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[Articles Home]  [Add Article]  

Portable QRP Antennas

from Len, K1LU on August 13, 2003
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Portable QRP Antennas

Relearning what I already knew.

Having been bit by the QRP bug a few months ago, I decided to try a QRP Field Day. The results were a little disappointing. I did some experiments with various table top and tripod mounted "portable" antennas prior to field day, thinking that 'if it works for them it should work for me' and when the band was really open they did work, but everyone wanted to keep QSO's short, a clear indication my signal was marginal.

I decided to try Field Day from my boat, thinking a good lake ground might be the answer. A commercial shortened tripod mounted dipole was pressed into service on the boat but it just didn't work. The QSO's I did make all had problems with drift. Not frequency drift, but drift on the anchor line because the wind/waves always seemed to change the boats orientation by 90 degrees just as I made contact!

I converted the setup to a vertical configuration, and removed one side of the dipole and substituted about 60 feet of bare copper wire, complete with a 9/16 socket (for weight), which quickly went over the side into about 90 feet of water. This seemed to work better than the dipole but it still was not very good.

Under less than ideal ionospheric conditions running QRP with a portable antenna was an exercise in boredom and repetition. After Field Day I decided to use the QRP rig on the Quad, and the results were astonishingly good. That led me to recall the ancient law I had forgotten sometime after my first KW rig was assembled: `It's the antenna, stupid'.

With a camping trip approaching I decided to try and redeem my QRP efforts by carting the FT-817 into the woods with a gel cell. This time, however I brought along the original ham antenna from my novice days about 35 years ago - a simple wire dipole.

With a couple of tries, that 20-meter dipole was up in the trees about 35 feet (you've got to love those sling shot contraptions) and I had a bit of an audience. Soon it was joined by a full size 80-meter dipole, which was too big for the chosen span so one end hung down about 15 feet.

The 20-meter dipole including feedline and string weighs in less than my "portable" manufactured antenna and the 80-meter job is not much heavier. Neither has a balun (too heavy) but both have a couple of RF choke ferrites on the coax, probably more for mental attitude than anything related to physics, but half of success is attitude so what the heck.

After a week of operating with simple dipoles in the woods at QRP power levels, I have only one recommendation to anyone considering camping or backpacking with a radio. Forget the cute antennas. Make yourself a simple dipole, get it up in the air between some trees or carry a portable mast (like the ones sold by World Radio), and you will have QSOs at an astonishing rate.

I filled several pages in the logbook using this setup, had a wonderful time, exposed several neighbors to ham radio (no TVI in the woods either) and had some really nice ragchews into Europe from the El Dorado National Forest in Northern California, and met some great folks on 75.

My advice to travelers is to carefully tune your antennas, use full size wire dipoles, and save your money. The weight difference, especially if you know your target band(s) is non-existent, and can be in favor of the wire dipole. I wish someone had told me this a few months ago!

With just a minimum amount of planning, a dipole or inverted vee can be put up in less time than it takes to cook dinner. If weight is an issue, you don't need multiple feed lines. Just attach a string to the center insulator, and leave the string on one end of each dipole long enough to lower the antenna. Lower the dipoles when you need to switch bands and move the feedline. Yes, I had an autotuner, and I was able to run 20 meters on the 80 meter dipole with my trusty little LDG, but the 20 meter dipole was always noticeably better. (I had two feedlines so switching was fast for comparisons.)

The tuner permitted operation on 40 meters but at 5000 feet the QRM from Asia was so bad the band was unusable. I thought we had 7-7.1 allocated exclusively to Amateur Radio, but I guess not everyone agrees.

Operating with a dipole and 5 watts was very similar to running 75 watts years ago with boat anchors, and every bit as exciting. There was some challenge to it because anyone with a modern station could clobber you, but once you established contact it was generally solid enough for a great QSO. I'm not ready to trash the QRO rig, but QRP under field conditions certainly works, it's reliable, and most of all, it's a darn lot of fun!

73,

Len

K1LU

Member Comments:
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Portable QRP Antennas  
by W3JXP on August 13, 2003 Mail this to a friend!
Just one comment. Fresh water makes a poor ground. Fresh water is a poorer ground than dry rocky soil. The only advantage a fresh water lake has is no local obstructions. Only salt water is a very good ground.

