I have operated portable from this location once already, using the 31ft. Jacktite fiberglass pole supporting a 27ft. vertical wire along with the associated ground radials. I made it as far as San Francisco with 2w on 20 meters. We don't have much in the way of mountains in IL, so this was as close as I can get ;)
The view from on top is really pretty spectacular for around here.
This  area is about 10 miles from my QTH.

I remove the top whip section from the Jacktite pole and a 1/2" plumbing elbow with a few inches of stiff plastic tubing over one end fits over the top of the pole. There is a rubber band attaching the wire to the tubing to provide a light tension on the wire.  I tried unsuccessfully lengthening the wire to 30ft. It would not tune on any of the bands with the ZM-2 tuner, but 27ft. works nice and has repeatable tuner settings that allow for complete extinguishing of the SWR LED for 40, 30, 20, 17 meters - no matter where I have put the antenna up. This has saved me on setup time and battery life. I keep reading that dipoles have more gain, and verticals are the worst choice for QRP'ers. However, in my opinion so far this antenna has provided for many more callbacks to my CQ than my original 44ft Norcal Doublet, and not just from Mt. Hoy.

    The 27ft fiberglass supported vertical wire plot is below. This is the antenna for when there are no trees, or when I want to operate at areas where wires are not allowed in trees (Like the entire county forest preserve system here).


   

This ground plane vertical has also made an appearance at another local 'summit', The landfill hill at Green Valley Forest Preserve that is second in height in the county only to Mt. Hoy (Above). This was a great spot to visit as there is a washroom and picnic tables at the top, and you can drive up there.
I hear it is often crowded though, and its only open in the afternoons, and only on the weekends, and only the warmer months of the year.
I'm definately going back there though!

I did not pick the best day as far as the weather for my first visit to Green Valley Hill. The temp was 49F but the winds were 25-30mph at the top. The Jacktite pole collapsed into itself once from the counter force of the guy lines. Check out the bow in the pole and wire that are both normally straight. Like I told one of the guys on the air, I felt like I was in Antarctica!

   

This antenna has also been to Hidden Lake Forest Preserve (Picture below). Luckily, the Park Ranger had no problem with it.

    I have begun experimenting with the end fed half wave antennas (EFHWA) for portable operating now as well. I have found that the colder it is outside the simpler the antenna, the better. The EFHWA antennas substantially reduce my setup time compared to the other types. I ran into an EFHWA design by WB3GCK called the "Dollar Store Special" and started looking at it in the EZNEC demo. I thought his use of modular counterpoise wires to change lengths was clever. The 50ft length of that design did not look too good to me at 20meters in the modeling software though.
  
     So  I made 3 half wave wires for  20, 30, and 40 meters that I use with single 1/4 wave counterpoises and so far the on air results have been great. I can now understand why I have read about QRPers liking the end fed half wave antenna so much. They are comparitively quick and easy to deploy and take down, and small and lightweight.

    The Emtech ZM-2 tunes these half wave antennas with their respective counterpoises just fine (Although it does not claim to).  
However after reading up on tuners, I began to worry about the ZM-2 losses matching 50 to 2000 ohms. I had read that losses become very significant when trying to match above 500 ohms on most tuners, so I looked around online for some more ideas and maybe a better way.
I think I found it at AA5TB's website .  I liked that he tested his matching network and had only .5dB of loss and he explained his methods well for this type of antenna/matcher setup. So I decided to try it out for myself. My goal was one tuner box for 20, 30, and 40m.

    Looking at the EZNEC demo I modeled the EFHWA's for the three bands using the exact wire gauge of the antennas I had with quarter wave counter poises and came up with the impedances 1836, 1960, and 2032 ohms. I selected a turns ratio of  3:19 that would equate to 2004 ohms.

    I did not have any poly varicons, but did have several air variable caps in the junk box. I selected one of the RX type of air variable caps I had that had about the same range as the poly varicons. I found most guys online used a -2 mix toroid for the matching transformer and I happened to have a T-130-2 in junk box as well! I love junk box projects - they are just the best.

    I wanted to include a SWR indication LED circuit though to keep this as a 'minimalist' antenna so I did not have to bring seperate metering.
I was lucky that I could grab some 1W 200 ohm resistors, and a clear LED at a local Frys store for the Tayloe SWR Bridge, and a plastic box at RS. I did not have an FT-37-43 core, but substituted a FT-50-43 core out of the junk box for the detector circuit using the same turns. Although AA5TB states the magic counterpoise length is .05 wavelenths, I could not duplicate this in EZNEC - which with my limited abilities in the software is not all that surprising. So I stayed with the standard quarter wave counterpoise lengths. I elected to use bullet connectors to form one 40m quarter wavelength counterpoise out of the 3 lengths neccessary for all three bands, and remove sections as needed for 20 and 30m.

    Pretty happy guy when it all worked and the light went out, but it is not perfect all the time. At the third location I was using this antenna at I had some trouble matching it. I have found in portable operating that a tuner is almost a must because every operating location is different and what works nicely at one spot may not match up good at another. This is just as true with dipole deployed heights as I also found it to be with this antenna set. So I have made an extra two foot length  of wire to be attached at the top of the antennas or at the end of the counterpoise with bullet connectors should it be neccessary for a good match. Using this extension wire as needed, or selecting different combinations of the three counterpoise wires has been successful so far and I have made the contacts with this setup to prove it and now join the choir of QRP portable Op's who sing their praises of the end fed half wave antenna.

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    UPDATE Fall 2008 ON THE EFHWA TUNER: Well I finally ran into a situation that I could not match wire combinations on ANY band. This was after the ground froze and was also covered with several inches of snow. So I decided to rewind the secondary of the transformer with taps at 17, 18, 19, 20, and  21 turns through a rotary switch to provide some additional matching range. Right now I am thinking that frozen ground and / or snow cover really affects the impedance of this kind of antenna.
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    UPDATE Spring 2009 ON THE EFHWA TUNER: What do you know? I have been out again to 2 of my favorite same spots and all 3 (20, 30, and 40m) half wave wires are tuning fine once again with the dedicated tuner shown below. There is definately some interaction between the frozen ground or snow and the impedance of the half wave antenna that puts it 'out of the ball park' of my dedicated EFHWA tuner. The ZM-2 still tunes the wires in any weather - though with some variances of the recorded settings..
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    Thanks to AA5TB for sharing some great antenna ideas (He no longer publishes his email address as he was swamped with emails). Now I can worry about other things besides tuner loss at high impedances. 

    Below are some pictures of my EFHWA tuner during verification testing of the bridge with a SWR meter in line at the park. I use a piece of heavy duty 3M velcro on the back of the tuner and attach it to a plastic tent stake in the ground.


    This is the plot for the 66.5ft EFHWA below. The 20 and 30m plots are similiar. This is the antenna for when there is not 2 large trees located together suggesting a dipole install, when time is more limited, its very cold, or I anticipate being out after dark.

                                


                                




    Other recent portable antenna projects are a 30m Bobtail, and a 40m Half Square. I have made contacts on both of these antennas, but right now I think they are too specialized (Monoband, low angle reception and narrow / directional gain patterns) for generally operating portable half of a day at a time.
If I were on a DXpedition at some atol - these would be the cats meow.

My favorite current portable antenna is a hombrewed SuperLoop 40 deployed as an inverted delta shape and fed at the bottom with twinlead. This antenna shines on the air as a 20m Bi-Square while still providing respectable results on 30 and 40m in a smaller than dipole length. It provides an approximate 50 ohm match on the 3 bands (A jumper is removed for 30m operation).