The Big Kansas Coil is a lightweight, portable, and durable base loaded vertical antenna system that when paired with a telescoping whip operates on the 6 through 80 meter ham radio bands. This coil offers some innovative features, including: 3D printed construction out of engineering grade materials, integrated coil scale, easy to use adjustment collar, and a wider diameter coil than anything else on the market.
So what makes the big Kansas Coil different than other base loaded coils? First off is the construction. This coil is entirely 3D printed out of engineering grade Glass and Carbon Fiber filled Nylon material. This coil is lightweight and durable. The material is weather and heat resistant so this antenna is rated for up to 100 watts digital modes with a 50% duty cycle.
The second is its size, or diameter of the coil. This coil is wider than anything else on the market. In building loading or inductance coils, the diameter of the coil will affect the Q or quality factor. Narrow coils will have a very high Q and extremely sharp bandwidth on the lower bands. If you make the coil wider, the Q is reduced and you end up with more bandwidth. I’ll demonstrate what that means a bit later in this video.
As a bonus, patrons can view the unedited phone contacts for this POTA activation. Visit my page on Patreon for details: https://www.patreon.com/kb9vbrantennas
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I meet up with Chris, N9CVR, of The Ham Radio Experience. He shows off his fishing pole vertical antenna and we use it to catch some contacts along the Wolf River at the Mukwa State Wildlife Area, (POTA US-4314).
The 6 meter band is hot in the summer time and there is no better way to exploit it than with a directional antenna like the 6 meter Moxon. The Moxon is a 2 element Yagi that is inexpensive and easy to build, but also offers great results with 5.5dbi of gain and a 25db front to back ratio
The Moxon is named after its creator Les Moxon, G6XN. It is best described as a rectangular two element Yagi antenna. I said rectangular as the ends of the driven element and the reflector are folded inwards, which reduces the amount of space it occupies, about 70% of the space of an equivalent dipole antenna. If you add lightweight spanners to the rectangle, you can rotate the antenna.
Typically, a 6 meter Moxon will have about 5.5dbi of forward gain, and exhibit a high front to back ratio, up to 25 dbi when elevated to the optimal height of about 18 feet. They also have a 50 ohm impedance at the feed point, so no matching network is required, which simplifies their construction.
To make this project more approachable, three of the parts are 3D printed, the hub, hub adapter, and feed point mount. I used PLA+ to print these parts. This is ok for temporary use, but if you are thinking of permanently mounting this antenna, I’d use something more weather resistant like Petg or ASA. All of my 3D printed parts are available on Thingaverse if you want to tackle this project yourself.
The KB9VBR 6 Meter Moxon Antenna Parts list: 4 – 48 inch x 3×8 inch fiberglass fence posts 1 – 3D printed Moxon hub 1 – 3D printed hub adapter 1 – 3D printed Feedpoint center SO-239 chassis connector 20 feet 20 or 22 ga wire 6 x ½ inch machine screws, nuts, and washers 8 small Ring terminals String trimmer line Painters pole: 15 – 23 feet
You may think the Rez Antenna Systems Recon 40 is like any other base loaded coil, but what makes this one different is that you can change bands with a flick of a switch
Rez Antenna Systems Recon 40 coil: https://www.rezantenna.com/product-page/recon-40
As you may know, I am a big fan of using a vertical antenna for my portable operations and Parks on the Air activations. I enjoy the speed of setting up a quarter wave vertical antenna for the higher bands, and I love the versatility of using a loaded coil to extend my operation down into the 40 meter band.
Knowing that many people like to take advantage of the efficiency of the 213 inch vertical whip as a ¼ radiator, Rez antenna systems has developed this product, the Recon 40, to extend the range of the 17 foot vertical whip down into the 40 meter band.
The Recon 40 is a fixed inductance coil system to turn a 17 foot whip, which is resonant on the 20 meter band, into a base loaded vertical antenna that is now resonant on the 40 meter band.
But with conventional coil systems, you have to add or remove the coil, or somehow bypass it in order to switch between 40 and 20 meters. The Recon 40 solves that problem by adding a bypass switch, right in the coil system. This switch, when turned on, puts the coil in line with the antenna and turns it into a 40 meter antenna. Flick the switch off, and now you’ve bypassed the coil and your whip is instantly resonant on 20 meters. Physically adjusting the whip will get you resonance for any other band above 20 meters.
Rez antenna systems loaned me a kit for this review. I’ve returned it and no further compensation was received. My comments and experience with it are my own without outside influence.
