DX Commander, Roly Coil Combo 80M Vertical

[@M0RMY]

Great job Mike - I like to think it will be forever known as the "Roly Coil".

[@mike-M0MSN]

I think so too!

[@ukm6yik69]

Has to be a roly coil 😁

[@RolyRJ]

Nice job Mike and i admire your tenacity in getting this coil assembly constructed. You mentioned in passing the BIG secret in making this thing with out too much hassle. If you can, find a friendly engineer who is able to turn a 5mm pitched thread into the pipe for you, It only needs to be 1 - 1.5mm deep but the "thread" will act as a guide for you and the need to glue-as-you-go disappears. The several hours of frustration in holding springy wire in place also magically disappears. Yes, the number of total turns is quite critical. 50 turns seems to be the magic number i have found. I have three taps at the bottom of the coil, The bottom tap is for the CW/FT8 end of the band and the top tap is for the SSB end of the band. Alternatively, the inbuilt tuners found in many rigs today will cope wonderfully in which case i would probably opt for the middle tap. Great nob Mike and it seems like it is destined to go down in history as the "Roly Coil".......................... Cheers, ROLY - ZL1BQD

[@mike-M0MSN]

Hi Roly, yes on the next build I will indeed get someone to thread the pipe. Cheers Mate. :)

[@stewartrv]

Hi Roly, what inductance are we aiming for here? I'm guessing yours is about 25-30 uH is that right? I am not sure I have the exact materials etc. but if I know the inductance I can make it using what I got and measure it with my meter I guess. (I have different wire and different size of former for example).

[@stewartrv]

Regarding the spacing I'm planning on winding the wire and some nylon cord as an insulated spacer together and then maybe removing the cord leaving a space, or maybe simply leave it in place as a spacer. Don't know if it will work yet - we'll see I suppose :)

[@RolyRJ]

@@stewartrv Watch this space. I am making a video at the moment to show the construction etc. That may help.

[@stewartrv]

@@RolyRJ OK thanks! Well I have to get my analyser on the 40m DX Commander element and see what it needs in terms of inductance in the meantime then. 😁. I've already sub'd to your other channel (ZL1BQD - Roly) I guess it will turn up there... 73 de HA5RV

[@markg6jvy135]

Great build video Mike, you say it took an age to space them but you gave us some good pearls, the glue, carry on, glue carry on will save lots of attempts for folks I’m sure. Cheers 👌

[@oldfartonabmx2122]

May have been said - one method for spacing is to wind a second or 3rd wire with the coil wire (whatever number and size works to get correct spacing) then unwind the spacer wires. Saw this tip somewhere, haven’t tried it yet but looked to work easily. And of course Roly’s way of getting a thread cut in it is probably the greatest!!

[@ZL1BQDRoly]

I am looking at costing the pipe with a 5mm thread cut into it and the mounting holes drilled. Supplied as a "former" will make the construction very simple and easy for sure. I will keep you posted.... :)

[@NICKGAR7]

UPDATE.... just built a coil. I decided on 1.8mm dia wire with a 50 OD tube and would to give me adequate 18 to 25 microH with various taps. I have adapted the 40m vertical for inserting the coil and will test and use in the next couple of weeks. Then perhaps a 160 coil with maybe a longer vertical wire. Thanks for the inspiration Mike!

[@martinvanek5951]

I built one of these for a 6M 5/8 wave element on my DX Commander. My technique for spacing was to use bare copper wire with window screen retaining rubber as a spacer/insulator. Instead of soldering several taps to the inductor I fashioned a tap out of thin copper sheet material that I could rotate up or down the inductor for tuning. If I build another one of these I would add a couple more movable taps so as to cover the entire band by switching the feed point. Nice build and nice video. Thanks KN4MNA

[@mikes6844]

Like it! And I like the way your'e experimenting - the only down side is that it's yet another little project for me to have a go at. BYOTA - Back Yards On The Air during lockdown and doing my favourite thing of experimenting and getting my /p kit ready for when we get out and about again. `Thank you for posting 73 de M0AZE Mike

[@mike-M0MSN]

Cool, thanks!

