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Author Topic: What is your ideal PORTABLE QRPp antenna?  (Read 51825 times)
KE7FD
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« on: November 05, 2010, 11:14:45 AM »

OK, let me take this one item off the radar right at the first: We all know that portable antennas are not as good as even the typical antennas we use and while high on portability they are low on efficiency, so please let's not beat that horse yet again.  And along with that, yes we all know a full-size 5 element 80m quad will out perform a hamstick.  What I've not seen in any recent posting is what portable antenna(s) have you actually used (not read about in a book or another posting) but actually used and tested, along with your QRP and QRPp station.  Let's keep antennas like dipoles out of this response because even though it can often be put up in many locations, it's really not portable in the strict sense of the word. Many of us have grab-n-go kits where we can grab a 100 watt radio and all the fixin's in a box or two and have a pretty nice set up, good enough for a Field Day site.  No, what I'm asking for is what can you cram into a backpack and run out the door with and maybe hike up a hill side where there aren't any trees.  Are we on the same page yet? Call it what you want, this would be a more extreme QRP site I suppose so share with the rest of use what you used in a minimalist station.
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WB6BYU
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« Reply #1 on: November 05, 2010, 01:13:53 PM »

I've operated from a number of locations over the years that might qualify as extreme:  a mountain peak
on a county line in California where the ground dropped 300' under my antenna.  Another mountain in
Alaska where the vegetation was a few inches tall.  Rocky cliffs overlooking the ocean in West Australia
and New Zealand.  A pasture in Nova Scotia, a beach in Hawaii, picnic areas in Queensland and Tasmania,
several wilderness areas in California, campgrounds in Maine, New Hampshire, Vermont, etc.  All were
operated out of a backpack, some where I just stopped for lunch and put quick antenna, others where I
operated for a few hours or overnight.  Definitely "portable".

And all made contacts,  working stateside from Alaska, Hawaii, New Zealand and Australia (including long path
on 20m on at least one occasion) and some other DX on my old Argonaut at 2 watts out, plus lots of local
work on 40 and 80m.  I haven't yet found a portable antenna that is as efficient, simple, easy to use, small
and light in the pack, and adaptable to many different situations.  Requires no tuning in the field, so I don't
need a tuner or SWR meter.  I can fit everything inside a quart zip-lock bag or the case of my HW-8 with
room to spare (though I have to take it out of the radio to operate or the frequency calibration goes off.)
The whole thing (5 bands - 10 through 80m) weights 8 ounces or less, and I could get that down further
if needed.   Did I mention cheap?

Quote from: KE7FD
We all know that portable antennas are not as good as even the typical antennas we use and while high on portability they are low on efficiency...

Actually mine can be quite efficient.

Quote
what I'm asking for is what can you cram into a backpack and run out the door with and maybe hike up a hill side where there aren't any trees

Yep, been there, done that.  And carried it in the backpack for weeks at a time as well, though the wilderness
or the Outback.


I carry a set of wire dipoles.

I know, you didn't want to hear that, but if you don't think of a dipole as an effective portable antenna,
you're not imagining them correctly.  True, they aren't as practical to use IN MOTION, but that wasn't
what you asked.  If you're thinking about hauling a painter's pole or something else to hold up your
antenna, the same support will work for a dipole (and quite likely a thinner, lighter support will work
as well.)  You can prop up the center on a stick, fence post, ski pole or a convenient rock if you
don't want to carry your own support (I don't, other than my walking stick.)  When situations permit I
can reconfigure the wires as a loop, long wire or other special design to fit the circumstances.


And I've never found a commercial portable antenna that beats it on performance, let alone size,
weight, or cost.

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KE7FD
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« Reply #2 on: November 05, 2010, 05:52:37 PM »

Thanks BYU.  Let me pose this another way.  Let's suppose the FCC imposes a new regulation that in effect states that wire antennas such as dipoles and end fed wires can no longer be used by remote QRP stations because these antennas are too efficient and the 80M/20M crowd can't get a word in edgeways because the QRPp operators are taking over the band.  It would be right up there listed with the rule that says not to use more power than is needed for communications. Are we there yet?  We pretty much know what dipoles can do in the right hands, but what we don't know is if an operator couldn't use a dipole for whatever reason, what antenna could/should be used (other than a dipole)?  Why am I asking this and so insistant? Simply becuase there may be a reason why a dipole cannot be used and some other rabbit needs to be pulled out of the hat.  Was it a pair of hamsticks, an EH antenna, a bowl of spaghetti, maybe it was a telescopic mast with eye of newt taped to the top?  What non-dipole portable antenna have you used that is Supercalifragilisticexpialidocious?
« Last Edit: November 05, 2010, 06:10:09 PM by Glen Roberts » Logged
N3OX
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« Reply #3 on: November 06, 2010, 10:52:23 PM »

This is one of my favorite concepts:

http://n0lx.com/short_zepp.html

Just take a short loaded dipole and voltage feed it instead of center feed.