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The Chameleon SA-1 is a compact easy to use antenna analyzer that will help you measure SWR and tune your multi band antenna, like the Chameleon PRV System or Wolf River Coil Silver Bullet 1000. The meter measures SWR from 1:1 – 19.9 in a frequency range of 1.6 MHz to 160 MHz.
The Chameleon SA-1 is a compact lightweight SWR analyzer that would be perfect in your portable antenna kit. Opening the box you will find, a Nine volt battery, a BNC to UHF adapter, and the unit itself enclosed in a protective velvet bag.
The SA-1 has a continuous frequency range of 1.6 to 160 Mhz so it will be able to test the SWR for anyHF and VHF antennas in the amateur radio bands. It can also display the SWR from 1:1 up to 19.9:1 for that antenna. Run time with the battery is approximately 20 hours or 15 hours when you use the back light.
On the top of the meter is a small power switch, a BNC antenna port, and a socket that is labeled serial. We’ll talk about the serial feature in a bit. But first let’s look at the front of the unit
The SA-1 does not come with any instructions. Instead, everything you need to know to operate the meter is screen printed on the front of the unit. When you power on the meter, you will see the frequency and SWR on the dot matrix LCD display. Every time you turn on the unit, the frequency also defaults back to 14,000 Mhz. To adjust the frequency, you first tap the knob to select the digit and then rotate it to change the number. The unit is constantly testing the SWR, so there is nothing else you need to do. If you want to toggle the backlight, press and hold the center knob. That’s it. The SA-1 does one thing, and that’s measuring SWR. so there is nothing else you need to set it up.
A single function meter like this can be really handy in the field as it doesn’t distract with unnecessary features. It’s all in the goal of getting on the air quickly. So let’s see how fast we can do that as I demonstrate setting up and adjusting a multiband vertical antenna.
Timestamp 00:00:00 Chameleon SA-1 Antenna Analyzer 00:01:35 Features and Specs of the Chameleon SA-1 00:03:31 Using the SA-1 SWR Meter 00:13:15 Chameleon SA-1 Secret Feature 00:15:30 My thoughts on the SA-1 Antenna Analyzer
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We take a road trip to northern Wisconsin to discover the origins of the Wolf River and then follow the scenic waterway downwards in this entertaining Parks on the Air activation.
As a bonus, patrons can view the unedited phone contacts for this POTA activation. Visit my page on Patreon for details: https://www.patreon.com/kb9vbrantennas
I do return QSL, if you made a contact with me and would like a QSL, please send me one. Return postage not necessary, but always appreciated. As they say, KB9VBR is ‘good in the book.
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Ham Radio Dude’s portable end fed half wave antenna, the Dudetenna, features a substantial toroid and reinforced radiating wire for 100 watt operation in both digital and sideband modes.
The dudetenna end fed half wave, like other end fed kits on the market is pretty similar to the others in construction and performance. I;ve always said that an end fed is an end fed and all the models on the market and going to work pretty much the same. But there are a couple of key differences in this antenna that set it apart.
First off, the Dudetenna uses a different toroid than the others. Most end feds that are capable of 100 watt transmit power will commonly use the T140-43 toroid. This antenna is different and its transformer is built around this larger Fair-rite 43 mix toroid. The bigger toroid has about three times the mass of the T140, giving you greater permeability and slightly more bandwidth. With a bigger toroid, it should handle a full 100 watts sideband without overheating.
The other two notable features are the use of an SO-239 or UHF female connection instead of a BNC, so no adapter will be required if your coax has PL-259s and finally, the kit comes with 75 feet of vectron fiber reinforced wire. Vectron fiber, much like Kevlar, will not stretch or break, giving your radiator wire greater mechanical strength for use out in the field.
The kit is also available with or without the wire, so you can build the transformer and then supply your own wire. It’s your choice.
Ham Radio Dude did send me a Dudetenna end fed half wave antenna kit to build and put on the air in exchange for a video. But my opinions are my own and there is no outside influence. So let’s head inside, build this antenna, and then put it on the air.
As a bonus, patrons can view an hour long video of me assembling the Dudetenna end fed half wave. Visit my page on Patreon for details: https://www.patreon.com/kb9vbrantennas
I do return QSL, if you made a contact with me and would like a QSL, please send me one. Return postage not necessary, but always appreciated. As they say, KB9VBR is ‘good in the book.
