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eHam Forums => QRP => Topic started by: KE7FD on November 05, 2010, 11:14:45 AM



Title: What is your ideal PORTABLE QRPp antenna?
Post by: KE7FD 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.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB6BYU 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.



Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KE7FD 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?


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: N3OX 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 ;D

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.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: AD5X 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


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB6BYU 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.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KE7FD 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.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB6BYU 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.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: W3JJH 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.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KH6AQ 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.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB2WIK 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. :D


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB4TJH 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.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WD4EIB 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


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KE7FD 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


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB6BYU 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.)



Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KE7FD on November 18, 2010, 06:36:45 PM
BYU, you mentioned a kite... Funny thing was that from the hill outside of Prescott Valley back then my wife and I brought a couple of paper kites with us and having forgotten tail material I fashioned something from litter that had blown up there.  The kites were so high up we couldn't see them due to the strong updrafts and winds around Mingus Mountain.  As we walked down the hill whenever we encountered more litter, I would pass it up the line where the draft carried it up towards the kite.  By the time we made it back to the base there was quite a long trail of trash I was able to reel in.

Here's a portable antenna of the genre I was thinking of:
http://www.w0ch.com/travel_antenna/travant.htm

Glen


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: N3OX on November 18, 2010, 08:33:21 PM
I ran some models and I think it's going to be a close call  in terms of performance between W0CH's "whip" and replacing the other half of a whip with another quarter wavelength wire laid out in the same way as the single "counterpoise" wire.

Note that Dale talks about propping up his dipole on really short things.  A couple-foot-high dipole might beat or equal the short whip and one counterpoise wire.  An eight foot high boulder might be like a tower for a dipole in this context.  I'm almost tempted, based on my modeling this evening, to call the type of antenna you're proposing a "short half-dipole with a heavy, loss-adding, breakable, bandwidth-narrowing, loaded counterpoise whip."

People build them all the time and try them and they work, and people think of it as a short ground plane vertical.  But it's just not quite right.

You might be tempted to figure that if you have to put  "counterpoise wire" right on the ground, it will radiate better if you have a short whip than a dipole on the ground.  But it doesn't really.  It's actually going to become very directional in the direction of the radial.  In that direction it will work only a couple dB better than a dipole right on the ground, but in the other direction it will be 20dB down or so.  Not really necessary to have a beam out in the field if you're going to run a few watts to a -15dBi antenna in either case.  It really only helps for reception, and you probably don't need help with that in the wilderness working people who can hear you.

I tried another case with the feedpoint up about four feet, and the four-foot-high-apex inverted vee seems to beat W0CH's design a bit (again, the whip+counterpoise seems directional)

These predictions would bear field testing (which I think Dale has already done a lot of), because we need some verification of really-close-to-the ground stuff.  I trust it a little more since N6LF's radial studies, so I think this might be the real situation.  And what it looks like to me is that there's not much reason to not take out the whip and coil and use another quarter wavelength wire in its' place.  It might seem against all that's holy in ham radio to use a two foot high or even an on-ground dipole, but that might actually be the better option

On the ground isn't a good antenna, not by any stretch of the imagination.  But it might not be especially worse than a 7 foot whip loaded with a PVC coated high reactance loading coil fed against one wire on the ground.  This is the thing you need to go ahead and test out.  Ultimately, you want the best antenna, not the one that makes you feel less weird.  It's deeply weird to me to consider a zero-height dipole or one propped up on a backpack or something.  But what if that's a better radiator than a more complicated and more easily broken antenna like W0CH's?




Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB6BYU on November 19, 2010, 09:19:10 AM
I've hoisted 150' of wire with a kit in a slight breeze (because that was all we had that day), but
it would require a bit more wind to keep it steady.  But that is a whole different discussion...


I'm certainly not saying that a small loaded whip won't work.  Again, a lot depends on each operator's
personal preferences.  It is much easier to make a short portable whip work well on 10 or 20m than
on 40 or 80m, for example.  A low dipole on 40 or 80m typically won't work much DX, but usually the
radiation pattern will be better suited for local contacts than a whip.  And if you are sitting by salt
water (especially in an aluminum canoe) it is hard to beat a vertical antenna for low angle radiation
on any band.  There is no "one best solution" for all operators.

Going back to N3OX's analysis - it is actually quite difficult to predict the performance of antennas
installed in irregular rocky terrain, especially the volcanic peaks that characterize much of the west
coast.  First of all, you don't know how much of the antenna will actually be close to the ground,
since the surface typically is very irregular.  Second, you don't know the characteristics of the
rocks:  some of the magma is heavy, with a high iron content.  Some is very light, like pumice.
The RF characteristics are very different.  I remember talking to a station in Nome who just
laid his dipole wires on the ground, because it was dry sand and nearly transparent to RF - the
antenna was effectively 100' high.

If the ground isn't flat you get other effects:  a low dipole can have a very low angle of radiation for DX
when installed at the proper height over sloping ground.  Looking off the edge of a cliff changes
the pattern as well (or tying the antenna between two rocks with a 300' drop beneath it, which may
be possible with old semicircular volcano remnants.)


