I need help building a hf wire antenna

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KF0AWL

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Hello everyone.
I tried a search in here but once again confused myself even more not finding what im looking for so I'm sorry if this has already been covered.
Im going in Saturday to pass my general exam and im trying to figure out how to make my hf wire antenna within boundaries of what I have.
I would prefer to pick up 80m through 10m but if not I would at LEAST like to work 80m (heard its the rag chew band) and 20m (contest band) but im restricted in my environment of work space....
1. My shack is on second floor approximately 12 off the ground with my tower next to my shack 40 foot tall 2m/70cm vertical up there.
2. The best space I have to work with runs along the house (steel siding and roof) along my property line.
3. From tower base to near corner of wood garage is 49' tower base to far corner of garage is 71' with property line about five feet past garage. (Photos will show working area)

Can someone point me in the direction of what to study to make a antenna design that can work in this space or better yet tell me in idiot proof terms what n how to build it?
Im willing to study and build all my parts but im not sure how to make this work,.
Please someone help me im confusing myself more the more I study for myself ☹
 

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merlin

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With your setup, I would go with an inverted V.
That steel siding won't do you justice, maybe think a vertical.
Best reference is ARRLs antenna book, good for those roll your own's.
Trapped dipole is another all band way to go.
I found arrl_antenna book_21st_ed.pdf online.
73s
 

W0JOG

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To get you on the air most quickly, I'd make an "unbalanced dipole" using the tower as its center. Put a pully about about a foot from the tower top and build a dipole out of Number 12 copper (spool of insulated from Home Depot or wherever). Get a skein of that white woven rope when you buy the antenna wire. That's what you'll string the antenna up with and use rest to make end ropes to edges of space available. Tie 'em off to the fence or a couple of fence poles at the ends of what space you can use. You now put an insulator at the middle of the wires, giving you an antenna with one leg longer than the other but neither a perfect length for any band. If yuou can't find insulators, cut up some stout plastic from a bottle or something and that will work. Now is where an antenna tuner enters the picture. Go to MFJ's site or one of the ham radio suppliers like DXEngineering, etc. Look for a differential tuner. It has a roller inductor and a capacitor. Run coax (RG58 will do for 100 watt rigs) from tuner to center of antenna up there on the tower. Add a good ground (number 12 insulated from tuner and rig to ground pole outside the window -- making sure you don't drive the ground rod into any utility buried there). It'll get you on the air on all bands and you can work people while deciding on what the "perfect" antenna is going to be later on.

See you on the air!

W0JOG
 

popnokick

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There are two possibilities you should not ignore; 1) an End-Fed Half Wave (EFHW) and 2) an Off-Center Dipole (OCFD). Both antennas are available commercially from several vendors or you can make your own. If you DIY the critical element of detail will be the balun… each antenna requires one. But both antennas are very adaptable to various installations (flat top, sloper, inverted V, some bends / angles allowed, etc). And both antennas are multi-band, even without a tuner (although a tuner will allow operation on even more bands). Main installation item to watch is to keep the radiating elements away from metal surfaces. Your tower…. Used as an end or center / off-center support… should facilitate that nicely.
 

KF0AWL

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Thanks guys!
I found this late last night after posting this.
Correct me if I'm wrong but if I take say the 53 foot length with proper insulatiors, slope it from top of tower to garage using parachord run garage end into the 9-1 and run my coax BACK to the shack into my tuner I should be good correct?
One other question is when they talk at the end about the unun being to high and needing a counter poise and ground would the corner of the garage be to high? Is the (ground) actually run to a ground spike? (I will be running my tuner ground to a spike outside the shack) of course but thats were I get confused when they don't specify all the info 🤯 20210527_074113.jpg
 

WB9YBM

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I'm not sure if they're still available but a few decades ago when I strung up some single-band dipoles the local ham store used to sell them as a kit that contained a ballun, wire, two insulators, guy rope, and instructions (in other words everything but the coax and a mast to mount the center to).

This approach worked very well for me with a minimum amount of problems in all cases (I ended up with several).