Timestamp: 00:00:00 Ham Radio Dude End Fed Half Wave 00:02:04 Dudetenna EFHW Parts 00:07:50 Assembling the end fed half wave antenna 00:09:02 Adjusting and tuning an EFHW antenna 00:14:53 Dudetenna on the air 00:17:24 Conclusion and my thoughts
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Like what you see? You can leave me a tip: https://www.paypal.me/kb9vbr
As a bonus, patrons can view the unedited phone contacts for this POTA activation. Visit my page on Patreon for details: https://www.patreon.com/kb9vbrantennas
I do return QSL, if you made a contact with me and would like a QSL, please send me one. Return postage not necessary, but always appreciated. As they say, KB9VBR is ‘good in the book.
Links may be affiliate links. As an Amazon Associate, I earn from qualifying purchases. This does not affect the price you pay.
The Frankentenna consists of parts from three different antennas to create a 25 foot tall vertical non resonant radiator that when combined with a remote antenna tune results in amazing performance on the bands. Join me at the Plover River State Fishery and Wildlife Area (POTA US-10054) in North Central Wisconsin as I put this park on the air.
As a bonus, patrons can view the full, unedited phone contacts for this Parks on the Air activation. Visit my page on Patreon for details: https://www.patreon.com/kb9vbrantennas
I do return QSL, if you made a contact with me and would like a QSL, please send me one. Return postage not necessary, but always appreciated. As they say, KB9VBR is ‘good in the book.
Links may be affiliate links. As an Amazon Associate, I earn from qualifying purchases. This does not affect the price you pay.
The Chameleon URT-1 is a remote outdoor antenna tuner for almost any type of antenna or model of transceiver. This wide range tuner matches resonant and non-resonant wires, verticals, and long wire antennas with its range of 5 to 1500 ohms of impedance. The URT-1 has a 50 ohm coaxial port and a wire beehive connector for added versatility. And the unit is weather proof so it can be mounted outdoors near the feed point of the antenna.
The purpose of an antenna tuner is not to ‘tune’ your antenna, but instead to provide a proper impedance match to your transceiver. Modern transceivers require a 50 ohm impedance and if there is a mismatch, the transceiver will respond, at the very least, by reducing output power, and at the worst, damaging the final amplifier components. So in order to deliver all available power to your antenna, a proper impedance match is required. This is a simplistic explanation, but sufficient for today.
Usually the tuner, either manual or automatic is placed near the transceiver. This is fine in most cases. If your feed line run is short, it won’t make a difference. But coaxial cable does introduce losses into the antenna system and if your antenna has a high impedance at the feed point, the mismatch will create standing waves, and the elevated SWR can be characterized as power lost in the feed line. Again that’s a simplistic explanation.
So how do we increase the overall efficiency of our antenna system? One method is to move the antenna tuner from the transceiver over to the antenna feedpoint. Situating the tuner at the antenna allows it to deliver the proper impedance match, which will be 50 ohms, to the feed line. Since impedance is matched at the coax, we can run longer pieces of cable without fear of losing energy due to high SWR on the cable.
Now remote tuners are typically used with non resonant antennas, either long wires or verticals. A resonant antenna, like a dipole or end fed half wave should have close to a 50 ohm impedance at the feed point. The tuner located at your transceiver will be used to fix slight mismatches or to extend the bandwidth of your antenna. Remote tuners would be overkill in these situations.
But with, say a 43 foot vertical antenna, the impedance may be between 400 – 900 Ohms. A 9:1 transformer could help knock that down, but using a remote tuner instead, will take whatever impedance the antenna is and deliver a consistent 50 ohms to the feed line, reducing overall system losses.
URT-1 Specifications
The URT-1 covers 1.8 to 54 Mhz and has 16,000 memories for quick recall when tuning. It can match any antenna with an impedance of 5 to 1,500 Ohms. That’s like a 30:1 match. And it can handle up to 125 watts sideband or CW and 60 watts on the digital modes.
Opening up the box, things may look a little familiar. This tuner is custom manufactured by Mat Tuner for Chameleon. It does look very similar to their MAT 40 remote tuner, but there are some key differences.
The tuner comes in two parts, the first is the coupler box. This connects to the transceiver and to a 12 volt power source. Then your coax cable runs all the way out to the tuner box which sits at the antenna feed point. You will notice that there are not separate control cables for the tuner. Power and tuner control are fed through the coax cable by way of a Bias-T circuit. The benefit to that is that you don’t have to run a second cable to the tuner unit, but the downside is that you need to initiate tunes by pressing the tuning button on the coupler.
The tuner unit is constructed out a aluminum alloy and it weather proof. On the top of the unit is a beehive connector for feeding wire or vertical antennas. On the bottom is a counter poise and ground connector along with two UHF female connectors. One UHF connector connects to your coax run coming from the coupler and the second is for feeding antennas that have a similar SO-239 connection point.
