End fed random wire

[KE5WCT]

I am considering putting up a end fed random wire. I live on a lot with lots of trees from the north corner around the west side to the south corner, about 700 feet. I would like to work 160 through 10 meters. the rig is a Yaesu FT-991A (auto tuner), and I aslo have a manual tuner if needed. I am not going to run very high power, right now 100W max, maybe 500-1000 later one.

Now the questions:
1) What type of wire would be best for this application?
Insulated (will be running trough trees), or bare?
Copper clad steel (multi strand, twisted copper clad or single strand copper clad)?
How long whould the wire be inorder to cover the desired bands (160-10 meters)?
2) The feed will most likly be coax, (about 100 ft). what size balun should be used (I'm thinking about 9:1)
One side of the feed point will be to ground directly below the feed point. (unless it would be better to run a counter poise (how long)?

This antenna will not be straight line, but will have to wonder in a random simicicular path. I'm pretty sure this will be more of an experiment but that's what we do.

I would appreciate and information or suggestions from anyone with any experience with end fed random wire antenna's. of course, information or suggestions from everyone else is welcome.

73, KE5WCT
Mike Wilson
USN RET

 

[merlin]

That is what I use. 108 foot is broadband and just squezes in 160 meters.
Length for 'RANDOM' should be chosen so it is not reasonant for ham bands otherwise your SWR will be like a roller coaster
with some bands good, others bad. (sorry, I misplaced my chart for that)
Bring your wire into the shack and into a manual/automatic tuner, unbalanced input. then 50 ohm coax to the rig.
Best wire is any, bare if nothing touching the wire end to end, otherwise insulated.
Coper clad steel has the best tesile strength so greater lengths between supports.
Stranded is fine, about the only difference between wire types is minor velocity factor between types so length should be calculated.
Only time you need a balun is going straight to the rig and that would be a 1:1 UNUN using the rigs autotuner.
Outbord tuners is my choice, they work better tuning out of band like for SWLing.
A storm brought my wire down, so cut to 88 foot. with my external ATU, I get great SWR, <2:1 from 3 MHz to 55 MHz
Good performer at 45 foot above ground. It runs WSW so best angle is ESE.
My wire is insulated #14-7 strand.
Ground everything except antenna best you can, the rig, the tuner, everything between the antenna and speaker, Ground it good.

 

[KE5WCT]

Thanks Merlin. That is about what I was thinking but wanted to hear what so others thought on the matter. That is what I will most likely do.

73 KE5WCT
Mike Wilson
USN RET

 

[K6GBW]

The "Random" wire antenna really should be thought of as a "non-resonant" wire antenna. The lengths are specifically chosen to not be resonant on any band. This lets you use a transformer to bring the impedance to something your tuner can handle. The non-resonant wire antenna is handy for multiple bands and compromised locations but know that it will always be a compromise antenna. For the low bands, 160-80-40 it will work as a decent short haul (NVIS) antenna if mounted down below its half wave height. For higher bands it can develop many nulls, so it will work, but who knows where your signal is really going. I've used them with success for regional communications on 40 and 80 meters, but you have to manage your expectations. Compared to a dipole the transmitted signal is usually much weaker. That said, if it meets your needs then it's fine. I used one for over five years before I put up a simple mast to run a dipole and it got the job done. We are at the top of the solar cycle, so right now it might work well for you. In four years...it might not.

Oh, and to answer your specific question, I've always used 14awg house wire from Home Depot. Works as good as anything else. As for the transformer...you'll want a 9:1 unbalanced to unbalanced version (UNUN) or a 4:1 will also work. You can make them or buy one from a reputable maker. I have them from both Balun Designs and Palomar Engineering and they both work great. The Palomar "Bullet" model is pretty handy and easy to deploy.

 

[W4AXW]

I've always used 14awg house wire

?? You use Romex/NM solid copper ?? Or 14awg stranded THHN?

 

[prcguy]

The National Electrical Code has minimum wire size for antennas based mainly on length vs strength. Here are some notes from Article 810.