In the end, perhaps the best recommendation is to try a number of antennas and see how they work
for your needs.  It's not hard to build the W0CH whip and a dipole and take both to the top of a hill
to see how they compare in the situations you typically encounter, on the bands you like to use.
People make different tradeoffs between convenience, size, and efficiency.  For temporary testing you
can use any sort of whip and a chunk of coil stock tapped with a clip lead.  Similarly, try the dipole laying
on the ground with one wire raised as a semi-vertical.

Experiment. Try different things.  Be creative.  And have fun.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KE7FD on November 20, 2010, 06:30:41 AM
Two very good lines of thought, N3OX and WB6BYU.  At the locations I spec'ed out, one would allow a dipole to be draped across the rock outcroppings while the other might not with dirt and small shrubs making the vertical the better option.  BYU's closing thoughts of build and take both is where I think I'd like to leave this train of thought.  Between now and the spring I'll have time to build two antennas for this purpose then try them out.  The results of such a test might not be all that conclusive but I suppose if there were hordes of hams that did this there might be some marginally meaningful information that would come of it.  I do think one item on the list of things to take will be a couple of collapsible fishing rods; light and small enough to stuff into a backpack with the rest of the gear without adding very much weight at all.

Thanks again.

Glen - KE7FD


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: N3OX on November 20, 2010, 08:42:26 AM
I suppose if there were hordes of hams that did this there might be some marginally meaningful information that would come of it. 

Yeah there would.  It's a shame that more people don't really test things.

A lot of people build an antenna, feel that "it works just fine,"  and then go ahead and recommend it with no further testing.  This really puts a kink in the process of people trying to figure out which antenna is best for them.  There are a proliferation of "antenna designs" by individual amateurs and commercial firms that have no accompanying predictions or test data, even simple solid A/B testing over a long time.  Sometimes I feel like people build a thing that isn't so terrible as to shut down all contacts and on that basis claim it's a "design." That's why I wrote this article:

http://www.eham.net/articles/20174

It's like "OK, fine, it "works" on the air, but why should I make my life complicated by building it?"  A simple scientific method is the best way to assess antennas, and I don't mean "with lots of fancy techniques or test equipment" when I say "scientific."  I mean:

1) Make some sort of guess or prediction for how your new idea is going to work compared to something else simple, like a dipole or ground plane.
2) Actually test that prediction and see if you were right or not.  If it's a tight race, be very skeptical and make the new antenna prove itself despite your best efforts to show that it's NOT working the way you predicted.

This is the hard thing, I think.  People don't seem to like to be self-skeptical.   It gets so bad that there are sometimes reported "results" on people's antenna websites that are literally impossible.  The more common thing is that people report stuff that's just not objectively useful, like "of course, it doesn't work as well as a dipole," without telling you how bad it is.  But every once and a while their design cannot possibly work like they say.  They've managed to badly mislead themselves, either messing up their on-air tests badly or by not including all possibilities in their explanation.

Oh well.  The ham who does solid comparison testing has a leg up on those who don't...


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: K4AHO on November 20, 2010, 02:28:27 PM
I have used several configurations of portable antennas in the local parks over the last few years.   I tried a 52’ center fed doublet as an inverted V and flattop using a balanced feedline, balun and K1 internal tuner with mixed results.   About a year ago I purchased a PAR 40/20/10 QRP EFHW antenna and have had amazing success with it…  I tried vertical, sloping and dipole configurations.   The most successful configuration has been the sloping configuration. After reading “Sloper Antennas” by OE5CWL I realized that anything less than 50 degrees of slope was a high angle radiator… I cut a ½ wave piece of very lightweight wire, hung  it from the top a MFJ mast, sloping at 60 Degrees and used the PAR Balun as 20 meter matcher. I had what I thought was a very successful 4 hour run during the QRP Afield Contest, 33 contacts, 5940 points and 3rd place.  And I am not much of a contester… Last weekend, I tried another site that allowed me to hang the PAR from a Pine tree and keep the lower end about 10 feet off the ground. Worked several SOTA guys.  Seem to work very well on 40 as well…

I also tested the issue of using a counterpoise with the PAR EFHW with an AIM 4170 completely isolated from ground and computer(using a Bluetooth RS-232 link).   I found that the PAR 40/20/10 EFHW only needs about a 3 foot counterpoise to work well and will happily work with any feedline over that. 

I think what really counts here is matching your mission Antenna to the prevailing propagation and available resources.  If you want to make close in contacts then a low dipole on 40 or 30 is great, On 20 you are wasting RF.  For DX contacts using a EFHW at 90 degrees vertical will do wonders, see the W1PID site. If you want  stateside contacts 90 degree vertical radiates at a too low Angle of Radiation to be effective. Spends too much time in the D layer and gets attenuated.   A 60 degree sloper has a slightly elevated Angle of Radiation which spends less time in the D layer, less attenuation and more successfully with  stateside stations. Of course working Washington/Oregon state from Florida, all bets are off.   Whatever works…

72

Jim
K4AHO


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: AURICH on November 20, 2010, 07:33:03 PM
My ideal portable QRP/QRPp antenna is the Par End Fedz 10/20/40. Short (40ft), end fed, rolls up small, 3 bands/no tuner, setup in any configuration, relatively inexpensive. I feed mine with 25' of RG-174.