The tuner comes with a set of rails so that you can mount it to a post or board using a pair of U-Bolts. An option 12 volt AC adapter is also available. So what’s different between the URT-1 and the MAT 40 tuner? Namely the addition of a 50 ohm coaxial output port and the removal of the brand specific control cables. The URT-1 is a bit more universal in that the coupler unit will work with just about any brand or model of transceiver.
How to use Use the URT-1
Using the URT-1 is pretty simple. We’ll first connect the coupler to our transceiver. My main antenna, a G5RV, is connected to my LDG auto tuner, so going to put this one onto the 2nd antenna port on my transceiver. A coax jumper goes from the radio to the coupler. The antenna coax is then connected to the other port on the coupler. Finally connect the power. The green power light should glow. If you see the red error light, that means the there is a short circuit somewhere in the coax connection between the coupler and the tuner.
When connecting the tuner, you can not have any devices like switches, diplexers, or meters in the path between the coupler and the tuner. These could cause a short circuit, potentially damaging the tuner or your device.
To initiate a tune, put your transceiver into a constant carrier mode like RTTY. Set the power level to 15 watts or less, briefly hit the tune button, and immediately key the transmitter. Watch the transceiver SWR meter and it will show the resulting SWR when the tuning cycle is complete. Unkey the transmitter. A complete tuning cycle will take five seconds or less.
At this point you can transmit normally. When changing bands, you will reinitiate the tune process. The tuner has 16,000 memories, so once the unit finds a good match, it will remember it for faster subsequent tunes.
Now let’s head outdoors and I’ll show you a couple of ways you can use the remote tuner in your portable amateur radio operations.
My experiences
What are my thoughts on the Chameleon URT-1 remote antenna tuner? First off, I must say that this unit is well constructed. The tuning unit consists of an aluminum alloy body that has a certain amount of heft to it. It wins points on that item alone. Taking this out into the field was a breeze as I didn’t have to run a separate control cable to the tuner for power. Operationally, it tunes fast and had no problem finding a match that was 1.5:1 or less. I think the only time I had issues with it getting a good match was with my 25 foot Franken-tenna on the 15 meter band. In that instance it gave up at about 1.8:1. But with the Frankentenna it did perform quite well on 10, 15, 20, and 40 meters despite the bands not being in the best condition. I made 210 contacts on those bands activating the Mountain Bay state trail, with the bulk of them on the 20 meter band.
With the end fed random wire antenna, I connected the tuner up to UHF connection on the antenna. The addition of the 9:1 transformer with the tuner made for super fast tune times. Every time it found a match at rocket speed. For that activation of Ackley Wildlife Area I ended up with 176 contacts on 10, 12, 15, 17, and 20 meters. The great thing about non resonant antennas is their agility. To switch bands, all I had to do was hit the tune button and I was good to go.
I had the same experience back here at home with the 71 foot non resonant wire. Once it learned the antenna, it would re-tune almost instantly. I was able to get matches with this wire from 10 meters all the way down to 80 meters. Operationally, the antenna performed just as well, maybe a bit better than with my other tuner located at the feed point. This antenna is being fed with 75 feet of RG-8X, so the better match at the feed point does make a difference.
As for things I don’t quite like about the tuner, First off these UHF ports are not labeled, so you need to look at the instructions to determine which goes to the coupler and which goes to the antenna. Also the ports didn’t come with covers. If you are using the bee hive connector, having a cover on the unused UHF port would be nice. I’ve got a friend that 3D printed some, so i did have something that worked. Finally, and probably the biggest, is that you have to press the tune button on the coupler to initiate a tune. If your SWR changes or you change bands, the tuner won’t automatically retune, it needs to be activated. That involves switching to a carrier mode like RTTTY, pressing the tune button, and then transmitting a carrier. Not the worst thing in the world, but also not fully automatic like some brands of remote tuners. But those require a separate control and power cable and up side of this tuner is that you don’t have to run a separate power and control cable to the tuner. Your power runs through the coax, which makes installation a breeze.
But, final words, I’ve been looking for a remote tuner at the hamfests. Everything I’ve seen is overpriced or in bad shape. It’s a bit serendipitous for Chameleon to be sending me this as it opens up the door to a bunch of different antenna configurations that I’ll be able to demonstrate. I’ve got some great ideas to use this tuner with, so you’ll want to stick around for that.
As a bonus, patrons can view the full, unedited phone contacts for this Parks on the Air activation. Visit my page on Patreon for details: https://www.patreon.com/kb9vbrantennas
I do return QSL, if you made a contact with me and would like a QSL, please send me one. Return postage not necessary, but always appreciated. As they say, KB9VBR is ‘good in the book.