[@rjinnh3933]

Mike, great bit of info, well done vid and HatTip to Roly. I'm planning on constructing a DIY DX Commander for 40Mtr on up and this coil will definitely be added to the mix. Tnx. And again, you did a realy good job producing this vid...... 73 OM

[@ChaplainDaveSparks]

I’ve seen you wind coils on a couple of videos, and I have a couple of questions: 1.) Does the spacing of the windings affect the _Q_ of the coil, or what is the reason for not winding the wires tightly? How important is it to keep the spacing uniform? 2.) On one you *appeared* to be super-gluing the windings in place, then spraying it with something. What were you spraying? Did you use some sort of adhesive that needed the spray for it to cure? 3.) I saw you showing your _inverted L_ on another video. It *appeared* to cross above some solar panels on your roof. Does that cause any problems, with either RF coupling with the panels, or the antenna picking up RFI in receive mode? I’m watching a number of videos to get ideas on a home built, compact, and portable NVIS antenna for 40 & 80 (and possibly 60) meters. I’m just trying to figure out how much strain it would place on the loading coil tube/pipe (with end caps) to support a telescoping whip for a horizontal loaded dipole. *73 de AF6AS*

[@mike-M0MSN]

Answers, 1 yes, in short. The more tightly you wind the turns together the higher the interaction between the turns the higher the inductance and impedance. 2 yes superglue, and yes the spray is used to cure the glue. 3 No issues with the solar panels no RFI. Cheers 73 Mike

[@PrimulaCarniolica]

Tnx to lockdown & your practical skills ANOTHER nice video Mike!!!

[@Steyrshrek1]

I usually take a dremel tool and notch the 5mm marks. It just allows it to stay in place. Thinking of 3D printing flat strips with 5mm spacing and just fasten them to the pipe.

[@Fix_n_Fly]

This looks very doable. Thanks for the video. Inverted L for 80 meters may be beyond my old shoulders and knees ;)

[@markhodgson2348]

Thats a great idea about using a lathe to cut grooves in the tube i will try that tip

[@dxscotland5901]

Good job Mike,The Roly coil certainly works and it’s a great way to get on 80m in a small garden 👍

[@ActinOut]

I know its been a bit, but this stirred some questions for me I hope you can give directions on. 1- all of your other elements are removed. Will a coil not work with the other elememts still on there? Does the coil interfere with the other elements? 2- assuming the coil doesnt interfere... a-would it be possible to run another 40 with the coil up the antenna in the place of the 30m part all the way to the top and overlap the existing 40 in the top loop and back down? OR B- run another 40 with the coil up to the top spreader in place of a 30m and then loop it back down from the top spreader. My main question though first is why remove all the other elements to put the coil on? Was it just convenience for this testing or, once you put on a coil, it will interfere with the other elements so the dx becomes a single band antenna only for the 80m? Im happy to experiment if no one knows about what will happen with 2a & b, but im really hoping especially to find answers on using a coil together with the other elememts still on there.

[@angelscomputers]

Im looking to build this and it blows my mind that with how popular the DXCommander is nobody have made this coils for sale, even as a kit. I was even thinking to use a Wolf River Coil somehow but I prefer to have the ability to run more than 100 watts making it myself.

[@mikepeirson1150]

As a SWL still learning, I watch as many videos as I can regarding antennas and the like. I play around with bits of wire and metal and do sometimes get surprising results. One thing that puzzles me is can I adapt these different antennas for RX only.

[@mike-M0MSN]

Yes, the great thing here is if it for RX only you can make them more efficient to your requirements, a ground loop is supper quiet but the SWR is sillily high so no use for TX.. :)

[@N3LJS]

Wow just need a way to switch back and forth from 40 and 80m....with out going outside....I am making one. GREAT JOB

[@ponttokamera]

An idea for easily getting the spacing right: Wind several vires one by one and remove all but one. You can use whatever wire for the "spacing wires".

[@PatAutrey]

Have you attempted an 80 m on a 10 m pole by going all the way up to the top and all the way back down again Linear loaded - Just curious if it would work and what kind of takeoff angle would you be looking at by doing it like that

[@mike-M0MSN]

Yes tried that, was not so good. but it did work.

[@DonDegidio]

Hi Mike, Nice build video. Like the Roly Coil name you gave to it. Stay safe. 73 WB3BJU

[@davidniemi4051]

I've wanted to build this since I saw Callum and Roly 's video chat. Thanks for the details. de VA3NIE Ottawa, Canada

[@mike-M0MSN]

Very cool!

[@IZ0MTW]

Hello Mike, Can you do the coil without spacing it ? It would much easier! The wire looks enemelled copper wire so why not thight? Just less number of turn to get the same inductance value. Could it be? Thanks and 73

[@mike-M0MSN]

I have not tried, give it a go..

[@radioarchives101]

Yes you can, the inductance will be greater if close wound with the same number of turns. For more info on this type of antenna look up "LPAM Antenna" in google search.

[@krisraps]

Wait, Its NOT A 40 Meter Element ! 5:28 Maybe 4 Meter ?

[@mike-M0MSN]

No it is a 1/4 wave 9.68M... for 40M

[@krisraps]

@@mike-M0MSN I Don`t understand this, can you PLEASE Explain? :( Or Maybe We Can Talk Somewhere? discord? I have so many HAM Questions

[@mike-M0MSN]

@@krisraps I am on discord now... DXCommander @KrisRaps, On the DXC Classic, you can put a base loaded coil (20 turns on a 75mm former or 32 turns on a 50mm former) of 15.5uH attached to the 40M (7.1MHz) element (11.2M wire length) and it will give you a vertical antenna for 80M. or 24 turns on a 75mm former ( 19.5uH ) if you use a 9.68M element for 40M........