The things to look out for are:
  • Height above ground. If it's less than a wavelength the impedance will be effected;
  • swap the nylon rope used for guy wires with some sturdier stuff like the stuff used for tents or even lighter lines used for climbing: it won't wear & break as fast as the nylon supplied in the kit;
  • since you're dealing with heavier gauge wiring, make sure you've got a big enough soldering iron to heat it properly when soldering (especially in cooler outdoor temps) so you don't end up with a cold solder connection.
 

popnokick

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mtand73 - Based on the plan you posted with the 9:1 balun (un-un) you'll be building an End Fed Halfwave antenna.... which is excellent since it is multi-band capable, unlike a dipole which at best will work efficiently for a couple of bands. Not real useful these days and band conditions... you want to be capable of operating on as many bands as possible. But without an aerial view of your property I'm having a little trouble understanding your installation plan. Based on what you posted, I think you are planning to put the feed point balun at the low end (your garage) and run the coax from the garage back to your shack. That's the opposite of what you need to do with an EFHW.... you want the feed point of the antenna (and balun) to be at the HIGHEST end of the antenna, which in your case would be your tower. Use some paracord or an insulated standoff arm to get the balun feed point 3 feet or more away from the metal of the tower, then run the coax back to your shack. Connect the "free end" to the low end (your garage). And don't worry about an RF counterpoise with an EFHW.... they're seldom needed for an EFHW, and can be added later if necessary. More than likely it's going to work fine without one.
 

KF0AWL

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I need to run the unun to (earth ground) as the counter poise for the other half of the dipole do I not?
I had brought up the unun up the tower on another fb group as like you I was thinking it would be a short loss through the coax and was told i have to go the other way so the unun can be run to ground for the other half of the dipole since its a random wire.
 

prcguy

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In my opinion you can get very good performance on 40 through 10m in 71ft of space and a half wave end fed or offset center fed is about 64ft. This will do 40, 20, 15 and 10m very well. A random dipole or inverted V that will fit in that space and fed with coax and a tuner in the shack will suck. Ok, you can make it work on one band but everything else will suck. Feed that same 71ft ish random dipole with 450 ohm ladder line and a balanced tuner in the shack and now you can do 80 through 10m but 80m will suffer somewhat and 40 through 10m will be very happy.

Please avoid a 9:1 transformer with various "magic" lengths of wire, a resonant end fed half wave or EFHW will blow it away but you won't get 80m on an EFHW that size, you need about 133ft for an 80-10m EFHW. Even though a 9:1 with 50 or 70 something feet of wire is advertised as working on 80m, it doesn't work very well and you give up so much on other bands its just not worth it. A 9:1 also relies on the coax as the other part of your antenna and the coax can radiate quite a bit.
 

tweiss3

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Note, when building an 80m thru 10m resonant end-fed or off-center dipole, 80m tends to be more aligned with the digital/cw side of 80m when the remainder of 40m-10m are middle of the band. It's not a huge issue, but SSB on 80m requires an external tuner, or turn the power way down and keep it's use to a minimum.
 

popnokick

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I need to run the unun to (earth ground) as the counter poise for the other half of the dipole do I not?
You do not if you use the correct length of wire and type of balun to make a proper End-Fed Halfwave antenna. Halfwave antennas are not dipoles and do not require a ground counterpoise. And your tower is grounded, is it not? Take a look at this balun (un-un) designed for use with EFHW antennas. See the wing nut terminal? Connect that to some shiny metal on your tower. Run the coaxial cable down the tower and at the entrance point to the house use a lightning protection device such as those from Alpha-Delta or Polyphaser. MEF-310-2K
Also read this about baluns - About BALUNs
 

KF0AWL

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You do not if you use the correct length of wire and type of balun to make a proper End-Fed Halfwave antenna. Halfwave antennas are not dipoles and do not require a ground counterpoise. And your tower is grounded, is it not? Take a look at this balun (un-un) designed for use with EFHW antennas. See the wing nut terminal? Connect that to some shiny metal on your tower. Run the coaxial cable down the tower and at the entrance point to the house use a lightning protection device such as those from Alpha-Delta or Polyphaser. MEF-310-2K
Also read this about baluns - About BALUNs
Ok i follow you, sorry im one of those that have taught myself to lock my brain in on the subject im working on because if I see something on a side path I'll go look at it and end up lost 😆
I'll do more study on the EFHV after I get the random theory locked in.
Thanks for your input tho.👍
 

prcguy

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Yes, 80m on an EFHW or OCFD is not harmonically related to the other bands of 40-10m and will usually resonate 3.58MHz and the VSWR in the phone portion of 75m will be a bit high. Not to worry, with a simple mod of cutting the 133ft of wire in half, inserting an insulator and an appropriate value HV capacitor, you can bring the 80m resonant point up to 3.9MHz or just about anywhere within the 75/80m bands. This only affects 80m and will have zero effect on the higher bands.