Links may be affiliate links. As an Amazon Associate, I earn from qualifying purchases. This does not affect the price you pay.
CaHRTenna Poseidon is the Coffee and Ham Radio’s take on the popular Rybakov vertical non resonant antenna. Today we’ll talk about Poseidon, show you how to build your own, and put the Greek god of the sea on the air.
Coffee and Ham Radio’s Poseidon is based on an antenna called the Rybakov. That antenna, created by Italian ham IV3SBE about 20 years ago is a non resonant ground ground mounted vertical antenna with a radiating element of 25 feet. At the feed point is a 4:1 unun or transformer to match the 200 ohm impedance the antenna presents. Radials of about a similar length provide the ground network for the antenna. With a tuner, the antenna will operate on the 80 through 6 meter bands, although it gets pretty inefficient on 40 meters and below. Your best performance will be on the higher bands and this style of antenna really excels on 10, 12, and 15 meters. As you get higher in frequency, the RF radiation angle gets lower and lower, making it an excellent DX antenna.
But why the name Rybakov? When IV3SBE designed the antenna, he envisioned it being supported by an 8 meter fishing pole. The antenna’s 25 foot length makes it perfect to deploy with a lightweight mast or fishing pole. Rybakov is Russian for fisherman, so it makes sense to give the fishing pole antenna that name.
Coffee and Ham Radios did send me a Poseidon vertical antenna kit to build and put on the air in exchange for a video. But my opinions are my own and there is no outside influence. So let’s head inside, build this antenna, and then put it on the air.
So what makes Poseidon different? I believe the key difference lies in the transformer. If you look at most 4:1 unun designs, they use a red T200 style toroid. The red toroids work well and offer very good overall efficiency, but a key design element of this antenna was to make is tunable with a transceiver’s internal tuner. That means you will need an SWR that’s 3:1 or less over the entire frequency range the antenna is designed for. Unfortunately the T200 isn’t up to that and you will get higher impedances at the lower frequencies. This green colored iron powder core that’s used in Poseidon offers an overall better impedance matching at a wider range of frequencies, with a slight tradeoff of efficiency. Is the tradeoff worth it? It is if you don’t want to bring an extra piece of gear out into the field. Also consider, lower impedance coming out of the antenna means less losses in your feed line. So overall, its a valid choice to make.
The second consideration with this antenna is that 4:1 transformers can pass along common mode currents, causing the outer shield of your feed line to radiate. This will affect your antenna’s radiation pattern. Proper 4:1 windings will also include a second toroid would as a 1:1 choke. In order to make this antenna easier to build, Poseidon does not use the double toroid winding, instead you will need a choke of some sort on your coaxial cable. Today I’ll be using an integrated choke on my feed line for this antenna.
Dave and I are mobile again for the Wisconsin QSO Party. This time hitting four POTA parks and five counties on our multi-multi-mobile road trip. Will we end up with an epic score or fail miserably?
Team K9M is Michael KB9VBR and Dave KZ9V. This is our second year as mobile operators in the Wisconsin QSO party. If you made contact with K9M during the QSO party and would like a card, please QSL via KB9VBR. As they say, I’m good in the book.
As a bonus, patrons can view the unedited phone contacts for the QSO Party and extended conversations between Dave and I. Visit my page on Patreon for details: https://www.patreon.com/kb9vbrantennas
Links may be affiliate links. As an Amazon Associate, I earn from qualifying purchases. This does not affect the price you pay.
3 years ago I did a review of the Chameleon Tactical Delta Loop antenna. At that time I had a mediocre feeling towards it. But taking a 2nd look, I am totally impressed on how this amazing antenna performs on the upper bands.
As a bonus, patrons can view the full, unedited phone contacts for this Parks on the Air activation. Visit my page on Patreon for details: https://www.patreon.com/kb9vbrantennas
I do return QSL, if you made a contact with me and would like a QSL, please send me one. Return postage not necessary, but always appreciated. As they say, KB9VBR is ‘good in the book.
Links may be affiliate links. As an Amazon Associate, I earn from qualifying purchases. This does not affect the price you pay.
I take a look at the 13th revised edition and first English translation of Rothammel’s Antenna book and compare is to the new 25th Edition of the ARRL Antenna Book. Which book stands out as the best?
