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Random wire question

Singularity35

DU7DVE
Jan 16, 2014
425
90
138
Small City, Philippines
Hey guys, I need your help again.

We are moving house once again. I may not be able to immediately put up an antenna where we're going but as a crazy ham, I'd still want to get on air as soon as possible. I'm thinking random wire into my tuner. 40 meters is where I want to operate in. How long should my wire be or is there any length that I should shoot for? Thanks in advance.
 

2RT307

Sr. Member
Nov 22, 2011
2,326
799
223
Texas
Hey guys, I need your help again.

We are moving house once again. I may not be able to immediately put up an antenna where we're going but as a crazy ham, I'd still want to get on air as soon as possible. I'm thinking random wire into my tuner. 40 meters is where I want to operate in. How long should my wire be or is there any length that I should shoot for? Thanks in advance.

Not sure which tuner you have... does it have a balun? I run a 9:1 unun on my random wire, and only had about 50 feet to run it. See if this link works (it's where I got my unun and wire calculations):
http://www.balundesigns.com/content/Wire Lengths for 4 and 9-1 ununs.pdf

73,
Brett
 

camaro1

Well-Known Member
Nov 2, 2012
1,077
463
93
wisconsin
i have 2 of the 9:1 unun's one is hooked to a 33' wire hanging in a tree and the other is a sloper from the top of my tower down to a tree 72' long, both work fine and have no problem making contacts on most of the bands
 

Singularity35

DU7DVE
Jan 16, 2014
425
90
138
Small City, Philippines
Thanks for all the quick replies, much appreciated.

Not sure which tuner you have... does it have a balun? I run a 9:1 unun on my random wire, and only had about 50 feet to run it. See if this link works (it's where I got my unun and wire calculations):
http://www.balundesigns.com/content/Wire Lengths for 4 and 9-1 ununs.pdf

73,
Brett

My tuner is an MFJ-949E. It's supposed to be able to handle a random wire. It has a terminal at the back for a random wire but I've heard that there are some lengths to avoid, for instance a half wave on the band I'm operating on.

I probably can't get a commercial unun because shipping from the states takes a long time to me and by the time it gets here, I'll probably be able to figure out a way to put up a loop or a dipole.

Is an end fed antenna the same as a random wire?
 
Last edited:

Captain Kilowatt

Professional Amateur
Staff member
Apr 6, 2005
16,992
11,420
823
59
Nova Scotia,Canada
I don't know that an EFHW is a "random wire" however.


Exactly. An EFHW is precisely measured to make a half wave. A random wire is simply that. Random. Take a roll of wire and connect it to your feedline/antenna coupler and start walking. When you get to a convenient end point stop. Cut the wire and hoist it up. THAT is a random wire. It is self explanatory. Random.
 
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DainBramage

Well-Known Member
Sep 28, 2014
536
317
73
62
Exactly. An EFHW is precisely measured to make a half wave.... Cut the wire and hoist it up. THAT is a random wire. It is self explanatory. Random.

... or you could just spin the VFO a bit and ............
hide.gif
 

Road Squawker

Sr. Member
Jan 19, 2011
1,954
1,510
173
You lost me. Not sure what that has to do with the difference between a random length of wire and one measured and cut.:confused:(n)

because by changing the freq,it wouldn't be exactly cut for the new freq and the EFHW would really be a random one, anyway,.. it was just a joking comment
 

Singularity35

DU7DVE
Jan 16, 2014
425
90
138
Small City, Philippines
Exactly. An EFHW is precisely measured to make a half wave. A random wire is simply that. Random. Take a roll of wire and connect it to your feedline/antenna coupler and start walking. When you get to a convenient end point stop. Cut the wire and hoist it up. THAT is a random wire. It is self explanatory. Random.

Thanks Cap, I think I get the difference between an end fed and a random wire.

Any lengths to avoid or to go for if I want to operate on 40 meters?
 

Chameleon Antenna

Versatile, Dependable, Stealth and Built to Last.
Nov 25, 2015
30
8
68
Santa Ana
chameleonantenna.com
Hey guys, I need your help again.

We are moving house once again. I may not be able to immediately put up an antenna where we're going but as a crazy ham, I'd still want to get on air as soon as possible. I'm thinking random wire into my tuner. 40 meters is where I want to operate in. How long should my wire be or is there any length that I should shoot for? Thanks in advance.

You should look at the CHA EMCOMM II. It's 60' wire antenna end fed. It can be installed just about anywhere and will performance great:

CHA_EMCOMM_II_5W_WRPS_2E0XCH.jpg


http://www.eham.net/reviews/detail/10895

http://chameleonantenna.com/BASE ANTENNA/CHA EMCOMM II/CHA EMCOMM II.html

Carl
 

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