With one support I can be operating in a matter of minutes while the next guy will be untangling wires and fiddling with seperate baluns, tuners, counterpoise wires, etc.

With the antenna horizontal a mere 6ft off the ground I have worked the Caribbean and Hawaii on 20m. In a near vertical/sloper configurations I have worked Europe and east to Russia, all with 5w or less SSB phone from here in Colorado. The furthest contact with the least power was to Austria on 2.5w which comes out to about 2100 miles per watt. Obviously good band conditions helped, but band conditions mean nothing if your antenna sucks.

Sure, with QRPp some sort of beam would really help, but in terms of KISS (Keep It Simple Stupid), and portability, the Par End Fedz excels.

Luke
KD0FIN


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KB1GMX on November 21, 2010, 11:08:23 AM
I have some portable work and FD experience and the antenna has been either the PAR EF40/20/10
or a home brew 20M endfed and for 10M a dipole or a 10M end fed.  Both cases for the mono band
end feds were oriented vertical using a tree or crappy pole to get it erect. That vertical configuration
is not a compromise antenna as it's full size and high enough.  The other I've done a sloper using
the EF 40/20/10 as thats 40ft long and with the far end at about 35ft from a tree and the feed end
at about 10ft using a fiberglass pole also proved to be very effective as well for even 40M.  Since
my preferred mode is SSB QRP and efficient antennas are a must and on 20M a 33ft half wave is only
limited by how high you can get it.  But at 10M it's not hard o get it a half wave or more up (16ft).

The other bands i like to run QRP from the field are 6 and 2M and the usual antenna is a square loop
or a small portable beams.  On those bands a portable antenna and mast of 10-15ft need not
weigh more than 10 pounds all up with 20ft of rg8x. This usually means a 3 element of 6 and
5 element on 2M.  From the hills I've tried that works very well. with 1-5W SSB.

Allison


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: W8MKH on November 22, 2010, 09:59:56 PM
I use a Pac 12 vertical from pacific antennas  have great luck with it it is light and fits into my go bag easily
also have used the super antennas mp1.
Ft 817 pac 12 has done me well for several years  also used mini mite 40mtr 350mw txer with it and have been amazed how well it works
did make new ground radials and it has improved it greatly from the stock ones.

No you cant beat a dipole but this is the next best thing


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: N2QGV on December 05, 2010, 02:22:59 AM
Keeping it simple, Par endfed 10-20-40 w/Icom 703+. No stories or history. It just works.

73
Art


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: AE6RF on December 08, 2010, 10:04:11 AM
Keeping it simple, Par endfed 10-20-40 w/Icom 703+. No stories or history. It just works.

I've used the Pac-12 and the Par end-feeds, both to reasonable success.

One suggestion is the W2FMI "umbrella" 40m vertical. But you'll be putting out radials. Not too big an issue on remote, rocky ground.

Another is one of the short vertical dipoles like some of the Force antennas. I have a buddy who really likes his Sigma-5 for portable work...

73 de Donald


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: AD6KA on December 08, 2010, 10:49:38 AM
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.
 
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.

First you say outdoors on a hill, then you say motel room. Big difference!

Quote
we can't pack cumbersome poles with us.

Not ALL poles are cumbersome or heavy. The thin wall telescoping fiberglass (or whatever) ones from MFJ and others are light and can be easily strapped to your backpack or day pack. I've used one in the field to make both wire verticals with and to support an inverted vee. (Not at the same time).
Use twin lead and a BLT for lowest loss, especially if you are going to use the antenna on more than one band. You may have to guy it if it's windy, and you'll have to put down some radials with a vertical, but there's no such thing as a free lunch.
Which, can I say, seems to be you are looking for.

73, Ken AD6KA


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KU2US on December 12, 2010, 07:46:01 PM
Use the Par 3 band qrp end fed longwire. Find a tree and you are on the air. No radials, no tuning, weighs less than 1 lb. and works great!


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: AD6KA on December 13, 2010, 10:18:30 AM
Use the Par 3 band qrp end fed longwire. Find a tree and you are on the air. No radials, no tuning, weighs less than 1 lb. and works great!

A good plan, but the poster said:
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. "





Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KE7FD on December 13, 2010, 09:11:31 PM
Wow, I'm very surprised this question has been going for over a month. (Your milage may vary.)

Ken, whether I'm hauling a QRP rig up a hill or operating from a motel room it's about the same.  The reason I would be in a motel room in the first place is because I'm probably somewhere on business and have other things to lug around  so toting a 20 amp supply isn't an option (for me anyway).  The backpack is quite literal.  I know this means I've got a compromised-compromise radio/antenna but if I can work a few QSO's instead of wasting time watching HBO or howling at the moon, I'm content.  I think we can look at most of the posts on eHam and can clearly see that assumptions are par for the course.  In this case, the way I operate while on the road or from a backpack differs from how I would say at home or even mobile.  IMHO, as a group we need to be open to the possibility that operating objectives will vary from site to site and situations.

