Revisiting an old topic.
I don’t do a lot of antenna articles because there is already so much information in circulation I can’t see much ground left to cover, at least that’s what I thought until new Off Grid Ham reader Rick sent a nice email that inspired this article. What are some cheap and easy ideas to make a portable antenna better, from an off grid perspective?
The off grid niche. portable antenna
To rehash the obvious, running off grid radio does not require a “special” antenna. Whatever works for conventionally-powered stations will also work off grid. However, off gridders tend to have different needs and operating goals. Some antennas fit these needs and goals better than others. portable antenna
I know from my own operating experience, running this blog for over seven years, and talking with other hams, that off grid amateurs disproportionally use QRP, lean towards portable operations (outdoors), and are less focused on having a big signal for the purpose of DX, contests, & awards. They also, by a very large margin, are involved with the survivalist/prepper movement and/or EMCOMM on some level.
If you are into amateur radio in whole or in part because you want communications when SHTF, then your equipment choices are going to be different from the guy who is a contester, DXer, or thinks it’s just a fun hobby. An analysis of those two demographics might itself be worthy of an entire Off Grid Ham article.
From the abstract to the real.
Now that we’ve lightly touched on the sociology and psychology of why operators may choose different equipment, the next question is “what are my options?” Your options as an off gridder are are for the most part the same as they are for everyone else. You’ll just have to make a few adaptations. As we have discussed many, many times on this blog, there will be tradeoffs and compromises. Here are a few ideas with a “cheap & easy” goal in mind:
The wire antenna. portable antenna
Perhaps the most fundamental of all antennas, the dipole has been around almost as long as radio itself. There are a few things an operator can do to make it more off-grid friendly. These ideas can apply to all other wire antennas too:
Lose some weight!
If you are running QRP power levels, there is no compelling reason to have a dipole with heavy gauge (16 or less) wire. Wire sizes between 18-22 gauge are perfectly acceptable for QRP. It’s less expensive, easy to work with, and coils nicely for easy transport.
Speaker wire is a popular material for light weight antennas. It’s easy to find and not particularly expensive. It would be a great choice. But there is something better. Much better.
The “holy grail” of off grid antenna wire.
The top of the QRP antenna wire pyramid is 22 gauge central office frame wire (sometimes referred to as cross connect wire). CO frame wire is incredibly strong for its size and does not easily stretch. It comes in a twisted pair. There is no need to separate the pair. Simply strip the insulation and terminate the bare wires together at each end. This turns the twisted pair into what is effectively one single conductor. The twist will have no meaningful effect on your send or receive signal.
Unfortunately, CO frame wire is used only by the telecommunications industry and is very hard to find for sale to the public. It can occasionally be found at swap meets. I was able to source this wire through my professional affiliations and can confirm that it makes a fantastic light weight antenna material.
The photo below is a 20 meter central office frame wire dipole with balun, rolled up for transport. It weighs 9.6 ounces (0.272 kg) including the balun and fits in a plastic sandwich bag.
Many hams work for the phone company, or have connections. Ask around. If all else fails, you’ve got nothing to lose by knocking on the door of your local central office and simply asking the tech if you can have some frame wire. He/she will know what you are talking about. Every year they pay contractors to haul away thousands of feet of the stuff to the scrap yard, so it’s not a big deal to give some away. Many telephone central offices are not manned full time so you may have to make a few attempts to catch someone while they are there. Since techs set aside unwanted wire for recycling, “dumpster diving” will not likely produce any results. In any case, it will be well worth your effort if you can find some.
If you cannot source central office frame wire, light gauge speaker or doorbell wire will work just fine but will not be as strong and stretch resistant.
Baluns and ununs.
Almost any antenna fed by coax can be improved by adding a balun or a unun. These devices are essentially transformers that manage the impedance difference between your feedline and the antenna and prevent common mode current. Common mode current is undesirable RF energy that flows along the outer braid or shield of the coax; it contributes to inefficiency and poor antenna performance.
A balun is used on antennas where all elements are the same length, such as a dipole. A unun is used on antennas where the elements are not the same length, such as a random long wire.
Commercially made baluns and ununs are relatively inexpensive. It is also fairly easy to make your own; YouTube has many great DIY videos.
Another popular cheap & easy option is the ham stick dipole. Two mobile antenna whips (intended for use on a car) are screwed into a mounting. A coax connector on the mounting directs the signal to the appropriate element. The fitting usually has a clamp for mounting on a mast or other support.
Ham stick dipoles are very effective & inexpensive antennas and can usually handle power higher than QRP. The disadvantages: 1) they have a tight bandwidth and can be difficult to tune. An antenna tuner may be needed; 2) they cannot be coiled up small like a wire, 3) they also require a support mast. Depending on your resources, needs, and logistical situation, transporting them for portable operation may be a problem. Lastly, they are only good for one band. You’ll need a totally separate set of ham sticks for every band you want to operate.
There are some great commercially made telescoping antennas that are about as close to plug-and-play as you can get.
The Chameleon CHA SS17 extends to 17 feet and is 27 inches when collapsed. The manufacture claims it will work on 20-6 meters with no need for a loading coil. MFJ offers the MFJ-1979, which is almost exactly the same as the CHA SS17. I have not personally used either of these antennas but OGH readers have reported excellent results with them. They cost between $70.00-$80.00 and you’ll probably have to also buy some adapters and mounting hardware to make them work. If light weight, small size, and portability are your top priority then a telescoping antenna is your best pick. portable antenna
Any antenna will technically work in an off grid application. However, there are many simple ideas one can employ to make a good antenna better and more adapted to specific off grid needs. These hacks are not necessarily difficult or expensive. With a little creativity, you can come up with a very effective —and very cheap & easy— antenna for your off grid radio station.
