Tag Archives: antenna

Lightweight Antenna Roundup 2 – Chameleon MPAS Lite v Wolf River Coils SB1000 TIA

When I was running mobile HF in the 1990’s and early 2000’s I accumulated a bunch of 3/8-24 mount antennas. There were hamsticks, Hustler coil-loaded whips, an Outbacker Perth, plain whips… Outbacker sold a metal tripod that was marketed as a ground plane and antenna mount in one. I didn’t spring for that. I just bolted a 3/8″ coupler to a cut-down surveyor’s tripod, made a quick and dirty radial plate, and gave it a go. It worked. It wasn’t great but it gave me a different way to deploy those mobile-mount setups. At that time these “stationary mobile” solutions were a novelty setup among the hams and publications I interacted with. A simple dipole was always going to crush that mobile antenna, and did.

FFW to the vaguely 2020-ish period and somehow ultra-portable field antennas, mainly for QRP use, are flying off the shelves. In the depths of a solar minimum, no less. The effectiveness of these systems is a tribute to the radio arts in general. Getting a signal onto the air is still job #1. The vagaries of propagation and the system on the other end of the QSO take care of the rest.

Three of the most popular categories today are end-fed wires, linked dipole/monopole, and coil-loaded verticals. Some designs hybridize these approaches. I’m leaving the brilliant DX Commander line out of this because I think they are portable with an * in that it isn’t a trivial thing to set up. I own one and will be giving it the treatment it deserves soon.

I currently maintain a small armada of portable antennas and they all have their strengths and weaknesses. Today I’m going to examine two designs that have some similarities, some differences, and I feel they fill a similar niche:

Chameleon MPAS Lite

The Chameleon MPAS Lite is an end-fed design based on a CHA Hybrid-Micro (roughly 5:1 un-un), a very nice 17′ stainless steel telescoping whip, and a burly stainless steel ground spike to mount them on. It also comes with 50′ of medium duty feedline RG-58-looking coax with a ferrite-bead common mode choke installed, and 60′ of tacti-cool PTFE insulated he-man wire on a heavy duty winder. A supplied stainless steel D-ring on a 3/8 stud allows the CHA Micro to feed a wire (The supplied wire or your own) for NVIS and other “mo’ radiator mo’ betta” setups. Not coincidentally it has the look and feel of the Jeep of portable antennas. I would not want to be on the receiving end of that ground spike wielded in anger.

WRC SB1000 TIA

The Wolf River Coils SB1000 TIA, Mega Pod is a self-supporting HF vertical antenna system. The SB1000 is a sliding-contact adjustable coil. This design is immediately familiar to any mobile HF op. In fact many users deploy the Silver Bullet series coils in HF mobile setups and their reviews indicate satisfied customers. Think of a screwdriver coil without the screwdriver. It feeds a stainless 102″ (8.5 foot) whip, and the coil is designed to load that whip from 80-12m. The kit comes with three 35′ wire radials, and the Mega-Pod. The pod is a machined aluminum hub with three 3/8″ tapped holes at 120 degree intervals, and a standard SO-239 to 3/8″ stud mount adapter mounted through the center. Three aluminum rods with threaded ends form the legs, which also act as radial attachment points thanks to the provided lock nuts. It’s a good, reliable design and the use of aluminum in the Mega-Pod helps keep the overall weight down.

Portability and Ease of Operation

Both antenna systems are light, portable, set up and break down easily. The Chameleon has a smaller footprint due to only using one (or zero) radials. The WRC needs a larger area to spread out the radials, which are key to both tuning and performance. The CHA Spike is quicker to set up and less fiddly than the Mega-Pod. The Mega-Pod can be a little springy and while not unstable is not rock solid stable. I don’t think it needs to be overbuilt. The threaded rods and lock nuts let you set the nut at a point before the rod bottoms out, and then tighten the rod against the radial lug. Don’t hesitate to put all three radials on one leg. It will work the same and it’s easier to set up that way. If you really needed it to be easier you could make lugs with extensions terminated in your choice of quick connector and then terminate your radials to match. I think that is overkill. The spirit of the WRC TIA is to have a working setup without a lot of fuss. The TIA Mega-Pod is more of a casual, less “tacti-cool” piece of gear, but it still effective.