John W3JXP
 
Portable QRP Antennas  
by KE6ZRP on August 13, 2003 Mail this to a friend!
Here is a great website to visit which has a table of different portable antennas which you can clearly see which ones are best. I know Ray personally, and we use his antennas at Field Day and only work QRP. We get good reports most of the time. Check it out:
http://autoinfo.smartlink.net/kq6rh/antenna/ant_magi.htm

73, Mark, KE6ZRP
 
RE: Portable QRP Antennas  
by W3JGG on August 13, 2003 Mail this to a friend!
I must agree, Len. I went on a camping trip this past weekend and brought along my 706/2g...Even though it requires a good amound of current, my 25 Ah gel cell was more than sufficient. After about 20 minutes, my dipole was up about 25', measured precisely for 14.050 mHz. It only took one "CQ" to establish contact. From northern FL, I received surprising signal reports; for example a 569 from a gent in G3 land. I managed to fill a couple pages in my log, and was able to work most everyone I heard with only 5 watts.
 
Portable QRP Antennas  
by K1RMS on August 13, 2003 Mail this to a friend!
QRP is the way to go!!!
I run QRP exclusively at my QTH and field trips I do. At home I use a 204ft dipole up approx 60ft as a flat top configuration. I also use a Yaseu FT817 and LDG autotuner and make 5watt contacts all the time. For field trips I use a 20meter dipole and a homebrew "Slinky antenna" and "Tape Measure antenna" for 2meters. My signals are always S5 to S9 and sometimes with no indication from the 817's meter I still make readable contacts. I agree the only way to go is with light-weight antennas but with good performance.
When using dipoles I recommend putting it up as high as possible as a flat-top, if you don't have the space or enough trees an extending mast (HomeDepot 12ft) will work great for an inverted-V. The main thing is getting the antenna high and tuning it for the best SWR. I know this all sounds simple, but let me tell you these are the antennas that I use all the time and I go against the "Big-Guns" and still make the contact!
Please check out my website for more QRP information: www.k1rms.vze.com
So put it up.....tune it.....and have fun!
73
Jim - K1RMS/QRP
 
Portable QRP Antennas  
by G3VGR on August 13, 2003 Mail this to a friend!
Back in the sixties, an old timer told me "it takes a helluva good antenna to beat a dipole" You've confirmed that still holds true now. I used end-fed halfwave antennas for QRP portable with mixed success. They are good if you only have one support. I'm now using a 44ft doublet with a homebrew Z-match for multiband use, or a 20m dipole if I only take along the DSW20. The advantage with operating QRP in the great outdoors is that there's plenty of space for full-sized antennas, so I wouldn't want to handicap myself further with using a tiny, compromise antenna
 
6m, portable 'Broomstick' Yagi  
by W8KQE on August 13, 2003 Mail this to a friend!
Earlier this summer, I built a small, portable 2 element 6 meter beam, whose plans I saw in Ken Neubeck's (WB2AMU) popular 6m book. I used a garden tool replacement handle as the boom, and Radio Shack telescoping TV whips as the driven and reflector elements, and fed it direct with coax. Not only is this antenna portable (the whips collapse), but sitting on top of a 12 foot mast slid into a patio table (I used an L-shaped pipe mounted to the boom to allow the antenna to simply slide over the mast, available in all sizes at places like Home Depot), I worked at least 25 states and 60 grids when the band was open during the July CQ 6m contest, and around that time (weekend)!!! The radio was a simple 25w Ranger 5054DX with the stock microphone. Great way to get on 6m quickly and 'on the cheap'. And the SWR was dead flat 1:1 across the whole lower portion of the band!
 
RE: 6m, portable 'Broomstick' Yagi  
by K9PO on August 13, 2003 Mail this to a friend!
An excellent article. I use a random length wire with a ZM2 tuner for my QRP ops and it works great. Have not loaded it up for 6m but I have used it on 2m.

I do fear, however, that since your article did not mention the code or the ARRL there will be many on thise site that are offended. The adminstrators may even onsider your article out of scope for the site.

So to help you I think you should have mentione dthat CW is a superior mode for QRP and that the ARRL sucks because it does not support QRP CW.

