Field Testing Chameleon MPAS & CHA SPIKE First QSO with Russia

Last weekend OH8STN went out to field test the “CHA Spike”. The CHA Spike is a new deployment option for the Chameleon MPAS, Hybrid Mini, or Hybrid Micro series of Broadband matching transformers. The CHA Spike is a 15inch (38cm) stainless steel ground spike designed to provide a stable base for collapsible whip style antenna systems. In this video OH8STN deploys the CHA Spike with the Chameleon MPAS and MIL EXT add-on, on top of a local hill, excellent radio spot, but unfortunately, devoid of trees.

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More pictures and info at the following link:

http://oh8stn.org/blog/2017/05/30/field-testing-chameleon-cha-spike-on-mpas-first-qso/

- C

 

OK guys, If you really do not have financial ties to Chameleon company at least learn the basics about antennas and stop propagating the wrong and useless counterpoise advice.

The single wire on the ground is just another stupidity to make already crappy/lossy antenna even lossier by warming the worms. Also, pointing the counterpoise wire to a correspondent makes such a small difference in the radiation pattern of that vertical that it is not important at all.

If you really want to improve that antenna efficiency, cut that counterpoise wire in at least 5 pieces and place them around as real radials. They can be as short as 1/8 of a wavelength which is on the 20m band just 2.5m or 8-9 feet long.

And first QSO to Russia from Finland! Really!!

Are you really that proud of such achievement?

You can make such QSO with 50 Ohms resistor across the coax and only that single wire counterpoise without crappy vertical.

Yes, I am being very sarcastic... can't stand looking at constant dumbing of a HAM population with all these videos which serve only to either create traffic to the youtube channel and benefit from advertisements for Chameleon to sell more of these super duper magic "broadband " antennas.

Danny, N4EXA aka E73M
the owner of MyAntennas.com
a home of real efficient broadband antennas

P.S. I am shamelessly advertising good products, at least I pay the advertisement here on QRZ.com

 

3. Monopole with one radial or counterpoise.

Observing the previous analysis, one can conclude that it should be of interest to improve the electrical conductivity of the ground plane to avoid distortions in the radiation pattern and a loss of eficiency. This can be achieved using radials or counterpoises. Using the name of radial or counterpoise has lead to controversy, deeply studied by L.B.Cebik (W4RNL).

The following analysis takes into account only one radial or counterpoise, which is the option chosen by several manufacturers of portable vertical HF antennas. Furthermore, we will consider that both the monopole and the counterpoise are very close to the ground.

There are several theories about the optimal length of the radials. The ARRL Antenna Book recommends a minimum length of half the working wavelength. In our experiment we will run an optimization process with 4NEC2 in order to find the optimal length for our counterpoise.

In the 4NEC2 simulation, in order to avoid the counterpoise to be in direct contact with the ground, we will rise the whole structure 0,1 meters above the ground.



3.1. Antenna design.
In 4NEC2, we simulate the monopole along the "Z" axis, perpendicular to the "XY" plane (fig.8).










Fig.8. 4NEC2 model of a 1/4 wavelength monopole with counterpoise.




In the simulation, the radial or counterpoise is extended all along the X-axis of the ground plane. We return to the initial value of monopole length calculated in the first analysis (5,16 meters) and run an optimization process with 4NEC2 to find the optimal length of the counterpoise, with the goal of achieving a minimum SWR. The result is a counterpoise of 4,79 meters with an SWR of 1:1,41. Please remember that this solution is only valid for this monopole, at this working frequency and over this type of ground.



3.2. Simulation results.
After our counterpoise length optimization process, the SWR is around 1:1,4 and almost flat in all the 20 meters band (fig.9).










Fig.9. SWR of the 1/4 wavelength monopole with optimized counterpoise.




The radiation pattern is no more omnidirectional: the antenna has more gain in the direction imposed by the counterpoise (the positive "X" axis, in this example).










Fig.10. 3D Radiation pattern of the 1/4 wavelength monopole with counterpoise.




If we analyze the vertical plane of the radiation pattern (fig.11), we can see that the main lobe is located in the general direction of the counterpoise, with a maximum gain of -1,3 dBi at a takeoff angle of 30 degrees. The front/back ratio is 4,6 dB, so it is recommended to install the counterpoise pointing to the remote station azimuth. The radiation efficiency is 16 %










Fig.11. Vertical plane radiation pattern of the 1/4 wavelength monopole with counterpoise.




If we compare the results with those of example #2, we see that, using the counterpoise, we have improved the antenna gain in 6,5 dB, having also three times more radiation efficiency. With an adequated counterpoise length we can also achieve the impedance matching in the working band.

It can be concluded that, for a monopole of given length, the use of a single radial or counterpoise of studied length will benefit the overall antenna efficiency and gain in the direction imposed by the counterpoise.

In fact, the counterpoise is another part of the whole antenna, so its length has to be studied to optimize the SWR.

Source: http://www.ipellejero.es/hf/antenas/monopolo/english.php#3

- C

 

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It's difficult not to get sucked into troll bait like this so I'll make this one post on this thread, and leave it at that.

