I'm not keen on the earth clamp idea as you'd have to check and adjust every time you wanted to change bands or even move between some points on the same band. I would prefer taps at the needed points on each band. Also as I would want it for use with the DXC Classic the separate feed point would not be wanted. However you have proven the viability of the idea. My only question is when would it be ready for sale?
@@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?
IF you do this.... BEWARE.... Make sure that you short out the unused turns. At high power the unused turns could be come a tesla coil with sparks radiating. That will get the neightbors attention and may not do your rig any good either.
IF IT FUNCTIONING ON 40 M BAND, IS IT THEN PLAUSEBLE THAT IT ALSO MAY DO THE JOB ON 15 M BAND? VERY NICE TO SEE YOUR PROFESSIONALISM! HIGHLY INSPIRATIONAL!
I was wondering if you could provide a close-up of the clamp that you're using on the coil maybe take a couple of photos and send them over I'm trying to determine how the clamp makes contact with the coil is it just from the thumb screw only or more than that
If the antenna is on a fold over mount I take it the height above the antenna base would still be input as zero as long as the coils is raised to the start of the antenna? Or is it supposed to be the height above ground
Half wave coil load deal for 160-meter band for the operator working from an apartment with balcony railing, that would be "the bomb" as we still say! I've been looking for a mobile application that would 1/4 wave on the 160-meter band. There is a mobile trap coil load antenna for the 80-meter band but for professional courtesy reasons I don't want to mention the name here.
Hello Mike this is n6zn good job good video too. I have tried to make several short verticals in the past with not do good results for dx. I think it was do to the loading and ground system. hey just a note. You most likely know this, but if you put your rx AGC on slow reaction it fills the back ground noise a lot. Just a note... thanks for the nice video.. Jim
Brilliant job Mike. It looks very professional. Nice to see you getting some contacts in the log too. Let us know how it's been performing after the winter when hopefully you will be able to work some nice DX. Hope to get mine made up before the winter. I wont tap mine, I just set set the coil inductance so when the adjustiwave is fully linear loaded the antenna is resonant on the bottom of the band, I can then just wind the reel in a bit to work the top of the band. 73 from Scotland.
Hi Mike do you know how they arrived at 11.15 meters for 1/4 wave on 40 Meter? Or maybe its a compromise to work with the loading coil ? 71.5 / 7.5 mhz = 9.51 Meters 1/4 wave.
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.
Hi Mike ... Hope you well ... I am at this time creating a coil for my resonant 40m vertical 32ft ... for 80m ... When you do your coil on the inductance your length is misleading to me as you put 12.5 yet you are in cm ... Can you Help .. Mike M0CSI
Great video. I take it the same can be done with my 43’ vertical to get to 80/160m? Would the bandwidth be greater given that the antenna is longer? More efficient??
Wow thanks for this video. So, if I am understanding correctly, you don't need to calculate the exact inductance when analyzing the antenna system (provided you did the calculations right when building coil), but can identify the correct tap/ground placement VIA VSWR reading alone?..
Thanks for this very useful information. But the problem that I think needs addressing is the ground plane. Those of us with the "small area problem" are struggling with trying to find a method of 1/ using the house roof as an effective ground plane, or 2/ not having enough usable lawn to put in a ground system of suitable length in any direction. To me, this would be the biggest unaddressed problem. Could a coil or inductance of some sort, be added to shorten/modify the necessary grounding system needed for vertical antenna.
I'm frankly flabbergasted..... I've not read all the comments but I cant see anyone picking you up on the fact you appear to be shorting turns on the coil, both at the top with the bolt and washer, with the earth strap and the earth strap itself is acting like a shorted turn! Its no different to having shorted turns on a transformer, you are destroying the inductance and Q of the coil. You'll be wasting loads of power heating up the coil.
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?
Excellent, but I am not sure I would want to nip out on a winters night to change bands, never the less, good job Mike. I had watched a couple of videos where they said Stainless steel wasn't good, that is why I wanted to see. But thinking about it, what is a steel whip made out of? Stainless steel. I think they were doing something wrong myself.
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
Excellent. Wondering if I could use this to convert my 5/8 gain master (10/11m band) antenna. Purchsed and installed for CB, now hardly used, as using mag loop for 40-10 m. Wondering if I could get 80m performance out if it .... hmmmm (great video as always)
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...
Just a quick comment ... MMANA-GAL can do all the coil calculations and number of turns/diameter/L etc for you. Just subbed and great content. Many thanks.
Curious, did you add more radials for 80/160? If not I wonder if they could help. SWR seems ok, are you getting 50 ohms also? Good project and as always with you, very precise and well made. I wish I had the tools and of course the ability you have. An old man now but never was as precise as you are. I really enjoy your projects and appreciate you sharing them, Thank you !!!
Thank you for making this video and sharing it with all of us. Do you have another video that shows how you constructed this particular coil? I am of course subscribed to this channel with notifications turned on and thumbs up! 73 W3GUY
If you could make the coil adjust like a screwdriver antenna as it drops into a pipe or aluminum it will keep the Q or even improve it. also it could be made to be adjusted remotely.