PY1AHD has some interesting ideas for magnetic loops:

http://www.alexloop.com/

though I think a magloop is going to be a bit worse than a similarly portable short dipole type
antenna in a lot of situations. 

I know you wanted "first hand" reports, but you'll not get them from those guys.  As far as I know they don't participate here.  Plenty of "first hand" reports at their websites.

Quote
Was it a pair of hamsticks, an EH antenna, a bowl of spaghetti, maybe it was a telescopic mast with eye of newt taped to the top?

That's an excellent list of the opposite of what you're looking for Grin

Truly good antennas don't have gimmicks.  They don't have fancy names, marketing campaigns, "new physics" BS or magical black boxes.  Good portable antennas have losses that are held to a minimum for the size, simple, rugged easy to adjust loading/matching systems and minimum weight.

There is one straightforward rule to building the best shortened portable antenna.  Decide on the length you want and then make the current as high as possible over that length, without making the antenna too heavy or unusably narrow in bandwidth.

I see very few projects that actually bother trying to do this. 

Quote
What I've not seen in any recent posting is what portable antenna(s) have you actually used

I think you're barking up the wrong tree.  I know that some people don't trust anything other than first-hand "real world" reports, but trust me... many first-hand "real world" reports have absolutely nothing to do with how well an antenna actually works. Lots of people will give opinions on things they use and are happy with even if those antennas are objectively terrible.  They never do any kind of accounting for variables other than their antenna.  They're never even a little bit critical of its performance as long as they don't get frustrated with it.   All they do is feel like it's working well. Other people's good feelings don't make your signal even a fraction of a dB louder.

Shortened antennas are very simple objects.  Anyone trying to do anything fancier than good lightweight loading coils is probably a little misguided or  blowing smoke up your mast trying to sell you something.  The Buddipole is an example of a decent way to build a short loaded portable antenna.  Some tubing, some coils, some whips.  Simple.  Boring even.  N0LX's antennas do exactly the same thing but instead of feeding them in the middle, he feeds them at one end against his body/backpack frame just like you'd feed an end fed half wavelength wire.

And if you really really need some "real world experience" to take this seriously, I can tell you that N0LX sounds pretty darn loud for a guy walking around in Colorado with his antenna strapped to his back and 5W of power.

So if you don't want full-sized dipoles, then move on to shortened dipoles with lumped inductor loading.  The endless quest for something better than this keeps coming back around to simple loading coils.  The huge number of different shortened antennas sold commercially and constructed by homebrewers is not indicative of a huge range of good choices.   A lot of people who play with different antennas seem to have being different as the most important goal.  Maybe they  think they're going to stumble on better but ultimately they're just building the same old loaded antenna in a slightly different way... and often in a worse way because their design process is something like "wind some wire on some sticks until the SWR goes down."  This even applies to a fair number of commercial products.

Some people do a very careful weeding out process where they pick the thing that gives them the strongest signals within their constraints... like Dale's dipoles.  The best antennas are probably going to be pretty simple and certainly aren't going to involve any eye of newt.
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73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
AD5X
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« Reply #4 on: November 07, 2010, 04:20:34 AM »

Tough to beat a dipole.  Here's what I use for all my portable operation - QRP or QRO:  www.ad5x.com/images/Articles/Dipole%20RevA.pdf.

It is full-length on 20-10 meters, and inductively loaded on 40 & 30 meters.

Phil - AD5X
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WB6BYU
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« Reply #5 on: November 07, 2010, 08:10:10 AM »

Quote from: AD5X
...Here's what I use for all my portable operation...

My only concern is the sharp angle where the wire leaves the lug at the center insulator - that looks
like a weak point.  I'd wrap the wire around the hanging rope or something to take the pull so that
the lead to the lug is not under stress - this is especially important when using small wire.


When hiking above timberline or in open grassland or desert with a bit of a breeze, you can use
a kite to hold a vertical wire aloft.  Oh, sorry, we weren't supposed to use wires for some reason...