--sarcasm off---

73
Scott
 
RE: Portable QRP Antennas  
by NZ5L on August 13, 2003 Mail this to a friend!
Your results from the lake might have been better if you had used a ground strap counterpoise in the hull for a fiberglass or wooden boat. An aluminum hull is almost as good as a car body - better, if you are in salt water. A fresh water "ground" is, unfortunately, no ground at all. Your good results with the quad only underscore how mediocre the average antenna is - with a good skyhook, low power and the ionosphere will usually do the job. Fine on being able to get the dipole up 35'. On my last camping trip, I could only get mine up about 15' and the ends at 5-6'. On 40 this resulted in a pretty fair NVIS set-up, and several stations were worked during the daylight hours out to about 500 miles with 3W. I tried the CW DX contest that night and could not get in to work any DX at all, except Canada. Next time I'll try a 33' vertical wire and a few radials
 
Portable QRP Antennas  
by N2CKH on August 13, 2003 Mail this to a friend!


Hi Len,

I have played with many types of true portable
antennae and things that radiate while TDY
and find that for DX, on the average, the best
thing is a very long wire as high as possible
using an antenna tuner or a resonant vertical
antenna.

I have military type full size portable antenna
that I use and I even designed a multiple purpose travel wire antenna a few years, you can find the
design at http://www.n2ckh.com/antfarm.htm

Mostly these days I go TDY and afield with a 5w
FT-817 since 2000, some times I bring a 100w
amp some times I use my FT-890AT, but mostly
I run the FT-817 and 5 watts. You really need
to get all of that 5 watts to the antenna and
radiated as efficiently as possible.

For resonant verticle, I been using the MP-1
portable antenna for almost three years now,
portable and mobile. Its great for 80m thru
6 meters, so are my full size antennna. The
MP-1 can be mounted in a number of ways and
with a counter poise it works very well.

However, depending on my baggage limitations
and method of travel, some times its just
my chalk-line reel out longwire antenna,
Budwig adapter and MFJ QRP antenna tuner.
I try to get a 6 floor or so room on the
appropriate side of the hotel and then reel
out, go down, pick up and string the wire
or some times just dangle it vertically
extended as far aware from the hotel as
possible with a telescoping fiberglass
pole and bungie cord affair. A 1/4 wave
of wire for the given frequency usually
works best along with a counter poise
inside the hotel.

Also, I find the little Autek RF Analyst
to be a great pocket sized device for
the QRPer.

/s/ Steve, N2CKH





 
Portable QRP Antennas  
by W7WIK on August 13, 2003 Mail this to a friend!
130 feet of dipole fed with TV twin-lead and a good tuner works well on 80-10.

A dipole fed with coax is usually a one-band wonder. Feed it with open feed and and tuner, and it becomes multi-band antenna.

Marco, W7WIK
 
RE: Portable QRP Antennas  
by N6AJR on August 13, 2003 Mail this to a friend!
do a search here on the elmers search, for FAN DIPOLE and see what you think..
 
Portable QRP Antennas  
by K0EX on August 13, 2003 Mail this to a friend!
I also vote for a dipole fed with open-wire and a tuner.

I have a 40m dipole (~66ft long) fed with 300ohm open-wire and tune it with a Z-match (like NorCal's BLT for $39!! Variations, in schematic form, are available from several websites if you wanna build one from scratch).

-Mark K0EX
 
Portable QRP Antennas  
by AB7JK on August 14, 2003 Mail this to a friend!
A half wave end fed wire in a tree with an artificial ground as counterpoise. Try it you'll like it!!
 
Portable QRP Antennas  
by W7TAV on August 14, 2003 Mail this to a friend!
Great article!!! A slap at the 'designer antennas'... as a newcomer to the hobby, it seems the real 'voodoo' is the study of antennas, with much theoretics discussed and far too little straight-talking practical advice. Thanks for the advice!
Jim Sinclair KC0QGW
 
Portable QRP Antennas  
by AB2KT on August 14, 2003 Mail this to a friend!
Earlier this summer I had the chance to spend several days trying out a number of different portable antenna configurations. The results were pretty similar to what you report here at QRP levels.

However -- and this is the point -- all of the compromise antennas *did* work satisfactorily at higher power levels, 30-50w. Big surprise, right? With enough power to burn, the compromise antennas work about the same as decent mobile setups.

The reason for bringing this up is dumbly simple -- if you really *are* stuck with a compromise antenna situation, you can make up for a lot of compromise with a little extra power. Not that this is any news, but it is a view that gets overlooked occasionally.