Great video! When I measure my 11m high vertical at 3.5MHz, I get an impedance of Z = 1 Ohm - 87*j Ohm. I understand that a loading coil can eliminate the complex part, but even then the impedance Z would only be around 1 Ohm, yielding an extremely high SWR. Nonetheless, you seem to be getting an SWR < 2 for a similar exercise. Any idea what I am missing?
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 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!!
Mike, nice video but judging by the huge bandwith at SWR=2 on 160 meters you have built pretty good dummy load :)
I'm not keen on the earth clamp idea as you'd have to check and adjust every time you wanted to change bands or even move between some points on the same band. I would prefer taps at the needed points on each band. Also as I would want it for use with the DXC Classic the separate feed point would not be wanted. However you have proven the viability of the idea. My only question is when would it be ready for sale?
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.. :)
💎💎💎💎💎🐿🐿👍👍👍👍👍🍀🍀🍀🍀👋👋👋👋 kind regards from germany. 73 Peter
when you use ssb, then its more plesant for the sound if agc is on slow... rgds fm oz1fjb - ou2v
Marvellous, Mike. Thanks for an excellent record of your experiments, and the links.
Many thanks!
Useful loading website and great tip on the earth strap, either as a temp or permanent variable fixing 👍🏻
Great job! I have to make this coil and antenna.
Hello! How were the carvings cut?
Nice transceiver! Please tell me its name? I liked the video. Now I want to make such a coil too. for going out into nature. 73!
IF you do this.... BEWARE.... Make sure that you short out the unused turns. At high power the unused turns could be come a tesla coil with sparks radiating. That will get the neightbors attention and may not do your rig any good either.
IF IT FUNCTIONING ON 40 M BAND, IS IT THEN PLAUSEBLE THAT IT ALSO MAY DO THE JOB ON 15 M BAND? VERY NICE TO SEE YOUR PROFESSIONALISM! HIGHLY
INSPIRATIONAL!
I was wondering if you could provide a close-up of the clamp that you're using on the coil maybe take a couple of photos and send them over I'm trying to determine how the clamp makes contact with the coil is it just from the thumb screw only or more than that
Cracking job Mike and for someone with limited space it’s a winner! I ordered a Roly coil and it’s on it’s way from Zl land 😀
you will not be disappointed
How did you order the Roly coil, please?
@@kellypaws email zl1bqd Roly,his email ok in qrz.com 👍
3' 3" or 3foot3, as we say= 1 meter. The only conversion I can remember, since it has a ring to it.
If the antenna is on a fold over mount I take it the height above the antenna base would still be input as zero as long as the coils is raised to the start of the antenna? Or is it supposed to be the height above ground
height above the radials. :)
Half wave coil load deal for 160-meter band for the operator working from an apartment with balcony railing, that would be "the bomb" as we still say! I've been looking for a mobile application that would 1/4 wave on the 160-meter band. There is a mobile trap coil load antenna for the 80-meter band but for professional courtesy reasons I don't want to mention the name here.
interesting videos i enjoy to see the results....
Hello Mike this is n6zn good job good video too. I have tried to make several short verticals in the past with not do good results for dx. I think it was do to the loading and ground system. hey just a note. You most likely know this, but if you put your rx AGC on slow reaction it fills the back ground noise a lot. Just a note... thanks for the nice video.. Jim
Some good information here Mike, thanks. I'm not able to turn a helix, so will have to try one of your alternative ways of doing that.73s
Brilliant job Mike. It looks very professional. Nice to see you getting some contacts in the log too. Let us know how it's been performing after the winter when hopefully you will be able to work some nice DX. Hope to get mine made up before the winter. I wont tap mine, I just set set the coil inductance so when the adjustiwave is fully linear loaded the antenna is resonant on the bottom of the band, I can then just wind the reel in a bit to work the top of the band. 73 from Scotland.
Hi Mike do you know how they arrived at 11.15 meters for 1/4 wave on 40 Meter?
Or maybe its a compromise to work with the loading coil ?
71.5 / 7.5 mhz = 9.51 Meters 1/4 wave.
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.
Hi Mike ... Hope you well ... I am at this time creating a coil for my resonant 40m vertical 32ft ... for 80m ... When you do your coil on the inductance your length is misleading to me as you put 12.5 yet you are in cm ... Can you Help .. Mike M0CSI
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).
Great video. I take it the same can be done with my 43’ vertical to get to 80/160m? Would the bandwidth be greater given that the antenna is longer? More efficient??
Yes, absolutely
Wow thanks for this video. So, if I am understanding correctly, you don't need to calculate the exact inductance when analyzing the antenna system (provided you did the calculations right when building coil), but can identify the correct tap/ground placement VIA VSWR reading alone?..
Spot on. 👍
Thanks for this very useful information. But the problem that I think needs addressing is the ground plane. Those of us with the "small area problem" are struggling with trying to find a method of 1/ using the house roof as an effective ground plane, or 2/ not having enough usable lawn to put in a ground system of suitable length in any direction. To me, this would be the biggest unaddressed problem. Could a coil or inductance of some sort, be added to shorten/modify the necessary grounding system needed for vertical antenna.