[@krisraps]

@@mike-M0MSN Sorry, But I Can`t Find You On Discord Anywhere. Can U Give Me The Code For The Server Or Your Nickname With The 4 Numbers Please?

[@mike-M0MSN]

Hey Kris been listening out for you on Discord no luck so far ?? discord.gg dx commander

[@deenunya7735]

If need be once all set up n checked, could it be all Wrapped in S A Tape ?

[@mike-M0MSN]

Yes I guess so, :)

[@deenunya7735]

@@mike-M0MSN Forgot to ask whats the make of those Crimpers, do they do Anderson power poles too?

[@mike-M0MSN]

@@deenunya7735 CK. RS Components

[@michealbell5042]

Hi Mike have you compared this with a mag loop for 80?

[@wyngw4tud177]

Great video Mike! Been waiting for Callum to create a video but you've beaten him to it! Just a couple of questions...you say to use 1.6mm wire, but the label shows 1.5mm? Brocott supply 1Kg reels...is that enough?

[@mike-M0MSN]

just checked yes you are right 1.5mm copper wire no big issue. 1Kg is about 100M

[@wyngw4tud177]

Cool! Thanks Mike! de Wyn GW4TUD.

[@chrisbartlett6022]

I have had to loose my 80 inverted L as have used the mounting point for a 40 odd m long end fed, I wonder if this coil could be used along side a fully loaded DX Classic so I can still use the other Elephants :-) give it a try is the answer I suppose.

[@BobHolowenko]

I'm loving your content sir. Keep it up! Cheers!

[@valeriem.2651]

Good job,Mike.73.Moldova.

[@mike-M0MSN]

Many thanks!

[@dennispeake1877]

Mike, what happens when the rain gets on the coil? does it change your VSWR having a wet coil. Is there anyway of protecting the coil from weather and storms? cheeers mate.

[@mike-M0MSN]

Hi Dennis, I have not seen any real change in the SWR with changing weather!!

[@kc3kop915]

Question, I have a DX commander and when you connect the 40M to the top of the coil to you pull the extra slack tight at the top and vise versa when you connect the 40M element to the plate? 73 Ian

[@mike-M0MSN]

I normally just let it hang to be honest.

[@kc3kop915]

@@mike-M0MSN ok cool I just checking, I did see in your other videos that I could just cut it shorter and bypass the coil to the driven plate with a jumper if I want

[@andylinton2798]

Nice idea. I have two questions: What you have for radials on that permanent installation? And do you leave the pole up unguyed? Do you have some sort of support running up the inside of the pole?

[@mike-M0MSN]

Hi Andy, Yes 64 radials between 3m and 10m in length 2 cm under the grass, up all year round, guylines at 4m and 6m points and centre glassfibre rod up to 1.5 metres inside the base

[@ctshean]

how about using timing belt as wire spacer on coil

[@richarde735]

Mike, how well has the glue held on the pipe? I’m wondering if we could build one for 160m that extends the 80m element of the new 18m “Neboola” as Emily calls it. a lathe certainly would have made the spacing easier.

[@mike-M0MSN]

it is in the planning stage.. :)

[@Joe-KN4IFI]

Tom Rowlands said it best: "Great job Mike - I like to think it will be forever known as the "Roly Coil". 73 Joe

[@peternilan4276]

hi mike what length of 50mm pipe did you use?? love your you tube video's Peter

[@mike-M0MSN]

About 45cm for this coil...:)

[@boxingday11]

Should work well for DX in the morning Mike to VK,ZL with luck🤞. Thanks.

[@mike-M0MSN]

🤞

[@temporarilyoffline]

That's a fiddly job, but you pulled it off well.

[@michaelm1keyhardy865]

you make it look easy very well done enjoy watching your utube films 73 Mike M1KEY M0FCG

[@markhodgson2348]

I can use this for my large 1800s style induction coil

[@MoTown44240]

Mate. Take a wire protectve sleeve, its already split the length of one side. With sissors cut the side opposite the slit leaving you with 2 halves. Now cut each half. Glue each quarter on the PVC pipe. Offset the remaining 3 quarters and glue to the PVC so you the turns will have the correct spiral. About every 5 - 10 turns glue the wire to the coil form. Use sand paper to remove the shellac from the copper wire then crocodile clips for find the tap you want to use. Tedious but good video. 72 de KB8AMZ

[@mike-M0MSN]

Terry Morris Great idea Terry. :)

[@nlo114]

Tall Asda spaghetti jar, (£3.95), keep the bamboo lid, hole-saw 2" hole in base, fit upside-down over coil. Hey presto, weather-shield for intermittent showers, plus transit-protection.