Receiving equipment. If lead-in conductors are attached to buildings, install them in a way that prevents them from swinging closer than 2 feet to the conductors of circuits of 250V (or less) or closer than 10 feet to the conductors of circuits of more than 250V. Keep all lead-in conductors at least 6 feet from lightning protection conductors [810.18].

In addition, keep in mind that:

• Underground antenna lead-in conductors must maintain a separation not less than 12 inches from power conductors [810.18(A)].
• Indoor antenna and lead-in conductors must not be less than 2 inches from light and power conductors [810.18(B)].

For the two preceding requirements, you don't need separation if you have installed the lead-in conductors or the power conductors in a raceway or cable armor. Indoor antenna lead-in conductors can be in the same enclosure with power conductors where separated by an effective, permanently installed barrier.


So exactly how big must the antenna conductor be? That depends on how long the conductor is and what it's made of. If the conductor is [Table 810.16(A)]:

• Less than 35 feet long — use 19 AWG copper or aluminum alloy or use 20 AWG copper-clad steel, bronze, or other high-strength material.
• More than 35 feet long but less than 150 feet long — use 14 AWG copper (or 14 AWG aluminum alloy) or use 17 AWG copper-clad steel, bronze, or other high-strength material.
• Longer than 150 feet — use 12 AWG copper (or 14 AWG aluminum alloy) or use 14 AWG copper-clad steel, bronze, or other high-strength material.

Transmitting (amateur radio). Amateur radio has additional requirements beyond those for receiving equipment, because of an additional function: transmitting. Thus, if the installation is an amateur radio system, it must comply with 810, Part III (810.51 through 810.58).

Obviously, the antenna conductors must be larger if you are also transmitting. If the conductors are longer than 150 feet, use either 10 AWG hard-drawn copper or 12 AWG copper-clad steel, bronze, or other high-strength material. If the length is under 150 feet, you can use 14 AWG in any of the aforementioned materials [Table 810.52].

With receiving installations, you can mount the antenna lead-in conductors on the surface of the building. But with amateur radio, the antenna lead-in conductors must be firmly mounted at least 3 inches away from the surface of the building [810.54]. If the lead-in conductors are enclosed in a continuous metallic shield (coaxial), you can secure them directly to the building structure [810.54 Ex].


As with receiving systems, each lead-in conductor from an amateur radio outdoor antenna must be provided with a listed antenna discharge unit (or other suitable means that drain static charges from the antenna system), except where:

• Protected by a continuous metallic shield that is permanently and effectively grounded.
• The antenna is permanently and effectively grounded.

Ground the antenna mast [810.15] and antenna discharge unit [810.57] as specified in 810.21(A) through (K), just as with the receiving stations. However, the operating grounding conductor for amateur radio installations must not be smaller than 14 AWG copper or equivalent [810.58(C)].

 

[merlin]

How many of these installs are not to code, Either NEC, FCC. or ARRL.

 

[K6GBW]

I would imagine more than 90 percent. I tried for years and years to find the magic end fed set up that would work well. Never found it. These days I pretty much consider end feds the antenna of last resort…well, after a CHA-250 anyway. Since I went to center fed dipoles my life has been ten times easier.

 

[G6FGO]

How many of these installs are not to code, Either NEC, FCC. or ARRL?

It is totally against the ethos of amateur radio. We are supposed to be qualified enough not to have to be constrained by "type approval" or other nonsense.

 

[lenk911]

I have a 43 foot random wire from my chimney to a tree-has a right angle bend in the antenna routing. It is fed with an Icom remote auto tuner on the chimney fed with coax and control cable. Station is an Icom 706 MKII. Works great 40-10 Meters. Tunes well even in the coldest of Minnesota winters.

 

[MUTNAV]

The National Electrical Code has minimum wire size for antennas based mainly on length vs strength. Here are some notes from Article 810.


Receiving equipment. If lead-in conductors are attached to buildings, install them in a way that prevents them from swinging closer than 2 feet to the conductors of circuits of 250V (or less) or closer than 10 feet to the conductors of circuits of more than 250V. Keep all lead-in conductors at least 6 feet from lightning protection conductors [810.18].