There's been a lot of replies for various wire antennas and some commercially made antennas.  If I can come up with something that would work well enough for a motel room/balcony, I would probably use it as a backpack-portable antenna as well.  Lots of ideas from guys who have tried some different things which I may try too.  I did just pick up a pair of 40m hamstick type antennas so before I take to the road I'll take the time to get them tuned up.  If they work after various tests then I'll report back, if not, then maybe I'll try something else.  I realize there is a certain amount of reinventing the wheel going on here but I enjoy the tinkering too, about as much as making contacts on-the-air.  Life isn't too short for QRP, but if we always use beams, quads and big amps, how will we know if it's our own skills and talents coming together to make a contact and not some products doing it for us?

Thanks to all!

g


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: N2QGV on December 16, 2010, 03:20:57 AM
Wow, hamsticks in a backpack. I am waiting to hear about that.
Anyway, as I said before, the Par 10/20/40 is the most versitile antenna I can take with me. I have even laid it across the top of a 6' wood privacy fence and worked stations. If I got to a place that could not even allow for that, then my "bad" and no operating. Or, I would just go to an area that offered a sky hook. If I knew before hand the Par was a No....... then I wouldl have to choose from my Buddipole Deluxe, Superantenna MP-1, or Miracle Whip. My favorite is still the Par, can't be beat for quick and stealth deployment.

73
Art
Have fun...............


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KATEKEBO on December 16, 2010, 11:51:10 AM
Here is what I use:
- three MFJ mobile whips (similar to Hamsticks) for 40, 20 and 15 m.
- one Buddistic "deluxe" 9 ft telescopic whip for 10m
- Super Antennas MP1 tripod
- four 1/4-wave resonant counterpoises (for 40, 20, 15 and 10m)
- one set of 8 radials (about 8' long each)

The MFJ "sticks" and the telescopic whip fit nicely on the MP1 tripod.  I use the 1/4-wave counterpoises when I operate the antenna elevated (on a wooden deck) or on concrete / paved surface.  I use the radials when the antenna sits to reasonably conductive surface (for example wet grass).

The nice thing about this setup is that it fits into a 4'-long, 4"-diameter cardboard tube for easy transportation, and it does not require a tuner.  Once the antennas are initially tuned, it's a "plug-and-play" setup that does not require field tuning.

I have made QSO's as far as 4500 miles with these antennas using 5W on SSB.

I also have the PAR ENDZ 40/20/10, which is great if you have something to hang it from.  It easily outperforms the "sticks", but the downside is that you need some trees to hang it from.

I also have a Miracle Whip which is OK for transmitting on 10m, and for listening on all bands.  I use a random wire extension (about 12' long) for 20m (never tried it on other bands) with the Miracle Whip transformer and a 1/4-wave counterpoise, and it seems to be comparable to the MFJ "stick".

KD8KQH



Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KV6O on December 19, 2010, 07:33:33 PM
I have traveled all over using my pac-12 antenna - packs small, lightweight - good for use in the field.  But the best portable antenna I have used is an end fed wire fed with an Emtech ZM-2. I can match just about anything with that tuner!  I operated from Puerto Rico with a IC-703, the ZM-2 and about 90 feet of wire thrown into the trees from my third floor balcony and worked all over Europe on 80M - and got great signal reports!

Once while in Framingham (outside of Boston) I was on the 7th or 8th floor of a hotel with the same setup - outside my window and about 25 feet away was the top of a large tree.  I tied one of the hotel shampoo bottles around the end of the wire (and tied the other end to the desk!) and threw the bottle into the tree, where it dragged the wire out about 25 feet, then down about 60 feet. From ground level if you knew where to look you could see the shampoo bottle hanging there :-)

This setup allowed me to work EU stations, as well as stateside with a pretty good signal. 

The Pac-12 works when there are no supports, and is pretty efficient on the higher bands, but nothing beat the end fed wire. Small, cheap, lightweight.

Steve
KV6O



Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB6BYU on December 20, 2010, 12:21:17 PM
 For those of you who use a portable antenna other than a wire - what is the maximum linear dimension
that you would consider practical to carry?  I'm looking at designing a tripod + vertical whip type of
antenna and am wondering what limits I should put on the lengths of the individual pieces.  The last
overseas trip I took I found that my sectional flag pole was slightly too long for my luggage.  At
the moment I'm inclined to aim for 18" or so - small enough that it could go in a carry-on bag.

Thanks!


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WD6GLA on December 21, 2010, 12:08:12 AM
A collapsable 20 foot fiberglass fishing pole  ( maybe  20 bucks )  and either a dipole fed with 300 ohm twinlead  , or a half wave end fed wire with a homebrew matching unit .  Light , cheap , portable , and it works ...... and very well too. 

The rub is the support to hold up the pole .    Now here you have to be creative ... a tripod is heavy to lug around . You said no trees or rocks and that makes makes it more difficult .  A metal support stake takes a hammer to bang it in the ground .  Its heavy .  If you have a vehicle you can use it to support the pole .  On foot  you dont want to lug all that weight .  So each case is different , play it by ear as to where you will be setting up to operate ........... but those two types of antennas are the best for portable work   ,  hands down .   

