Author Topic: Recent shorter-range HF antenna project, it works  (Read 10924 times)

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Quietus

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Recent shorter-range HF antenna project, it works
« on: April 17, 2012, 05:53:28 PM »
There is a thread in this area, lower down, which talks about NVIS antennas.  It might be worthwhile to read first, as background.  Take the below FWIW, from a newbie.
 
There may be a gap in communications capability between short-range VHF even if it's helped out by repeaters which may or may not be in service... and traditional long range HF.  What fills the mileage gap, and the service gap between you and your more local friends, are antennas built to send a lower frequency signal (80m, 60m, and 40m) at a higher angle to the ionesphere than most HF antennas do.  This sort of radiation, is called Near Vertical Incidence Skywave (NVIS).  Signals from antennas constructed for this strategy are designed to depart from 45 to 90 degrees, and come back down in a comparatively small area.  This closer area to you, is the one not served well by what you've been told as to how to put up your "best" antenna.
 
The other thread refers to the military antenna called the AS-2259.  The other thread has a link to a dual band inverted dipole that propagates on some off-band frequencies, don't know why.  Some of the hardware ideas from that link, are useful.  The advice on wire cutting is not real useful, if you choose to continue to be broadcasting on amateur frequencies.
 
Last week, RazorCityDen and I built a shorter-range HF antenna in my front yard, tested it for SWR, talked on it some, then took it down.  Our opinion, is that it will do just fine for regional work.  Might have to tweak down the power some,  to make it more local.
 
The basic design, is a tri-band inverted dipole for 80m, 60m, and 40m.  Mast height is 15', done with 1.5" PVC, each pipe got cut in order to make it a three-piece mast  for easier stowage.  Feedline got run from an elongated entrance hole just above ground level, inside and up the PVC, to the top of the mast.  Dipole head was two-terminal RadioWavz with a 1:1 voltage balun.  It was a very loose fit inside the top of the PVC conduit.  A person could have cut a long hole in towards the top of the mast in order to grab some RG-8 out of it and make a choke, we didn't.  This last could be done as a temporary choke thing with each rising of the mast, it's an option.
 
Basic orientation of the antenna, was for the 80m and 40m to be on the same axis and on top of each other as the dipoles ran.  60m provided guying support, perpendicular to the other's axis.
 
The end of each wire, was supported and kept 2' off the ground, by a 3/4" x 2' PVC stabilizer.  Each wire was set up this way:  a common terminal to the head;  strain relief;  the antenna wire; an insulator; 550 cord to insulator; the stabilizer, drilled out and floating on the 550 cord; and a tent peg on an adjustable tautline hitch on the 550 cord.  Each leg of wire has its own one dollar Home Depot ladder-type cord reel, for extension and retrieval.  Do the above, six times, with the appropriately cut lengths, if you are making it for three bands.  Do it four times, if you're looking for 80m and 40m only..
 
Wires were cut for low-down on the voice bands, with an extra six inches per wire for making strain relief at the head, and for the wrap at the insulator.  They were plenty long, as the SWR meter showed.
 
Per the SWR meter, we ended up shortening the 80m dipole by 32" total in two trials; the 60m was fine; and the 40m got shortened 6" or so.  No cutting was done on the shortening, just a wrap.  No antenna tuner was used.
 
RCD got into a net on 40m, got an initial full copy but low ss with caveat from the guy running the net.  He stayed on it and got a later 57 from too far of a distance, 600m.  There was not opportunity to talk to folks closer, plus the antenna was blocking my driveway, so we took it down.  Individual wire reels are an important thing for this portable antenna.  It gets reeled in from the head side, all goes on the reel, including the PVC stay, the 550 cord, and the tent peg.
 
There was another thing not tested:  the idea that an antenna cut for 40m will work for 15m.  Maybe, with this short mast, maybe not.  The mast height was done with the intention of local/regional on lower bands day and night.  Fifteen meters during the daytime with this antenna, would be a bonus, but it would not be ...just... local/regional.
 
If a person was going to put up this tri-bander by himself, there's another source which recommends driving a steel T fencing stake as initial stabilizer for the mast... this would be a fine idea, otherwise it's a two-man proposition.  For final tweak, it would be good to have a 1' x 5/16" rebar for each 2' stabilizer.  Tension the wire, locate the stabilizer, then drive the rebar halfway in and slip the base of the PVC over it.
 
