End fed half wave multiband for HF

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KG5YWM

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I've been giving serious consideration to buying one of these

https://myantennas.com/wp/product/efhw-8010/

It would solve some serious installation problems that I'll be running into running a 1/4 wave dipole.

It says no tuner necessary, but I'll likely be using a tuner anyway. What would be the opinion of the guru's here? Has anyone had experience with these, good or bad?

Thanks!
 

prcguy

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I completely endorse these antennas and over the years have made about 20 copies of the half wave resonant end fed from the 100w range to about a kW. They are problem solvers where the coax does not end up in the middle of the yard and it only needs two tie points to hang it.

They radiate basically the same as a center fed dipole of the same size and should not need a tuner within their resonant range. This type of antenna resonates as half wavelength at the lowest design frequency, then at multiples of a half wave on even harmonics.
However the 80-10m version resonates at the very low end of 80m near 3.6Mhz because its tuned for around 7.15MHz, 14.3Mhz, 28.6MHz, etc, and for those to work you have to give up resonance in the voice portion of 75m in the favored 3.8 to 4Mhz range where you will need a tuner.

Another recommendation is to use a very effective choke balun near the antenna because if you get away from the resonant points of these antennas they will light up the coax with some RF. It turns out MyAntenns makes the most effective choke baluns I have seen and their CMC-130S-3K or CMC-330-5K baluns would be a good choice for the 80-10m antenna unless you want to spring for their most effective CMC-130-3K at additional cost.

On my home made 80-10m versions I get around the 3.6MHz sweet spot problem by using a 40m trap at the 40m resonant spot about 63ft down the wire from the matching transformer, then custom tune the 80m leg for 3.9Mhz which covers the 3.8 to 4.0Mhz phone portion of the band just fine. You can do the same with the commercial versions, just buy the transformer only from MyAntennas, or set the supplied wire aside and experiment with your own wire and 40m trap.

These are NOT to be confused with the popular but crappy 9:1 or 6:1 end fed types which radiate noticeably worse and have lots of hot coax problems. Some worse performing brands that come to mind are Maple Leaf, Chameleon, Alpha Antenna, Ultimax, HF EDS, EARCHI and many others, especially off Ebay.

Danny Horvat who owns MyAntennas is one of the more savvy engineers in the business and used to work for Cushcraft where he designed the R8, R6000 and others. Everything I have bought from him in the past has been first class in quality and workmanship and I use his 80-10m offset center fed dipole as my main HF antenna.
prcguy

I've been giving serious consideration to buying one of these

https://myantennas.com/wp/product/efhw-8010/

It would solve some serious installation problems that I'll be running into running a 1/4 wave dipole.

It says no tuner necessary, but I'll likely be using a tuner anyway. What would be the opinion of the guru's here? Has anyone had experience with these, good or bad?

Thanks!
 
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KD2JCR

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Castleton on Hudson NY
I've been giving serious consideration to buying one of these



https://myantennas.com/wp/product/efhw-8010/



It would solve some serious installation problems that I'll be running into running a 1/4 wave dipole.



It says no tuner necessary, but I'll likely be using a tuner anyway. What would be the opinion of the guru's here? Has anyone had experience with these, good or bad?



Thanks!



I as well am kinda curious about this. It would solve all my problems being restricted on room. I’m currently running a end-fed cut to 20m. It’s fun but I’d like to be able to use all the other bands my radio has to offer.
KD2JCR


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prcguy

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So Cal - Richardson, TX - Tewksbury, MA
The 80-10m version is about 133ft long and the 40-10m version is about 64ft long. If you have room for either one they will perform like a similar size dipole in the same spot but you will get between four and eight bands depending on the model.

You can add a custom length of wire to the transformer and make just a 20/10m version if you only have 33ft of linear space or 26ft of wire will get you a 17m only version or 17ft of wire will do just 10m, etc. You can also go vertical with a single band version and a 33ft fiberglass mast will hold up a 20m or 17m or 10m mono band and they work great. You can't do more than one band vertical because the 2nd harmonic will have a really bad takeoff angle and a null near the horizon, but the main band will radiate well at a low angle.