In addition, keep in mind that:

• Underground antenna lead-in conductors must maintain a separation not less than 12 inches from power conductors [810.18(A)].
• Indoor antenna and lead-in conductors must not be less than 2 inches from light and power conductors [810.18(B)].

For the two preceding requirements, you don't need separation if you have installed the lead-in conductors or the power conductors in a raceway or cable armor. Indoor antenna lead-in conductors can be in the same enclosure with power conductors where separated by an effective, permanently installed barrier.


So exactly how big must the antenna conductor be? That depends on how long the conductor is and what it's made of. If the conductor is [Table 810.16(A)]:

• Less than 35 feet long — use 19 AWG copper or aluminum alloy or use 20 AWG copper-clad steel, bronze, or other high-strength material.
• More than 35 feet long but less than 150 feet long — use 14 AWG copper (or 14 AWG aluminum alloy) or use 17 AWG copper-clad steel, bronze, or other high-strength material.
• Longer than 150 feet — use 12 AWG copper (or 14 AWG aluminum alloy) or use 14 AWG copper-clad steel, bronze, or other high-strength material.

Transmitting (amateur radio). Amateur radio has additional requirements beyond those for receiving equipment, because of an additional function: transmitting. Thus, if the installation is an amateur radio system, it must comply with 810, Part III (810.51 through 810.58).

Obviously, the antenna conductors must be larger if you are also transmitting. If the conductors are longer than 150 feet, use either 10 AWG hard-drawn copper or 12 AWG copper-clad steel, bronze, or other high-strength material. If the length is under 150 feet, you can use 14 AWG in any of the aforementioned materials [Table 810.52].

With receiving installations, you can mount the antenna lead-in conductors on the surface of the building. But with amateur radio, the antenna lead-in conductors must be firmly mounted at least 3 inches away from the surface of the building [810.54]. If the lead-in conductors are enclosed in a continuous metallic shield (coaxial), you can secure them directly to the building structure [810.54 Ex].


As with receiving systems, each lead-in conductor from an amateur radio outdoor antenna must be provided with a listed antenna discharge unit (or other suitable means that drain static charges from the antenna system), except where:

• Protected by a continuous metallic shield that is permanently and effectively grounded.
• The antenna is permanently and effectively grounded.

Ground the antenna mast [810.15] and antenna discharge unit [810.57] as specified in 810.21(A) through (K), just as with the receiving stations. However, the operating grounding conductor for amateur radio installations must not be smaller than 14 AWG copper or equivalent [810.58(C)].

Ok... question....

Based on

Receiving equipment. If lead-in conductors are attached to buildings, install them in a way that prevents them from swinging closer than 2 feet to the conductors of circuits of 250V (or less) or closer than 10 feet to the conductors of circuits of more than 250V. Keep all lead-in conductors at least 6 feet from lightning protection conductors [810.18].

But I'm trying to envision an instillation that a recieving equipments feedline is at least 6 feet from lightning protection conductors.

For example, on a tower, the feedline has to be 6 feet from a lightning protection conductor? Without a really large tower width, I don't see how that is possible.

To say nothing of the spacing recomendations based on

https://www.mikeholt.com/instructor2/img/product/pdf/17LED-1498-sample.pdf

Thanks
Joel

 

[prcguy]

Ok... question....

Based on

Receiving equipment. If lead-in conductors are attached to buildings, install them in a way that prevents them from swinging closer than 2 feet to the conductors of circuits of 250V (or less) or closer than 10 feet to the conductors of circuits of more than 250V. Keep all lead-in conductors at least 6 feet from lightning protection conductors [810.18].

But I'm trying to envision an instillation that a recieving equipments feedline is at least 6 feet from lightning protection conductors.

For example, on a tower, the feedline has to be 6 feet from a lightning protection conductor? Without a really large tower width, I don't see how that is possible.

