That’s such a relief after having a dismal flop two days ago. I was scratching my head.


I wanted an easy to set up one pull rope or a rope toss to pull up an antenna and got interested in the Km4ACK design.  Multibands, no tuner on 10, 15, 20, and 40,....add 80 if you add wire.  I wanted to get just to 40m and higher bands.



I wanted to keep it fairly light and compact and have it on a winder.  I cut a Dollar General plastic cutting board into three pieces. Kept the one with a handle hole for the end fed winder.  I used a single fair rite 140-43 toroid and wrapped 16 ga magnet wire 3:21.  used a plastic Barnes Bullets box to hold the toroid, the BNC female socket, a blue high voltage 100 Pf capacitor, and the stainless steel antenna and ground studs.  My studs were cap head bolts that did double duty holding the box to the winder.  Washers, hex nut and wing nut to finish.

I had a chance to test it the first time the other day and it was a flop.  Before testing I caught one mistake, my toroid wrapping 3:21,.....I wrapped three double like I was supposed to then wrapped 21 more turns. .   My quickie fix was to unwrap the three last wraps leaving it asymmetrical figuring electrically it should be fine.  

Spent a fair amount of time looking for my Rig Expert. . By the time I got set up I didn’t have too much time.  Rigged up as a sloper with the high side about 24’ up in a tree (actually short of the tree, the pull rope went over it.  Ran the Rig Expert and got mostly very high SWR 12-15 and just two deep dips no where useful.  First wire was 31’, second wire was 51’ iirc grabbed from reported good length list.  Not really any improvement, tried several counter poises ( KM4ACK design I don’t thing shows a counterpoise provision on his, but hey I used two bolts to attach my unun box!   That didn’t seem to help.  Called it quits after trimming wire and not getting anything that looked right.

Had a nasty rain day to go over things.  Took the unun apart and rewrapped it symetrically.  I really didn’t want a wire that long but figured I’d try the KM4MACK length of 67’,...actually started a lot longer seeing the optimal ranges some people listed.

Edit because I accidentally submitted before I was done.

Did some more research and picked up on the general opinion you really may need a common mode choke at the rig.  So i put ten turns of my 35’ rg58 coax into a 31 mix snap on ferrite.  

Today’s session went much, much better, got a bunch of dips that made more sense for a multi bander.  Took my time and folded back wire, recheck it, snip off folded part, recheck, fold back again, test, snip the folded part, recheck, ad naseum until I got the 40m tuned.and around 2.0:1 swr, 20m, 15m were very good close to 1:1 and 10m was very usable with only the high end getting above 3:1.  Playing with counterpoise length brought it down more. on 10m.

So now I got a home made end fed antenna that works at least in that set up.  

Got any pictures or sources of your design?

Awesome! I have had good luck with 14:2 turns (49:1) and 67' of wire. In fact, after I get done with an elderly lady's grass I have to cut, I am going to set up my 13m pole, and a 7.2m pole and string up and tune an EFHW for portable use. My home antenna works so well, I am going to try to reproduce it for portable use.

I don’t have a photo host but I can email a couple photos.  

I need to do so minor tweaks,....I think I want to add a wire for 80 on rare occasion so I want to put a plug connector on and a bungee to retain the wires.  I need to put some appropriate insulators on the end too.


Ugh, arf email doesn’t let you insert photos.

I followed the guidelines here for the unun


http://www.gnarc.org/wp-content/uploads/The-End-Fed-Half-Wave-Antenna.pdf

About halfway down they show a diagram for a 1:49 unun with 2 primary and 14 secondary on a 240-43 toroid.   Farther down in the link they have a chart of applicable combinations.

I went with the qrp sized one with the 140-43, but thought about doing one with two 140-43 toroids stacked.

Just don’t do what I did on my first unun wrap job ever.....3 doubled wraps and 21 single wraps.  
. 3:21 is 3 doubled wire primary wraps and 18 wraps of single secondary wire.

My case was a Barnes Bullets box they originally had 50 6.8mm bullets.   It is a little taller than I wanted and later thought about cutting a rectangle through the cutting board to split the thickness of the box.  Way easier to drill holes and bolt the two together and make the bolts do double duty as terminal lugs.