Hello ECR Family, and welcome to The Antenna Farm. This is your friendly Antenna Farmer Charles, KC6UFM.

In this visit to the Farm, we’re going to look at portable antennas for VHF/UHF operations. This does include antennas made for use with Handy-Talkies (HT, walkie-talkies, handhelds, and a few other less common names) as well as portable operations from locations other than your home QTH.

Rules similar to those is Articles 11 and 12 still apply, particularly about grounding and ground planes, but there are some variations specially applicable to the portable world. It is assumed here that you have read and understand the prior two articles, so you may want to review those if you feel a little shaky on the concepts there.

This article will look mostly at antennas for VHF and higher bands. We’ll look at similar systems for HF in a later article.


Let’s start off looking at the use of portable antennas at a remote location…

Generally speaking, most people will not think about VHF/UHF operations when considering a Parks On The Air (POTA) or Summits On The Air (SOTA) activation. That’s kind of a shame because it gives the impression that, somehow, Technician Class operators are excluded from this aspect of the hobby. When most of us conjure an image of a POTA (or SOTA) activation, we picture someone with an HF radio and a dipole for one or more of the HF bands set up in a national park someplace working DX all over the world. I’ll grant that this might be the majority of activations—maybe even the vast majority—but this is by no means all there is.

Want a real challenge? Grab your QRP 2m all-mode rig and the needed accessories and hike out to some mountain top. Set up a 2m clothesline beam pointed in the right direction, and activate the SOTA station. With a good 2m clothesline and 5 watts of PEP on SSB, you should have little trouble making contacts out to as much 400 miles. That is if you do everything right…low loss system, good quiet radio, good power connections, a good ground system, and a high-gain antenna. That’s really just the tip of the iceberg, but you get the idea.

As with all antenna systems, you need a good ground. For portable operations, this may be a challenge since some locations will not allow you to drive a ground rod. If at all possible, drive at least one ground rod. If not, you may be able to get by with a radial (ground mounted or elevated) system.

The bottom line is that anyone can pump 100 watts into a 20m dipole and work the world. This station can literally be thrown together using all manner of bad practices, and if your longest QSO is only 500 miles, you’ve done something very wrong.

The 2m station will require planning and thought to get every last milliwatt of energy coming out of the antenna. The planning alone will, believe it or not, improve your operating skills as well as increasing your knowledge of how this all works.

OK…pull your head out of the clouds for a bit…

Essentially, any antenna that you can use at your house can be used on POTA and SOTA expeditions (or anything even remotely similar). There are only two issues you need to consider…

    1) First, can you physically transport the antenna and it’s related subsystems? Many POTA/SOTA activations require that you walk in to the final location, and that distance can be anything between a few dozen feet to a few dozen miles. Do you REALLY want to carry a beam with a 10 foot boom along with its rotor, cables, mast poles, and other hardware for 5 miles? I don’t! A better choice might be a dipole or a vertical that can be broken down into small, light pieces. 

    2) Secondly, can you power the various accessories the antenna system will need? The big idea behind POTA/SOTA is to operate without a connection to the power grid. Think of it as a kind of mini-Field Day. This means that everything needs to run from batteries, solar panels, and (maybe) a generator. Personally, I would no more want to carry a bunch of batteries, panels, and a generator up the side of a mountain than I would a large antenna and/or rotor, but remember that all these things need power. If you decide to carry that rotor to the top of the mountain, you’ll also have to carry the batteries to power it.

These two limitations will boil down to placing what appear to be severe restrictions on what you can do for an antenna system, but again, it’s all in how you look at it…this is an opportunity to get creative and do a little experimentation.

One specific antenna that lends itself very well to expeditions, especially HF, is the EFHW.

I mentioned above the idea of a “Clothesline Beam” and while it’s beyond the scope of this article to get into designing and building such an antenna, let me tell you a little about them.

As the name implies, a clothesline beam looks like one of the old clotheslines you may have had in your back yard at some point, just two (or more) poles with two (or more) lengths of rope running between them. On these ropes, you position the various elements of a Yagi-Uda beam antenna. You will have at least one reflector behind the single driven element (either a dipole or a folded dipole), and some number of directors in front of the driven element. The general rule for Yagi-Uda beams is that as you add more elements, the boom gets longer and the gain gets higher. There are some side effects we’ll talk about when we look at beams, but this is the general idea. Let’s say you take two T-shaped poles and string two runs of cord between the poles from the ends of the T crossbars, and you can get the poles 50 feet apart. On the two cords, you lay, let’s say, two reflectors, the dipole driven element, and then 25 directors. If your poles are such that you can get the ropes 6 feet off the ground and you position the several elements properly, this beam with a 50 foot boom will give you about 32 dBd forward gain. Yes, I said 32 dBd of gain. That will make your 5 watt PEP signal look like nearly 8000 watts coming from a simple dipole.

