Ham Radio: Base loaded Coil testing on 80M and 160M and Just how many Henry's do you need? 

Many thanks!

You bet!

Thanks Roly.👍.

Thanks 👍

you will not be disappointed

How did you order the Roly coil, please?

@@kellypaws email zl1bqd Roly,his email ok in qrz.com 👍

Cheers Joseph.

Maybe one day!

@@mike-M0MSN Can't help thinking, all you actually need, is something to control the former's rate of screw, and a drill...

Thanks 👍

Fingers crossed!

thank you.

Many thanks Tim. :)

No, sorry

Thanks

The GM 5/8wave is a Stub matched antenna for 27MHz, so would not work on any other frequency without changing, well everything. you could however use the shell/frame work to make a vertical for 80M...

Many thanks, still only the one radial, :)

Thanks for the tip.. :)

Spot on. 👍

Good tip!

www.kiowa.co.uk

I will have to experiment with this one, but I would think using loaded radials would work…

now there's an idea.. :)

I have a pamphlet on how to homebrew a screwdriver antenna. Do you want a copy?

Yes, absolutely

thread cut into the pipe.. :)

@@mike-M0MSN Lathe or by hand? Lot of work by hand! HI HI

@@gregnewberry4813 Watch the earlier video - or was it later? Les

For sale, lol... I use the clamp because I can then use the coil on different element lengths ie the DXC classic, expedition and lite.. :)

@@mike-M0MSN I could get all the parts needed for this except I have no way of cutting the grooves into the pipe. Any suggestions as I do not have access to a lathe?

@@A.R.O.T.A. Run some double sided tape up the pipe and mark between it 5mm spaced dots and slowly turn the coil.. good luck.. :)

Yes maybe, stainless does seems to be working. :)

To both of you. => thanks that you are touching a kind of material. Yes, this is very important too. “Why you are use a stainless steel for a coil ?), it was my question too (watching your previous video). 73’s

@@voytekfid7734 At least if it works, it will not rust.

Having found the correct taps for the correct bands, could a relay be used to remotely switch it?

@@paulsengupta971 Think about it, most ATUs have a load of relays in them to do the tuning.

For this set up and only for this test, the vertical radiator was 11.15M and only one ground radial of 20M..

@@mike-M0MSN Hi ~ shouldnt it be 4 x wavelengths 40m / 32 or 16 or 8 or 4 ?

don't know, why don't you try it and let me know.. :)

height above the radials. :)

Yep, do not get tangled up with these measurements, 11.5 Metres is only on a linear loaded DX Commander the true length of a quarter wave on 40 metres is: 300/f = 300/7.1 = 42.2535211268 x 0.92(correction factor for a PVC coated Copper wire antenna) = 38.8732394366 / 4 = 9.71 metres (trim to SWR) this is a guide not 100% as every installation is unique.

There is never a bomb question just stupid answers, The line/wire you have seen is a counterpose (20m ground radial).. :)

Inverted L is better but if you do not have the space....

I think is was 25Watts and yes with that coil.. :)

Hi Mick, OK the coil calculation I made was in metric, so 50 turns on a 7.5cm dia 12.5cm long (for a 32 foot long antenna).

DXC Classic

Hmm just measured my antenna @1.930MHz VSWR 1:1.1- Z=45 - Phase=0 - R=44 - X=3.. @3.700MHz VSWR 1:1.3 - Z=37 - phase=10 - R=36 - x=6 Maybe a ground plain issue?? I will read a bit more into this for you...

What are you using to load the antenna at the base and what is your ground (counterpoise)? Also, is that where the SWR dip is? If you adjust the antenna until the imaginary impedance Z for say -j13 or so, then you could use a Smith Chart to plot the impedance and solve for shunt inductance you need to bring the impedance to 50 ohms. I use Smith chart software to do the work for me, it's worth the time researching it. Since you have the means to measure real impedances, you can solve any Z problem. I always adjust my antennas so the impedances, real and reactive, fall on the Smith chart curve that leads back to the center of the chart. That gives me the shunt solution for 1:1 SWR. You could also use trial and error. Shorten the antenna as above so you get -j13 or so and wind a 2 uh coil and place across the feedpoint. Then squeeze or expand till you get near 50ohms. You could then adjust the antenna a little at a time and readjust the shunt coil till you get near 50ohms. The -j13 is just a start. It may need to be higher if the real R is higher. When my R=25 ohms, for example, my -j needs to be near -20 to -24. I hope this did not make your eyes glaze over.

@@captaintripps7354 LOL, a little dizzy but a great tip.. many thanks...

James, I assume you are not using the loading coil? What are you using for ground/counterpoise?

@@captaintripps7354 thanks all for your replies, I am trying to make sense of it all. Let me clarify, I have a 40m vertical from Ultrabeam. SWR is great at 40m. Measuring its impedance at 80m (to deduce what coil to use) I get this very small real part. I use a ground rod at the base of the antenna and have around 30 radials in the grass. At the moment indeed I am not yet using any coil, just trying to understand what kind of coil I would need. I think the Ultrabeam has a balun inside, maybe that balun is not working at 80m and that's the reason? Thanks for any advice!!

9,6 metros de altura, obrigado

No idea, use the website.. :)

ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-DLDdOepaq7k.html

Well it works and is a great solution for the small garden, 10watt copy into Italy and Slovakia on 40 and 80M inter G on 160m. Go figure

I looked at some of your other videos of other coils which are fine, enamelled copper with taps. Its just so wrong in my book to have shorted turns. I'm sure it must work better with tapped windings where you arent shorting any.

The earthing strap used, is a moveable tap similar to the system used in wolf river coils or the mini-Tarheal screwdriver antennas it dose not short out any of the turns. It becomes the last turn in the coil…..

I agree the strap becomes the last turn, but its a shorted turn. The clamp itself is effectively a shorted turn plus its shorting a number of other turns underneath it. The magnetic field from the active section of the coil doesnt stop dead at the last turn, its passing through the shorted turns. I'm not sure exactly how the two coils you mention make physical contact with the coil but I doubt they'd have a metal strap round the outside. If you look at roller inductors they only make contact with one turn as they rotate and theres a good reason for that.

@@666Bern666 I'm no expert on these things, but doesn't the coil "stop" electrically as soon as it meets the strap around it, then the strap to the wire becomes the last turn? It could short out all the rest of the turns up the coil but would still be the same, surely?