Didn't go to Hamvention, so thanks for bringing these products to our attention. Regarding the faraday cloth: i folded the edges, and secured the fold using the faraday tape which comes with the cloth. Keeps the edges from fraying. I also purchased a grommet kit (they are very inexpensive on Amazon), punched 8 grommets on the periphery of the faraday cloth, and lay it down and stick in small Aluminum tent pegs. Keeps the faraday cloth secure and in place, and holds well in fairly gusty winds. Also, i had mentioned in another video, several people here use chicken fence wire rolls, way cheaper than window screen and available in any length you want, works well too. I like the faraday cloth best because it fold up compact and is the lightest. Also carry 4 radials as a backup.

@Jimscoolstuff

Ай бұрын

Thanks for sharing this information.

Grew up in nearby Huron. Left Ohio in 1975,became Ham 40 yrs. Later. Enjoyed video,especially Lake Erie History! 73 W7OT

@Jimscoolstuff

Ай бұрын

Thanks for your comment. 73 KQ8E

Interesting innovation. I wonder how much loss there is in the inductive coupling? It would be good to measure this with a VNA like the nanoVNA.

Great video. Just found your channel. 73

@Jimscoolstuff

2 ай бұрын

Thanks for your nice comment. 73

Thank you, Jim.

I like the simplicity of design, adjustability and ability to lower SWR shown in the video.

@Jimscoolstuff

2 ай бұрын

Thank you for your comment.

Excellent very good presentation. I like the dip curves

@Jimscoolstuff

2 ай бұрын

Thanks for your comment.

I'm not a fan of PVC pipe construction. Nonetheless, nice to see this application of variable inductive coupling and integration of a matching network -- what's old is new again.

@Jimscoolstuff

2 ай бұрын

Thanks for your comment.

Jim, have you by any chance had a chance to play with the new 25 ft whip from Chameleon with the Amratek coil. With either the loading coil mode or in the matching network mode, i am having no luck getting a resonance point (using a rigexpert to sweep the band). Any advice appreciated.

@Jimscoolstuff

3 күн бұрын

It should work just fine if limit the length of the whip to 17.5 feet.

@jbammi

Күн бұрын

@@Jimscoolstuff Thanks Jim, yes i understand that, and 17.5 works just fine. My objective here is to have the maximum amount of metal in the air and the minimal amount of fake electrical length/coil, for max efficiency and widest bandwidth with a given SWR. Looks to me like the 30/40 coil does not have enough range to make this happen I was hoping that the matching network mode of the coil may be able to work, but i cannot find a resonant setting with that either. Are there any other possible configurations (like the 30 M one) that are possible that i could try. 73 de ws1m

@Jimscoolstuff

Күн бұрын

@@jbammi The Amratek coils were designed to work with common 17 foot whips. 73

@jbammi

Күн бұрын

@@Jimscoolstuff Yes, the coil design is superior compared to the common stainless steel wire with a slider approach (ala Wolf River), and the non contact idea is brilliant. Perhaps the next version can be made with a little more range and does not end up as a "one trick pony" like this version. I was hoping the matching network mode may work, but that seems to have the same limited range. I'll experiment with some shunt capacitance to see if i can bring the system to resonance.

@Jimscoolstuff

20 сағат бұрын

@@jbammi The minimum inductance of the Amratek coil is 6.8 uHy. To resonate a 25 foot whip at 7 Mh requires an inductance of about 3.8 uHy. You could connect an inductor of 6 uHy in parallel with the coil, or you can remove several turns from the slider coil. Simulations with EZnec show that at resonance the input to the antenna will be about 16 ohms. this will give you a minimum SWR of about 3.1:1. I hope this helps.

Thank you for making this video and sharing it with all of us! I am subscribed to the channel with notifications enabled and thumbs up! Question: Before you add any kind of coil, when you have the antenna whip acting as a quarter wave antenna fully extended to 17 feet and ground radials connected, what is the maximum power rating of that configuration? Reiterating and clarifying my question: When just using the quarter wave with the telescopic whip and any required radials, no coil connected, which is why my example would be 20 m through 6 m, what is the maximum power that that set up can handle?

@Jimscoolstuff

29 күн бұрын

That arrangement should be good for full legal power depending on the wire size of the radials and the coax voltage rating.

