Tag Archives: antenna

Lightweight Antenna Roundup – Episode 1 -The PAR TF 402010

My first HF transceiver was a Ten Tec Triton IV with analog dial, followed by a TT Argo, A Yaesu FT101, and then one of the original, “shack in a box” radios, the ICOM IC706 (and later a MKIIG). For reasons mentioned in the previous post on this blog I moved on to running a Yaesu FT-857D, a FT-817ND, and an original FT-817. That gear, along with an assortment of V/U/SHF equipment for VHF contesting, and various FM HTs, was the basis of my experience with transceivers. I got to know what I liked and what I didn’t. The Triton IV was the most fun CW rig I have ever used. The receiver was easy on the ears, the QSK was fantastic (like listening to yourself on receive), and it was fairly portable. The IC706 rigs were more versatile, covered more bands, had more power, and included at 20/70cm all mode. And it wasn’t a bad all-mode. After seeing my gear pile dwindle to almost nothing I started putting together a new station. I was looking for something fun and portable and found myself looking at the uBitx. I worked up one kit but just felt like it was not going to handle what I wanted to do. Then Xiegu released their G90 and that radio got me back on the air for over a year. It’s a great rig, but it came with the question of what antenna to pair it with?

Having used wire dipoles and a few commercial multiband verticals for fixed operation, and hamsticks, base loaded whips and other compact designs for mobile use, I had something to refer back to. My experiences with those mobile antennas was not great. Yes they work. But no, they are no comparison to a full size antenna. I used those in both fixed and mobile setups and I was happy for any contact I could make. To be honest hey were not good performers on either transmit or receive. Once band conditions improve you will be able to regularly work some sweet DX at 20W into a 20M hamstick on a mag mount. Now is not that time. If you can’t put up a perfect antenna, at least try for the least-bad antenna you can manage.

It turns out that while I was off not paying attention to ham radio equipment there has been an explosion in “compromise” designs like end fed wire antennas and they can be built/purchased to suit anything from an altoids-tin rig to a legal limit linear. The development of these antennas revolves around two fundamental designs: A half-wave radiator with a 49:1 un-un at the feedpoint; or a 9:1 balun feeding a non-resonant wire. In practice the use of a counterpoise is either unnecessary or misunderstood. From an optimal antenna standpoint these designs leave much to be desired. The matching unit is being asked to make a large impedance transformation into a rather blunt radiator, without the typical array of ground radials or even a counterpoise of any kind. However, from a real-world standpoint these designs are proving to be both effective and easily erected while also being cheap to build. That is rare.

After perusing many different designs I purchased the PAR 402010 Trail Friendly. It is advertised as covering three popular bands with no ATU, and it is light enough to be supported by just about any support. This is a design antenna with a history of being made by several builders and Vibroplex now markets them with the PAR branding. It features a 41′ lightweight insulated/stranded wire radiator with a 40M trap to make it resonate on both 40m and 20m, and it will also load on parts of the 10m band. The lightweight build still feels sturdy, and has proven durable over a year of regular use. The tip of the radiator can get mashed up a bit, especially if you have a mast collapse. Note my use of a heavy wrap of electrical tape at the tip of the mast. It helps with setup and fits in the collapsed tube.

About that mast… (12M Spiderpole Mini-Review Alert) At the same time I was searching for antennas I found another member of the Vibroplex line, Spiderbeam, and their 12-Meter Spiderpole. Often nicknamed “the beast” It’s built like a tank and can hold up much more than this little low-power wire vertical. Interestingly they do fit like they were made for each other. “The Beast” isn’t a backpacker pole unless you are a glutton for punishment or take your Cross-Fit habits onto the trails. It isn’t terribly compact, and it isn’t light. What it is is a borderline overbuilt 41 foot weatherproof antenna support.

The Spiderpole is overkill, a luxury, though a versatile luxury at that. It is a big, heavy telescoping mast and needs to be well secured at the base. It has more wind load than I guessed and exerts a lot of leverage on that base section, so you want it to be well secured while avoiding hard points where the fiberglass tube wall could fail under a sudden or heavy wind load. The upside is you get a 41′ vertical skyhook. Nice. It also shrinks the footprint compared to what you need for a sloper or inverted vee and allows you to work where there is no overhead support. I am surrounded by beaches, so something like this lets me operate from more locations and not be limited by the presence/absence of a large tree(s) and I create less of an attractive hazard for lookie-loos. It appears to be a law of physics that as soon as you put up an antenna some random mammal will walk directly into it within 5 minutes. All you can do is pad the odds in your favor.