Do you know of any off grid antenna hacks not mentioned in this article? Tell us in the comment section below.
to Chris of Off Grid Ham,
Hello Chris from Pete Barth, W6LAW.
I have not read your blogs for a few years.
A real nice surprise to run across your OFF GRID HAM heading.
Cheap & Easy Portable Antenna Hacks!….Yummy!
Always time for another antenna build!
I never did get much more power out than a 8146 would give in the old tube days.
I did get a Henry 1.5 KW but I never did put a power plug on it. Always wanted one-never used it.
I had a Swan rig in my Alfa Romeo Spyder… that was fun.
Now I have a ICOM 706 in my 20 year old SUV.
I have never liked any whip antennas that are so common on cars.
I did do a trailing wire counterpoise against a base loaded whip off the back of my BMW cycle for awhile. I used a two square inch light cloth to keep it up in the air at speed.
20 meter CW out on a midnight ride between Hollywood and anywhere waw always fun, into my then KX2, then MY KX3. With that BMW and its cruse control, a coldsuit on and CW with a bug attached to the handlebar was good.
SO, now I will get serious with micro wire antennas!
I had some “CO frame wire” over the years but never knew what to call it.
I will build some baluns / unins, that will be fun.
I have two extendable fiberglass poles that will help.
Chris, I think that you will be instrumental in getting my 81 year old ass up off the laptop and back on 20 CW with about 15 watts!!
Hi Pete, I too am a BMW motorcycle owner. Actually, in my “real life” I’m a huge motorcycle nut. I’ve been riding my entire adult life but never set up my bike for ham operations. Riding is dangerous enough…I don’t think I have the attention capacity to operate radio at the same time.
I’m glad to be helpful in getting you back own the air. Stop by again sometime and update us on how you’re doing.
I traveled all over the country on a BMW K-1200 LT with my wife. We were everywhere from Wyoming to Maine on that thing. I traded it off on a Goldwing back in 2013. The Honda was a nice bike but I always missed that BMW. I would have bought another but BMW decided to stop making that particular model and turned it into a “sports-touring” bike that was one of the most uncomfortable things to ride I’d ever been on so I bought the Honda instead.
Nice rundown on some of the most useful types of antennas for easily made and quickly set up antennas, Chris. Some people in the amateur radio community seem to think antennas are some kind of complex and mysterious artform but they are very, very easy to make in a variety of different forms and from different materials. All you need is some wire and connectors. When Radio Shack went out of business I picked up a half a dozen large spools of wire of various gauges and types. Watch for deals. Sometimes the big box home improvement stores will sell remnants of spools of wire cheaply as well. And it might be worth a trip to places like Habitat for Humanity’s resale shops too. They’ll sometimes get wire left over from contractors.
My primary antenna for many years now has been an OCFD hanging at around 10 feet, and I’ve worked 37 countries and worked all states on that antenna usually running 50 watts or less, so you don’t really need to get it up to eye watering heights to get a useful antenna either.
Just renewed my FCC license! And yes, it was a pain in the neck that took far longer than it should have. Best advice for those of you who need to renew your license is HAVE PATIENCE! And read EVERYTHING on the page. Sone of the requirements are easy to miss. That’s what happened to me. There is an 800 number on the bottom of every page that you can call for help. That’s what I ended up doing. Surprisingly I got through to a real person in just a few minutes and they got things straightened out in just a few minutes. So call for help if things get messed up!
Hey there Randall. You are correct. Antennas are complex in theory but relatively simple in practice. For my home station I’ve never used anything more than a dipole or similar wire antenna. For portable operations, I have four types of antennas to choose from: Ham stick dipoles, a random long wire, the frame wire dipoles mentioned in this article, and an Alpha Antenna FMJ. The Alpha is the only commercially made antenna I own. For portable use, I try to rotate my antennas to keep my skills sharp, but the Alpha is used the most because it’s so easy to set up.
Great info as always. I have been experimenting with various verticals and found this one on Ali Express:
It is great quality, 17Ft 2 inches long and is only $22.92 US including shipping plus sales tax. The only issue is it has a M8 thread on the base. I re-tapped half of a 3/8 X 24 coupling nut and it works fine for my use at a super price. BTW Ali Express has improved greatly, but you still have to shop around as a lot of times E-Bay and Amazon have the identical stuff for the same or less price!
Dave K. KC3HHA
I have a spool of what looks like co or phone twin lead wire that my aunt and uncle had.
I also have two end fed half wave antennas that I am putting together.
The MFJ whips are nice but heavy. If you use a pair of them in a dipole configuration they have a pretty serious droop. A single whip with loading coil and counterpoise/radials works pretty well.
If you can find one, Radio Shack used to have a very long telescoping whip that was very light and made a great vertical. When I got my general my first HF antenna was one of these with PVC loading coils. Worked well but a wind gust bent it up unfortunately.
A telescoping antenna will droop and possibly break if used as a dipole. It would likely work as a vee, though. For a small-ish dipole I recommend ham sticks.