With either setup you can be on the air in about 5-10 minutes. The CHA will set up faster, but neither is a chore. It hasn’t escaped my imagination that the CHA Spike is a really nice way to mount the WRC. In fact you could also imagine running the 17′ CHA Whip on the SB1000 and having a 80/40 setup with a better radiator.

Tuning/Matching

The user can get the WRC tuning very close by listening for peak noise on the band of interest. Once the user gets close it can be a bit of a chess match to get it zeroed in. The TIA is easiest to tune if you have an antenna analyzer or other SWR sweep device. I first used this antenna with a Xiegu G90 and the internal SWR sweep/analyzer was a big help. My old MFJ-259 makes it easier still. The key is being able to sweep around the band to determine if your current tuning is low or high. Once you are close it only takes small tweaks to move the resonant point. Without much fuss I was able to tune it on 80m through 12m. You can get it on 10m by shortening the whip, or just using the whip alone.

The tuning reference points in the WRC instructions will get you in the ballpark, but all kinds of external factors can change the amount of loading you will need. Tuning the stock setup with the three radials over average ground is what the instructions are based on. YMMV. As discussed in a previous blog post I consider a base-loaded whip to be in the “tuned circuit” family. The whip isn’t resonant, but the coil is making a resonant circuit for the frequency of interest. The apparent Q of the design is “moderate”. Not razor sharp, not super broad, but it can be touchy once you get the coil contact close to your tuning point. You probably won’t need a common-mode choke, but I always bring one because… RFI Happens.

The MPAS Lite is a whole different concept. It is not designed to show a low SWR on any band. The design assumes you have a matching device between your rig and the Hybrid-Micro. You might get lucky and see a sub-2:1 one one band and it might be fine. I typically see SWR values between 1.5:1 and 5:1 without a tuner. My 991A has a built in tuner and matches it with no complaints. I use a LDG Z817 with my IC705 and that matches it easily as well. With a manual tuner you are back to peaking band noise then fine tuning. My MFJ 901 will tune a watermelon, so it’s no news that it was great with the MPAS.

Radial/Counterpoise

The three 35′ radials supplied with the TIA are both the bare minimum, and also seem to be enough. I tried adding three bundles of three 20′ radials in addition to the supplied ones and it didn’t seem to help much. If I was trying to improve on the system I would try three 20m radials marked off at the 1/4 wave points for each band of interest. Just unroll the radials to the band marker. Of course this means you need over 60′ in each direction on 80m. Tuned radials have the potential to improve the performance of this system. It could be an interesting project. It also might not matter too much.

As for using a counterpoise or radials on the MPAS… one, zero, five, nine? In my experience the performance of these systems is unpredictable in the literal sense. If it gets you on the air it is working as advertised. Counterpoises in an untuned system are a funny business. When the radiator is not a resonant length I think you can do more harm than good trying to run tuned radials. I typically attach the CHA Radial and lay out about 25-35 feet of it in a convenient direction. If you are having tuning issues just change the counterpoise length/config or remove it entirely. Like a 9:1 end-fed the function of the counterpoise is debatable. It also might not have the same function in every deployment.

In a related topic, the MPAS isn’t limited to using the 17′ whip. You can attach whatever radiator you want and it will probably work. I believe the best to approach to sizing a wire radiator is to keep the suggested lengths for 9:1 un-un operation in mind. The transformer ratio might be different, but you still don’t want resonant lengths if band flexibility is on the menu.