I will have to experiment with this one, but I would think using loaded radials would work…
I'm frankly flabbergasted..... I've not read all the comments but I cant see anyone picking you up on the fact you appear to be shorting turns on the coil, both at the top with the bolt and washer, with the earth strap and the earth strap itself is acting like a shorted turn! Its no different to having shorted turns on a transformer, you are destroying the inductance and Q of the coil. You'll be wasting loads of power heating up the coil.
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?
thanks for the video mike. now to find a way the get a former with grooves
Thanks Mike 👍🇬🇧❤️
Very well made. Good work. 73 DD1TA
Excellent, but I am not sure I would want to nip out on a winters night to change bands, never the less, good job Mike. I had watched a couple of videos where they said Stainless steel wasn't good, that is why I wanted to see. But thinking about it, what is a steel whip made out of? Stainless steel. I think they were doing something wrong myself.
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.
Excellent. Wondering if I could use this to convert my 5/8 gain master (10/11m band) antenna. Purchsed and installed for CB, now hardly used, as using mag loop for 40-10 m. Wondering if I could get 80m performance out if it .... hmmmm (great video as always)
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...
Which dx commander are you using ?
DXC Classic
Just a quick comment ... MMANA-GAL can do all the coil calculations and number of turns/diameter/L etc for you. Just subbed and great content. Many thanks.
Thanks for the tip.. :)
Curious, did you add more radials for 80/160? If not I wonder if they could help. SWR seems ok, are you getting 50 ohms also? Good project and as always with you, very precise and well made. I wish I had the tools and of course the ability you have. An old man now but never was as precise as you are. I really enjoy your projects and appreciate you sharing them, Thank you !!!
Many thanks, still only the one radial, :)
Is base coil better or not as good as inverted L for same frequency. Thanks.
Inverted L is better but if you do not have the space....
Could this Coil also Work on a Moxon Antenna or a regular 2/3 Element Beam to keep it Small like a 6m Band Antenna for the 12m or so ?
don't know, why don't you try it and let me know.. :)
Thank you for making this video and sharing it with all of us.
Do you have another video that shows how you constructed this particular coil?
I am of course subscribed to this channel with notifications turned on and thumbs up!
73 W3GUY
No, sorry
Really Interesting work Mike. Do you have a link to the pipe you are using? Thanks M0EDV
www.kiowa.co.uk
I’m going to ask the dumb question. What is the lead running out from the base of the coil? Where does it go and what’s it for?
There is never a bomb question just stupid answers, The line/wire you have seen is a counterpose (20m ground radial).. :)
nice setup. may you tell us the length of vertical radiator, and how many radials do you use in your vertical? tnx for any help. 73 de PR7TU
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 ?
Well done Mike, Looks good. 73 Joe
Cheers Joseph.
Thanks Mike!! I could watch you build coils all day!! Thanks for all the Great Information!!
73 N9RAN
You bet!
Brilliant informative video. Thanks
I see corrosion on the bottom plate of the antenna. It may be good to add anticorrosive spray once in a while to keep it making good contacts.
Good tip!
If you could make the coil adjust like a screwdriver antenna as it drops into a pipe or aluminum it will keep the Q or even improve it. also it could be made to be adjusted remotely.
now there's an idea.. :)
I have a pamphlet on how to homebrew a screwdriver antenna. Do you want a copy?
god job Mike
thank you.
Nice one Mike... Looks to be working like a charm... Cheers
Thanks Roly.👍.
great job mike ! and understandable.....
Thanks 👍
great video. How did you wind the coil so uniform? Are there grooves in the PVC pipe? If no grooves, how do the windings stay in place? Thanks. WB7DUO
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
That's very, very nifty. Just wish I had access to someone with a lathe. Super neat idea that.
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...
Hello whats is this app for Android for coin calculator
No idea, use the website.. :)
Boa tarde amigo muito boa antena que tamanho tem esta antena
9,6 metros de altura, obrigado
Thank you Mike for one more instructive video
Thanks 👍
nice......
Thanks
Great job Mike and very well presented as usual 73
Many thanks Tim. :)
SWR ?
SWR ?
theres a new version of wsjt x out btw the way ,its 2.2.2 , oh and btw how many watts are you running on top band ?? i take it was with that coil ??
I think is was 25Watts and yes with that coil.. :)
Great demo Mike. It will be interesting to see how it does during the cooler months when the QRN is down.
Fingers crossed!
Great video! When I measure my 11m high vertical at 3.5MHz, I get an impedance of Z = 1 Ohm - 87*j Ohm. I understand that a loading coil can eliminate the complex part, but even then the impedance Z would only be around 1 Ohm, yielding an extremely high SWR. Nonetheless, you seem to be getting an SWR < 2 for a similar exercise. Any idea what I am missing?
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!!
what about 11m antenna build
th-cam.com/video/DLDdOepaq7k/w-d-xo.html