Bob
N7BDY


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: K2QPN on December 31, 2010, 08:10:55 AM
I have been a fan of verticals since the 1960's. I had been using a Super Antenna MP-1 vertical for years for portable QRP and QRO operating. I had replaced the 6 foot whip with a 12 foot whip. I added a sturdier tripod from Blue Star antennas. Always worked well.

While operating QRP portable his summer I needed to make a quickie antenna. I went to RadioShack and bought 50 feet of speaker wire. I built a NorCal doublet - cheap, easy, quick. Fortunately, my PFR-3 has a built in tuner. 

While doing an ham radio demo for some Boy Scouts, I had the opportunity to compare the MP-1 vs the doublet. The doublet won hands down. I compared them on 40, 20 and 15 meters and the doublet's signals were a good S unit stronger. I was impressed. I bought a 20 foot crappie pole to support the doublet center in an inverted V configuration. I am going to do another comparison but right now a Norcal doublet is my new portable of choice.

73, Bob K2QPN


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB6BYU on December 31, 2010, 09:14:50 AM
Thanks, Bob.  That's the type of comparison that is useful, though of course it depends on the
stations you are trying to work, the soil type, etc.  It isn't so much that  any one antenna is
always better than another (though that may be true sometimes), but rather that certain
conditions will favor one type of antenna over another, and we need to understand the tradeoffs
in our particular circumstances and make a good choice.

We had an emergency communications event a few years ago with units from two adjacent counties
set up in the same parking lot.  One group had 100 watts to a 5-BTV, the other had 5 watts to a
thin wire dipole fed with RG-174.  It was a "valuable learning experience" when both groups checked
into the state-wide 75m net with the same signal strength:  the group with the vertical brought their
radio over and plugged it into the dipole just to see how much difference it made.  Needless to say,
that group now uses dipoles for NVIS operation.  The situation would have been very different if
they had been set up on a salt marsh trying to work DX.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: ZENKI on January 01, 2011, 04:16:43 AM
Dont forget the pseudo Brewster angle,  makes or breaks vertical antennas not the type of antenna.

I operate my K2 from all over the place.  My favorite antennas are these.

Low band interstate short skip work a low dipole. You get 6 db ground reflective gain  roughly. I generally use a 80 meter doublet fed with open wire feedline.(light tv ribbon)

For DX work I like the verticals.  I like using the end fed halfwave for  20 meters. I do use it with 2 gull wing radials. It works well when the ground conductivity is average to good. When its poor I use a 9 meter fiberglass pole  fed with a 4:1 unun as a  all band vertical with as many radials as possible. Near saltwater its a killer antenna.

The best 14 to 30 mhz dx antenna that I have ever used is the HF Skeleton  slot antenna. When this antenna is strung up into a tree say at 35 feet its a killer antenna from 7 to 30, best from 14 to 30 mhz.  I use a spiderpole to erect it and feed it will ladder line for all bands.

The best low band portable/semi portable antenna that I have used for low band DXíng  is the single wire double magnetic slot. It does not require a lot of height and will  keep with with a 4 square. The DX pileups on a magnetic on 7mhz is incredible and it requires no radials.

I am mainly a DXér, i dont put up antennas to talk down the road even when operating portable or QRP. I regularly get accused of not being QRP or a being BS artist by stations running home stations with the typical low G5RV stapled to the house gutter. These are the hams who dont really understand how effective  and important a low take off angle is. All these antennas that I have mention all achieve a very low takeoff angle  when installed at modest heights that can be found at many portable QRP locations.

Needles to say I dont mess with low dipoles, kite antennas or longwires. My first priority is always the takeoff angle then the efficiency  combining factors of ground loss or brewster takeoff angle.

 Try the antennas that I have mentioned and you will be impressed. If you  just want to talk to your friend in the next state a wet string will do on 40 meters. For this I carry a end fed wire thats fed with a 9:1  balun.


If I had to chose one location for portable operation it would be a island surrounded by sea water. Even a miracle whip works from a salt water location, however  the above antennas have given me a good feeling of being LOUD when portable.



Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB6BYU on January 01, 2011, 09:17:00 AM
Quote from: ZENKI

Needles to say I dont mess with low dipoles, kite antennas or longwires. My first priority is always the takeoff angle then the efficiency  combining factors of ground loss or brewster takeoff angle.



Exactly - you have to understand the advantages and limitations of the different antenna types and
how they apply to the communications you are trying to accomplish in your own particular situation.

But don't rule out long wires entirely - they can be quite effective when combined with the proper
topography.  I operated my Argonaut from some logging camps on the islands of southeast Alaska,
and my main antenna was a 130' wire zepp fed with 300 ohm twinlead (since those were the materials
available.)  The best setup I had was for Field Day one year when I hiked to the NW point of the local
salt water sound.  I tossed a rope over a cedar tree at the water's edge then, at low tide, I walked
out on the tide flats and tied off the end of the wire to an improvised support.  When the tide came back
in I had a sloping longwire over salt water pointing Stateside.  That was good enough to break pileups
on KG4 and KZ5 (back when they were DX prefixes.) 

My station was set up on a plank across a driftwood log, operating out of a garbage bag to keep the
rain off the equipment and with the antenna tuner under a plastic hard hat.  I was so busy operating
that I didn't notice the tide had come up to the back side of the log - I almost went Maritime Mobile!


