Author Topic: Expedient HF Antenna  (Read 7288 times)

Offline Carl

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Expedient HF Antenna
« on: May 18, 2014, 03:30:58 AM »
Though I rarely "GO" anywhere ,I have had a quest to know how to make an effective,easy,quick antenna for some time.This is ,so far,one I have found that is the yardstick that I compare all others against.

WIRE.

I use 35 feet of wire,tied to a plastic water bottle and tossed over a tree limb or sometimes just a bush. With an LDG automatic tuner,though a manual tuner will also do,35 feet of wire with a ONE to ONE ,or better 4 to one balun. is a HALF wave  END FED on 20 meters (my favorite band) plus it is a quarter wave on 40 meters and works well on 15 meters ..I also attach a 17 foot 6 inch counter-poise as a good balance to ground , with one to 3 counter poises being really effective.So it is effective on 3 bands as is ,and tune-able to use on40 through 6 meter bands.

 As  the first thing a signal must do for distance is BOUNCE off of the ionosphere...HEIGHT IS NOT CRITICAL...in fact for best local (on 40 and the 80 wire) it is desirable to KEEP IT LOW ,so as to take advantage of NVIS.

HF works best at long distance...BUT HOW CAN SOMEONE FAR AWAY BE OF ANY HELP??

Well NVIS on 40 and 80 meters allows you to talk to far off...and not so far off stations. The NVIS signal goes up,and back to earth at a much higher than "normal" angle. You can fill the gap between VHF (mostly short range to 50 miles) and HF (mostly 200 miles plus).

  The LOWER antenna also allows for LOWER NOISE..if you can't hear them ,you can't communicate.

For 80 meters through 6 meters I use a 65 to 68 foot wire ,with the same  17 foot 6 inch counter poises.

Note...Where did 17 foot 6 inches come to be the 'proper' length for counter poises???
  From my experiments with HAMSTICKS and other "MOBILE" type antennas on a low (3 foot) camera tripod. I found that measure and 3 or 4 counterpoises to be most tune-able and effective . 17'6" worked with 80 meters down and ,at 10 and 6 meters ...folding them in HALF (easy with gator clips on each end) made for a happy and effective tune.)

I have a number of gator clip equipped 17'6" wires that are used both as counterpoises AND clipped END TO END,also make up the longer part of my 40 or 80 meter antenna.

The mobile whips were effective , and easy to deploy, BUT came nowhere close to the capability of the described wire antennas above. An antenna does not have to cost mega bux to be effective, most of mine are made from donated and garage sale extension cords that I salvage the wire from...and when asked I tell them it is a TH-11 or other MONSTER BEAM and they genuflect and are impressed.I think if I told them it was a wire from the garbage,they would not think it so effective.

The NVIS principals were a MAJOR ASSET during communications during the Katrina aftermath when the HAM community stood tall with emergency and health and welfare traffic ,

This link is to a time compressed audio (it was edited) of one of the events that changed lives ...it is on my GOOGLE DRIVE

https://drive.google.com/file/d/0B5ZIZLZV4AwIVVFOSnUzNFF3Vnc/edit?usp=sharing

Still makes me a bit water-tight,even though it is off the subject.
 

Offline Alan Georges

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Re: Expedient HF Antenna
« Reply #1 on: May 18, 2014, 07:43:01 AM »
Yep, when it comes to regional emergencies, NVIS is perhaps the very best part of ham radio.

Thanks for the audio clip.

Offline Carl

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Re: Expedient HF Antenna
« Reply #2 on: May 18, 2014, 12:06:11 PM »
Thank you for letting me know it downloaded and worked properly,
I was on duty ,as volunteer, for 16 hours plus each of 8 days and the
stress was beginning to show, (day 5)and elder couple came out to
give me a break,and the call to me with results was due to me
going home for a nap as after 4 days ...there weren't as many to rescue.

I had final conversations with many ,as waters rose,who chose the attic
as an escape. How did I talk to them?? SKYPE and the fiber internet allowed
me to call most people even when regular phone service was overloaded
and Cell towers had lost backup power.

Another thing I learned 'on the fly' when DOT cameras in Baton Rouge
and New Orleans were still operational..I discovered I could
call people (listed phone numbers allowed address verify to cut down on hoaxers)
over SKYPE and let them know ,as I got word from HAMs in Florida and Ohio ,that
rescue had been dispatched.

Not everything we tried worked , some things made all the difference.
The Orleans Prison audio was ONE of over 1700 calls that I logged that
8 days,and it was a major effort from all involved.

