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Antenna building


KF0BMX
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I have a problem to solve: Yes
Problem types: Antenna

I am still kind of new to this hobby, so I am going to have a lot of questions. I got my license in September of 2020 and built a small 2m/ 70cm antenna that works fairly well, I want to build a 6m antenna and would like to know if I can combine  Vertical and Horizontal antennas together and have it work properly ??

Thank you in advance for any advise that can help.

Carl KF0BMX

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ELMER

Nope, that won't work. I'll give you some short answers and then point you to some concepts and reading.

First the drawing implies a ground plane but only on side at a time. You're going to have directionality issues. Also, your drawing shows no lengths so no idea which band you're tuned for. Finally, you're creating a relationship between active elements and passive ones that will create a rather bizarre signal.

I love antenna design. It is my personal favorite aspect of amateur radio. I also love experimentation and I did notice that you built your own first antenna. But, as with most arts and skills, think martial arts, think fighter jet flying, think surgery; any of those require the basics first. Even if you have already built one, and especially if you are keen on building more, I would first study up on, and practice with, simple, basic, true and tried designs. I'm not saying you have to buy them, you absolutely can, and there are some amazing ready-to-use designs out there, but think about it. Right now you want to get on the air and have fun. Why not do it with the best possible equipment first? Then, once you're on the air and loving it, you experiment, but you do so after having read some of the antenna books, some of which are masterpieces. There are some that are geared towards theory, others are more DIY oriented. There are VHF/UHF books vs. HF ones. There are specific apartment dweller books, vs. the large arrays or super-high towers. Take your pick based on your personal interests and start experimenting away.

Here is a simple, available, not too expensive option on the, ready-to-use antenna front: https://amzn.to/3OXMEkB. There are many others. Just Google 2m 6m combo antennas and you'll have them at your fingertips. As far as books are concerned, if you are an antenna nut like me, the reference is: https://www.arrl.org/arrl-antenna-book. Again, many many others, some maybe even better, but this is a go-to, must-have-in-your-library book.

As with all advice, I may be completely off the mark and if I am, apologies, but hopefully some of this response will get you closer to getting on the air actively and with great success.

73

Jim

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ELMER

Hi Carl, and welcome.

The short answer is yes, absolutely no problem, inasmuch as you will only be transmitting with one or the other, never with both simultaneously.

If you're asking if you can have a vertically polarized antenna in proximity to a horizontally polarized one, there the answer will be more nuanced. The 'other' antenna will interact with the transmitting antenna the same way any other metal surface would. If you have a balcony and it's metal, there you go. If you have a large metal picnic table and bench nearby, there you go. And even non-metallic surfaces will interact.

The devil is in the details. If you want to be extreme, you can do an advanced modeling exercise. That will take some work and will only be theoretical and likely quite inaccurate given the likelihood of multiple interacting surfaces. Will you place them one above the other? How close? etc... are all questions that would influence the answer.

So in principle, yes, you can easily put two antennas of two different bands and polarizations in reasonable proximity and do fine.

If you're asking whether you can make a single antenna that does 6m and 2m, that too is possible though you probably did not mean that otherwise you would not have asked about the interaction of a vertical one with a horizontal one because, de facto, it's one or the other 😎

Does this help? Maybe not, so feel free to fire away any follow ups.

Jim

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I appreciate your quick response, thank you. So if I would connect a coax to 4 radials, the center going to one vertical and one horizontal and also connect the shield portion of the coax to the other two radials I will still only transmit on one or the other. I will include a drawing ( very crude )

483FD50A-3906-4697-8DB0-D12EA3D90DAA.thumb.jpeg.79f9c59cf14a5d96e38d264e7c56a39e.jpeg

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Okay Jim, thank you for your response, that’s what I was looking for, some straight forward advice from someone who was been doing this for a while. I appreciate the reference to the material that you may use. I enjoy building things that I can, for one thing I always feel that I spending more than I should for what I could build a bit cheaper. ( I guess that I am just a bit of a tight wad LOL ). But again thank you for your help, I will look into the reading materials and go from there. Have a great weekend be safe and 73. 
 

Carl KF0BMX

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ELMER

You're very welcome Carl and the more questions the merrier.

Last point: when you do build stuff, please show us 😉 Love to see people hard at work being creative!!

Thanks again for being part of this young and growing community. We appreciate it.

Jim

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