And other than the two poles, this will all roll up into a bundle about a yard long, 6 inches in diameter, and weigh about 5 pounds.

I also want to warn you about a few things relating to clothesline beams in case you decided to jump ahead and build one…first of all, these antennas are EXTREMELY narrow-banded, a KHz or so is typical on the high end. Second, there is no way on earth to easily turn such a beast, so you set it up and work that direction. Lastly, and this is VERY important, no matter what band you use a clothesline beam on, DO NOT let anyone—yourself included—get in front of the antenna when it is active. At 2m with 8000 watts, you can cook yourself pretty quickly. As you go higher in frequency, it gets worse in terms of tissue heating and exposure limits. Never forget that high levels of RF can be dangerous.

Sometime I’ll tell you about a little trick you can do with a clothesline beam during a hidden transmitter hunt. Some people claim it’s a dirty trick. I call it creative foxing.

Anyway, POTA/SOTA is not only possible on the Technician Class bands, but in many ways is even more fun and challenging. And don’t forget that as a Technician, you also have privileges in the HF segments for data, CW, and phone on 10m plus CW on 15m, 40m and 80m.


HT Antennas

I don’t know how many different HTs are on the market from various manufacturers. I know there are a lot of them. Every HT comes with an antenna. When you add in all the many different aftermarket HT antennas, I think it would be a good bet to assume there are about five times more HT antennas available than there are HTs.

That’s a bunch of antennas.

And all of these antennas share one common problem: They are all compromise antennas. Every single one of them.

As you’ve learned, every antenna system must have a ground or ground plane to work against. Without this, efficiency and performance fall off quickly. We make this work with stationary antennas by having a ground rod system. The same applies to portable fixed stations like for SOTA/POTA. In mobile systems, we use the vehicle body to sort of “fake” a ground. Ground Plane antenna types create an artificial ground for the antenna to work against. The fact of the matter is, HTs lack an efficient ground system.

Electrically, the HT uses it’s own chassis as a ground plane. Look at your HT…the chassis is very small compared to the wavelength of the band you are using. That means that the HT does not have a good ground. Some of the manufacturers will say that the very act of you holding the radio adds your body as part of the ground. Careful analysis of this idea shows that it is, basically, nonsense and marketing hype. What we’re talking about here capacitively coupling your left arm to the HT.

This lack of a good ground severely limits the performance of HTs. It doesn’t matter what antenna you have for your handheld, it just will not perform like a properly designed and installed system. This also explains why you can work great distances on 5 watts with a proper antenna yet your HT can only reach out a few miles with the rubber duck.

Now let’s look at a couple of HT antennas you may be familiar with.


The Rubber Duck



See Figure 1. This is the type of typical antenna that comes with almost all HTs. It is usually covered with rubber (more likely some kind of plastic) and is somewhat flexible. The length and diameter vary based on band and manufacturer preference, mostly the latter.

Inside the rubber covering, all rubber ducks are the same…there is a coil of wire that looks like a screen door spring that is made from steel (not the best choice for an antenna at all due to ohmic losses) and with the turns insulated from each other in some way.

Electrically, the rubber duck antenna is one big loading coil. Loading coils are quite lossy and very inefficient. But that’s all you have, right?

Not really…

There are many, many aftermarket rubber ducks for just about every radio, band, and personal choice. The prices are all over the place, ranging from fairly cheap up to about as much as you paid for the radio you plan to use it with.

But they are all the same.

I can assure you that if you have one of the “Big Three” Japanese HTs, the rubber duck it came with will outperform any other duck you can buy. That’s simply because Yaesu/Kenwood/Icom spent a lot of money on designing and building the stock rubber duck so it performs as best as it can given the limitations of the antenna type. Don’t waste your money on aftermarket rubber ducks.

If you have one of the lower end HTs from the several Chinese builders, you might be able to do better than the standard duck, but honestly, it’s kind of a gamble…the Chinese makers just buy an off-the-shelf antenna from a third party, maybe have it private labeled, and slap it in the box. There is no effort to custom match the antenna to the radio. If you buy a new duck from a third party, you could very well be getting something that is, basically, identical to what you already have.

If you want actual better performance, you will likely need to abandon the rubber duck in favor of something else.


“Tactical” Antennas

OK, let’s make it clear right up front…most of the so-called “tactical” antennas are nothing more than a section of a steel (again, bad choice) tape measure that has a connector put on one end, a protective cap put on the other end, and painted so it doesn’t look like a tape measure anymore. One of the largest makers of tactical antennas is also the largest customer of Stanley Tools buying up scrap tape measures that fail quality control.

Now…



See Figure 2. Tactical antennas are also flexible, but not like a rubber duck. The tactical units are designed to fold up to fit in your pocket or bag…just like a section of tape measure. Oh, I said that already.