Power Handling

Both matching units have loss issues that result in heat buildup. The WRC SB1000 is rated at 100W SSB, 50W CW, and 20W Digital. Similarly the CHA Hybrid-Micro is rated at 100W SSB and 50W continuous. I think a conservative approach to power output is wise here. You can smoke either device if you get too aggressive with the power. On the TIA the coil is trying to load a 102″ CB whip on 80m or 40m. This is a lot to ask and there are plenty of examples available on forums like eHam attesting to either deformation of the coil former, or outright failure when pushing the power ratings. On the Hybrid-Micro I would just assume the match at the feedpoint is bad, and that will make a lossy system worse, and that makes more heat. Heat Bad. I won’t run more than 35w in digital mode on either, and no more than 50w in SSB/CW.

Performance

I will be running a side-by-side test of the two systems soon. For now I will just give my impressions of them based on using them in the field using the same radios under similar conditions. I’ll get the bad news out of the way first: Neither is a fantastic antenna system when compared to almost anything else. Short radiators and lossy base loading are not a recipe for great antenna performance. However these antennas are not marketed as high-performance DX machines. Their calling card is portability and ease of deployment. In that respect they are both very good systems. Perceptions of on-the-air performance will have a lot to do with expectations, operating style, location, and whether making a specific contact at a specific time is essential. I have used both on POTA and POTA-style outings and they both hear much better than they get out. That’s normal. I felt like I was taking advantage of my “always loud somewhere” approach on every contact. I would be unable to work a solid 4-lander from RI (normally a given) but I might be getting 59+ reports from Kansas or Idaho. You will make contacts on either. You will make a mix of stateside and DX contacts. And no, these are not just pricey dummy loads.

The TIA got my initial performance nod based on my preference for tuned circuits over broadband transformers. But the TIA uses a whip that is half the length of the MPAS, giving up some if not all of that advantage. Also, if you run those TIA radials out to full length (recommended) you will need something like a 60-square-foot area to lay it all out in. The design is a little quirky and the user needs to be more involved with those quirks. It’s built out of hardware store parts and stainless wire. That isn’t a knock. Any ham will look at it and know that WRC puts a lot of care into their product and they are getting good value.

If you are intending to do a lot of band-hopping you will be much happier with the MPAS. Hitting “TUNE” and being ready on a new band is certainly seductive. It comes at the cost of additional system losses, but if you are making the contacts you want to make it doesn’t matter too much.

Straight Talk!

Aside from being a snap to set up in the field these antennas are providing regular HF capability to hams who may have given up on running a “real” HF antenna on their property. That’s great and the easy setup, small footprint, and low visibility are big selling factors. A concern I have expressed here and in other places is that there seems to be some confirmation bias among hams who haven’t worked with better antennas. I’ve seen excited reports of working monster Slovenian contest stations with one of these antennas and 10W, and I hate to tell you that is not a measure of *your* antenna’s performance. I’d also point out the fine work of Thomas Witherspoon, K4SWL, on his YouTube channel. He has many great real-time videos of an array of QRP rigs with different portable antenna solutions including the MPAS line. Note that he is almost exclusively calling CQ, hence pre-selecting stations that can hear him. If he was chasing stations with the MPAS he would need to take a very different approach. I don’t mention this as a negative on these antennas or the users. I mention it as a point that might be of help interpreting on-line reviews including this one.

Bugs and Observations

None of these issues are “deal-breaker” serious, but each antenna has some quirks and design issues:

I found that I needed to keep wrenches in my kit for the WRC because the 3/8″ hardware gets stuck together. It was a little annoying and I think a couple of inexpensive adjustable wrenches are a good accessory to keep with the WRC kit. Disassembly might also result in the SO-239 to 3/8 adapter coming loose on the Mega-Pod hub. I have a spare Hustler quick release that I am thinking of using to knock these issues down.

As I mentioned, the WRC Mega-Pod can be a little springy. Some care is required when deploying it, especially making sure you have slack in case of a trip or snag. The WRC whip isn’t going to take too many flops before it needs serious attention.

