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.

CaHRTenna Poseidon Vertical Antenna: https://coffee-and-ham-radios.square.site/product/cahrtenna-poseidon-vertical-antenna

The Rybakov Antenna: https://ve3gam.webqth.com/am-work/rybakov/rybakov.html

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.

Graphical contact map provided by: https://www.qsomap.com/
Thank you for your support.

How I record my contact audio: https://youtu.be/tOqzZPphE7k
My headset trigger switch: https://youtu.be/b5Wu8BlrSF0
Heil Ham Radio BM-17 Dual headset: https://heilhamradio.com/product/bm-17-2/

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Links may be affiliate links. As an Amazon Associate, I earn from qualifying purchases. This does not affect the price you pay.

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The post Building the CaHRTenna Poseidon: A non-resonant vertical antenna powerhouse appeared first on KB9VBR Antennas.

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.

Coffee and Ham Radios Apollo End Fed Half Wave: https://coffee-and-ham-radios.square.site/product/cahrtenna-apollo-end-fed-half-wave-/8
Chameleon CHA F-Loop 3.0 Magnetic Loop: https://chameleonantenna.com/shop-here/ols/products/cha-f-loop-30
213 inch whip antenna: https://amzn.to/3O3Bvkm
Feather Flag Base: https://amzn.to/3O6O7al
Antenna mirror mount jaw clamp: https://amzn.to/48yzRPL
3/8×24 SO-239 stud mount: https://amzn.to/3Sjre69
Aluminum window screen: https://amzn.to/3Sii0Ho
Faraday cloth: https://amzn.to/3vCru7r
Yaesu FT-891 transceiver: https://amzn.to/3RSg4DO
Heil Ham Radio BM-17 Dual headset: https://heilhamradio.com/product/bm-17-2/

How I record my contact audio: https://youtu.be/tOqzZPphE7k
My headset trigger switch: https://youtu.be/b5Wu8BlrSF0

Bill Cross was a fascinating ‘character’ in pioneer history: https://www.wisconsinhistory.org/Records/Newspaper/BA1204

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Links may be affiliate links. As an Amazon Associate, I earn from qualifying purchases. This does not affect the price you pay.

The post Which is best? POTA Antenna Showdown in the Wild appeared first on KB9VBR Antennas.

N9SAB sent over a care package filed with lightweight, efficient, stealthy antennas for portable and fixed station ham radio use. Let's unbox them together!

January 13, 2024: To most people, Hatley Wisconsin is blip on Highway 29 in eastern Marathon County. Driving past at 65 mph, you probably notice the gas station, the Dollar General, and maybe the large Catholic church. This little village of about 500 people is more of bedroom community for the larger Wausau metro area. There was a veneer factory that is long gone and the rail line that established the village in the late 19th century was converted to a state trail about a 100 years later. And this connection is what brings me to Hatley for a Parks on the Air activation of the entity, K-9806 Mountain-Bay State Trail.

I’ve written two prior blog posts about the Mountain-Bay, so I won’t go into a lot of that detail, you can read more about the trail, here and here.

The Mountain-Bay runs the entire length of the community, but there is one particular spot that I prefer to operate from, The parking area of the Hatley public library. This parking lot is the local trailhead and it is also the crossing point of the Ice Age National Scenic Trail K-4238. Setting up here gives me a twofer: activating two Parks on the Air entities at one time. I also like this spot as it is a short, 20 minute drive from my home.

Weather

I normally don’t say a whole lot about the weather in my activations, but this time it’s significant. We had just come off of a major winter storm. The southern and eastern part of the state received up to a foot or more of snow, while the northern tier fared much better. In Wausau we got just under five inches. But the snow is only part of it. On the tail end of the storm were blustery winds and frigid temperatures. We’ve been lucky for most of the winter, experiencing above normal temperatures, but this storm ushered in a deep freeze with air temps below zero Fahrenheit and wind chills -20 and colder. Fortunately on Saturday, when I did the activation, the temperature was still around 19, but it wouldn’t stay like that for long.

After getting the driveway and sidewalk cleared, and the car scraped off, I drove east on some marginally clear county roads until I got to Hatley to activate the Mountain-Bay State Trail.

Setup

For this activation, I went back to my old standby antenna, the 1/4 wave vertical. Looking at the POTA spots page, I noticed that there was a fair amount of activity on the 15 meter band. The solar forecast also showed favorable conditions for the upper bands. I didn’t feel like dealing with the hoards of operators that comes with a 20 meter activation, so I set the antenna up for 15 meters.

With my vertical, I have three choices for the ground network: radial wires (I use 8 16 foot radials), a 36×84 inch aluminum window screen, or a 42×108 inch piece of Faraday cloth. It was cold and windy, and I felt the faraday cloth would be the fastest to deploy.

