Results: The ARS Sojourner's Trail Friendly Antenna Survey

Dipoles are easy to make. They don't require radials or tuners. They're not hard to put up, and they work very well. I usually hike where there are few trees, and I often have only an hour or so to operate.

A 12-foot telescoping painter's pole is an acceptable walking stick, and makes a quick and easy center support for an inverted V. I like to put my antennas on the side of a steep hill as near the top as I can. The antenna sees the drop-off in front of it as height, and the mountain behind it as a reflector. (SEE N7XJ's FULL ARTICLE ON THE WALKING STICK ANTENNA IN THIS ISSUE.)

My dipoles are made using ideas from commercial antennas. For the center connector, I drill a small hole through a rubber stopper, pass insulated antenna wire through it and force the stopper into a PVC tee. A BNC connector is glued inside the pipe with epoxy, and everything is capped off with heat shrink tubing (illustration).

Heat shrink tubing makes a pretty good insulator for an inverted V all by itself if you prefer to permanently attach the coax (illustration). I use loops in the wire for end insulators (illustration) and hook kite string to them to hoist the ends of the wire into trees or bushes or to attach them to small tent pegs.

As feedline, I like to use flexible RG58U computer cable. RG174 is more lossy, but it is very small and light. Twenty-five feet of RG174 introduces about one-half dB of loss, compared to about a quarter of a dB loss with RG-58.

The 'hot' ends of my dipoles are marked. I have pulled the hot end into a tree and used the dipole as a sloper or a vertical (with the feedline exiting at 90 degrees). I've also had fun experimenting with wire reflectors on the ground under my dipoles (NVIS).

FROM BRUCE GRUBBS, N7CEE:

Probably like everyone else, my field antennas are always evolving. But here's what I'm currently using.

I've been using a 40 meter full wave horizontal loop at my home QTH for over two years with such great results that I tried it for Field Day - only it grew to 160 meter full wave (270 feet of No. 14 flexweave). The home loop is fed with RG8X and a tuner, but for Field Day I used transmitting ladder line and a ZM-2.

The loop heard well, tuned easily on all bands, and netted us our best QRP Field Day ever - 261 QSOs and 3,000 points.

I liked the big loop so much that I made up a backpackable version from 270 feet of No. 26 teflon insulated stranded wire, fed with 50 feet of TV twin lead. I used it for this year's Flight of the Bumblebees.

The disadvantage of horizontal loops is that they require four supports. It took me an hour to set up the Bee loop.

On backcountry trips where radio is not the primary purpose, I like a setup that is quick. These days, as an outdoor writer / photographer, I find myself spending much of my backcountry time working with the light and location - often hiking furiously during the middle of the day, and shooting late and getting up early to do it again.

I find that if an antenna takes too long I just won't bother to get on the air.

So I strongly prefer single support antennas. My current multi-band favorite is a triangular delta loop made from 140 feet of the same No. 26 teflon wire, supported at one point, and fed from a lower corner with a 10 foot piece of twin lead.

I use it with a ZM-2 and Sierra. I set one for the Bee event and it compared very favorably with the higher and larger horizontal loop.

For serious backpack trips, where I'm carrying a 40 meter SST, I'm currently using a 40 meter inverted V fed with 40 feet of RG174.

I've measured the loss of the RG174, and it's less than a dB. I'm playing with the idea of using twinlead or field-assembled ladder line and a small 4:1 balun.

All the No. 26 antennas, even the 270 foot loop, are erected by throwing half-filled water bottles over tree limbs, and supported with 20-pound monofilament. The Flexweave Field Day loop is supported with 3/32 dacron line.

For situations where there are no trees, I've messed with a W6MMA SLV but didn't much care for it. I've ordered a DK9SQ 33' mast to use with the delta loop. So that's where my TFA farm has wound up, for now.

FROM DOC DRAKE, W5TB:

Most of my trailside hamming is done while canoeing or a short distance from the car. In both cases I usually have a multi-band rig or on occasion separate rigs for 40 and 20 so a multi-band antenna is crucial to me.

Although I used a random wire and counterpoise as my trail antenna for years I have recently changed to a 'drooping doublet' which is erected inverted V fashion with only one high support - preferably a tree limb up about 30 to 40 feet. The ZM-2 tuner end of the twinlead terminates in two Radio Shack solderless banana plugs.