The MPAS Lite has fewer parts and doesn’t have much to go wrong. Still, I feel like the knob used to secure the counterpoise feels tacked on. It’s has red plastic knob and a small threaded rod which will only grab the eyelet on the CHA Radial by a corner. It doesn’t seem like it will make solid, reliable, electrical contact. It stands out mostly because everything else is so burly. Note: Unlike the SB1000 coil, the CHA Hybrid-Micro is not rated for mobile use.

WRAP

As you can tell I want to review these systems for what they are. They both work as designed to allow quick setup in tight spaces and allow operation across the HF bands. They both use standard 3/8-24 hardware allowing the user to mix, match, modify, and experiment with the provided building blocks. I haven’t touched on cost but the MPAS costs more than twice the tag on the WRC. Value is so subjective that I will just say that both feel like they are priced right. Also, I don’t feel like one is a big performance winner over the other.

If I was looking for an affordable portable setup to use around the campsite, for instance, The WRC TIA is a great option. I’ve covered the setup and tuning procedures. The result is being able to work on many HF bands with no additional tuner needed.

If I had to deploy something as fast as possible, with the least hassle, the winner is the MPAS by a large margin. You will draw very little attention, take up very little space, and get on the air. Even though a transmatch is required it doesn’t seem to be much of a hurdle. I used several matching units, including the MFJ-901, and they all worked just fine. You can also load a long wire, end-fed inverted vee, vertical wire… so the system is more flexible than the WRC.

I hope this post has been helpful. I have enjoyed using these systems, and can see why they maintain their popularity. As long as your expectations aren’t for some miracle system that gets big antenna performance in a small package then you can expect to get a lot of enjoyment out of either.

The Resonance

The reason why I would bother with this topic is twofold: One: I think better antenna systems are actually better; and Two: Technical concepts are central to amateur radio and should be understood and employed as often as possible. I’m discussing these antenna concepts in simple terms in the interest of keeping it accessible. Hopefully it leads to some further investigation and a different way to think about antenna systems.

WHAT IS RESONANT?

In the Venn Diagram world it can be said: Not all 50 Ohm feedpoints are resonant, and not all resonant radiators present 50 Ohm feedpoints. I have seen much confusion between “resonance” and “impedance match” on internet forums/platforms/videos. This what drove me to churn out this post.

Resonance in an RF radiator actually does make a difference. I’m a fan of Hemholtz and resonance is a real thing. When I assess a antenna design I start at the radiating element or elements. If that element is not a known and desirable harmonic relation to the fundamental frequency of interest I consider it a non-resonant design. If there is a matching unit connected to a non-resonant radiator I consider it a tuned circuit. When the goal is efficient and predictable RF radiation you have resonant radiators, and then everything else.

Recently there has been an explosion in the use of end-fed wire antennas. I use a few of them and they are an easy way to get on the air, usually on multiple bands. I have made plenty of contacts on these antennas, but at no point was I under an illusion that I was using an efficient antenna system. The now ubiquitous End Fed Half Wave is a strange bird, It utilizes a half wave radiator with a feedpoint impedance of about 3000 ohms, and is operated without a traditional ground plane or counterpoise. The high impedance feedpoint is matched to somewhere near 50 ohms with a 49:1 or similar toroidal un-un transformer. That is not a recipe for efficiency. The power ratings on the matching transformers tell you all you need to know: These matching units get hot, and that heat is your RF not making it out into the world.

PAR Trail Friendly on a Spiderpole

That’s not to say it’s a bad design. It solves a few of the issues that keep many hams from being able to get on HF. You can hang it from a single support, as opposed to needing two or three for a horizontal dipole. It’s also easy to erect on demand, which is great for hams who want to operate portable stations or if they have a compromised (small, HOA, etc…) QTH. I use a 12m Spiderpole and a PAR Trail Friendly when Inwant to get on the air quickly. Also, thanks to the magic of harmonic resonance, it is common to find a match on more than just the fundamental frequency.