For the most part it was, except the wind was taking the cloth everywhere. I didn’t have any weights or branches to hold the cloth down, so I did the next best thing. I grabbed several chunks of frozen snow from the snow pile at the edge of the parking lot. This provided enough weight to keep the cloth in place even though the winds were gusting up to 20 mph.

In setting up the vertical, I extended the whip and sort of eyeballed its length. I’ve gotten pretty good at doing this as when I check the vertical on my analyzer, I was coming in at 1.44:1 on 15 meters. That’s good enough for me so I left it at that.

For the rest of the setup, I got out the Yaesu FT-891, 20ah LiFePO4 battery, headset, and logging computer running Hamrs. The radio was set to 50 watts transmit power. I like to set the radio on the front dash of the car and sit in the passenger seat. That gives me plenty of legroom and no steering wheel to contend with.

Activation

Turning on the radio and tuning to 15 meters, the first thing I noticed was the noise. Background noise was coming in at about an S5. Usually this area is pretty quiet with an S1-S2 noise floor, so the higher noise level was a bit unexpected. I’m guessing this was atmospheric as there isn’t any industry in Hatley, and being a Saturday, any noise generating businesses would be closed. Despite the noise, when I started calling CQ, the contacts started to roll in and and most everyone as at or above the noise level, so copying stations wasn’t that difficult. Once I got established on the band, contacts rolled in at a steady rate, not overwhelming, but steady. I seemed to have a pretty good path to the west coast, getting many California stations, along with the northwest and rocky mountain states. I logged 82 contacts on 15 meters in about an hour.

As 15 meters was slowing for me, I decided to jump to another band to finish out the activation. Still not wanted to go to 20 meters, I did the next best thing and set up on 17m. Extending the whip a bit, I was able to get a really good match, with an SWR of about about 1.1:1. Again that was mostly by eyeballing the whip length as I extended it. Noise on 17m was almost worse than on 15m. Not only was it still at an S5, but I also had a buzzing and clicking in the background that made copying weaker stations very difficult.

I had more pileups on 17 meters than I did on 15m as was evidenced by my run time, 70 contacts in 40 minutes. I also got some DX on 17m: Alaska, Dominican Republic, and Barbados. The band was open but noisy. The clock hit 2:30pm local time and I have over 150 in the log. I was also nearing the limits of my listening to the noise, so when there was a lull in the contacts, I did ‘last call’, got two stragglers, heard nothing else, and shut down.

Conclusion

This was my 5th activation of the Mountain-Bay State Trail, netting 152 contacts on 15 and 17 meters. So far at this park, I’ve made 742 contacts and worked 5 bands and I’m pretty much the leader at this park. So ignoring 20 meters wasn’t so bad (In one activation I did 20 meters exclusively and made 209 contacts). I’ll come out here again, most likely on a Friday afternoon and do a big 20 meter activation to give the park more exposure.

The snow chunks kept my faraday cloth in place, it didn’t blow away that afternoon. A couple of the sections on my whip had frozen, I’m guessing there may have been a touch of moisture inside the whip from a previous activation. But they broke free, it wasn’t enough to totally freeze them in place.

And finally, staying warm. In weather like this I can usually operate for about an hour in the vehicle before I have to stop, start the engine and warm up. I keep the engine off during activations to help reduce noise. My fingers are the first to feel the cold, but I was parked facing south and got just enough afternoon sun to help keep things warm inside the car. I didn’t have to pause to warm things up again. I’ve got a few strategies for staying warm during cold weather POTA activities and that will be the topic of a video in a week or so.

K-9806 Mountain Bay State Trail 15m contacts with 1/4 wave vertical antenna

K-9806 Mountain Bay State Trail 17m contacts with 1/4 wave vertical antenna

Map visualization of contacts courtesy of qsomap.com

If you go

Mountain Bay State Trail passes through the communities of Wausau, Weston, Hatley, Norrie, Eland, Bowler, Shawano, Bonduel, Pulaski, Anston, Howard, Green Bay. A State Trail Pass needed for bicycle and horseback riding

Hatley, WI Trailhead
Marathon County Public Library, Hatley Branch
435 Curtis Ave
Hatley, WI 54440
Open weekdays and Saturday, hours vary

The post Activation Log: Sometimes you just have to Improvise appeared first on KB9VBR Antennas.

Gabil’s GRA-7350TC is a compact vertical antenna that is designed for portable operations. The antenna itself is relatively lightweight and consists of three componants: a 102 inch telescoping whip, an adjustable section with internal loading coil, and an additional coil for the 80 meter band. You can also add an option compact portable tripod to complete the set. I previously used the Gabil system last fall and was not terribly impressed by it’s performance. Either the antenna was being lackluster or the bands weren’t in my favor.