Recently on the livestream we had a discussion about antenna books, specifically the Rothammel Antenna Book. This substantial tome is frequently called the antenna bible, for its comprehensive scope. Up until recently the book was only available in German, but now an english translation of the 13th edition is available. That translation opens this guide up to a whole new audience and many hams are discovering what a valuable resource it is. We’ll look inside the book in a bit, but first the specs,
Rothammels antenna book is 1600 pages, dimensions are , and it weighs about 4 pounds. The paper has a textured finish and the text is set in 10 point type. This smaller typeface can make it a bit harder to read, so get your reading glasses tuned up for it. Cost of the book is 59 euros. I ordered it online direct from the DARC, the German amateur radio association and with exchange and international shipping, my cost was $87 US dollars.
We’re going to compare that book to the American standard antenna guide, the ARRL Antenna book. The ARRL antenna book has been around since 1939 and the new 25th edition has some pretty substantial updates in it. The latest edition was released in the fall of 2023, so this is the newest guide available. This book is no slouch either, it weighs five pounds, is inches and and has 1120 pages. While the Rothammel guides paper has a duller texture, the ARRL antenna book is a smooth coated paper set in an easier to read 12 point type. The paperback edition is $69.95 and is available direct from the ARRL or from online retailers.
For full disclosure, both books were purchased by me with my own funds.
In perusing the books, you’ll spot some key differences right away, so lets open them up, take a look at the contents and talk about the information inside.
So which book is right for you. Rothammels is certainly more comprehensive with its quantity of antenna styles and variations. The content is direct and too the point. While it may not be comprehensive, it does give you the references and links so you can go off and explore.
On the other hand, the ARRL guide may not catalog such a diversity of antenna styles, the information it has is a bit deeper and well rounded. The ARRL antenna book also offers a substantial amount of electronic content to supplement the printed version and has plans and diagrams for antenna projects you can build.
One thing I’ve noticed between these two books is that the ARRL guide is more of a snapshot of what is the current trend in amateur operation. If you’ve followed past editions of this book, you’ll see content added and content taken away. If a design or style of antenna falls out of popular favor, it may be eliminated or have a diminished presence in the book. That’s one of the reasons why past editions of the antenna guide are still quite popular.
On the other hand, it feels like once an antenna makes its way into Rothammels, its pretty much there to stay. You’ll find information on antennas both old and new and there are some pretty esoteric styles that are covered in the book. Not having any experience with previous editions, as they are all printed in german, that’s my feeling in reading this revised 13th edition. From a research standpoint, this extreme depth is great as you can look up an antenna, search the citations and reference material, and go on from there.
Which may be the biggest comparison between these two books. Rothammels is a starting point, a guide to get you going on a project or antenna design, while the ARRL antenna guide is the one stop shop with theory, design, and plans.
If you are starting out on the journey to build your own antenna systems and want to know more about the theory and design, I’d add the ARRL antenna book to your library.
If you are looking for ready reference, maybe not so much a construction book, then I’d go with Rothammel. Although you can certainly build much of anything thats in the Rothammels guide. It just takes more work to put the formulas, charts, and sketches together into a working antenna. I’ve found Rothammels to be valuable in looking something up, getting a concise overview and working from there. Final word, I think both are excellent books and both are valuable in their own regard. I own previous editions of the ARRL antenna guide and was glad when they finally came out with a new edition this last year. And I’m also glad that an english translation is available for this seminal geman antenna book. I’ll be using both in future antenna projects.
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Timestamp 00:00:00 Introduction 00:00:23 Rothammels Antenna Book 13th revised edition English 00:01:42 ARRL Antenna Book 25th Edition 00:03:07 Look ARRL Antenna Book 25th Edition 00: 10:40 What’s inside the Rothammels Antenna Book 00:17:51 Which is the best antenna book
The Chameleon CHA Stinger Kit is a versatile solution for a vertical antenna counterpoise or ground plane. The Stinger kit consists of six 48 inch stainless steel elements with all weather banana plugs on one end and a teardrop on the other. The Stingers are a quick deployment option for times in which you may not have the space to put out a conventional radial network, like if you are operating on a patio or deck, or other high traffic areas.
Chameleon antennas recently introduced the Stinger kit. This is billed as a versatile solution for a vertical antenna counterpoise or ground plane The Stinger kit consists of six 48 inch stainless steel elements with all weather banana plugs on one end and a teardrop on the other.
For antennas, like the Chameleon PRV system, you insert the 2 mm banana plugs into the holes of the radial puck that comes with the antenna. For other antennas, like the MPAS 2, an optional 6 port puck is available to convert the antenna counterpoise to the Stinger kit. Stinger kits can be ordered either with or without the puck, depending on if you need that part or not.