Another common design is the random length end fed, usually known by the 9:1 un-un transformer used to feed the non-resonant radiator. The trick here is to find a radiator length that is not resonant on any band you want to work. The hope, and I do mean hope, is that the feedpoint impedance will be somewhere in the 200-800 ohm range, where it can be matched to 50 ohms using a second matching device. Again it has the advantages of ease of setup and multiband capability. The tradeoff is even steeper than the HWEF. This design is force-feeding a non-resonant radiator, has an even lossier (IMO) un-un, and requires a second matching device to get all the way to 50-ohms.

A problem both designs share is the difficulty in modeling a radiation pattern. Even with many analyses and many users over many years nobody seems to be able to say much beyond “omnidirectional”. That’s not too helpful. The main issue in modeling these systems is properly representing the ground/counterpoise. Most installations (mine included) require a common mode choke (CMC) near the radio end of the coax to keep RF from energizing the radio’s earth ground. How efficient does that sound? Do we have any idea what these antennas are actually doing wit the RF that makes it out into the world? Empirically I think we do. Scientifically, predictably, I don’t think we have a good handle on it.

So, how important is the efficiency of a transmitting antenna?

Hams with even some basic experience on HF know that you can make contacts on almost anything. Take a simple transmatch design like the MFJ-901, hook it to a rain gutter, and make a contact. Do we know anything about the radiation pattern, efficiency, or bandwidth? No. We are just interested in forcing something conductive to radiate RF, and hope for the best. The magic of radio waves takes care of the rest. If enough of your RF makes it out in the correct direction you will make a contact. Your signal might even be strong! But this is where it helps to be aware of confirmation bias. The science of radio communications involves being able to control where your signal is going, and control the system design to connect you with the intended destination. Having made some contacts is almost inevitable. Making the contacts you want to make when you want to make them is where the game gets interesting.

In the food-chain of antenna designs these lossy designs are somewhere in the “krill zone”. A good efficient design, properly installed is somewhere in the “cordata zone”, and a very efficient directional design mounted high and in the clear with directional control is “blue whale” territory. At some point the operator is limited by their Effective Radiated Power (ERP) and the weakening of the transmitted signal with the square of the distance from the antenna. Using 10-30% of your RF to warm a toroid is cutting in to your effective range. Every system has limitations, but when running 10, 30, 50 watts at the finals, I feel that making the most of it is important. Every improvement in efficiency and pattern control brings you up another link in the radio food chain.

Mitigating Factors:

Certainly the parallel popularity of end-fed wires and weak-signal digital modes, best represented by FT8, are not coincidental. FT8 allows working at lower signal to noise ratios which is like getting that lost RF back when compared to working SSB or RTTY. More efficient antennas are always an improvement, but an entry-level HF rig, a HWEF, and WSJT-X is a great path of entry to the HF bands. I’ve gone on about this earlier, but there is nothing in-stone about needing to start with CW or SSB. Hams can get on the air, interact with DX, and get some good contacts in the log. I see nothing wrong with that.

Compact, Broadband, Efficient: Pick Two

In the HWEF and 9:1 design cases the user is giving up efficiency for a more compact, more broad-banded (lower Q) device.

The HWEF, thanks to its resonant radiator, is somewhat more efficient, but the price is being paid for getting wide frequency coverage on a single radiator. Some designs find ways to better balance the equation by sacrificing some bandwidth and band flexibility to increase efficiency. One QRP design I use is the PAR 102040 Trail Friendly. This design uses three techniques to get a three-band end-fed vertical into a single 41′ wire radiator package. Trick 1: It uses a trap to isolate the 20m half wave element from the 40M extension. Trick 2: It uses the characteristic electrical lengthening effect of the trap to keep the 40m extension (and overall length) shorter than a simple 40m half wave radiator. Trick 3: using the second harmonic of 20m to realize some usable bandwidth on 10m. The transformer is pretty much handling the design goal of representing a 3000 ohm feedpoint as a 50 ohm load to the rig. No additional trans match is needed if you have trimmed the 40m extension properly and are ok with the tuning points. It isn’t brilliantly efficient, but it’s not horrible.