  We used HAM VHF and HF (the recordings were my vox recorder on ONE repeater)
also SKYPE and Echo Link...plus internet for GPS co-ordinates (for rescue location)
 and phone verify addresses and to email some data to HF HAMs in Ohio so they
could pass info into the gulf region.

There I go,wandering again, I just hope someone can benefit (beyond those who already did)


Offline Carl

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Re: Expedient HF Antenna
« Reply #3 on: January 03, 2015, 09:09:14 AM »
 8)  This remains my favorite portable antenna. LOW COST,easy up,pocket size,and good gain on the 20 meter band. Dollar store speaker wire works GREAT! The $1 antenna.

Offline armymars

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Re: Expedient HF Antenna
« Reply #4 on: January 09, 2015, 06:51:11 PM »
  When I broke my ankle this year my son tossed a 30 plus foot wire over the top of my gazebo on the back deck. On the floor of the deck a 17 foot piece of wire for a counter poise. I could not get to my shack because I could not get up and down the stairs. I lived for 12 weeks in my Lazy Boy with my Icom 706.   I goofed up and connected the counter poise to my center pin and the 30 plus wire to the shield. I was still able to check in to my Mars nets by digital most days. It was not until two weeks later I found my mistake. My PL 259 with alligator clips is now labeled. The wire was 24 ga bell wire fron a small MFJ tuner. The 30 wire ran out the top of the window and the 17 foot piece through the bottom.
  I have a friend who has done a lot of research on end feed wire antennas and the proper transformer is 9 to 1.
 

Offline Alan Georges

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Re: Expedient HF Antenna
« Reply #5 on: January 09, 2015, 09:04:18 PM »
Here's an only slightly confusing chart for picking out random wire lengths, depending on the bands you want to tune:
http://udel.edu/~mm/ham/randomWire/
Yes, I know that makes it not quite so random anymore, but I wanted to stack the odds.  Math: taking the mystery out of life and making it easier since 3000 B.C.

Ran a 136' wire around the yard back around Christmas, tuned up on the 160m PSK31 calling frequency (table: http://www.qsl.net/darn/PSK31.htm), and bagged my first 160m QSO within ten minutes.  Random wires are practical... and fun!

Offline armymars

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Re: Expedient HF Antenna
« Reply #6 on: January 11, 2015, 09:15:43 AM »
  PSK31 is cool. I love copying signals I can't hear , but only see on the water fall. Ghost signals. Hi Casper.  Grin

Offline Greekman

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Re: Expedient HF Antenna
« Reply #7 on: April 29, 2016, 01:36:55 AM »
Carl, where to yuo connect the counterpoise wire?
On the tuner or on the BALUN? (i think the latter)

Offline Carl

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Re: Expedient HF Antenna
« Reply #8 on: April 29, 2016, 05:50:09 AM »
Carl, where to yuo connect the counterpoise wire?
On the tuner or on the BALUN? (i think the latter)

connected to the balun and in one case of an indoor antenna,also one connected to the radio with a counterpoise of 6.5 for 10 meters,17 for others bands to 40 meters,and 34 feet for 80 meters and up . The arrangement of antenna and surrounding soil and structures effect how the antenna reacts...also I prefer LDG EXTERNAL matcher as radio/internal tuners often do not have the range (matching ability) to cover all bands well..though this antenna was used by me on 6 through 40 meters .

Offline Carl

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Re: Expedient HF Antenna
« Reply #9 on: April 29, 2016, 05:54:25 AM »
Here's an only slightly confusing chart for picking out random wire lengths, depending on the bands you want to tune:
http://udel.edu/~mm/ham/randomWire/
Yes, I know that makes it not quite so random anymore, but I wanted to stack the odds.  Math: taking the mystery out of life and making it easier since 3000 B.C.

Ran a 136' wire around the yard back around Christmas, tuned up on the 160m PSK31 calling frequency (table: http://www.qsl.net/darn/PSK31.htm), and bagged my first 160m QSO within ten minutes.  Random wires are practical... and fun!

Good chart ALAN, Random is confusing but actually refers to random FREQUENCY which makes them more specific than the "any old piece of wire will work" theory.

Offline Carl

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Re: Expedient HF Antenna
« Reply #10 on: September 17, 2016, 07:01:43 PM »
With increasing antenna activity ,I thought it perhaps good to cause this subject to float to the surface again.
The first post about some of my antenna experiments...