[@G1WHP]

Well done mike. Do you think this could be done with heavy gauge insulated wire wound directly on the original DX Commander pole. I can’t see why it wouldn’t maybe I should be brave and give it a go. Cheers 👍🇬🇧👍🇬🇧👍

[@mike-M0MSN]

Yes, absolutely you may need to make an additional turn or two but the diameter is pretty close.

[@MM0OPXFieldRadio]

Great video Mike, I'm playing around with a coil for 160m although it's a bit simpler not needing tapped. Out of curiosity, did you already have enough radials down for 80m?

[@mike-M0MSN]

Yes, I already run 80 as an inverted L.. :)

[@pu4mksmarkussalustianosalu783]

Parabéns amigo pela antena de 80metros

[@Ray_M0MXN]

Great video 👌

[@mike-M0MSN]

Thanks 👍

[@kellypaws]

Waaayyy easier going with the lathed groove for the coil.

[@mike-M0MSN]

Most definitely

[@James_Bowie]

DX Commander meets Wolf River Coils. 👍

[@mike-M0MSN]

I like it!

[@paulshaffer9674]

I am going to work this with a Magnetic Loop, I hope.

[@NICKGAR7]

Super job Mike. Well explained. How did you find it on DX? I would imagine it better mid/DX than local. According to my approx maths and your commentary....50 turns on a 50mm dia former = 7850mm. Correct? Cheers

[@mike-M0MSN]

Close, the ID of the pipe is 50mm so the OSD is 54mm so it's around 8,5m. It is a good starting point as the wire may have a slightly different velocity.

[@NICKGAR7]

hollyend01 thanks Mike. Yep, realise you had actually used larger 54OD pipe and had compensated by shorting/eliminating top 2 or 3 turns. Good stuff. I’ll give it a try with a 40m GP. One other ‘coil locating’ method could be to make a hacksaw mark on the plastic tube. Best wishes. Nick M1DDD

[@mike-M0MSN]

NICKGAR7 Nick if you use a smaller diameter pipe the Inductance will be less than if you use the 54mm you will have to increase the turns to around 67 to get the same value in micro-henries. But give it a go. :)

[@NICKGAR7]

@@mike-M0MSN All understood. Seems to me that the inductor is circa 19-25 microHenry with tweaking of taps for portion of frequency depending on a few other variables like position to feed point, exact vertical radiator length etc. All good. I just spent some time re-working my physics and electrical engineering formulae ! Thanks Mike

[@mikes6844]

Wire ordered !!!!

[@stevenaustin2860]

i bet you it took ages lol good video thou and i might try one and ill let you know how i get on

[@dirkr7891]

If there not much buildings around, u will get good results with a base loaded vertical or inverted L! gl

[@mike-M0MSN]

yes defo a expedition antenna for me...

[@timg5tm941]

Great build Mike 73

[@mike-M0MSN]

Cheers Tim

[@ianxfs]

Excellent 👍🏻

[@pd1jdw630]

Nice ! 👍🏻

[@mike-M0MSN]

Thanks! 👍

[@hobbyrob313]

look for the spacing: kzbin.info/www/bejne/b3Komqiha6qnpNE I also made a coil if you wind up neatly, the coil will be beautiful!

[@cliffcollins4124]

Sorry but this is a complaint,, I just wish you Guys would listen/watch to one of your own videos over the computer from end to end. Honestly, you have great knowledge to be passed on and for me, I'm just about inside the computer trying to watch and listen to what you are trying to pass on. The volume is fairly high so I can hear and I am concentrating on you and what you are doing. then you hit us with music at a level that basically hurts.We are not here to listen to your music, and if you must add it to your video put it in at a volume level lower than your voice. Let it be a background to tools dropping or the glue setting, I would rather hear you swearing at the wire than being blown away to the point of closing the volume down and missing what you are saying

[@richarde735]

Mike, you must not be married... my wife would be having a s__t fit! taking over the kitchen counter to build an antenna 😳

[@mike-M0MSN]

LOL, My wife is good to me, however I better not damage the worktop....

[@stevenaustin2860]

i surpose it won,t be water proof lol

[@mike-M0MSN]

steven austin once you find the sweet spot, you could solder the tap in place and spray clear on it !

[@steeplejackdibs]

Please can you stop saying SODER it is SOLDER and you.re not American they are butchering the word you should know better!

[@mike-M0MSN]

Ah. That be because I is from Devon, It has taken me 60 years to learn English…

[@n6tdgtiedyeguy117]

Well then, one could take this same design and turn my 80m inverted L into a 160 with the "Roly" Coil design.

[@mike-M0MSN]

Yes you could, not sure on how many turns you would need, I will have to calculate that one.