73
Frank
AB2KT
 
Portable QRP Antennas  
by AF0H on August 14, 2003 Mail this to a friend!
I use a Linear-loaded vertical made from window-line, like the old mor-gain dipoles used. Easily hung from a tree branch. The coax shield is connected to a ground counterpoise (or ground-rod) and the center to one side of the window line. The top ends are connected as in a folded dipole, but are open at the bottom. Using 150/f for the length, I can string up an 80-meter with a length of only 41' 8". Trim the open side (bottom) of the window-line for swr match. Don't shorten the overall length of the antenna. At 40 meters, it's only 21'! Easily accomodated in portable/restricted locations and vertically polarised.
20 meters is short enough to use just a standard 1/4 wave wire and not have to compromise performance.
This is an easy way to have a 1/4 wave ground mount vertical and 40% shorter without traps or coils.

BTW, fed with 50-ohm coax and no balun required.

73 de AF0H
 
Real Info on Portable Antennas  
by KQ6XA on August 14, 2003 Mail this to a friend!
You can get real dB information on exactly how efficient a bunch of different portable antennas are. Commercial and homebrew.

HFpack Pedestrian Antenna Shootout Reports

http://www.hfpack.com

73---Bonnie KQ6XA
 
Portable QRP Antennas  
by KG6BYX on August 14, 2003 Mail this to a friend!
I have used a variation on the portable half wave dipole on extended rafting trips. You can make a combination 20/40 meter dipole with insulators at the ends of the 20m lengths (near middle of the 40m lengths). Carry clip leads to bridge the insulators for 40 m. Some extra length in the clip leads allows you to somewhat tune the 40m dipole. You can also just clip the extra length to the ends of the 20m length to tune it (lower). Before you travel, tune it up by tuning the 20m version first, then trip ends of the 40m version. The 40m length also will work on 15m just fine. This method of tuning is actually better than a tuner, even a balanced line tuner, because you actually achieve pretty near 50 ohm match right at the antenna, so nothing gets wasted in the transmission line (assuming you use 50 ohm line also). Pieces of pvc tubing make fine insulators. I have also used folded plastic 6 pack packaging (those things that hold 6 cans together). Very lightweight. Getting the dipole up high is nice for dx, but for simple backcountry communications a high pattern is just as good, sometimes better. I've found that low hung antennas do well down in the grand canyon. Near vertical radiation gets out better than low angle.

 
Portable QRP Antennas  
by KC8PMM on August 14, 2003 Mail this to a friend!
I found on last field day that a pair of dipoles facing at 90 degree angles worked great. One was for e-w and the other for n-s. Just like a rotatable antenna.
 
Portable QRP Antennas  
by KK2QQ on August 15, 2003 Mail this to a friend!
Hey all:

I admit I had been standing on the sidelines for BPL (although I did
contribute a decent amount of money to the ARRL Spectrum Defense
Fund), however, it wasn't until I saw the ARRL's Video depicting the
actual interference that BPL generates that really made my blood boil
and got me to file my comments to the FCC.

Here is a link to the shocking video (PLEASE WATCH IT):
http://216.167.96.120/BPL_Trial-web.mpg

Here is an EASY link to let you file your comments about BPL:
http://gullfoss2.fcc.gov/ecfs/Upload/

Tick the top Docket: BPL 03-014
Then Click the Continue Button at the bottom of the page.
Then fill in the form with your comments and hit submit.

If BPL really goes through, I'll be putting almost all of my Ham
Equipment up for Sale -- although it'll probably be worthless except
for scrap metal and silicon.
 
Portable QRP Antennas  
by NB1R on August 18, 2003 Mail this to a friend!
Good article! I live in a condo and have good relations with the Association. So, I set up a 20 meter rotary dipole recently that uses two Quicksticks [similar to Hamsticks] I also inserted two extenders [Budd-i-pole]at the inboard ends. The result shows me about two S units better than the G5RV. It digs out the QSO's for me. I also fashioned one for 40 meters that is marginally better than the G5RV. I'm a CW op, yeah, I know, and even the mobileers on CHN read me!
Cheers,
Ned, NB1R
 
Portable QRP Antennas  
by WA2JJH on August 18, 2003 Mail this to a friend!
yUP, The good old dipole or inverted V, always would give you the best range period. The exception of course is a beam.

I have set up inverted V's for hams. Full bandwidth with no tuner. Nice having a 50 ohm antenna from the get go.

The dipole is good too. Faster setup, just a 1.1.5 SWR. No big deal for qrp or qro.

Make them for a few bucks. Some wire, insulators, and if budget permits a balun.

Nice low angle of radiation on the inverted V as well.

The VERTICALS can never touch the performance or bandwidth. The other fancy expensive crap dont cut it either.
 
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