"Portable" Antennas

Started by KC9TNH, June 18, 2013, 03:08:46 pm

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gil

Hello Davide,

My 40m end-fed is a half wave. The bottom it about ten feet from the ground. Now, the length of it is 40ft, because of the choke. It's a 40/20/10m model. It must work pretty well because I worked Estonia on 1.2W on 40m, 5200 miles. I do get Russia regularly using from 3 to 6W...

Nice graphs, what program do you use?

Gil.

gil

QuoteIf you're going to DIY a magnetic loop antenna, you could also DIY the variable capacitor...
http://www.alexloop.com/artigo21.html


Well, sure... Or I can work an hour or two and make enough to buy one... I love building stuff, but even though it isn't always cheaper, I try to consider the labor cost benefit...

Gil.

cockpitbob

If you are car camping, a lot of this sounds good, but I wouldn't want to hump the fishing pole, tuner, stakes and guy-lines for the pole and a long feed line.  My end-fed has a tiny coupler and the feed line can be just a few feet long.  I only have to get 1 end of it up in a tree.  I do bring a spool of mason's string, a slingshot with a fishing reel hose-clamped to the side and a few 1oz weights.  After set-up the sling shot has other fun uses.

IZ2UUF

September 09, 2013, 04:31:09 pm #33 Last Edit: September 09, 2013, 05:31:46 pm by IZ2UUF
Quote from: gil on September 09, 2013, 10:52:14 am
Nice graphs, what program do you use?


Hello Gil.

I'm using 4NEC2, a free frontend based on the classic NEC-2 engine.

Davide

gil


IZ2UUF

Quote from: cockpitbob on September 09, 2013, 10:56:13 am
If you are car camping, a lot of this sounds good, but I wouldn't want to hump the fishing pole, tuner, stakes and guy-lines for the pole and a long feed line.  My end-fed has a tiny coupler and the feed line can be just a few feet long.  I only have to get 1 end of it up in a tree.  I do bring a spool of mason's string, a slingshot with a fishing reel hose-clamped to the side and a few 1oz weights.  After set-up the sling shot has other fun uses.


You are right but the situation is not as bad as you are depicting it: I'm also very concerned about weight, since I have to carry it for hours.
- the "long feed line" is 450 ohm window line, which is very light; it could be 300-ohm twin lead, even lighter;
- I carry no stakes, just one fishing pole;
- to hold the fishing pole, I have velctro ties in case I find a little tree or other suitable fixed structures; otherwise I use what I find, like stones;
- the setup time ranges from 10 to 15 minutes, depending on what kind of support for the fishing pole I find.

Finally, my altitude usually is so high that there are no trees:




Davide

Archangel320420

Is it just me, or is IZ2UUF the kind of person we need to come to the USA?  :)

KK0G

Quote from: IZ2UUF on September 09, 2013, 04:56:55 pm
Finally, my altitude usually is so high that there are no trees:



Which brings up a good point; sometimes we forget that our environment can have a huge impact on how we operate portable. Here in the midwest there are tall trees everywhere it seems and my end fed works perfectly in that environment. When I took a trip to Las Vegas last year and went into the mountains and desert to do some portable operating one day, I quickly discovered that I wasn't prepared very well antenna wise for that environment - in many places finding a suitable tree was very difficult to impossible in some places.
"Those who would give up essential liberty to purchase temporary safety, deserve neither liberty nor safety" - Benjamin Franklin

KK0G

Geek

Quote from: Archangel320420 on September 09, 2013, 05:10:58 pm
Is it just me, or is IZ2UUF the kind of person we need to come to the USA?  :)


Seeing his photos, I am tempted to go there.   :)

IZ2UUF

Quote from: Geek on September 09, 2013, 08:43:08 pm
Quote from: Archangel320420 on September 09, 2013, 05:10:58 pm
Is it just me, or is IZ2UUF the kind of person we need to come to the USA?  :)


Seeing his photos, I am tempted to go there.   :)


Don't, it's a dangerous place: there are wild and ferocious animals that like to tear down antennae!  ;D



Davide

gil

Maybe she smelled your socks from a long way off...  ;D

Gil.

IZ2UUF

Quote from: gil on September 10, 2013, 03:45:24 am
Maybe she smelled your socks from a long way off...  ;D


This is a very good point to be remembered for the future: never put boots and socks near the antenna!  ;D

Geek

Cow pies surrounding the spot you left your shoes!   :(

IZ2UUF

Quote from: Geek on September 10, 2013, 08:33:41 am
Cow pies surrounding the spot you left your shoes!   :(


That would be a real nightmare! When I'am surrounded by cows or goats I choose an high and flat stone, something I can defend like a bastion. I've seen cows eating shoes, socks and t-shirts: they chew them for a while, then they spit them out all green colored. Glad that weren't mine! :-)

Davide

KC9TNH

Quote from: KK0G on September 09, 2013, 07:31:48 pm
Quote from: IZ2UUF on September 09, 2013, 04:56:55 pm
Finally, my altitude usually is so high that there are no trees:



Which brings up a good point; sometimes we forget that our environment can have a huge impact on how we operate portable. Here in the midwest there are tall trees everywhere it seems and my end fed works perfectly in that environment. When I took a trip to Las Vegas last year and went into the mountains and desert to do some portable operating one day, I quickly discovered that I wasn't prepared very well antenna wise for that environment - in many places finding a suitable tree was very difficult to impossible in some places.
Yep, there it is. As Davide points out, lichen do not count as vertical structure.  ;D
Those who go above the tree line regularly - or for "that guy" luxuriating on the beach with his Buddipole & KX3 - either accomodates based on what's at hand; rocks, tie off to a shoe & bury in the sand, etc.  Being in a situation like "that guy" is on my bucket list but further down. In my real-life I'm blessed like KK0G with lots of antenna supports that give off oxygen. We seldom get the fantasy, it's what we do with what's in the windshield that defines.