The Stingers are a quick deployment option for times in which you may not have the space to put out a conventional radial network, like if you are operating on a patio or deck, or other limited areas.
Performance of the stinger kit is good. Using the 58 inch whip on the Chameleon PRV antenna, I was about to get the SWR down to around 1.5:1 on the 20, 15, and 10 meter bands. Chameleon states that a tuner may be necessary for 40 meter operation in this radial configuration. On air reports were good on those bands.
Similar results were achieved with the MPAS 2 non resonant vertical antenna.
Not stretching out radials, like in limited spaces and high traffic areas may be a benefit to some portable operators, and the Chameleon Stinger Kit offers that convenience and versatility in those situations.
The Chameleon Stinger kit can be found online at chameleonantenna.com. Thank you to Chameleon for sending me a stinger kit for this review. Links to their online store are in the video description.
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It’s a POTA road trip! I head out to activate three new to me parks while using a different antenna at each one. Ride along with me for an epic Parks on the Air activation as we find out which one will be the best
As a bonus, patrons can view the full, unedited phone contacts for this Parks on the Air activation. Visit my page on Patreon for details: https://www.patreon.com/kb9vbrantennas
I do return QSL, if you made a contact with me and would like a QSL, please send me one. Return postage not necessary, but always appreciated. As they say, KB9VBR is ‘good in the book.
New Parks on the Air Activators often ask: how do I find a good spot to do my activation? In this video I give you the resources you need to find those awesome POTA locations.
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In the proper sense, small magnetic loop antennas are not considered a compromise. With a properly sized loop, they have the efficiency of a properly mounted half wave dipole*. The Chameleon F-Loop 3.0 antenna unleashes that power with a magnetic loop design that is easy to deploy and offers a broad range of frequency support between 10 and 80 meters on the HF bands.
Magnetic loop antennas consist of three components. The first, and most noticeable is a large primary loop. This loop circumference is typically within ⅓ to ⅛ the operating frequency range of the antenna. Inside this primary loop is a smaller conducting loop. RF energy is fed into the conducting loop and the electromagnetic coupling between the two are what creates the RF radiation. The third part is a tuning capacitor, which is connected to the large primary loop. Loop antennas have a low radiation resistance and the purpose of the capacitor is to eliminate reactance so that the loop becomes a resonant radiator. Since it is a resonant antenna, no antenna tuner or transmatch is required.
Since magnetic loop antennas have a low radiation resistance, high currents flow through the primary loop. These current flows are what radiates the RF energy in the form of electromagnetic coupling. These current flows are a limiting factor of magnetic loop antennas as if you give them too much transmit power, the capacitor will arc and short circuit.
With that said, magnetic loop antennas are a great choice for QRP or lower power operating and we’ll talk about those benefits and features in a bit, but first, let’s look at the Chameleon F-Loop kit.
Tuning a magnetic loop antenna
Now we get to the fun part, tuning your F-Loop antenna. Magnetic loop antennas have a very high Q, or quality factor. What that means is that their 2:1 bandwidth is very sharp and pronounced. As you go lower in frequency, the bandwidth shrinks. This loop will have 210 KHz of bandwidth on the 10 meter band, but on 80 meters, that bandwidth drops to 6 KHz. This is due to the function and size of the radiating loop. To a certain degree, a larger loop will give you more bandwidth on the lower frequencies, but even at that there are limits. Basically if you want to change frequencies, you will have to readjust the antenna.
There are two methods of adjusting the loop. The first is to use an antenna analyzer. Connect the analyzer and turn the tuning knob until you see a dip on the meter. As you are tuning, you will notice that touching the unit will slightly detune it, so as you are tuning, you will need to step away from the unit to get a more accurate reading. The knob is very sensitive and the 6:1 reduction drive lets you do precise adjustments. When you get in the ballpark, it will take very slight movements of the knob to hit the sweet spot.
The second method to tune the loop is to listen to your transceiver. As your turn the knob, you will hear the noise level increase and then decrease. This point of maximum noise is the sweet spot of the antenna and the result of your tuned frequency. After adjusting for maximum noise, make a test transmission to check the SWR and make any minor adjustments until you are at the minimum. You may not always hit 1:1 match, but anything under 2:1 SWR is fine and the antenna will operate well.
With magnetic loop antennas, you should never use a tuner or transmatch. These antennas are designed to work without a tuner and should only be adjusted to their resonant frequency using the tuning knob.
Once the antenna is adjusted, go ahead and transmit. If you need to change frequency, you will need to readjust the antenna.