To say nothing of the spacing recomendations based on

https://www.mikeholt.com/instructor2/img/product/pdf/17LED-1498-sample.pdf

Thanks
Joel

A "lead in conductor" to me means the actual antenna wire and not the feedline. A lightning protector usually goes in the feedline and if that is 6ft or more down the coax from where the antenna wire terminates to a transformer or even to coax that should be fine.

 

[MUTNAV]

A "lead in conductor" to me means the actual antenna wire and not the feedline. A lightning protector usually goes in the feedline and if that is 6ft or more down the coax from where the antenna wire terminates to a transformer or even to coax that should be fine.

That would be the only way for the N.E.C. to even start to make sense with the 6 foot rule.

(ref: ARTICLE 810)

Like in this paragraph that supports your viewpoint.

Part II. Receiving Equipment — Antenna Systems

1. Material. Antennas and lead-in conductors shall be of hard-drawn copper, bronze, aluminum alloy, copper-clad steel, or other high-strength, corrosion-resistant material.Exception: Soft-drawn or medium-drawn copper shall be permitted for lead-in conductors where the maximum span between points of support is less than 11 m (35 ft).

although this paragraph strongly gives the impression that lead ins and antennas are different.

Supports. Outdoor antennas and lead-in conductors shall be securely supported. The antennas or lead-in conduc‐ tors shall not be attached to the electric service mast. They shall not be attached to poles or similar structures carrying open electric light or power wires or trolley wires of over250 volts between conductors. Insulators supporting the antenna conductors shall have sufficient mechanical strength to safely support the conductors. Lead-in conductors shall be securely attached to the antennas.

Also, everything else I see shows that the lead-in is the feedline, and seperate from the "antenna".

Like in In the illustrations of https://www.mikeholt.com/instructor2/img/product/pdf/17LED-1498-sample.pdf.

Honestly, (IMHO) if everything were written a little better, we would never even have these questions, and observations.

Of course, people that run a single piece of wire from a tree outside and through a window pane directly to their receiver doesn't make it easy for anyone

Thanks
Joel

 

[Grounded]

Oh, and to answer your specific question, I've always used 14awg house wire from Home Depot

Disregard that advice; it is dangerous and violates electrical codes.

Electrical codes are crystal clear, and every HAM should know them. NEC Table 810 specifies what conductor types can be used as outdoor antennas. Electrical codes see antennas as overhead electrical conductors carrying voltage and currents. Building power and lighting wire is soft-drawn copper and cannot tolerate spans. It will stretch, break, and eventually fall to the ground. So, for some strange reason, first responders and electrical professionals panic when electrical conductors hit the ground. The size of the wire depends on the length of the span. If every ham adhered to NEC 810, all of your grounding and electrical safety concerns would be resolved. The codes are designed to help you maximize the performance of your equipment while ensuring safety.

To make it easy, Mike Holt and I made a document specifically for amateur radio operators. It will bust a lot of myths ham use like placing a ground rod outside the shack is extremely dangerous. Download your free copy. It will introduce you to what professional operators do like
Single Ground Point. Enjoy and download your copy https://www.mikeholt.com/instructor2/img/product/pdf/17LED-1498-sample.pdf

 

[G6FGO]

Disregard that advice; it is dangerous and violates electrical codes.

The authorities have no business trying to regulate Amateur radio, bar licencing. The whole point of it is "The self training of the Licencee" and experimention. Marconi would have achieved nothing with Nanny breathing down his neck.

OK an aerial snaps, there is some self training right there and the response would be to investigate (self training again) to determine the failure mode and then erect a better aerial. This assuming that it's on your own land of course, but then we shouldn't be stringing aerials across public areas anyway.

 

[MUTNAV]

Disregard that advice; it is dangerous and violates electrical codes.

Electrical codes are crystal clear, and every HAM should know them. NEC Table 810 specifies what conductor types can be used as outdoor antennas. Electrical codes see antennas as overhead electrical conductors carrying voltage and currents. Building power and lighting wire is soft-drawn copper and cannot tolerate spans. It will stretch, break, and eventually fall to the ground. So, for some strange reason, first responders and electrical professionals panic when electrical conductors hit the ground. The size of the wire depends on the length of the span. If every ham adhered to NEC 810, all of your grounding and electrical safety concerns would be resolved. The codes are designed to help you maximize the performance of your equipment while ensuring safety.