This setup allows me to be on the air very quickly and covers all bands 40 through 10 meters - loading very easily with the ZM-2.

I've experimented with various lengths of twinlead and 45 feet seems to work best for me.

The doublet is constructed of 33 feet of No. 14 stranded wire to a leg and is fed with 45 feet of the light, thin, and cheap Radio Shack twinlead. The antenna weighs only about a pound and is easy to erect and store.

One leg is constructed with red wire and one with black to make untangling easy during setup. I toss a rope over the limb and pull the center of the doublet as high as I can.
Each leg end has about 25 feet of parachute cord which can then be run to a tree, bush, ground stake - whatever's handy.

Since the parachute cord is non-conducting I don't use insulators at the leg ends but simply create a small loop in the wire to which I tie the cord.
I use OD or 'camouflage' parachute cord for esthetic reasons. You want an angle of 90 to 120 degrees between the legs. Don't go less than 90 degrees or you'll get excessive cancellation of your signal.

The center insulator is constructed using a small PVC pipe cap with a screw eye at the top for connection to the center rope and holes drilled in the sides for the wire legs. The leg wires are knotted on the inside of the pipe cap to provide strain relief and are soldered to the twinlead.

Once everything is in place, fill the plastic cap with silicone caulk and allow it to cure for 24 hours before use. You could instead use a 'laddergrabber' commercial insulator or go wild and create your own design - my most creative to date involved a discarded computer diskette and some duct tape.

Whether I'm operating from the banks of the Buffalo National River while canoeing or just enjoying a quick stopover at a roadside park, this multi-band antenna goes up and comes down easily in well under 10 minutes and produces excellent results.

FROM BOB EDWARDS, W4ED:

(Editor's note: This item is a shortened version of Bob's original article, which appeared in The ARS Sojourner's Trail Friendly Radio roundup. Readers are encouraged to consult that article for specific details on radiation patterns and construction details.)

The TFR Dual Band Wire Vertical is a lightweight antenna for 20 and 40 meters designed to be carried in a backpack with quick setup and take down by one person.

One halyard lofted over a tall tree limb is the main support. It is field tuned by adjusting the height above ground, and doesn't require a tuner. The height above ground (tuning) is adjusted by manipulating the halyard. The vertical radiator is strung from the halyard downward to the feedpoint. There it is soldered to 6-inches of flexible stranded insulated No. 18 wire.

The No. 18 wire goes into one position of the 2-wire male Molex connector. The other wire in the Molex connector goes to the slanting horizontal radial.

The slanted horizontal radial is the only counterpoise and goes down from the feedpoint to an approximate 10-foot length of braided builder's twine.

The far end of the twine is either tied to another tree or staked into the ground with a 'U' pin. Likewise, the opposite side of the feedpoint is secured by builder's twine and is either tied off to another tree at the far end or staked with a second 'U' pin.

If operating on 40 meters, the 50 ohm coax is connected directly to the feedpoint. One end of the coax has the mating connector to the Molex already mentioned.

If operating on 20 meters, then insert the 300 ohm twin lead Q-section between the feedpoint and the 50 ohm coax Molex connector.

The Q-section has corresponding mating Molex connectors for this insertion.
The opposite end of the coax needs a connector that matches your rig.

As for performance, I have used this antenna four times so far, it does work. The initial use was for design confirmation and involved setup, wire trimming, making a few contacts, then rolling it back up for storage.

The second outing was to the Appalachian Trail. On that trip, I quickly made two 40 meter contacts on one watt (WV/599; IL/559).

The third use was for the NEQRP Field Day, in my back yard. With a power of 950 milliwatts, I made eight contacts ranging from Alabama to New York during a few good hours, and worked around one nasty thunderstorm.

The last time was the recent setup and test prior to the QRP ARCI Fall QSO Party. (An elevation plot appearing in the original article) shows performance gain in dBi on a slice along the azimuth having greatest gain, for both bands.

The 20 meter gain was 6.9 dBi while the 40 meter gain was 4.6 dBi. SWR was 1.38:1 on 40 meters and 1.06:1 on 20 meters.

