Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: Prev 1 2 3 [4]   Go Down
  Print  
Author Topic: What is your ideal PORTABLE QRPp antenna?  (Read 52256 times)
NX1P
Member

Posts: 2




Ignore
« Reply #45 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.
Logged
KL7IPV
Member

Posts: 984




Ignore
« Reply #46 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
Logged
KC8VWM
Member

Posts: 3119




Ignore
« Reply #47 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

« Last Edit: May 08, 2011, 07:27:42 PM by KC8VWM » Logged
ND6P
Member

Posts: 94




Ignore
« Reply #48 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
Logged
KF5IIL
Member

Posts: 22




Ignore
« Reply #49 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.
Logged
AD5VM
Member

Posts: 26




Ignore
« Reply #50 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...
Logged
W1JKA
Member

Posts: 1716




Ignore
« Reply #51 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
Logged
WB6RQN
Member

Posts: 484




Ignore
« Reply #52 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
Logged
Pages: Prev 1 2 3 [4]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!