This project was a tri-bander.  Sixty meter capability is not a real strong reason for me to make more complexity.  It could have been a dual-bander, with the 40m leg perpendicular to the 80m as its guy support.  Whichever way it is built, this local/regional antenna has a good-sized footprint:  on the long leg, call it 120 or so feet.  Best have some clear ground for the setting up of it.
 
This was a fairly quick project to put up.  A person can decide beforehand how it's going to be done:  whether with camo net poles and to use its' spreader hub to locate the terminals and their strain relief; whether to use a sacrificed spreader arm to carve  and drill from it a guy plate for the mast joints;... and etc.  Or whether to use a production dipole head which proved to be a slip fit inside the top of the mast.
 
Point here of posting this for the Prepared Ham, is to illustrate the easiness of it for two people working together to make a copy of a .mil antenna used for HF local/regional work.  Possibly, just to test out the  board some.  The board has the right name and all, but seems to me to be more focused on testing for Extra, than for running radios in other-than-fine conditions.
 

AD

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Re: Recent shorter-range HF antenna project, it works
« Reply #1 on: April 17, 2012, 06:43:07 PM »
Good job guys.  Where are the photos and videos?
The only dumb question is the one that did not get asked!!

Quietus

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Re: Recent shorter-range HF antenna project, it works
« Reply #2 on: April 17, 2012, 08:03:48 PM »
No pics or vids were made, none will be available.  That's how we roll.  In the hinterlands, results beat out processes.
 
The bigger deal with this antenna construct, is with the outcome.  It's an old design, meant to do a particular thing.  We done it, and showed that a longer wire construct of the military design, can be done quite easily  and accomplish its limited range purpose.
 
AD:  from reading here, you and I may be about the same age.  Our wants for HF radio might be divergent.  I just put this up to counterbalance emphasis on studying for the next test for whatever that has seemed to be to be the dominant talk on this Prepared Ham forum, lately.
 
I've been thinking all along that stopping the truck, putting up a short mast and some wire...was the better venue as far as how the Prepared Ham talks to his other like minded individuals.  Thus the above post on putting up a quick and dirty, measured length AS-2259 cut for amateur use.
 
This emphasis on testing... and most talk being about testing, or how to prepare for testing and how we congratulate ourselves after testing...it is losing me on this "Prepared Ham" site. 

AD

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Re: Recent shorter-range HF antenna project, it works
« Reply #3 on: April 17, 2012, 08:30:18 PM »
Q
The main goal of the site is to develop a network of like minded hams who have privileges on the HF bands necessary to make contact across the country and practice the craft so they have the skills ready to deploy.

You need several things to make this happen

1. To get new folks licensed, hence the talk of getting licensed.   The main thing is to get those who dont have access to those HF bands necessary to talk to the rest of us, up and running on those before The SHTF.  This has always been the number one goal of this site.   Should not be a suprise. 

2. Get those with the new tickets experenced at Running their rigs and learning about everything that effects the signal getting out.  Practice, practice, practice!


3. Then its thread like yours(with photos or videos) to help those new bees who have never built an antenna, interested in it and letting them see its not all voodoo.  The antenna on the run so to speak. Different types of antennas and different modes. Cant do any of this unless they have a license.

4. Get groups to start regional nets so not only do they know the time of day, the freq and modes , but also the people from this group that they build relationships with to help build not only comfort in operations but with the others as individuals.

5. Get those regional nets linked together through "regional team leaders" who have the ability and skills to make contacts with others from the group to pass info, news and events around, if normal comms go down. 

So talk about getting licensed, you bet!

Talk about building expedient NVIS antennas for regional comms, absolutey  bring it on!

Talk about digital modes, cant get enough of it!

We are only 2.5 moths old and growing.  Old hands may be bored with license talk, i get that.  so i challange you to stimulate converstations into area you want to share with us. 




« Last Edit: April 17, 2012, 08:32:58 PM by AD »
The only dumb question is the one that did not get asked!!

Quietus

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Re: Recent shorter-range HF antenna project, it works
« Reply #4 on: April 18, 2012, 11:28:21 AM »
AD:  I agree on most all of what you wrote, although I'll stick with the low end of tech.  I got into this because of realizing the necessity of learning and getting the General ticket for HF, and not because I like the whole concept.  Call me a reluctant Echo.  The learning of HF is pretty much just for me and my tribe.

KC9TNH

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Re: Recent shorter-range HF antenna project, it works
« Reply #5 on: April 18, 2012, 08:39:54 PM »
Quietus & RCD: Am tickled beyond words that your efforts bore fruit. Great job guys. The 600mi contact on 40m - chalk it up to "catastrophic success" on one of the best-but-most-finicky bands on the planet. Well done indeed gents!

