software or calculator for wideband resonance antenna

When I hear some extraordinary claims about a new antenna construction especially if "Patented" or "Pat.Pending" is the main selling argument, my initial reaction is "Snake Oil". So far I haven't had to change these initial reactions. Often the measurement method contain several (intentional?) errors.

Since you apparent live in an apartment building, I would suggest forgetting the 160 and 80 meter band operation and possibly even 40 m operations and concentrate on the shorter wavelengths, for which quite reasonable antennas can be fit into the balcony.

One thing with unbalanced (typically vertical) antennas in an apartment buildings is the lack of a proper RF ground. The true RF ground might be tens of meters below the antenna feed point and this ground line will be resonant on different frequencies. Using the house ground wiring will create some kind of undefined counterpoise with unpredictable frequency response.

In an apartment building a balanced antenna will have advantages, e.g. a short dipole with loading coils in the base. The loading coils could be moved indoors into a balanced antenna tuner and connect the tuner and antenna with a short balanced ladder line.

An other alternative could be a tunable magnetic loop and in some cases this tuning capacitor is motor driven, so the antenna can be tuned from indoors.

The above are just two examples of symmetrical antennas that can be remotely tuned and models suitable small suitable for balcony installation and work reasonably well on upper HF and 6 m.

In an apartment building, the noise level at MF and low-HF is going to be huge. So even if you manage to transmit something with reasonable radiated power at these frequencies , you will not be able hear anything. One possibility would be to use a multiuser remote receiver. Take a look at

wrote [snippage]

OK I won't continue to argue with you on the points I have already made.

But on the matter of SDR let me add. I have the most popular SDR that has an input bandwidth from ~50 MHz to ~1.7 GHz. I also bought the linear amp designed for it from Holland. The rig really needs an enclosure but I have not yet acquired a large enough metal cigarette box.

My device works fine with Android software and receives and gives a meaningful waterfall display for stereo FM channels using the dinky antenna that came with it. With my Android phone I can get a good ADS-B display over a radius of 200 miles, outdoors, at 1.09 GHz. I have all the SMA adapters, for instance for TV coax, e.g. F-connector. I may use coax as feedline out to the balcony. A ham has posted design for a barrel size fractal antenna that cover the bandwidth of SDR. There is a limit that legal software can decode, like for cell at 900 MHz.

On a sunny day (Mon, 8 Feb 2016 09:13:11 -0800) it happened "Norm X" wrote in :

I was having some sardines a while back, that metal box facinated me, now to make a nice lid and solder it on:

So, healthy and free!

The lid could be made from a PCB, jigsaw, copper on top.

Box is magnetic, not alu, should solder.

When an antenna is matched, the receiver does not see the reactive component. I have seen many reports of VSWRs of 1.2 and even 1.1 dB.

If you want a narrow antenna, yes. If you want wideband and small, you need to deal with the reactance in a... more creative way!

Tim

Really? Impedance matching no longer works?

The impedance matching methods are narrowband or huge, maybe both.

Or active.

When they say that you can "cancel inductive reactance with capacitive reactance", you can only do that over one frequency range. It's not a unique solution, though: negative inductance will do the same, for all frequencies.

The only problem is finding that elusive anti-choke! :)

And no, you can't use a finite network of L and C to implement a -j impedance that rises proportional to f: at best, you can achieve that at finitely many places, with a series and parallel resonance between each instance.[1] There's a theorem about that, somewhere.

I don't think negative inductance violates causality or linear network theory, but that negative inductance cannot be synthesized from a finite number of LC components, so you're stuck using an amplifier at some point.

The most common implementation would be an active impedance inverter. But that's literally exchanging antenna efficiency for amplifier efficiency: no free lunches. (At a sufficiently low frequency, you could use a high efficiency amplifier to beat the system, but this would be terribly hard to generalize over, say, the SW band.)

Tim

Right. For transmitting, the electronic active solutions are out of question. Automatic motor tuners are being used, but they are narrow- band in my classification.

Short antennas are capacitive, so there you'd need a negative capacitance here.

"Jeff Liebermann" wrote

Thanks for the link. I downloaded the zip onto my Acer and took it down to the local ham club. I showed it to one club member and he endorsed it. While it may have a steep learning curve, I have time but no money.