The azimuth patterns are nearly circular. The 20 meter azimuth pattern had a 2.2 dB front to back ratio in the direction away from the radial. This simulation included a rocky soil ground, 300 ohm Q-section on 20 meters, and No. 22 copper wires.

I made several iterations on both 20 and 40 meters, back and forth until the readings were achieved.

One way to describe this vertical is as an off center fed dipole. That is an accurate statement for 40 meters. A more accurate description for 20 meters operation is as a 5/8 wave vertical, hence some low angle gain.

This antenna needs a tall tree to act as a sky hook. There are lots of tall pines here in Georgia, especially on the AT. This also means there needs to be a way to get the halyard up there in the first place.

I use a collapsible fishing rod and reel with a golf ball as the 'lure.' The cast I make is half toss, half cast. It has worked well for me, but then I've done a lot of fishing, too. I've been into more trees than fish, when fish'n, as I recall.

Also the horizontal members can be low enough to present problems for people and critters. I tie on bright fence flag tape in case the horizontal wire becomes a people hazard. Critters beware.

FROM MARK SANDLER, K7MAS:

Well, it's not a homebrew antenna, but my vote for the best 2-meter trail friendly antenna is easily the Back Packer's Yagi and/or the Walking Stick Yagi - both made by Arrow Antennas of Wyoming.

These are the best made, strongest and most effective 2-meter backpacking antennas I have ever come across. I have worked 250 miles plus on 2-meter SSB using no more than 2.5 watts output, while in the mountains - high peaks. (A link to Arrow Antennas is: http://hometown.aol.com/Arrow146/index.html)

FROM THE AUTHOR, CAM HARTFORD, N6GA:

The antenna I use most often in portable settings is a 40 meter dipole fed with 300 ohm twin lead. Most times I go outdoors to play radio, I go to places with big trees, so finding a couple supports and getting the dipole up is no problem.
This antenna needs a tuner, so I take along a small homebrew Z-match. This makes the antenna a multi-band radiator, which is good for operating contests such as the Flight of the Bumblebees, FYBO, etc.

Since I spend the bulk of my time on 20 and 40 meters, the antenna does a great job. On 40, it acts like a dipole (no surprise here!) On 20 it has a broadside radiation pattern with a couple dB of gain over a dipole and a somewhat narrower pattern. On 15 and 10 the pattern breaks down into multiple lobes.

If I'm unlucky enough to find only one support, the dipole can be erected as an inverted V and works almost as well.

Here's a second antenna I use. For truly portable operation, I carry a small case which contains a 20 meter SST and a Bique 20. Yes, radio fans, that's right, a Bique 20. I can hear the howls already, the claims of excess loss in the RG174 feedline, the gnashing of teeth over lost milliwatts. But for a truly portable, lightweight, easy-to-erect antenna, this one has merit.

For those of you not familiar with this antenna, it is nothing more than a dipole made of lightweight wire and sawed-up parts of a tubular plastic disposable cigarette lighter. The lighter body is cut into three pieces, two being used as end insulators and the third as the center insulator and feedpoint connection spot.

The feedline is traditionally RG-174, which is soldered directly to the dipole wires. Some have gone as far as potting the center insulator after the feedline is connected, but for truly portable use this shouldn't be necessary.

I chose to make the feedline 24 feet for two reasons. First, in a portable location it's not likely I'd be able to get the antenna up much higher than this. Second, it keeps the feedline losses to a minimum.

Yes, RG-174 is lossy at 14 MHz, but with the antenna pruned to give a very low SWR at the operating frequency, this length of feedline has a total loss of about 1.2 dB.

Not much to give away considering it weighs a mere 6 ounces, including BNC connector. The whole portable package weighs about 22 ounces, which includes antenna, SST, 8-cell AA pack, keyer paddles, earphones and a spool of string for hauling up the antenna.

At Pacificon a couple years ago, I pitched the Bique 20 out the hotel window, sloper style, and worked the east coast during the QRP ARCI Fall QSO Party. Not bad for a tiny package with a lossy feedline.

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Cam Hartford, N6GA, a contributing editor to The ARS Sojourner, is a veteran QRPer, avid builder and outdoorsman living in Claremont, CA.