I as well am kinda curious about this. It would solve all my problems being restricted on room. I’m currently running a end-fed cut to 20m. It’s fun but I’d like to be able to use all the other bands my radio has to offer.
KD2JCR


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kk4obi

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Apr 28, 2016
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It really helps to understand how the various radiation patterns form for each harmonic of the EFHW-8010 antenna.

Check this: EFHW Straight

If you cannot deploy the antenna straight, the following link will help you will understand why it is advantagous to make an “L” bend at 1/2, 1/4, or 1/8 points if you have to make a bend:

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If you have only a single support, the following links will make it understandable what happens to the radiation as a wire angles toward ground:

EFHW Sloping
EFHW Inverted-V

All of these antenna configurations have a feedpoint around 40 feet from ground. Lower elevation means poorer results on 80, 40, 30 and 20 meters. Never-the-less the antenna will make contacts with just about any way of stringing it up. I know because I use one with my motorhome because it is easy to deploy.

I generally can use it “as is” but tuning varies a little bit each at each campsite. Having a ground sometimes makes a difference. If the antenna needs to be a bit longer a wire “stinger” hanging from the feed point or between the end and and feedpoint works. If it needs to be shorter a loop through a torroid will adjust things by the size of the loop. I have a tuner if I do not want to mess around.
 

KD2JCR

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Castleton on Hudson NY
The 80-10m version is about 133ft long and the 40-10m version is about 64ft long. If you have room for either one they will perform like a similar size dipole in the same spot but you will get between four and eight bands depending on the model.

You can add a custom length of wire to the transformer and make just a 20/10m version if you only have 33ft of linear space or 26ft of wire will get you a 17m only version or 17ft of wire will do just 10m, etc. You can also go vertical with a single band version and a 33ft fiberglass mast will hold up a 20m or 17m or 10m mono band and they work great. You can't do more than one band vertical because the 2nd harmonic will have a really bad takeoff angle and a null near the horizon, but the main band will radiate well at a low angle.



Ah very well! Thank you for the info! If I can make the inverted V work I have room for the 80-10m which is most likely the way I would go. Thanks again and sorry for jumping the original post


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prcguy

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So Cal - Richardson, TX - Tewksbury, MA
To add more confusion, be aware this and any other long antenna operated on multiple harmonic bands will have corresponding gain lobes and nulls where performance can drop way off on the nulls. An 80-10m version at 25-35ft above ground will be nearly omni directional on 80m and will work great for NVIS on 80m and 40m plus will still do ok for DX on those bands. Higher bands will work great as long as you have a lobe facing that direction.

Its nice to predict where the lobes and nulls will land before you install the antenna since its hard to rotate the house after the antenna is up. I run an 80m offset center fed which has similar radiation patterns to the 80-10m end fed and the only place it will fit my property gives me poor signals to the east from my west coast station.

I have a friend with a 40-10m half wave end fed that he puts about 15ft high at a local park a mile from me and talks to a friend in Oklahoma from CA on 20m all the time. My 80-10m antenna is very poor to the same location on 20m so I got an NA4RR Hexbeam to supplement the wire antenna is its a great combo. I can rotate the Hexbeam where I can't rotate the wire antenna. Just something to think about.
 

K6GBW

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Montebello, CA
I have the 80-10 meter version now. Its up about 25-30 feet running from the house to a tree and then back down to a fence in an L configuration. Works great! I've talked to Japan and all across the country from Los Angeles. I tried a vertical but this wire antenna worked so much better. I doesn't require a tuner for most of the bands but for best effect I use one. I have to tune a bit on 80 and 40 meters and some of the higher bands. 20 meters is pretty much flat without a tuner. Just remember that HF is finicky. Some days I'm talking to Alaska and some days they can barely hear me in Sacramento. It's all up to the atmosphere and the sun.
 
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