Then I started chatting with another club member who referred to 150 years of physics. Some people have not studied and do not know what is rhetoric.

Later I was talking about my Baofeng and how happy I was with the wideband rubber ducky antenna, with a bandwidth greater than 300 MHz, covering all of VHF to beyond UHF. Since most hams denounce the Baofeng rubber ducky, I had purchase a VHF and UHF set of antennas from Baofeng. I did not get much better performance. Perhaps I was able to broadcast a signal across the Salish Sea and get a ping from one repeater out of a dozen that I had programmed. The special purpose antennas provide a gain of perhaps 3 dB, not of any usefulness.

The US patent I have is for a rubber ducky but I don't think it is still of commercial importance. I guess I should look up the patent for the Baofeng rubber ducky. Following the normal statement in a patent, one skilled in the art could scale the dimensions for any desired frequencies.

What I know of the internals of the Baofeng rubber ducky comes from a Youtube on how to repair it. There is a helix with an off center tap with a capacitor. It is SMA so it is 50 Ohms and a rescaled shortwave antenna should work with my 50 Ohm coax feed line & BNC.

VE7AJX

This doesn't meet your requirement for ULTRA BROADBAND.

I expect that the connector has little to do with the actual return loss of the antenna system. When they sell the whole radio for $24, I expect that the cost target had more influence on the design than performance.

What did you learn when you put a return loss bridge at the base of the antenna? For transmitting, matching to the load is a significant part of the problem. Surely someone has posted a network analyzer plot for a rubber ducky.

Learning 4NEC2 and EZNEC is not difficult if you already know something about antennas, transmission lines, and magic. You can also learn quite a bit about how things act by changing conditions. There are tutorials on YouTube. Questions can be asked in the forum:

(...)

You're drifting badly in topic. The Baofeng is VHF/UHF. You were previously asking about a 2 to 30 MHz wideband antenna. At this point, I have no idea what you are trying to accomplish or what problem you are trying to solve. I can recommend all kinds of antenna modeling software, but without knowing what you're trying to do, I'm likely to miss. For example, if you have an HF antenna system with a buried ground, NEC2 won't do it and you'll need to buy NEC4.

"Jeff Liebermann" wrote

"mike" wrote

Hi Mike & Jeff,

Think of my design objective as to rescale a rubber ducky to my desired bandwidth. The rubber ducky is a mistuned circuit that provides 0 dB gain. If I make an antenna with some aperture, I should be able to capture some broadcast power, from plane wave propagation. The magnetic loop antenna that some hams endorse does not meet my objectives. It is directional when hung in the vertical plane. It needs to be tuned. It is an inconvenient size and shape for an apartment.

The amplified mini-whip antenna has very little aperture but it has been endorsed by some at my club and here in this thread. I have one on order from Russia that looks of good design.

I have a small bandpass filter 1.7 - 30. MHz with BNC connectors for the feedline. Noise of any source will pass through it at the bandpass. Because I wish to receive at my apartment I may need to mount tin foil on the picture windows to shield noise from within. I live on an island off the wet coast of Canada. Other sources of noise I must live with. Under inconvenient circumstances I have received HF from Russia, China and India, Australia, Cuba and other places in Latin America. I would like to receive the local ham fest signals in HF but even they cannot (yet) receive there own broadcast. I have a friend with HF on his 41' boat. Marine HF and ham HF are always broadcast in SSB. In the middle of the ocean, SSB HF is easy.

The HF bandpass filter is sophisticated. I have forgotten most of what I have learned. If you wish, you can Google for the micro ceramic RF circuits now in use.

For my design objectives you can think of me simplifying the bandpass filter and then scaling it up for sufficient aperture for some useful signal amplitude.

Antennas are circuits. The 1971 ARRL handbook shows the broomstick antenna with a matching network. Filters are circuits. When scaled up to have aperture they are antenna.

I'll try to post the frequency response curve of the 1.7 - 30 MHz filter.

Maybe on a good day at specific frequencies, with a trailing wind and your tongue hanging out of the left side of your mouth while making offerings to the deity of your choice.

Gain across any significant bandwidth will be minus quite a few dB.

Which - apart from differing from your 0dB claim - is an arbitrary figure you pulled from exactly where?

A sweeping generalisation. Ever consider they may be right?

Rest of your s/g's flushed.