End Fed for 40 and 20M

I made a stupid newbie error and bought a 80-6M Random wire with 9-1 UnUn 20M long wire thinking the internal atu in my FT450at would suffice for 80-6M...........Wrong
It tunes 30, 17,15 & 10 fine but not 40 & 20 which are two that I really want with 20M being the most important.

Any suggestions of a way without an external atu as a compromise to get at least 20M, my Imax 2000 brings in 17,15 & 10 ok so even if the longwire only gets 20 I will be a happy bunny.

I plan on building a ATU when I can find a suitable variable capacitor at a sensible price!

TIA
Tony

Tonyvic wrote:

I made a stupid newbie error and bought a 80-6M HW with 9-1 UnUn 20M long wire thinking the internal atu in my FT450at would suffice for 80-6M...........Wrong
It tunes 30, 17,15 & 10 fine but not 40 & 20 which are two that I really want with 20M being the most important.

Any suggestions of a way without an external atu as a compromise to get at least 20M, my Imax 2000 brings in 17,15 & 10 ok so even if the longwire only gets 20 I will be a happy bunny.

I plan on building a ATU when I can find a suitable variable capacitor at a sensible price!

TIA
Tony

OOOPS

Hi Tony,

You could start chopping bits off the end of the antenna thus destroying it but maybe getting it to work......or, add another length of wire to it at the end. Six foot or so should do the trick.

Worth a go and nothing to lose that way.

Best of luck.

Hi Tony,

Just a suggestion but I've worked the world with this on 20 & 40.

https://www.gwhip.co.uk/421-triband-antenna

73's Gary.

Don't chop any off fold it back on itself first.
My 5:1 with 20mtr of wire tunes on all bands 160m to 6m.

Coo, ain't lengths of wire expensive Gary?
(Just kidding, seems that way when you build your own..... Alan, making much on yours?)


Tony, the secret is you want it non-resonant (despite the EFHW referencing) and usually your bit of coax would act as a counterpoise (dirty word) to bring down the antenna impedance.

You can lengthen the coax, chop wire off (the antenna Gary suggested falls nicely at 12m/39ft), as Alan suggests, fold it back on itself or as I suggested lengthen it all a bit. The other option is to have a go at mounting it all as an inverted 'L' and see if that brings down the impedance.

It's all fun this antenna malarkey.  


All the best.

(BTW, most of this sort of information abounds on the old t'internet if you look in the right places......usually by someone who isn't trying to part you of cash.)

I have found this link usefull -

http://www.dxsupply.com/produktfiler/Wire%20Lengths%20for%204%20and%209-1%20ununs.pdf

That's the kiddie Richard.


"On the shoulders of giants we stand"

Victor wrote:

That's the kiddie Richard.


"On the shoulders of giants we stand"

Hi Victor, I have found it as an excellent starting point and as it has been stated above just shorten (or lengthen) to tune it. 2 or 3 trims and you get a feel for how it is going. I always start off with a quoted length plus a few feet already bent back on itself.
I started off saying "starting point" as I know you are aware that different qth conditions have an effect on apparent resonance.

Yes indeed Richard, EFHW's are one of those antennas that work well for one but not another and usually due to some interaction of how it's mounted at the QTH. (Dipoles and Doublets are much more well behaved. )

I know some complain end feds are noisy but get them right and they're awesome as many will attest to.
(Enough people use them whether horizontal or vertical.)

If I wasn't in a mid terrace with a short garden I'd happily sling one up instead of this multi-folded lawnmower lead monstrosity I currently have!

Tony, I am sure you'll get it working on all the bands you want and more if you read all the advice in this thread and have a play wound with it. The link Richard posted is very useful. It details counterpoises, don't know if you've added one or not?

I've been playing on and off with a 10m piece of wire fed through a 9:1 and I find what I do with the counterpoise makes a lot of difference. In the 3.5MHz thread you'll see one way I set it up for 30m and it worked on 80m with no atu needed. Today with the same 4m counterpoise kept inside the house running it along the bedroom floor out onto the landing underneath the 10m wire brought it in close enough for the rig atu to make it work on 160m.. probably shockingly badly, but a match nonetheless.

Try adding a counterpoise or two, if you haven't already, and play around with the lengths of them and see what happens.

Hey Vic,

To be fair I bought mine as an M6 and just didn't have the confidence at the time to make the balun and the coil for the 40 meter band part of it. It's definitely a quality product though with Kevlar wire and top quality potted balun etc. Not cheap though but works well for me. Next time I'll definitely build my own!!

73's Gary

Thank you guys, all very good info and I will start with the easiest for me which is use the page that richf linked (Thank you Richard) and double back on itself to 53ft.

Victor as usual some very good tips which will be my next route along with Neal's suggested counterpoise. Yes Neal I saw that thread, brilliant that you do so well on it.

Gary, thank you but if I spend anymore on radio equipment the Station Manager will have a heart attack or worse & I will have to do my own cooking, laundry, housework etc.

Alan, you are just a lucky bu*%$r, I don't have that luck with anything to do with antennas!
I don't want any sympathy thanks.

My main problem is that my feet don't do what I expect and my hands are wearing out. (Old age, I guess) So it's always try the easiest way first.

ps. Bernie (Wheelnut) what's with the

Quote :

OOOPS 

that's rich coming from someone who didn't get the correct programme added when buying a radio.  