My experiences with magnetic loop antennas
So what are my experiences with the F-Loop magnetic loop antenna? Generally, I had a lot of fun with this antenna. It sets up and tears down quickly, it is reasonably efficient, and by virtue of its use of the H or magnetic fields, it is highly resistant to man made noise. That makes these antennas great choices if you are in an urban environment or a residential area that is prone to RF interference.
I took this antenna out for a few Parks on the air activations to test its performance. This antenna paired really well with my Yaesu FT-817 QRP transceiver, but I would think this is an excellent companion also to the Icom IC-805, Elecraft KX series or the Xiegu G90 or 6100 low power rigs.
Magnetic loop antennas are often characterized as QRP antennas and the F-Loop can handle up to 25 watts sideband and 10 watts CW or digital. If you use more power than that, the air capacitor inside the tuning unit will start to arc. And therein lies the misconception that magnetic loop antennas are poor performing antennas.
In reality, they are not. A magnetic loop will work just as well as other antennas. At their best, a magnetic loop on the upper bands is comparable in performance to a dipole. At their worst, they are 6 dB or 1 S unit lower than an optimized three element beam. Which brings me to my on air test.
Looking at the data, the magnetic loop performed quite favorably when compared to my customary ¼ wave vertical antenna. On FT8, the signal reports where pretty equivalent. Using my Yaesu FT-817 set to 5 watts, I ran both antennas on the 20 meter band for about 45 minutes each and in that time period received about 18 contacts on each antenna. With the magnetic loop I gave an average signal report of -9 and received a report of -11 dB. With the vertical, I gave a signal report of -13 and received a -12 dB. To me, that isn’t much of a difference. In fact, the only difference that I can spot is that in looking at the maps of contacts, the distances achieved with the vertical were further than the magnetic loop. But that could be attributed to the vertical antenna propensity for having a lower RF angle of radiation.
So what are the down sides of Chameleon F-Loop antenna. I don’t think there is really anything negative about this antenna on it own, this is a highly engineered and well constructed piece of equipment. But the negatives relate to magnetic loop antennas in general. First is its low power capability. I know a lot of people aren’t into QRP operation so the 25 watt limit on sideband may be a turnoff. Chameleon does offer an optional power compensator that allows you to use up to 60 watts sideband with the loop, but still these are categorized as low power antennas.
The second downside is the relatively narrow bandwidth. If you change frequencies, you will need to re tune the antenna. You certainly have more bandwidth on 10 and 15 meters, but 20 meters and lower, the bandwidth approaches paper thin ranges. That can be great for rejecting adjacent noise and signals, but if you are the hunt and pounce type of person, you will find the bandwidth highly limiting.
I think these two limitations of magnetic loops really lend themselves to digital and CW operation. The weak signal modes like FT8 and the narrow bandwidth of CW really make these antennas shine. And being that we are at the peak of the solar cycle, we can also take advantage of their enhanced performance on the higher HF bands.
Since magnetic loop antennas also exploit the H or magnetic field, they can be successfully used indoors with a minimal performance loss. H fields have better penetration through walls and glass, so If you live in an apartment, condo, or have HOA limits, this may be the type of antenna that gets you on the air at home. In a high RF noise environment, their enhanced signal to noise ratio will also be of a benefit, and you may be able to hear things that you miss with other antennas.
Links may be affiliate links. As an Amazon Associate, I earn from qualifying purchases. This does not affect the price you pay.
Timestamp 00:00:00 Introduction 00:00:30 Chameleon F-Loop 3.0 Magnetic Loop Antenna 00:01:02 How do magnetic loop antenna works 00:02:26 Chameleon F-Loop 3.0 Kit Options 00:04:38 Assembling the Magnetic Loop Antenna 00:07:04 Tuning your Magnetic Loop Antenna 00:08:59 Chameleon F-Loop 3 80 meter band 00:09:51 Personal Experience with the F-Loop 00:14:15 Magnetic Loops are NOT compromise antennas 00:16:35 Who are magnetic loop antennas good for
Team K0M is back and we are on the road for the Minnesota QSO Party! Will we beat last year’s score? Can we hit our stretch goal? Watch now in this rapid pace adventure.
Team K0M is Michael KB9VBR and Dave KZ9V. This is our third year as mobile operators in the Minnesota QSO party. If you made contact with K0M during the QSO party and would like a card, please QSL via KB9VBR. As they say, I’m good in the book.
As a bonus, patrons can view the unedited phone contacts for the QSO Party and extended conversations between Dave and I. Visit my page on Patreon for details: https://www.patreon.com/kb9vbrantennas
Links may be affiliate links. As an Amazon Associate, I earn from qualifying purchases. This does not affect the price you pay.