• I don't work or get paid by any company to make videos or blogs. That's a rumor which was started by Steve from alpha antenna when I called him out for blatantly lying about his less than honest marketing practices. I'll say this one last time I don't get paid for creating content.
• Ads on my blogs and traffic to the channel support (wait for it) the cameras, the memory cards, the servers, the editing software, the batteries, solar panels, paying customs fees for gear I sometimes have not ordered, trips to Lapland to test the gear, ...
• Dumbing down of ham radio? Really? The point of my channel is showing people how to operate with less than ideal circumstances. Nobody watching my videos is interested in dxcc, it's all about amateur radio as a utility, using less than ideal gear, ...
• QSO to Russia. No, not proud, showing an example of a solution working. The days of some boring talking youtube head, explaining something from a script to a camera in an office in front of a green screen are over. People want to see real life examples in the field. On that day it was Russia. The previous day was Croatia, other days hsve seen Scotland Germany Italy...
• Last April i suffered frost bite on my hands to shoot the RADAR Challenge just to post it to YouTube and the blog (which are loss making), with the hope of inspiring radio operators to get outside with their gear. In 2015 it was a hike above the Arctic Circle, pulling all my gear with a homemade hiking trailer, to bring that experience to operators who might be afraid to try a qrp camping expedition. Anyone watching the other 80% of my videos know it's not about the money. Perhaps you thought I was one of the YouTube Network channels working for profit (K6, N4, ...)
• If you have a problem with Chameleon not paying for advertising on qrz, attack Chameleon and qrz (who must have approved this post i would imagine). Otherwise you look like another troll, angry because nobody buys your gear.

Finally another part of the reason I do what I do on my blogs and on YouTube is to support small Amateur radio manufacturers. Yes Einstein, even your small amateur radio manufacturing business. And that's not even a one-time thing. It appears that I work with companies because I present product videos repeatedly on the blog and channel. You might see the same thing on the channel 5 times over a year or two. That's because you can't know if a product sucks or not using it from an office or backyard one time on a sunny day in Spring. Another example. I've spent the last two weeks working on a video for sotabeams, which will never pay for itself, simply because it's a good product. Then I had to delay that video to publish a tutorial for a couple of operators who were having trouble figuring out another piece of gear. Again something I'll never recoup my time or effort from . Now I'm taking time out to write this silly response to your trolling when I should be editing the sotabeams video. I do this because I don't want your hate to be considered the truth on this thread. So wanting to help present a product to people who want to see how I use it, is not a bad thing for the community. I've presented gear on the channel and blog from lots of different companies. The biggest cost associated with the blog and channel, are the things that I send back to ham radio manufacturers having the unfortunate task of telling them a video would be negative if I made it. Giving them the advice about how I would improve it for my environment, and hoping that advise is enough for their product to thrive. Nevermind the gear that I give away to operators once I'm done with it.

A clever business would have reached out, allowing me or any one of the awesome channels out there to showcase their gear in the field instead of using their energy for trolling people on qrz.
Nobody sees the effort it takes to put these videos together. Nobody sees the hundreds of editing hours each month. No one sees when I have to be rushed to the hospital after being bitten by a Viper. Nobody sees or hears the pain and suffering of cold wet fingers during the radar challenge which would have been exponentially simpler without filming it. And you know what, they don't have to because I'm having a blast making videos for the one guy or gal who shows some kindness in the comments.

Good luck with your business. What was the name again?
Julian

 

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Good video, Julian. I always enjoy your portable HF work. Excellent!

 

Yes, the technical analysis is good and necessary.

I wouldn't choose a single counterpoise vertical by default, but I have used one for 80-30m in the form of an inverted-L.

Was this a total waste of time? A useless, inefficient antenna? A thing that only a real idiot would deploy?

Well, I have made very many perfectly good QSOs, DX and otherwise with that antenna.

I think the technical analyses these days do tend to forget that 'compromise' antennas today are far less of a 'compromise' than in days gone by, thanks to the weak signal digital modes. The analyses also tend to ignore the often severe space restrictions that many hams have to put up with.

It's right to persuade people to consider the merits of any particular antenna and strive for the best possible.
But don't let this perpetuate the myth that a reasonable compromise antenna will prevent you from making good QSOs. That is not true, and dissuades people from potentially enjoying an acceptable antenna solution.

I'm also bound to say that the nature of ground and the environment is almost universally ignored in 'analyses'. From years of WSPR testing, I know that good antennas in urban and semi-urban settings can be easily outperformed by less ideal antennas placed on a clear rural hillside with mineralised ground. Les Moxon agreed, years before WSPR and non-human biased modes.

Like the planet-building Slartibartfast said in The Hitchhiker's Guide to the Galaxy: "I'd rather be happy than right, any day".

 

I love watching the videos OH8STN makes and I have to say he has inspired me to "get out" more and play less radio from inside a shack. I am now planning on activating SOTA at W4/SH-002 "Stony Man" summit using a Chameleon CHA-MPAS with the spike. I will also be taking the CHA P-Loop 2.0 to test it out. I love Chameleon products and never had issues with customer service. Every time I send an email about a product or inquiry, I get a quick response and solution if needed. I did purchase the new Spike and P-Loop 2.0 based on OH8STN's review. Thank you guys for the hard hard work and Keeping it real! - de K4LCT Lars

 

Seriously: I own your antenna (check your sales logs), and they don't out perform others bought on ebay of similar build.
Yet up until now, I regarded you as another manufacture that I would pay my money to support (and I did).... but your post puts you in the league of b!itch whining vendors that foam at the mouth to see their competitors get support.

Stay in your lane, build great products and when the time comes for promotion: let others do it for you.

I just unsubscribed from your company mailing list.

 

On a hopefully less controversial note... nice dogs!

Good on ya' for getting out there and doing it, whatever equipment you may choose to employ. Cheers... Jim

 

That looks almost good enough to eat!

 

Yeah, they don't work. But I wonder why I was able to work Cuba, PSK-31, on 2.5 watts, from north central Texas, with a BuddiStick clamped to the patio railing at the pub.

Now I didn't have a $50 stainless ground spike made from a dead Pope's dentures, just a cheap camera clamp.

 

Nice review! thinking about that antenna...just wish Chameleon's website was easier to navigate. The antenna packages/accessories list are confusing(to me at least). I also followed your CHA vs Alpha videos; great work!