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB4TJH on January 22, 2011, 07:36:37 AM
I like my Par Endz fed half wave qrp antenna for 40, 20, and ten meters. I also use a dipole fed with 300 ohm feedline and an MFJ qrp tuner with built in balun. Both are superb antennas systems.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: IZ4KBS on March 01, 2011, 02:02:32 PM
A couple wires and a small tuner make more sense to me for backpacking.

I've just stumbled upon this interesting thread, so let me step-in. I agree with the two wires and tuner suggestion. I have tried all sorts of setups in the quest for the "perfect" /P antenna: resonant, non-resonant, tree-supported, kite-lifted, basically everything conceivable. Each solution has its pros and cons, of course. In the end I settled on the two-wire-and-tuner, for:

  • Full-size wires: in most practical /P situations they get detuned by the surroundings: think of an hotel room, a balcony, the wire casually hoisted into a convenient tree, etc, so you'll end up needing a tuner anyway. Plus, it's not always (almost never ?) easy to accommodate the 10 meters of wire needed by a full-size dipole, neither vertically (hotel), nor horizontally (crowded beach, hotel room/balcony, etc.).
  • Short whips: terribly inefficient if all you can feed them with is QRP(p). I don't like them.
  • Kites: great fun, but go figure about handiness :) .
  • Trees: rarely mother nature places a suitable one where I need it, if at all.
  • Hoisting weaponry: slingshots, guns, crossbows, you name them. All but safe, clumsy to carry/use, forget them (throw-bags are better, but they still need trees: BTW, tree branches and leaves are lossy, too).


I mean, all the above can be used in specific situations where it makes sense, but none of the above can be seen as an all-purpose /P solution, if that's what the OP is asking for. Hence the two wires, both of 25-28 feet in length: one is the radiator, the other one is the (single) counterpoise. The latter doesn't even need to be laid straight, and it can usually be supplemented by a convenient metallic structure nearby, or often by nothing at all if on 20m and up, where capacitive coupling, the body of the operator and all that can provide all the "ground" that is (reasonably) needed. The radiator can be set up more-or-less vertically with a lightweight fishing pole of suitable length, so that you don't need to rely on local supports, that may not be available. The radiator does not need to be vertical, nor straight, so it can be made to lean out of an hotel balcony/window, and that. Of course you need a tuner, which needs to be small and have a built-in SWR indicator, like the fine NorCal BLT (which can handle unbalanced antennas just as well), or an even smaller homebrew one (here's an inner view of my own 20-40m L-network, which is really tiny: http://www.strozzi.it/users/carlo/hamradio/misc/epsn4945.html (http://www.strozzi.it/users/carlo/hamradio/misc/epsn4945.html)).

Performance-wise, I do not know of any /P antenna which is not a compromise, and resonant wires are no exception: I believe that a low dipole, albeit resonant, isn't all that more efficient than my own two wires. EFHWAs are fine, and Dale's dipoles are the best ones I know of, but try and set them up half-decently out of a hotel balcony or on a crowded beach (unless it's the 6m version, of course). Plus, I have found that over rocky soil, such as atop high mountains, you do need some sort of counterpoise, be it one (or more) separate wire or a run of feedline providing the same function.

Caveat: I'm only concerned with /P setups. Going pedestrian it's a very different problem I have no experience with.

Just my 2-cent, hope it helps.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: N1JWW on March 02, 2011, 04:11:42 PM
Par Electronics End Fedz here...  I have several of them..... 

N1JWW  Jeff


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: NA7U on March 22, 2011, 11:40:01 AM
The simplest pack antenna I ever made and was pleased with was one using a length of 300 ohm twinlead (like Radio Shack sells). You need enough to make a 20 meter dipole plus enough extra length to make a 1/2 wl transformer (can't remember the exact dimensions, but you can calculate it easy enough, be sure to take VF into account). It's all one piece of line. Put a couple of fishing swivels in the end and hoist it up. Works as a 20 M dipole (obviously) and on 40 meters it radiates on the whole line, horizontal and vertical. Light as a feather.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB6BYU on March 22, 2011, 12:30:51 PM
Quote from: NA7U
... and on 40 meters it radiates on the whole line, horizontal and vertical...


Can you explain this further?  Are you changing the feed system on 40m to make it
unbalanced to get the feedline to radiate?  Otherwise the currents will be equal
and opposite in the two wires of the twinlead and it won't radiate.

While this approach does give a good match to 50 ohms on 20m (half wave dipole fed
with 1/2 wave of 300 ohm twinlead) it won't match on 40.  The impedance at the
center of the dipole is probably around 15 -j1000 or so, and the impedance at the
transmitter end of the line would be about 6 - j100, with over 5dB of power lost in
the twinlead (even using an optimistic model.)


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: K9JWV on April 09, 2011, 11:45:41 AM
I do some hiking to activate Summits On The Air (SOTA) and have tried various portable antennas....the ONE that works the best for me and appears to be the most effective, yet simple to erect is this:

A 28' Jacktite collapsible mast with an End Fed Half Wave (EFHW) hanging from the top.  The tuner is a KI6J EFHW tuner ($27.00 in kit form) that will tune from 40 through 15 meters.  The counterpoise is about six feet of wire.  The length of the coax from the tuner to the rig (either an ATS-3B or ATS-4) is about six feet.