I decided to give the antenna another shot. I like how the GRC-7350tc is compact and my hope is that it will be a foundational element of my growing QRP kit. As I’ve been used to running the full 1/4 wave whip on 20 meters and above, I think my expectations have been set pretty high in how the Gabil is to perform. But I gave it another shot.

November 24, 2023, the day after Thanksgiving, is known as black Friday to the rest of the world, but being self employed, the boss (me) gave me the afternoon off. I used the time to give the Gabil another test and to activate one of our newer POTA entities: K-9806 Mountain-Bay State Trail.

Mountain Bay State Trail

The Mountain-Bay State Trail runs for 83 miles from the western terminus at Weston, Wisconsin eastward to Green Bay. As it’s name implies, it is to connect Rib Mountain in the center of the state to the Green Bay near Lake Michigan. This corridor is an old Chicago and Northwestern rail line, which makes for a easy and beautiful ride. I like to set up at a trailhead in Hatley, Wisconsin in the Marathon County Public Library’s Hatley branch parking lot. At this point the Mountain-Bay intersects with the Ice Age National Scenic Trail (POTA K-4238) for a twofer.

This is the third time I activated the trail, you can read about my initial activation of the park here.

Setup

It is getting chilly so I’ve switched to operating out of the vehicle. My preferred setup is to put the Yaesu FT-881 on the dashboard of the vehicle and sit in the passenger seat so I’m not encumbered by the steering wheel of the car. For an antenna I’ll be running the Gabil GRC-7350TC vertical. The library is closed today so I have a practically empty parking lot to work with. The antenna was set up about 15 feet away from the car on the edge of the parking lot. Instead of using the window screen ground, I used 8 16 foot ground radial wires. The manufacturer recommend 4 10 meter wires, but I’ve had better luck with more, shorter radials, so I put my proven radial bundles to work. First up, the 15 meter band.

Tuning the Gabil is a bit finicky. Moving the coil slider up and down, you can easily miss your mark, so it takes very small movements once you are in the ballpark to find the perfect spot. On the 15 meter band I was able to get the SWR down to about 1.44:1, which was good enough for me. I’m not one to fiddle until it’s perfect, so if it is in the neighborhood of good, I’m fine with that.

Activation

The solar forecast for that day called for active conditions, I believe there was a solar storm predicted for later in the weekend but Friday had good numbers with the SFI over 170 and the A of 8 and the K of 2. As I started out on 15 meters, the conditions were slow with a lot of fading, but things kind of settled out and I consistently received good signal reports. I had a good, long run on 15 meters, about 110 contacts. No DX but plenty of Canadien stations. Since the band was hot, I decided to move up to 10 meters.

With conditions like this, we need to spend more time seeking out contacts on 10 meters. I had a bit of concern with tuning the antenna as an 102 inch whip is close to a 1/4 wave on 10 meters, so I anticipated that I wouldn’t need to use much coil. And sure enough, I was hardly at the -1- setting on the laser engraved scale. I got the SWR to about 1.5:1. Nothing special, but good enough. Calling on 10 meters, I racked up 15 contacts in about a half hour. Not like the run on 15 meters, but still respectable.

Since I was doing well, I decided to give 12 meters a try. Futzing with the coil, I got a match and we soon rolling. I picked up 8 contacts in about 8 minutes, including two stations: VE1BQC and KR5EEE that I worked earlier in the day on 15 meters. I also got an interloper that waltzed through my frequency and let me know ‘contesting’ isn’t allowed on the WARC bands. Fortunately POTA isn’t a contest so I didn’t give him the time of day.

To finish things up, I dropped down to 40 meters. I had activated the Mountain-Bay trail two week prior and had a long 200 contact run on 20 meters, so I felt like this time I could skip that band and concentrate on some of the others. Getting a match on 40 meters was a little more difficult. It could be partly because the coil has a higher Q on that band, or maybe my shorter radials are to blame, but I could only get it to about 2:1. That’s a bit on the edge for my tastes, but 2:1 match is only an 11% power loss and as long as the radio doesn’t complain too much, I’ll go with it.

Let’s just say that the losses weren’t much of an issue as I had no problem, at 3:00 in the afternoon local time (21:00z) in attracting a crowd. I ran for 15 minutes and got 25 stations with mostly good signal reports. I was at about 7207 KHz, so by this time the international broadcasters were starting to filter in. Which was fine as the sun was getting low in the sky. So I packed it up.