The only advantage that a tactical antenna has over a rubber duck is that it is longer. Maybe. The shortest effective antenna is ¼ wavelength. In the case of the duck, if you were to uncoil the wire, you will find that it is about ¼ wave at the lowest transmit frequency of the intended HT. Being coiled up introduces loss and kills efficiency. The tactical antennas are designed to offer either ¼ or ½ wave at the lowest frequency, and they do it in a straight line instead of as a coil. This leads to lower losses and increased efficiency. All that said, a tactical antenna longer than ¼ wave is putting a huge mismatch on the transmitter. Most HTs are fairly tolerant of mismatch, but sooner or later—probably sooner—the high SWR will burn out the finals. Remember that a ¼ wave vertical will show about 73 ohms in free space. In practice, it will be close to 50 ohms. A ½ wave will show an impedance of about 3000 ohms, and that is putting an SWR of about 60:1 on your radio, and that’s ignoring reactance. If you’re lucky, the HT has fold over circuitry. Odds are it will only reduce it’s output power when the magic smoke comes out of the final amplifier.

So, everything else being equal, a tactical antenna WILL give you a better signal than a rubber duck. There is no question about that. Just being a straight line instead of a coil will work better.

But even that $50 tactical antenna will be outperformed by leaps and bounds when compared head-to-head against a 1/4-wave ground plane standing in the corner of your living room.

Why is that? Because the ground plane has, well, a ground plane. The tactical antenna (or the rubber duck, for that matter) does not.

There is no way around the fact that an antenna needs a ground or ground plane to work against. That simple fact brings us to the only viable solution to improve the HT signal yet still maintaining something that is portable…


The Tiger Tail



See Figure 3. Most HT antennas—both rubber ducks and tactical—are ¼ wave verticals. You’ll recall that a ¼ wave vertical is simply half of a simple dipole. All we need to do to boost the performance of the HT antenna is to add the other half of the dipole somehow. This gives us the same performance as any dipole. Luckily, this is pretty easy to do, and the tiger tail will provide a noticeable improvement in performance in most cases.

All you need to build a tiger tail is an appropriate ring connector, some heat shrink tubing, and a length of stranded wire (anything larger than about #20 AWG will work, and remember that smaller wire is more flexible but may be less durable).

For the ring connector, look at the back of your HT. You should see one (or more) screws that hold the case on, usually near the top of the radio. You want a ring connector that will fit these screws. Resist the urge to use one of the screws that attaches the belt clip to the HT…in many radios, these screws do not go into the chassis. If your HT doesn’t have any screws visible on the back, see below.

Just cut an appropriate length of your wire according to the following:

        2m – 19.5”
        1.25m – 11.5”
        70cm – 6.5”

Strip back enough insulation from one end of the wire to crimp on the ring connector. It would not hurt to also solder the wire to the connector, but this is not strictly needed. Put the heat shrink tube over the wire and terminal connection and shrink it into place. On the other end of the wire, slip a bit of heat shrink over the wire and shrink it into place. This is to cover any exposed strands of wire that might poke your finger or hand, and to prevent your body touching the exposed end of the wire, detuning the tiger tail. You could use electrical tape here, but the heat shrink looks better. I have also used the liquid vinyl sold to coat the grips of hand tools…just dip the end of the wire into the liquid and let it cure. Makes for a very nice, professional look.

Lastly, put the screw through the ring connector and tighten the screw back into place. Do NOT over-tighten the screw or you may strip the threads.

As an added note, if you have a dual-band (or more) HT, you could put more than one tiger tail on, one for each band. If you do this, you can use small zip ties to bundle the tiger tails together to make things look neater.

Ideally, when you use your HT with the tiger tail in place, you want the tail to either hang down in line with the antenna position or you want the tail at a right angle to the antenna.

You should see a more than noticeable improvement in both receive and transmit performance.

Now, if you look and see no screws in the back of your HT, you’re not out of luck. First, skip the ring connector. Now look at the antenna and where it attaches to the radio. Odds are, if your radio is a Japanese rig, there will be a female SMA connector. If you have a Chinese radio, it will likely be a male SMA connector. No matter what you have, you will need a “Barrel” connector to go between the radio and the antenna. If in doubt, the good folks at most of the ham radio shops (HRO, GigaParts, DX Engineering, etc.) will be able to help you figure out what connector you need. Install the connector on your radio. Strip back enough insulation to be able to wrap one end of your wire around the outside of the barrel connector as tightly as you can. Now reinstall the antenna. You’re good to go.

I have seen tiger tails for sale on eBay for around the $10-$15 range. Not a bad markup considering there’s about a dime’s worth of parts and 5 minutes of time.


So, while both portable and HT operations usually involve compromise antennas, this does not mean that you’re stuck with a bad signal. There are many ways to improve your signal quality and engage in some creative thinking.

In the next Antenna Farm, we’re going to take a short side trip to look at the various connectors you will encounter. We’ll look at the good, the bad, and, of course, the ugly. We’ll also banish a few myths about connectors that seem to never die.

Take Care & 73
de KC6UFM
Charles