I've worked plenty of EU stations from the summits I've activated out here in s/w Utah.

Let's see....$27.00 for the tuner, couple of bucks for the coax and wire, $55 (or so) for the Jacktite - not a bad total cost for an efficient antenna that can be set up in minutes and doesn't need a tree!

Regards, Jim Rodenkirch, K9JWV


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: NX1P on April 12, 2011, 11:13:40 AM
Wire is your friend.  I pack a k2 for adventure motorcycle riding (carry full support and camp way out back on forest roads and trails).  I started out with a roll of #30 bus wire and just ran a wire and counterpoise.  I let the k2 auto tuner to the rest.   That was great but very limited in where I could stretch the wire and I had no idea what the wire lengths were so It was hit or miss on the four bands I had in the k2.  Then I saw someone with a 20 meter full wave delta loop at a camp site and decided to build something a bit more predictable.  With some creativity I built the delta loop fed with 450 ohm feed line and set up the ends so I could close the loop or open it (giving me 40 meters).  I also allowed the ends to detach and become a doublet.  For the final addition, I added two extra lengths of wire, the same length as one half of the delta loop, and provided connectors at the feed point so I could make it a 20 meter ground plane.  depending on the size of the wire you use and length of feed line, this can be very compact and very versatile.  The final addition was a tennis ball loaded with some sand and leader for attachment to a masons line and hand held water balloon slingshot.  This let me get the ends up or center up at about 50 feet in the trees if I wanted.  When sitting on top of a ridge or mountain you can work the world with .5 to 5 watts.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KL7IPV on April 28, 2011, 08:58:30 PM
This is self serving but NOT a for sale reply. Look here: www.antenna-to-go.com

Frank


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KC8VWM on May 08, 2011, 07:14:47 PM
For the person who says tripods are heavy, they dont have to be. The right one can be extremely ultralight and it's folding design can even fit inside a backpack. Did I say ultralight? Yes, I think I did...  

http://i629.photobucket.com/albums/uu18/kc8vwm/QRP/MVC-004F.jpg

http://i629.photobucket.com/albums/uu18/kc8vwm/QRP/MVC-003F.jpg

http://i629.photobucket.com/albums/uu18/kc8vwm/QRP/MVC-013F.jpg

http://i629.photobucket.com/albums/uu18/kc8vwm/QRP/MVC-004F-2.jpg


Anyways here's the link to a maximum performance "take anywhere" QRP antenna. Many photos and detailed information:

http://forums.qrz.com/showthread.php?241775-Clothesline-Reel-AKA-Yo-Yo-Antenna-of-Inslulated-Wire

All bands, no tuner, tree or no tree support required (your choice), and it fits inside a 20" long nylon pouch which includes the feedline.


72, 73



Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: ND6P on May 08, 2011, 07:53:31 PM
Mine is a backpacking antenna that I use when there will be no trees available. 

It's got 5 main parts.

1. A wooden breadboard from the supermarket, with a mobile 3/8x24 mobile antenna mount at one edge.  The breadboard will fit into a backpack for transport and can be held down with a large rock to provide a base for the antenna.

2. A base section from a Hustler mobile antenna.  It's solid aluminum and about 4 feet long.  I use a bolt that has it's head ground into something of a point on the female end and a makeshift handle on the other end to fashion it into a walking stick for helping with the hike.  I remove those and screw the base section into the breadboard when I assemble the antenna.

3. A 12 foot MFJ telescoping whip, fortified with a stainless steel clamp at its base.  This connects to the Hustler base section to operate on 20 meters and can be tuned for any freq above 20 meters by adjusting the whip length.

4.  Homemade loading coils that insert between the base section and the MFJ telescoping whip for bands below 20 meters.

5.  Ground wires, 4 for each band, with alligator clips for easy installation.

This antenna has worked very well as long as the wind is not too strong.

73, Jim, ND6P


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: KF5IIL on May 17, 2011, 03:01:43 PM
In recent months, I have been using a Yaesu ATAS 25 (the manual tuned vertical) with a tremendous amount of success.  Once tuned, it is a pretty slick and effective antenna and works well with my FT 817nd.  A friend of mine and I have made several DX contacts using it as well as many cross country contacts here in the USA.  I especially like it because it packs up into a pretty small package that can be packed out easily and quickly assembled.

I found that it is important to get a really good feel for how to set up this antenna to be resonant and efficient on various bands.  You cannot just casually get "close" and expect good results.  So it is worth it to spend some time with an antenna analyzer and recognize the most effective radiator setups and tuning position combinations on the different bands.  Its accompanying user manual/sheet should only be used as a rough guideline (and ignored on occasions).  Trust the analyzer and especially get a feel for how much (or more importantly how little) twist tuning is needed for specific frequency ranges.

The payoff here is that once you get this tuned, which after some practice and knowledge of this antenna's performance curves, doesn't really take that long, this antenna will work quite well.


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: AD5VM on May 20, 2011, 01:06:37 PM
Ok, I haven't read all the posts but here's my .002.