73 all

Tony,

Really glad that so many people here were able to give you good advice and do their very best to help you out. The members of Charlie Tango truly are an awesome bunch.  

Where there's a will there's a way and I know that even with my own physical difficulties I can get some sort of antenna strung up even if it involves the use of a 'willing' volunteer. (Or shoving my unwilling wife up the loft for me!  )

I hope you get sorted out (you surely will with such exemplary help) but most of all have fun with it.

Oh, I bagged three old air spaced variable caps from the 'bay' a while back that were listed as a bit 'scratchy' for the princely starting bid of 99p! (Cheap postage too!) Bit of a soak in meths, de-oxit on the wiper contacts and some lithium grease back in the now clean bearings and they work a treat using them for all sorts of antenna tuner experiments. (My 160m tuner uses one of them.) Worth keeping an eye out for 'tuning capacitors' as usually a bargain or two pops up now and then.

I doff my hat to you for experimenting with antennas and considering building an ATU/Matcher.

All the best.



Gary,

Apologies for my off the cuff remark about antenna prices but I still get shocked that others charge so much for wire or the knowledge and simple construction of basic inductors. I agree that a quality product helps for certain scenarios and know that if I were a SOTA/Field operator slinging antennas up and down all day the product you describe is right up the alley for such ventures.  

I know far more about antenna theory thanks to a lot of people here at Charlie Tango enthusing my interests since joining and thank every radio amateur that openly and willingly shares such information. 

All the best.



To All,

Gentlemen, a very fine job of helping out a fellow radio enthusiast and well done to all.

I say 'radio enthusiast' as the ethos at Charlie Tango is all embracing and everyone does their very best to help each other out regardless of their field of interest, frequencies, mode of operation and even whether licenced or not.

Awesome stuff. 

A guy in South Wales living in an old miners cottage is running the same 5:1 as me with 20mtr wire.
He has a 12ft yard with a 7ftwall round it.
He ran the wire round the wall then up the soil pipe and along the gutter.
He is working all bands and well happy.
Just shows as long as you have wire in the air well sort of you will figger it out one way or the other.
Keep playing Tony you will get there and smile when you sort it out.

Just a quick question/thought, but you mention HW (Half wave??) and a 9:1 unun.  You won't match a Half Wave End Fed antenna anywhere with a 9:1, so I assume you mean "random" wire, i.e. NOT a half or quarter wave on any frequency you want to match?

If so, these are non-resonant everywhere, and as you have found, sometimes have a SWR higher than the 3:1 an internal tuner can match.

This is probably one of the best known articles re wire lengths to use:

https://www.hamuniverse.com/randomwireantennalengths.html

So if you have 20m of wire (66 feet) try folding back to 58 feet and see if that gets you a better match on 40 & 20.  You're probably way too close to a full wave on 20 and half wave on 40m, which likely is putting the impedance of the wire way outside what your tuner can handle.

A 9:1 will match 450 ohms (hence 9:1 as 9x50 is 450) whereas an end fed half wave of wire will be several thousand ohms, and why we use 49:1 through to 64:1 transformers to match those....

Again I would like to express my gratitude to all who contributed to this topic.

I doubled back to 53ft as per the link Richard posted: And that got me the 40 & 20M that I was after as well as 80.   A great result and the easiest for me to do. 

I don't possess a swr meter except for 11M or vna but I hope to enlist the help of John CT4515 at some time to fine tune the wire, the radio's swr meter isn't up to the job IMHO.

43CT016 wrote:

I assume you mean "random" wire, i.e. NOT a half or quarter wave on any frequency you want to match?

Correct, and thanks for pointing it out. I amended my OP.

Victor I sure will keep looking for the Variable Caps as that will be a must.

A quick test on 20M gave me 4 contacts in 10/12 minutes, that was at a time when conditions weren't good for the band.

Thanks again & 73 all.

Point taken

Tonyvic wrote:

Again I would like to express my gratitude to all who contributed to this topic.

I doubled back to 53ft as per the link Richard posted: And that got me the 40 & 20M that I was after as well as 80.   A great result and the easiest for me to do. 

I don't possess a swr meter except for 11M or vna but I hope to enlist the help of John CT4515 at some time to fine tune the wire, the radio's swr meter isn't up to the job IMHO.

43CT016 wrote:

I assume you mean "random" wire, i.e. NOT a half or quarter wave on any frequency you want to match?

Correct, and thanks for pointing it out. I amended my OP.

Victor I sure will keep looking for the Variable Caps as that will be a must.

A quick test on 20M gave me 4 contacts in 10/12 minutes, that was at a time when conditions weren't good for the band.

Thanks again & 73 all.

OK so at the moment you are happy with the resonant frequencies with 53 feet, if later on you wish to experiment with a longer length that may give you additional frequencies with a better swr have a look on the Sotabeams website at their "Band hopper" and use a similar method with an extra length of wire and 2 crocodile clips. (In the description of the antenna the last picture illustrates their methodology".

Alan Pilot wrote:

Don't chop any off fold it back on itself first.
My 5:1 with 20mtr of wire tunes on all bands 160m to 6m.

Hi Alan,

Is your 5:1 home brew?

If so can you post any details?

Sounds very interesting.

Richard