Very Vertical

I was curious how this antenna would perform, especially compared to a 9:1 unit I had built and used on this same Spiderpole support. Mine is the basic trifilar design over a T200 core. The 9:1 works, but I always feel like I am working “up-hill” with it. That perception is based on ability to work stations I hear, and the signal reports I receive. There are worse options than a 9:1 into a chunk of wire sized to a convenient non-resonant length, but it feels very lossy in operation. When I first rigged the PAR I had my doubts. Rated at 25W SSB it isn’t much to look at. The matching unit is smaller than a fun-sized candy bar, the wire looks like overbuilt dental floss. Once I attached it to the Spiderpole and got it fully extended the ultralight wire It seemed out of balance being supported by “the beast”. Happily I was more than surprised at how well it performed. I observed much more parity with the stations I was hearing and working and logged several nice stretches of contacts on both FT8 and SSB. I was using it with both a Xiegu G90 and a Yaesu FT-991A, and aside from needing to watch the power output it did what it says on the tin. Three bands, no waiting. I don’t hesitate to set this up for a quick evening of casual operation since setup and take down require about 10 minutes each.

Here it is lashed to a deck railing in my back yard (or “garden”. You know who you are). If I was expecting gusty conditions I would have a 4-way support at the top rail and the base. In calm conditions the bongo ties hold up just fine. Just use as many as you dare. This thing puts a lot of stress on the support system.

When erected the matching unit sits about 3″ off the deck.

Technical Aside: These end-fed matching devices are indeed lossy. You don’t need to break out a calculator to know this. All you have to do is look at the designs for different power ratings. The size and number of the ferrite toroids (typically 43-Mix) need to be increased to withstand the increased field density of each higher power rating, and the heat that comes with it. A good portion, perhaps as much as 30%, of the power making it to the matching device gets siphoned off as resistive/heat losses. [tl/dr YOU ARE MAKING HEAT NOT ERP] But hey, you know the setup is a compromise going in. That compromise is lower overall efficiency in exchange for ease of setup and portability. I found that going from 5W to 10W output caused a sizeable step change in the contacts I was able to make, but that is to be expected, since my ERP was probably going from 3W to 7W. Certainly you can make a lot of contacts with this antenna, but you will probably be be several dB down from where you *might* be on a more efficient antenna system. The upside is that you can get on the air quickly with not much fuss, which translates to more time operating and less time reading long winded blog posts. But I digress.

A Phalanx of Bongo Ties and Clamps

One big question with “the beast” is how to support it, and one of those lightweight drive-on flagpole mounts is not likely to get it done. I currently use a phalanx of bongo ties, woodworker clamps, ratchet straps, and U-Bolts. None of them are perfect but I can lash it to a variety of improvised bases. I’m thinking a 36″ tubular support welded to a 2″ trailer hitch is about what it would take to have real peace of mind with this thing while operating car-portable.

Wrap Up: My feeling about this antenna has done nothing but improved each time I deploy it. I feel like this particular design gets overlooked. That’s a shame because it is a solid performer. It hears very well, is easy to tune, and I am always surprised at how well it works. We can hope all we want to have a low loss resonant radiator over a dense field of copper radials, or a big dipole/doublet/windom/curtain a half wave up on solid supports, but it seems that what many/most hams typically need is a way to get on the air under sub-optimal conditions. We also want to be able to actually operate once we get set up. What I would love to see is a 200W CW Rated version with the same 41′ design. Right now I guess I have to build one. Vibroplex has a potential two-fer on their hands if they can match a 41′ triband wire vertical to their affordable heavy-duty 12m Spiderpole. That opens it up to running CW or digital/RTTY at a full 100W and having a solid safety margin at the feedpoint.

I hope this was informative, or at least I hope you had a good nap. 73, N1QDQ

Always Loud Somewhere

I’ve been a licensed amateur radio operator (ham) for almost 30 year and have had both runs of heavy involvement and runs of “doing other things”. I’ll delve more into these details, but hams in the USA are licensed by the FCC and have access to some very nice chunks of the electromagnetic spectrum. The equipment is readily available and well supported. To me it is the original “tech nerd” hobby. It goes back to the dawn of radio, and the dawn of the vacuum tube. At that time if you wanted to be a ham, you built the gear. Now… there is a lot of great commercial equipment and for most ops homebuilding is secondary.

Every operator has a central thesis, a set of goals, or a set of constraints that inform their pursuits. For some it is “MORE POWER GOOD”, for some it is “mnmlsm”. One of mine is that two-way radio works, but not everywhere all the time. I call it “You Are Always Loud Somewhere”. I can set up a radio and antenna, pick a mode of operation, and call out to the radio wilderness in search of other operators. In ham parlance, I am calling CQ. Seek You. Get it? Hams are a cryptic bunch.