@ErnestGWilsonII

29 күн бұрын

@@Jimscoolstuff thank you for replying! What would it take to make one of those new style low loss coils that you have shown in your video to be made to handle 1500 W digital? Specifically on 40 m band. Could you scale one up to a size that would handle 40 m at full power without worry of overheating?

@Jimscoolstuff

29 күн бұрын

@@ErnestGWilsonII It could be done, but it would be expensive and I don't think very many would be sold.

@ErnestGWilsonII

28 күн бұрын

@@Jimscoolstuff I agree this is not a high demand item. How much do you think it would cost? Could you design one on paper? I just spent $1300 trying to solve this using a screwdriver antenna that claims 1500 W ICAS. In the end, I'm not looking for something that does 80 m at full power, but I am looking for an efficient coil that would bring me into the 40 m band at full power without heating up, so making something substantial would be required. 73. W3GUY.

The ground screen off to the side like that will drastically affect the omni-directionallity of your vertical. Put the cloth in the direction you want to work.

@Jimscoolstuff

2 ай бұрын

A ground screen over "good ground" capacitively couples to that ground/earth. I have conducted tests using WSPR and wsprnet and could not detect any directional bias. When used over poor ground (like rock) you may be correct. kzread.info/dash/bejne/oZyirdyin8a6qKw.htmlsi=arffHqircQ0lq18x Thanks for your comment.

@KA4UPW

2 ай бұрын

@@Jimscoolstuff Ive done extensive testing and modeling and found that the directionallity is affected. At first i thought the other directions were affected due to ground losses but modling showed the path of least resistance dominated and the signal was warped into the direction of the ground. I havent tried this over a salty marsh but i live 5-miles from the coast on relatively good conductive soil and still can see the benifits. I actually went as far as to switch in and out groups of ground radials to favor a weak signal or to null out a noise source.

@Jimscoolstuff

2 ай бұрын

@@KA4UPW Thanks for sharing this information. What modeling software did you use ? Those that I know of are poor at handling non-uniform ground configurations.

@KA4UPW

2 ай бұрын

@@Jimscoolstuff I cant remember. It was a long time ago when i lived in WI before moving to Europe. I have been in Florida for the last 10 years. So yes probably 15years ago. I did the emperical data loading up a 40ft flagpole. Then used used the long WI winter to play with and manipulate the models until i had a reasonable fit. I wish wisper was a thing back then. I think i have a write up on it on my QRZ page. I have a 68ft pole on stand-by for my current QTH here by the beach.

Thanks for the nice walkthrough. While the stinger is a bit longer than the 17’ telescopic whip, it looks nice and robust and aluminum is a preferred material with less resistance. So if you put the capacitor in the circuit, since it connects to the tripod, it could be said that it tunes the ground system a bit (and then you further refine the total match with the inductor that’s in series with the whip)?

@Jimscoolstuff

2 ай бұрын

The counterpoise is part of the tuned circuit. The ultimate counterpoise is 1/4 wavelength radials which are inconvenient to use. A "tuner" is a matching network that uses an inductor and capacitor to present a desired impedance to the transmitter. kzread.info/dash/bejne/oZyirdyin8a6qKw.htmlsi=CDqyiXUpV92J-krh Thanks for your comment.

Add a capacitance hat near the top of that stinger will improve the radiation resistance on 40m-80m

@Jimscoolstuff

2 ай бұрын

That is true. Thanks for your comment.

I assume i can leave the coil permanently attached to the base and the stringer to the coil., and when i want to use 20 thru 6M i just bypass the coil with a clip lead. That way i can also switch quickly between 20 and 40M, Kindly confirm that this wont pose any harm to the coil? 73 de k1jbd, Bammi

@Jimscoolstuff

Ай бұрын

Yes you are correct, and the coil will not be harmed. 73, KQ8E

I assume the 80m slider will also tune 60m, 40m, and 30m?

@Jimscoolstuff

Ай бұрын

No, the 80M slider will not work on higher frequency bands with a standard 17 foot whip. It could be made to resonate by using a shorter whip, but a high SWR may result due to the very low radiation resistance of a very short whip.

Link is not working?

@Jimscoolstuff

2 ай бұрын

I just tried it and it worked OK. perhaps the site was down when you tried it. Thanks for letting me know.