or #20 stranded copper wire between the whip's end-tip and base. Also, when pairing a SS whip with a SS loading coil (or a high loss transformer like the G8JNJ 5:1 UNUN), the total resistive loss further increases which works great for broad-banding and lowering SWR, but at the cost of reduced signal strength. Whether or not any of this significantly degrades communications capability is debatable.

Ha..ha..ha.. You are trying to compare an apple to an orange. The SS whip's nature of inherent construction is that each segment is connected by means of Be-Cu springy contacts; had you ever disassembled (or tried to mend a broken one) a whip (which is usually a Ni coated brass tubes fitted to form a telescopic structure), you might have known it, I think. Surely, the connection between each segment depends on the tightness, and the inherent higher resistance of the Be-Cu compared to that of a pure copper. Moreover SS or Nickel -Chromium alloy has higher resistance when compared to copper. When you keep shaking, definitely the resistance factor would keep varying. Your Al whip has been tightened by means of screw clamps at the overlaps. And you never shook the whip to show that the resistance didn't vary, in the video. And the long wires used for measuring have finite resistance and voltage drop across; let us assume the temperature factor constant. All said, you may want to reconcile and make another video to make the answe not stupid to to the so-called stupid question. You know very well that the telescopic whips were (are) great antennas for the battery operated portable Solid State radio receivers. Hams are always ambitious and the manufacturers started making such whips of 17' or more for ease of operations like POTA etc. Many hams find these contraptions very useful 😀 De VU2RZA

My antenna mount is attached to a cargo rack mounted on the roof of my car. Rubber pads to prevent vibration electrically isolated it from my car, although there was some capacitive coupling. To improve the connection, I installed two stainless steel straps from the rack to my car body just inside door openings. That was done by drilling holes in both. The result seems to work well enough. I have SWR's of 1.4 or less with Hustler antennas on the 40, 30, 20, and 10 meters.

Gracias sr. White ... i do been learn a lot from You ... saludos , desde Mexico , aprecio mucho su tiempo y el ejemplo de vida qué usted comparte ...

Your mention of the resistance of stainless steel versus copper in loading coils has interested me in developing a coil from one of the WWII B-17 Command set antenna tuning coils I have. Unless my understanding of metals is wrong, they're made from silver, which is an even better conductor than copper.

Those who want to take full advantage of ground spikes can find 8-foot, copper or copper-plated grounding rods used for home electrical installations at building supply stores. They run about $20. Installation can go easier if you dig a hole around where the rod will go. Fill it with water and jiggle the rod to loosen the ground as it goes in. Epson salt in the water will also improve the conductivity.

I have not done as extensive testing as you have done, but my research agrees with yours. I find that as I add more radials, the SWR does improve and as you found out there's a point of diminishing returns. I usually add no more than 6 of the 32 foot radials as after that, the SWR doesn't get much better. During your testing, you had the screen first on the ground, then 3 inches off the ground and finally 7 inches off the ground. My question is if you tried something similar with the elevated radials, how would they react? For instance you could try elevated radials 1 foot off the ground then 2 feet off the ground and finally 3 feet off the ground. I have seen some videos showing elevated tuned radials 3 or 4 feet off the ground. To go along with that, the 1/4 wave radiating element is also 4 feet off the ground on a tripod. I have not tried elevated radials yet, however I believe that it would be an improvement to my portable setup. I will be trying that next summer. Thanks for an informative video. N3EDO.

Jim , could the crocodile thin wires have an influence on your result.. ? Always enjoy your content. Johan zs2cx

Hi Jim, I do really enjoy your in-depth videos. I have a question for you.... it is regarding telescopic mast antennas.... the question is... " which is a better radiator, a stainless steel telescopic whip or one of the same length and dimensions but made from aluminum". Aluminum is a better conductor than stainless. How would we go about testing this? Thanks for all your efforts Jim. 73 Art W1SWL

Old Dutch windmills had 4 Horizontal placed wooden frames slightly at an angle with fabrik on them, this way an operator could roll up the fabric like a curtain and stop the rotation. Ofcourse these were flat frames and not helix shaped, later discovered to be more efficient with less drag. Nerds who believe in Perputal motion had Horizontal wheel designs that try to minimize drag at a certain point of the wheel so it would be pushed (pulled) indefinitely less or more by gravity. That ofcourse is not possible. Same with your sail design. At a certain windspeed the rotation is to high and the sail is pushed outward by cenrifugal force. This will therefore only work at low rotation speed and I think that is not what we all want. I am not sure, but its a rough guess.

Now show how to fix.

You need to put the meter in a temperature controlled environment and test the CJC works properly to prove the meter is good quality. You would not use a thermopile type IR sensor to read aluminum, the emmisivty is not ideal. You need to use a special wave length and probably a cup to block out outside influences.

I just picked one of these up. Unfortunately I dont have the receipt. I tested mine when sterilizing it. Sure enough it leaks. Since it's screwed as far as air tight, I'm going to break out the Dremel tool, and some plastic filler I have and do the finishing work they should have done. Heck I may even go ahead and put a light nontoxic adhesive between the o-ring and the lid just to get a good seat. Thank you for this. I know what to look for to try and salvage it. Worst case scenario I'll store my MRE's in it.

Nice solution to the solution Jim. I really like the way you apply your knowledge to mould your environment to your wishes and overcome the obstacles. Thanks for sharing. Best wishes, Michael

I’ve been looking for an adjustable air crate system. I’m definitely going to try my best to follow your instructions. They are clear and concise. I like the ability to have higher control over the foam

jim , good info. have you ever considered making a video feeding the endfed 1/2 wave with a lc tuner :)

shortcut, you can just delete the audio channel, and it will take out the audio track as well. you can also hold the ctrl button while stretching the video, without having to choose the cursor tool

wouldn't a 100v 47nf mylar cap between emitter and collector be a better option for over voltage protection of the transistor?

Very good info. Some may want to add some thin plastic between the foil and the paintwork to increase slightly the thickness of the dielectric. One question. If I have a dipole around 73ohms in impedance and I wish to match it down to 35 ohms into coax. What ratio balun should I make? A 2:1 should be good?