The 2-way element of radio involves a second station listening on the same frequency I am transmitting on, and being able to reply and be understood. It actually works better than one might think. There are 750,000 licensed hams in the USA alone. It isn’t great by TV ratings measures, but it’s respectable. Also, hams might have outsized influence due to their proclivity for… communication. Of all kinds. For better or worse.

Another thing that hams rely on is a phenomenon whereby the effect of solar radiation on the ionosphere effectively turns it into a “radio mirror” reflecting radio energy back toward earth. Some of the energy from my radio signal is directed up toward the ionosphere, gets reflected back down, and I am now audible 800 miles (for example) away. That can happen multiple times, allowing my signal to travel halfway around the world, or more. Once our signal leaves our continent (roughly) we call that DX (distance). While useful, that kind of “enhanced propagation” is a fickle mistress. Some days it is like transmitting into a lead sponge. Other days you are chatting to an operator in South Africa on less wattage than it takes to power a clock radio.

So that is the backdrop for “always loud somewhere”. You might not be loud where you want to be loud, but somewhere your signal is crushing it. There might be another op there. We can only hope.

Hams have some tools to increase the odds. One obvious tool is to create a stronger signal by emitting more power. Think of the difference between your local AM pea shooter and something like WTIC or WFAN (for those of you who still own an AM radio). One of them is always strong over a large coverage area. The other is community scale. It requires less power, but still communicates well. Also, there are many ways to tailor the radiation pattern from an antenna for a specific goal. Do we want to work distant stations, or communicate locally? Do we want to create a very high uptime communications link, or are we looking for a bit of sport?

I’ll wrap this post with an example (we now go full ham lingo mode. strap in):

I have been experimenting with both homebuilt and commercial portable/lightweight antennas for the past two years. I haven’t had a fixed setup at home, so even if I am operating from home, I am still “portable”. One antenna I recently acquired is a Chameleon MPAS Lite. It’s a “military grade” portable antenna system, and is designed to be easy to set up and still perform well. This is not the norm. In the “engineering triangle” the lighter and easier to set up an antenna is, the more compromised it is and the worse it performs. Also, some of my favorite wire vertical antennas, like the PAR Trail Friendly, require an overhead support or a portable mast. That raises the complexity, weight, and logistics hurdle. The MPAS Lite is self-supporting, low visual profile, and can be configured for local coverage or to give you at least a fighting chance at long distance stations. I had heard good things, so I gave it a shot.

Here is a map of contacts I made on March 23, 2021 using an Icom IC-705 transceiver at 10W into the MPAS Lite. This was done during an afternoon here in southern New England, and conditions were very poor. I tuned across the entire 40M band and it was dire. Like “is my radio broken?” dire, and triple checking antenna connections dire. Then I moved up to 20M and it wasn’t great, but I could at least hear a few strong stations. There was a bit of solar storm effect happening, marked by deep and rapid fading (QSB). I was seeing stations drop 7 S-units in under a minute, and then rise back up. On FT8 I expected to be riding the waves. However, as it was my first real wring-out for a new antenna I decided to at least tune it up (MFJ 901-B, the “cockroach” of ham gear*) on a few bands to see how easy that would be (it was easy).

I was working my way higher in frequency and ended up on 10 Meters. This band has been my nemesis for the past 12 months. I always check it, and never hear anything. Even on FT8, the propagation beacon that has become a global phenomenon, I was 0-fer. That’s hard to do, because it seems that at any time of day, somewhere in the world every FT8 calling freq is choked with activity.

This day was different. I ran into a trans-equatorial opening to South America. Who knew if I could make any contacts, but I could at least hear them. Also, it had less rapid fading than the lower bands. It was fading in a 3-5 minute cycle and not fading as deeply as 40 and 20. In meteorological terms it was like a “radio inversion” instead of lower bands being in better shape, and conditions falling off as you go higher, the real action was at 28MHz. Since we are right at the vernal equinox this could have been a seasonal thing or tropospeheric ducting. Regardless of the propagation mode I will deinitely make a 10M check more often.

Here’s what I was able to do on a low power (10W) radio and an antenna that I have no expectations of for DX work:

The green icons are 10M contacts. Orange 20m, Red 17m, Blue 30m. That stray green icon in Europe… That’s a fail on the mapping app. It is actually J79WTA in Domenica, showing up under his Swiss call HB9MFM. This is also an Islands On The Air (IOTA) station, NA-101.

I have some thoughts on the different portable antenna options I have been using and am working up a kind of “shootout” over weight, ease of setup, performance, and durability. I hope to be posting the first of them soon. Until then, go be loud somewhere.

Pete, N1QDQ

*cockroach = will be the last thing still working before the sun swallows the earth