To make it easy, Mike Holt and I made a document specifically for amateur radio operators. It will bust a lot of myths ham use like placing a ground rod outside the shack is extremely dangerous. Download your free copy. It will introduce you to what professional operators do like
Single Ground Point. Enjoy and download your copy https://www.mikeholt.com/instructor2/img/product/pdf/17LED-1498-sample.pdf

View attachment 177021

Thats great to here that you and Mike Holt made that helpful graphic up.

Maybe you could help with the part about 6 feet spacing minimum between the feedline and the ground conductor.

I just don't see how that could work on a mast or small tower (like a glidslope tower) where the aeriel terminal is at the top of the tower and the grounding conductors run down the tower legs, along with antenna feedlines.

I just posted a question on the NFPA website about it. Under the design and instillation forum. Hopefully they will be able to help also.

Thanks
Joel

 

[K6GBW]

Dangerous is walking to your car at 0200 in East Hollywood. Using a 14awg wire for a freaking antenna...you'll survive just fine. BTW, virtually ALL of the commercial antennas you can buy use 14awg or 16awg.

 

[MUTNAV]

The authorities have no business trying to regulate Amateur radio, bar licencing. The whole point of it is "The self training of the Licencee" and experimention. Marconi would have achieved nothing with Nanny breathing down his neck.

OK an aerial snaps, there is some self training right there and the response would be to investigate (self training again) to determine the failure mode and then erect a better aerial. This assuming that it's on your own land of course, but then we shouldn't be stringing aerials across public areas anyway.

At first I was mildly annoyed at what you said, then I realized your just saying that if you want to run 22 gauge from a fencepost to a tree 15 feet away (less than a 150 meter span), you should be able to..., fully agree.

In addition there is the old adage that if your antenna didn't fall down last winter, it wasn't big enough.

The rule of 810.52 doesn't seem to really fit well for a lot of antennas, (like you put up a stripline antenna (with copper sheet on a PCB substrate for example).

Although the OP mentioned transmit, for Receiving antennas it seems a little more resonable (up to 150 feet open span length with 19 gauge hard drawn copper).


Nit picking, I know, but still...
Thanks
Joel

 

[MUTNAV]

Dangerous is walking to your car at 0200 in East Hollywood. Using a 14awg wire for a freaking antenna...you'll survive just fine. BTW, virtually ALL of the commercial antennas you can buy use 14awg or 16awg.

According to table 810.52, the 16 gauge ones would be illegal, right?
and no, I'm not looking for trouble, just that rules need to be either a little less restrictive, or done a LOT better.
Thanks
Joel

 

[AK9R]

There's a difference between codes, rules, and laws.

Breaking a law is illegal.

Breaking a rule is non-compliant.

Breaking a code is, well, that depends. The NEC, NFPA, etc., isn't going to send out the Code Police to arrest you if you violate one of their codes. On the other hand, if a state or municipality has adopted a certain code, then it becomes "law" in that jurisdiction. The building inspector can demand that you change something that does not conform to the code. The building inspector can also refuse to issue a certificate of occupancy if you put up a building or make a renovation that isn't compliant with the adopted codes. The real "enforcer", though, is your insurance company. They can choose to not pay your claim if you sustain a loss and the insurer can demonstrate that you didn't follow the adopted codes.

"Lightning struck your ungrounded 14 gauge THHN antenna wire and the resulting fire burned down your house? Ooh, sorry, we're denying your claim."

Or, worse yet, "Lightning struck your ungrounded 14 gauge THHN antenna wire that you strung across the fence to your neighbor's tree and the lightning energy exploded a tree limb that fell on your neighbor's house? Ooh, sorry, we're denying his liability claim against your home owners insurance. And, we won't defend you in court when your neighbor sues you."