Chameleon MPAS Lite – Mini Review:

In early 2021 I picked up that Chameleon MPAS Lite and wanted to give it a run as a portable antenna system for POTA. This unit is extremely compact and is comprised of a ground spike, a un-un, a heavy duty stainless whip and 65’ of wire to use as a counterpoise. With the engineering triangle in mind I knew I was giving up a lot of efficiency for a very compact, very broadband system. And that’s what I got. It works well enough, especially if you are calling CQ and self-selecting stations who can hear you. I found that replying to anything but the loudest stations was a bad recipe for success. In a Chameleon forum I made the comment that these antennas aren’t good DX setups. I stand by that. It isn’t that you won’t work any DX, you would just work more DX more easily with a better DX design. For mid-range and NVIS work I think it is a solid solution. That assumes you are able to make the contacts you need to make. Also, watch the power rating because the un-un will get warm, and will fail under excessive power and duty cycle.

The MPAS system uses a 5:1 un-un design to feed anything from their very nice stainless whip, MIL Whip system, a longwire, or whatever conductive item you decide to use. The 5:1 takes a conservative approach to the non-resonant radiator problem, and a second transmatch (internal or external unit) is required unless you get lucky and dial in a 250 Ohm (or 10!) feedpoint impedance for the Un-Un. Chameleon publishes a perfect omnidirectional pattern for their antennas. That’s a good assumption for the operator since non-resonant systems are difficult to model accurately. Just assume your RF is going in all directions equally. Might as well! In practice I have made contacts and successfully activated a few parks using the MPAS Lite. Chameleon builds a beautiful and rugged product, and supports their users well. II feel like it is a good system and the user will get the best out of it by realizing it’s strengths and weaknesses.

One concern I have from following a few antenna forums, including a Chameleon product support forum, is the number of users claiming to have “resonant” solutions. An actual resonant radiator would provide a terrible match with a 5:1 un-un. What users are doing is finding a radiator length that presents a 1:5 feedpoint impedance to the CHA transformer so the radio sees 50 ohms(ish). That approach may be usable on that band with no additional matching, but is likely to be worse on other bands.

Another constant question on these forums regards radials and counterpoises. Strangely the solutions discussed are often none, one, or several short radials. All of these are poor solutions. However, when the central design concept is to never be resonant, not require radials, and use almost anything as a radiator, I don’t know what a good solution looks like. The Chameleon counterpoise kit is 65′ of very hunky insulated wire and can help you play with the counterpoise dimensions/layout and maybe help in finding a match. That said I feel like users are trying resonant counterpoise lengths and I think that does more harm than good. With a single counterpoise, stick to the game plan. Why make the two impedances different?

The Chameleon 50′ RG-58-ish feedline with a ferrite bead choke on one end is a decent way to control the stray RF. And it is necessary. Every time I have used it I had to control RF that wanted to energize the radio’s earth ground.

The best application I have seen for these matching units is Chameleon’s own Tactical Delta Loop which uses the CHA as the feedpoint in a system where 5:1 isn’t a bad design value. I will be cobbling a test setup soon out of various Chameleon and Wolf River parts.

Wrap Up

If it sounds like I am down on end-fed designs, I’m not. They have a proven track record and get hams on the air. What I would like to get across is that I hope ops get some time on other designs. Building a nice 1/4 wave vertical over a good set of radials is very easy and cheap. Think of a it as a single-band DX Commander style build. I think it is worth the time and small expense to see how a resonant design works and maybe make a few on-air comparisons.

If you stuck with this post I owe you a pint. I don’t write these to be concise blurbs. I like to compose my thoughts on these topics and I figure sharing it is part of the experience. Let me know what you think! Reply on the blog, or look me up on QRZ and drop me an email.

Get on the air, and always have fun. 73, Pete N1QDQ

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