Conclusion

All in all, I netted 157 contacts on the Mountain-Bay State Trail that afternoon. Not too bad of a haul on an antenna that I initially panned in my review. Using the Gabil GRC-7350TC again, I have have thoughts on its performance. First off, the antenna works better on the upper bands than the lower ones. I hit the time of day right with my 40 meter activation, later in the afternoon as the sun was starting to set. The broadcasters hadn’t totally overrun the band and being a holiday weekend, there were people looking for me. 15 meters and above, I can really see this antenna excelling.

Second, a good ground network reallly is key for this antenna. You are at a compromise with the lack of radiator, so a substantial radial pattern will really make a difference. A greater number of shorter radials will actually increase your gain on the upper bands than fewer, longer, radials will. This article by Rudy Severns, N6LF, explains why that is the case. I’m going to have to experiment using the window screen with this antenna. The Gabil tripod is non-conductive so jumper wires are necessary to get good continuity with ground mesh. But I will give it a shot and report my results.

I’m not ready to dismiss the Gabil antenna, but won’t quite throw my full-throated support to it. I think it fills a portable operation niche and will take it places where my 1/4 vertical and large metal tripod are too cumbersome to travel.

K-9806 Mountain Bay State Trail 15m contacts with GRC-7350tc antenna

K-9806 Mountain Bay State Trail 10m contacts with GRC-7350tc antenna

K-9806 Mountain Bay State Trail 40m contacts with GRC-7350tc antenna

Map visualization of contacts courtesy of qsomap.com

If you go

Mountain Bay State Trail passes through the communities of Wausau, Weston, Hatley, Norrie, Eland, Bowler, Shawano, Bonduel, Pulaski, Anston, Howard, Green Bay. A State Trail Pass needed for bicycle and horseback riding

Hatley, WI Trailhead
Marathon County Public Library, Hatley Branch
435 Curtis Ave
Hatley, WI 54440
Open weekdays and Saturday, hours vary

The post Activation Log: The Gabil antenna, maybe it’s not so bad appeared first on KB9VBR Antennas.

Looking for a portable and easy-to-use HF antenna? The Chelegance MC-750 Portable HF Vertical Antenna is designed to provide a hassle-free setup process and an efficient, high-performance antenna for portable ham radio operations.

Introduction:

If you are looking for a portable and easy-to-use HF vertical antenna, then the Chelegance MC-750 Portable HF Vertical Antenna system is worth considering. These antennas are designed to provide quick and effortless setup without requiring tools, making it ideal for field operations and emergency services.

Features:

The MC-750 Portable HF Vertical Antenna is built to provide an efficient quarter-wave vertical ground plane antenna for 40 through 6 meters. It can handle up to 100 watts and features a female SO-239 connector and jacks for up to 4 preassembled, 11.48 ft. counterpoise radials. Additionally, the antenna comes with a 7 MHz loading coil, 1.64 ft. extension, 17 ft. telescopic whip, and a cable winder, all packed in a carrying bag for easy portability.

Takeaways:

The Chelegance MC-750 Portable HF Vertical Antenna provides a hassle-free setup process. The antenna offers good efficiency for a compromised portable ground based antenna. The telescoping whip and preassembled radials make it easy to get on the air quickly, while the included carrying bag makes it easy to pack and transport.

How To:

Setting up the MC-750 is simple and straightforward. First, unpack the kit and extend the telescoping whip to its full length. Next, attach the 7 MHz loading coil to the base of the antenna and connect the antenna to your radio using a coaxial cable with a PL-259 connector. Finally, lay out the preassembled radials on the ground in a star pattern, ensuring that they are evenly spaced, and connect them to the antenna base.

FAQ:

Q: How does the Chelegance MC-750 Portable HF Vertical Antennas perform on different bands?
A: The MC-750 is designed to operate on the 40 (with loading coil) through 6 meter bands.

Q: What is the maximum power handling capacity of the MC-750?
A: The MC-750 can handle up to 100 watts of power.

Documentation @ DX Engineering:

https://www.dxengineering.com/parts/nce-ch0010009

Conclusion:

The Chelegance JNCRadio MC-750 portable HF antenna, is a good choice for portable or emergency use. It is easy to set up and comes in a compact well designed case for easy transport. The reference marks etched into the antenna sections make it easy to get the SWR in the ballpark,

Note that the antenna base/spike does not use the standard 3/8×24 mount. The base uses a metric M-10-1.5 thread so other antenna systems like the MFJ-1979 would require some type of adapter.

In terms of performance, the Chelegance MC-750 is a reliable ground-based vertical antenna that provides decent RX and TX capabilities for the 20 meter band and up. The 40 meter loading coil is a compromise at best but will get you on 40 meters. The Chelegance MC-750 is a good option for situations where no trees are available or quick activations are in mind.