I've got a 10m Ringo with a broken ring that I can tune as a quarter wave vertical on 10 - 20m that will
work for portable, though it is a bit big for backpacking.  I've also got a some 4' lengths of tubing
from old CB antennas that I can stack up to 32', and another set of tent poles that currently go to
15' (but I've got three more sections to add to it once I get them properly swaged to fit together.)
Either set would make a reasonable vertical for 40 - 10m, and they are light enough that they aren't
too heavy in my pack (though the length isn't as convenient.)  If I was going to be serious about it
I'd probably get some 6' telescoping aluminum sections and use them nested for my walking stick, then
extend them to 20' to 29', depending on what bands I was planning to operate.  But I can't speak
from experience on that, as much of my portable operation has been local work on 40 and 80m, and
a dipole far outperforms a vertical for that, so the tent poles only get used as antenna supports.


A full length CB whip makes a good half wave end-fed vertical for 6m operators.
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KE7FD
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« Reply #6 on: November 08, 2010, 07:16:58 PM »

All, thanks for all the comments, really.  What I was trying to do was get a little bit beyond the illumination of the typical antennas that get the spotlights.  If I'm operating from a motel room, most 40m dipoles just aren't going to work, and for that reason I wanted to know what other non-dipole antennas were working.  At the same time, it's entirely possible that I might grab the qrp gear and head off to a bald spot of a hill, so one never knows.  Most likely the grab and go kit will have a dipole in there too, like a spare tire in the trunk, take it or you'll wish you had.

Right now I'm toying with a "notebook" antenna, http://www.io.com/~n5fc/notebk_ant.htm, and depending on the results might keep it on the shelf.  And though I have an antenna tuner to take with me, when I'm on the road, getting to try out some of the more motel room friendly antennas will surpass anything on HBO.  Other operating sites may offer a tree to hang a wire antenna but if there isn't one, maybe I'll ask you Dan about using a balloon.
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WB6BYU
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« Reply #7 on: November 08, 2010, 08:40:18 PM »

Part of the problem is that there are so many antenna options, and so many different situations that we
may find ourselves in, making it difficult to generalize.  So a question about "what to use from a hotel
room" would get very different responses from what to take to the top of a bare hill, and the answers
also depend on the band and distance you want to cover.  Those are big variables - working DX on 20m
or 15m takes a very different antenna than local ragchews on 40m or 80m.

The last two times that I remember operating from a hotel room I was able to get a wire outside - one
tossed over the roof from the balcony and the other used a grappling hook made from a wire coathanger
tossed into the rain gutter of the building across the back alley and fed against the radiator for a ground.
(So I had two radiators in the circuit - one of RF, one of heat.)

We all end up designing our stations and antenna systems to our favorite style of operating and the
situations we are likely to encounter.  If you stay in motels you can often park close enough to run a coax
out to the mobile whip on your car, which is probably better than a lot of other options.  If I regularly
operated from hotel rooms I'd look into other options (though the notebook antenna IS, after all, a wire
dipole...)  It also depends on the relative priority of operating HF vs. other activities:  when the windows
don't open and I'm enclosed in a steel building for one night on a business trip, I'm likely to
sleep rather than trying to set up an antenna.  If I'm vacationing for a week by the ocean it may be
worthwhile finding a way to set up a temporary vertical on the beach to enjoy the effects of the salt
water.  (Assuming, of course, that I have room for ham gear in my luggage.)


So perhaps a productive approach for this thread is to look at different situations and what antenna designs
could be useful.  I know one time that I wished I could put up an antenna and my dipole wires were
unsuitable was riding the train across Australia for a couple of days - though I discovered that the conductor
was also a ham, and he told of a friend who had managed to put a 10m mag mount on top of the caboose.

At one apartment where we were staying for a couple weeks one summer I used a commercial mobile
whip (Bandspanner) stuck horizontally out the upstairs window, held by a rope that ran out from the
top of the window.  The building had aluminum window frames which were all bonded together making
an excellent ground plane.  A telescoping fishing pole supporting a wire would also work in such a
situation.
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W3JJH
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« Reply #8 on: November 09, 2010, 04:09:12 AM »

None of the portable antennas that I've used that will fit in a backpack and that don't have at least one long piece of wire (as, for instance, a counterpoise) are particularly useful.  I have an Outbacker Outreach that packs into a thin bag and that is no bigger more difficult to carry than a fishing rod, but it doesn't fit in my backpack--and it requires either wire radials or the much more bulky Alpha Delta stand.  With the stand or the radials, it works well from 40 m up, but it's dumb on 80 and deaf and dumb on 160.

A couple wires and a small tuner make more sense to me for backpacking.
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WX7G
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« Reply #9 on: November 09, 2010, 04:36:46 AM »

I almost always use a resonant dipole. I QRP where there's a tree to support it.