For others, there are some pretty good homebrew versions of the venerable AS-2259 out there, google can be your friend. Tip: just read them thoroughly as there are some who are quoting recipes for that antenna running dimensions for the mil bands they were spec'd for. So do your math & cry less. A few already have tweaked the recipe for the results that Q & RCD speak of. Maybe you have some old camo netting poles around or extra PVC from a project anyway. Use your imagination & develop the situation and remember that if you learned something when it didn't work, it was worthwhile as long as you factor it in the next time.



idial1911

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Re: Recent shorter-range HF antenna project, it works
« Reply #6 on: April 20, 2012, 10:04:15 AM »
Quote
The board has the right name and all, but seems to me to be more focused on testing for Extra, than for running radios in other-than-fine conditions.

It was never the intention or purpose to have it turn into a testing for extra forum. Actually we spoke about this offline as admins that we are shocked/surprised at home many got their extra vs new technicians. It just kind of happened that people are getting their extra and I expect and anticipate that a year from now we look at the number of licensees in each class and the new technicians far outnumber the extra's.

Quote
AD:  from reading here, you and I may be about the same age.  Our wants for HF radio might be divergent.  I just put this up to counterbalance emphasis on studying for the next test for whatever that has seemed to be to be the dominant talk on this Prepared Ham forum, lately.

I agree there has been a lot, but for people that aren't licensed and want to get licensed that is why they come here. For those of us who have our licenses we'd love to build the network and get more involved. I've tried multiple times to get an on the air roundtable going, so we can do just that, test out gear, chat, build friendships and most importantly find weaknesses in our systems and see just who can chat with who. It has been met with a disappointing lack of response.

At the end of the day the site is, what you all make of it. Possibly as admins we need to do a better job of isolating the test related talk, to the test related areas of the website, this way people that aren't interested in that, and are interested more in the preparedness side of it, or the technical side of it can just avoid those areas.

We are also open to suggestions on solutions to what you see as an issue. So feel free to just throw it out there. How do you want it change? What can we do?

The more I learn, the less I know.

W.Lynn

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Re: Recent shorter-range HF antenna project, it works
« Reply #7 on: April 20, 2012, 09:39:16 PM »
Since some of us are done "studying for the next test" - it's just as well there are other things here for us to read.

asatrur

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Re: Recent shorter-range HF antenna project, it works
« Reply #8 on: April 23, 2012, 01:46:51 PM »
As one of those new extra class operators, I am excited about threads like this. I have a new to me Icom IC-740 and am researching my first antenna and it is overwhelming to say the least. I would be happy if I could find a document on how to build one antenna for talking one band for now, just get practice and on the air in the HF world.
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RazorCityDen

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Re: Recent shorter-range HF antenna project, it works
« Reply #9 on: April 23, 2012, 02:34:25 PM »
Good write-up Quietus!  8)

Antenna has been up a few days now in the Ennis, MT area and I regularly make contact with folks in the MT, WY area on 40 and 80 meter with good signal reports.

Not much else to say that hasn't been said.

If you need a three band, portable, free standing, NVIS antenna that is cheap to build with stops at Radio Shack for a SO-239 connector and to Home Depot for 14 gauge multi-strand, some PVC conduit and some misc. eye bolts, washers and nuts (if you don't already have a center connector that will take multiple elements). This is the antenna for you.

Take care, 

AD

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Re: Recent shorter-range HF antenna project, it works
« Reply #10 on: April 23, 2012, 03:14:53 PM »
For my dipole building efforts, i love this kit http://www.alphadeltacom.com/pg11.html

Just add wire of the lengths shown, divide by 2 for each leg of the dipole  ie. a 10 meter antenna would need 8ft 3 inches on each leg.

You dont need this kit and can do it with house hold materials you have in your shop, but this kit make is simple and easy. 

You will need a tuner to complete you antenna building projects to ensure your SWR is within the range your radio can handle.
The only dumb question is the one that did not get asked!!

Quietus

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Re: Recent shorter-range HF antenna project, it works
« Reply #11 on: April 23, 2012, 03:26:24 PM »
asatur:  Congrats on your Extra class status, I took that test and got a big thumbs down, <50% correct answers.  I appreciate your interest in this thread on an obscure and limited-use antenna.  Currently, constructs such as the knock-off AS-2259 have only limited and personal utility.  Down the road a few months or years, the knowledge of putting up this field expedient or similar shorter range HF antennas, may become more important for you and your tribe, or for other readers looking for close range HF capabilities.  This knock-off of the AS-2259 should probably not be anybody's first choice for a home antenna.
 
