What I discovered by modeling the MFJ -1846 Hex Beam (

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I describe the status of erecting the new MFJ-1846 six band hex beam, plus I show G3TXQ's EZNEC+ model of the antenna and what it has to say about gain, beam pattern and SWR on each band, 20, 17, 15, 12, and 10 meters. (Hint: good things!)
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Опубликовано:

17 июл 2018

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Комментарии : 29

@schoocg Год назад

It is so refreshing to see analysis and real world experiments with antenna designs used by the majority of Hams. Not like 'you are waisting your money, and will have a bad experience, if you are not 100' up a tower and a 6 element Yagi at full legal limit'. You have to work with what you can afford, have the space for and within possible local restrictions.

@pacificparts 2 года назад

I am building a portable hex beam from parts, your analyses is very helpful for my project.

@polymath5119 5 лет назад

Thanks Dave! Quite helpful.

@MoTown44240 6 лет назад

This is off topic but I just my QSt and read your article Symbolism and the FCC Seal. Very interesting Dave. Just a few more parts to collect and cut into shape and I will begin the build of my DIY Hexbeam. 73, Terry - KB8AMZ

@brianjester123 2 года назад

Thanks Dave!

@SuperAWaC 6 лет назад

cool antenna design

@donalddavis581 5 лет назад

I have read multiple articles that suggest leaving out the 6 meter option because of skewed patterns on some of the other bands because of it. My hex will be going up soon. I opted to leave off the 6 meter....

@williamstaylor5449 6 лет назад

Looking forward to seeing, and hearing, the antenna up. Also, could you do a sweep with your antenna analyzer on the beam's bands once it is erected?

@davecasler 6 лет назад

I hope to do a good on air analysis this coming week. Look for it in an upcoming video.

@brianogram5194 6 лет назад

Thank you for this Dave, a hex beam has been a consideration for an upgrade path from the MFJ cobweb.

@bobclarie 6 лет назад

Thanks Dave, keep up the most appreciated effort. Bob N7ISU

@kenburnett 6 лет назад

Very interested to watch your next video on this hex beam. Always enjoy your videos. Ken - K9LDO

@bobcrunch 5 лет назад

Does the EZNEC+ model give any insight to the feedpoint details? In the model, I see just "blue boxes" at the feedpoints. My 4nec2 model of the Hex Beam shows feedpoint R = 24.5 ohms at resonance which gives a SWR of 2.4:1. I modeled a beta match (hairpin match) at the feedpoint which got the SWR down to 1.01:1. The beta match works quite well if the difference between transmission line and feedpoint impedances are small (feedpoint impedance must be less than the transmission line impedance). If the differences are too great, the Q of the match rises and bandwidth suffers. For the Hex Beam, the required Q is about 1. I modeled my antenna at 70 feet, but when I bring it down to 20 feet, it matches your gain and pattern results very closely, but the SWR rises to about 1.3:1. It will be interesting to see what your measurements are.

@davecasler 5 лет назад

I think I modeled it about 22 feet because that's how high mine is.

@ssubaihi 6 лет назад

Thank U Sir Dave for such demonstration .. Hopefully you may devote an episode to demonstrate Step By Step (How to use .. EZNEC+) or any similar (Easy to use , Free Software) to Test/Predict such (Hex Beam Antenna) or (Such Rhombic Antenna) as you did in previous episodes ... You know Sir.Dave ... Some Antennas Modeling Software has (Only Limited Antennas List to Choose from) and you have a choice over a Wire Gauge/Length and Frequency .. but What i mean is , i need to know how you did Tweak the Software to meet you own intended Antenna type or design (let say such Grounded Antenna from top end) or circular antenna ..

@davecasler 6 лет назад

EZNEC is a very powerful program and I'm just learning the basics. The model that I used for the hex beam was developed by the inventor.

@ssubaihi 6 лет назад

oh i see

@jeromegrzelak8236 5 лет назад

I would order a unbroken part

@etxfire 6 лет назад

This is not related to the hex beam..... Where did you get your LED call sign that is in the video?

@davecasler 6 лет назад

A place called gifts4hams.com.

@joewilson2258 6 лет назад

What is the gain at 5 , 10 , 15 degrees above the horizon ? Because the lower the degrees above the horizon the better for dxing and the other degrees above the horizon are good for short distance communication of 2000 miles and less away from your location .

@davecasler 6 лет назад

You can see the gain in the figure shown in the video. The main lobe is rather high. We'll see how it performs on the air.

@billbrown3414 6 лет назад

Make a follow up video. Use ELNEC to model 2-elements that are straight to compare gain an f/b versus the hex. Better yet, model a 2-element quad. DE KG5AR

@RickLightning 6 лет назад

I believe you are misstating the gain of the antenna in your commentary. Since the antenna is modeled over ground even a dipole when operated over ground at the same height has "gain" when referenced to dBi. So it is better to compare gain to a dipole at the same height above ground as the antenna in question. I recommend reading www.w8ji.com/antennas.htm 73. Rick- W4DQ

@davecasler 6 лет назад

There are lots of ways to reference gain. The only universal one is dBi. A dipole at the optimum height (half wavelength) has a gain of a bit more than 2 dBi.

@donalddavis581 4 года назад

I would like to make one fact known or in short maybe save someone else some grief......hopefully FYI.......IF your hexbeam design uses bare crimp on ring terminals on the ends of the driven element ends for connection (knots) to connect the spacer cords.(dacron, kevlar, paracord) ..B E W A R E! running higher power to this antenna! Voice of experience speaking...my antenna design, followed to the letter in the instructions, with in seconds of running 1KW..... the spacer cords were burned in two! FYI my hexbeam was published rating of 2.5KW..... damage occured at way less than half that.....

@davecasler 4 года назад

I run up to 500 watts and haven't had a problem with the MFJ version.

@donalddavis581 4 года назад

@@davecasler It would seem the great folks at G3TXQ have seen this and have a fix for it. Their wire elements have a non-fabric insulator to handle power. I admit... I was running 1KW. But with the published rating of 2.5KW , I put the thought out of my head, but I will admit during assembly... this crossed my mind.... I guess always listen to the little voice...

@donalddavis581 4 года назад

update: I still have not heard back from G3TXQ and a company called "DX Wire" also sells the insulator they use. Spiderbeam...kind of like a hex...uses actual insulators on their high power antenna....David.. my friend I wouldn't try more than your 500 watts.