For a 133ft 80-10m EFHW a capacitor around 250pf puts you right about 3.9MHz and will give a great match across the 3.8 to 4.0Mhz phone portion of the band. For a 133ft 80-10m OCFD use about 150pf to achieve the same result. One commercial antenna mfr uses a pair of large disc type capacitors but I just get a big HV doorknob cap off Ebay for about $10 to $10 with a 7.5kV to 15kV rating. Here is one way to mount a large doorknob cap in the middle of the wire. I usually cover the cap and its connections in heatshrink and Ty-Rap it tight up against the insulator.

end fed cap.JPG


Note, when building an 80m thru 10m resonant end-fed or off-center dipole, 80m tends to be more aligned with the digital/cw side of 80m when the remainder of 40m-10m are middle of the band. It's not a huge issue, but SSB on 80m requires an external tuner, or turn the power way down and keep it's use to a minimum.
 

W0JOG

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You now have more answers than you have problems. Just choose one or some or none and build "something" as opposed to nothing and try it to get on the air and ask questions there. If there is a local ham club, go there for help too. It'll all make sense once you get over the first unknowns. Only thing I'll add here is make that ground connection for the shack more than "a stake" as you wrote. Get a ground rod at an electrical shop. It needs to be 6-8 feet down, if you can do it. And be sure to call the local number for utilities and let them know you're going to pound something into the ground. They come and make sure you won't run into anything like buried water, sewer or electric lines and mark where to go. And it's free.

Happy hammin'.

de V
 

KF0AWL

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Your exactly right I'm going to start experimenting with a couple now that I have info on the two im most intrested in 😁
The whole stake in the ground thing was just a general easy speak lol
I actually have a ground rod I put in on the tower and I got lucky and they left the ground rod from the former TV antenna I assume thats my ground for the shack in a perfect spot for me to run down to 👍
 

W0JOG

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My ham career started in Des Moines in 1962. I'm still at it at 89 years old and hope the best for you and all of ham radio for years to come.

73 de W0JOG
 

prcguy

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Any ground rod you put in would need to be bonded to the house main electrical entry point ground with no less than 6ga copper wire per NEC.

You now have more answers than you have problems. Just choose one or some or none and build "something" as opposed to nothing and try it to get on the air and ask questions there. If there is a local ham club, go there for help too. It'll all make sense once you get over the first unknowns. Only thing I'll add here is make that ground connection for the shack more than "a stake" as you wrote. Get a ground rod at an electrical shop. It needs to be 6-8 feet down, if you can do it. And be sure to call the local number for utilities and let them know you're going to pound something into the ground. They come and make sure you won't run into anything like buried water, sewer or electric lines and mark where to go. And it's free.

Happy hammin'.

de V
 

N4GIX

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Having been disappointed for the past three years with a compromise G5RV-Jr I have now constructed an EFHW from a 'kit' sold through ARRL for $59.95. It comes with 70' of wire and all the parts needed to build a 49:1 un-un...
http://www.arrl.org/shop/End-Fed-Half-Wave-Antenna-Kit-for-10-15-20-40-Meters/
...now I just need to get a warm body to help me get it airborne, and a dry day! I'm getting antsy to get it up and running!
HKrR5.png
 

prcguy

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An EFHW with a 49:1 or 64:1 transformer is easy to make and I can post links to instructions. A single FT-240-43 core that will handle up to about 400W SSB is $10. A nice NEMA box from Home Depot is about $7. The connector, capacitor and wire don't cost much and its a great project that works really well.


Having been disappointed for the past three years with a compromise G5RV-Jr I have now constructed an EFHW from a 'kit' sold through ARRL for $59.95. It comes with 70' of wire and all the parts needed to build a 49:1 un-un...
ARRL :: Antennas :: End Fed Half Wave Antenna Kit for 10/15/20/40 Meters
...now I just need to get a warm body to help me get it airborne, and a dry day! I'm getting antsy to get it up and running!
HKrR5.png
 
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