When using the Elecraft KX1 I use two 25' wires, one on the ground and one to a tree.
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WB2WIK
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« Reply #10 on: November 09, 2010, 08:14:13 AM »

When a dipole/inverted vee or similar is simply impossible to deploy or I have no time at all to mess around, the portable HF antenna I've been using for years is this one:

http://mfjenterprises.com/Product.php?productid=MFJ-1788

It's small, it's light, it works incredibly well and you don't need to drag along a tuner because it has its own tuner built-in.  It fits in my trunk, and I've put it on the luggage carts at dozens of hotels and had it brought up to my hotel rooms.

Hung this from a piece of string tied to an overhead planter on the balcony of the Disneyland Hotel in Anaheim several years ago when we were staying a few days on vacation during a school break and busted pileups with it on CW with 2.5W from the FT-817ND on battery power.  Of course, the balconies there are up about 16-20 stories above ground, so the antenna had some elevation; but I've had great success hanging it from a low tree limb at campgrounds.  Takes about 90 seconds to set up and install, and it "tunes itself" in a handful of seconds.  Works 40-30-20-17-15 meters (no 80m or 10m).

You might consider it; I think it's one of the best investments I ever made for portable operation -- have had it about 10 years now and used it dozens of times, so the "cost per use" comes down every year. Cheesy
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WB4TJH
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« Reply #11 on: November 11, 2010, 08:35:20 AM »

My Elecraft K2 and my Par Electronics 40/20/10 end fed antenna are a good, workable combo. I also carry a length of random length wire and an MFJ qrp tuner.
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WD4EIB
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« Reply #12 on: November 14, 2010, 04:12:28 PM »

Glen,
     I use a 16' flag pole from Harbor Freights, on top where the ball goes i put a 1" bolt which is 3" long,I use the mini dipole at the top,I add 5' of 1-1/2"Poly
pipe at the bottom gives me 21 feet total height I use 50 feet of coax make air choke at top
Use this with my 9040 and 9440X at the beach N.C and in WVA.
                           Roy WD4EIB
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KE7FD
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« Reply #13 on: November 18, 2010, 12:45:23 PM »

Thanks for all the posts to this thread.  When I was much younger, I used to live in Prescott, AZ where there are many very remote and hard to reach locations (nothing like places found in say  Alaska however...).  Two such sites are Thumb Butte mountain (4.546811,-112.519613) and a bald, extinct volcano outside of Prescott Valley, AZ (34.591107,-112.371203).  Use google maps and take a look at these places.  There are no trees to hang wires and just getting safely up to the peak requires the use of two free hands (Thumb Butte anyway). We're not talking about the picnic grounds at Ft. Tuthill but barren volcanic rock jutting up with grand vistas in every direction.  While I no longer live there, I still like to seek out these kind of sites because if I can squeeze enough juice out of my Rockmite (etc) into my _____________ antenna, then I'm pretty certain an airlifted full gallon rig with a small antenna farm in crate would work great.  This wasn't an attempt at the Kobayashi Maru (http://en.wikipedia.org/wiki/Kobayashi_Maru for all you non-Star Trekkers); we can't alter the environment of the setting like James T. Kirk did.  We can however, make do with what we can bring with us and sometimes a dipole won't work because there are no trees and we can't pack cumbersome poles with us.

I'll admit, I set the parameters pretty narrow in my post at the beginning and as expected, there are a lot of Captain Kirks out there who would like to change the "no-win scenario" of no wire antennas.  Still though, there were several posts that managed to convey what really worked for them in actual remote ops.  Overall, I would say that everyone still contributed great ideas because more often than not, we do have some control over the sites we set up at.

Thanks again.

Glen
« Last Edit: November 18, 2010, 12:49:43 PM by Glen Roberts » Logged
WB6BYU
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« Reply #14 on: November 18, 2010, 01:48:34 PM »



Sounds rather like when I set up on the NW edge of Thunder Mountain on the Alpine/Amador county
line for the California QSO party ( 38.675727, -120.093055 ).  (I think that is the right point -
it was 30 years ago and the map doesn't show the county line.)  I couldn't take optimum advantage
of the mountain itself because the county line ran just West of the peak.  I combined my wires in
various ways hanging from the rock outcroppings.  Weight was critical, as I was camped out overnight
along the ridge and needed all the water I could carry.  My HW-8 and Argonaut got the highest score
in both counties that trip, though I took a rather relaxed operating approach.

You just have to be creative sometimes in how you install your antenna!

(A fabric parafoil kite hoisting a wire is another solution for such situations.)

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