I am primarily a portable op. I've had the MP-1, buddipole, buddystick, hamstick dipoles, MFJ-apartment antenna, B&W AP-10A, Miracle antenna, MFJ-18XX loaded telescopic whips, MFJ-933 portable magnetic loop tuner and homebrew versions of pretty much all of those. I've also done the remote-base thing with full size mosley tribanders on 30 foot masts, Traffie Hex-beams all band doublets and full size dipoles and once i spent two days at my campsite at 10,500 feet on the top of mt Withington, NM installing a full size 160 meter loop at no less than 45 feet high in the tree tops and fed it with ladderline to a Palstar BT-1500A balanced tuner.... I like operating out of doors... a lot... and I'm also not a CW guy.. Not because I don't know code, I'm currently  #284 on the RufZXP high speed CW toplist. But almost all of my operating is SSB.. Which puts me at even more of a disadvantage when running low power with compromise antennas.  Currently I'm building a Super homebrew buddipole. Using two of the long spreader arms, a homebrew coil on 3" PVC with a tap for 40 and 75 meters and an MFJ-1979 16.5 foot stainless steel collapsible whip. If you don't have an MFJ-1979 yet... Order one. Once the word gets out about this new product, they will be backordered for months. I've also got a ZM-2 tuner and a bunch of precut wires.

All of those antennas preform exactly as you would expect..

-The micriacle antenna and MFJ loaded whips work ok on receive only.
-The B&W AP-10A, hamsticks and hamstick dipoles, buddistick, Apartment antenna will make a few contacts but I found that even though I "worked just about everyone I heard" the signal reports were lousy and and I found myself shouting into the mic and had to repeat everything I said.
-The Magnetic loop tuner actually worked quite well, I sold it but wish I hadn't. I used 1/4" ice maker tubing as the elements but you need one for each band cut to something like 1/10th wavelength. And that is a lot to carry in a backpack.
-The full size buddipole with 10 foot whips on a 16 foot mast/tripod is also a pretty good performer if you don't mind leaving everything else out of your pack...
-The ZM-2 and a bunch of pre-cut wires is a great combo.. Hard to beat, I have an 80 meter loop fed with cheapo 300 ohm twinlead that works well on all bands.
-My favorite remote base antenna is my 40 foot spiderbeam mast with an Icom AH-4 clamped directly to the base. I use a 43 foot wire very loosly coiled all the way up the mast and I have twelve 15 foot radials each with an aligator clip on both ends. I have a six inch piece of ground braid hanging off the ground lug of the AH-4 so I just clip one end of each radial to the braid and the other end to a stick or weed to keep them straight. This works well with my IC-7000.

The best portable antenna in the world is the Par end fedz series. I have an EF-20 an EF-40 and an EF-10/20/40. The EF 10/20/40 will work with any half wave wire 5MHz through 30MHz. I either throw a line over a tree limb or bring my spiderbeam 40 foot mast if I can drive there. The EF-20 and the MFJ-9420 SSB adventure radio and a 5Ah gell cell battery will have DX stations scratching their heads when you tell them you're QRP portable...


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: W1JKA on May 21, 2011, 09:13:10 AM
     As per AD5VM,keep it simple and get a PAR endfed.I like building my own wire antennas but reluctantly sprung for a PAR 20 & 40 meter unit and glad I did.Inverted L configuration hanging from the half way point works best for me with my CUBS and K-1. I do a lot of portable and MM work,get all the contacts I can handle with no tuner or radials to mess with.As always the so called secret! to qrp & qrp dx is your antenna and learning your day/night band proagation.   experiment and have fun.   73   Jim


Title: RE: What is your ideal PORTABLE QRPp antenna?
Post by: WB6RQN on May 30, 2011, 12:08:18 PM
One of my students compared portable wire antennas for a back-pack station for his science fair project two years ago. (He won 2nd place in the Electronics and Electromagnetics category at the California State Science Fair for this project.) He compared four types of antenna:

1. half-wave dipole;
2. full-wave delta loop;
3. 1/4 wave ground plane with 4 raised radials;
4. end-fed, non-resonant wire with a tuner and a counterpoise laid on the ground.

All four antennas were evaluated in the following categories:

1. ease of construction;
2. ease of erection;
3. bulk (it has to fit in a backpack and leave room for other stuff);
4. mass (if it is too heavy, you won't carry it);
5. electrical performance.

He came up with a formula to weight each of the categories in order to provide a single "coefficient of goodness" by which to rank the antennas.

The most interesting factor was, of course, electrical performance. The antennas were compared using my Flex 5000 using one antenna connected to RX1 and the other connected to RX2. Many different PSK31 signals were used as test signals as they are effectively constant power. He took literally thousands of data points and then averaged the results. The loop had 2.3dB gain over the dipole. The dipole and ground plane performed equally well. (The difference in level with polarization changes was dramatic but in the long run, neither had an advantage over the other.) The end-fed wire was the big loser in the performance department, being over 10dB down from the dipole in average use.

FWIW, when he ran his formula, the good old half-wave dipole came out on top with the end-fed wire being #2 based mostly on bulk, mass, ease of construction, and ease of erection.

73 de Brian, WB6RQN/J79BPL