You say that you're looking for a doc on how to build one antenna for one band:  Huh.  That statement says that you are not buying transmission capability  out of a catalog, since you say  "build."  If you can, find the USMC pub called MCRD 6-22D "Field Antenna Book".  Another book from online or similar, from the USMC, is "MCI  2515H, Antenna Construction and Propagation of Radio Waves."  Treatment of the subject is different between the two books.  Both will give some good learning to a person seeking knowledge as to how to construct antennas.  (The testing process didn't go through that much, did it?  Huh.)  Or you could buy an ARRL book on antennas, there's many  ARRL books on that, check out a catalog to pick one.
 
From one newbie to another, I'll tell you that you should shop for a tuner compatible with your IC-740 radio, then build an antenna that the tuner will help you out with, on multiple HF bands.  I can't see another newbie limiting himself to one band, just because of an antenna construct in his head.  Make the antenna high and long enough to be versatile for multiple bands, then get a tuner to make that happen.
 
I get what you say about "overwhelming."  For your first build, make it simple, effective, and flexible with tuner.  As a newbie, I'll give two rules:  1) It's hard to be wrong with an 80m dipole and a good tuner; and 2) Height of antenna rules all, get your antenna as high as possible.   Dipoles seem to rule, for home HF antennas, and for field expedients both.  Unless you want to measure out loop routes, and have heights to make that loop route come true for you.  Yessir, your choices are overwhelming.
 
I'll close here with a couple of math things to consider, starting with the second and most-ignored thing first:  Your wire height should a quarter wave of your desired frequency, above ground.  In many places without upfront cash whipout or high trees, this is hard, but it is important to try for that height.  Can't get there?  Then consider another way, don't knock your head on the ground for some weeks wondering what is wrong with your wire if you can't get it up high enough.  Consider something different instead of ramming your head in the ground as you try to make something work, that won't.
 
asatur, the other math thing to consider is the basic "what's that number" question that is considered every day by many people, civilian and military.    The number is 468, it gets divided by freq in order to cut a wire or two to your specs.  This is said, because you are talking about rolling your own.  Feel free to PM... as you relax.  What you are wondering about is no big deal.  If you look hard enough, the quantity of information that you will find as to how to make one antenna, will be enough to make most people's heads explode.  Breathe deep, then think about how high you might be able to get a dipole up.
 
asatur, the antenna described above should not be your first effort.   This low masted and portable antenna is a vertical bounce thing for short range use.  Glad for your interest, though.  I'd recommend for your first antenna, that you make a dipole and get its center as high as you possibly can, and cut it for 3.800 or 3.900, your choice.  Have fun.
« Last Edit: April 23, 2012, 10:37:18 PM by Quietus »

asatrur

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Re: Recent shorter-range HF antenna project, it works
« Reply #12 on: April 23, 2012, 09:47:10 PM »
Thanks for all the advice and responses and the congrats on the extra ticket. To be honest on that, when I got my tech book in January, I was of the idea that I would be testing for my tech in April, not my extra and sometimes like now, I wonder if I rushed my exams. Keep studying and you will get there, I can already tell you are way smarter than I am.

I guess when I was saying one band, I was thinking it would simpler to start there and move on as time and money permits. Right now, I am sort of stuck between money for an antenna tuner or a good antenna, but hey everyone has that problem, right  ;)
I have looked at the ARRL antenna books and some others and they are the ones that make my head explode. I will keep folks updated on my experiments. What are folks opinions on a project like this?
http://www.preparedham.com/forums/index.php?topic=209.0
Thanks and 73,
Asatrur
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BillinNM

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Re: Recent shorter-range HF antenna project, it works
« Reply #13 on: April 23, 2012, 10:21:55 PM »
I just thought that I'd throw my .02 in. 
Yes, I'm testing for Extra this coming weekend.  Does that mean that I'm not interested in the theory and reality of regional comms?  Not in the least.  In fact, I'm currently trying to get my brother, who's been an Extra for years, the work with me and see if we can arrange something.  He was the first in the family to get his ticket, now 4 of have our tickets.  He hasn't had a rig/antenna up since he moved 12 years ago.  He lives right about 65 miles away, with a mountain range in between us.  NVIS and/or the Quietus version should be perfect.  It would just be nice to be able to test out our ability BEFORE we HAVE to use it.  I'll keep hammering on him, and see if I can help him find the time to get an antenna up and operating.
So just because some of us talk the talk about the AE test, doesn't mean that we don't walk the walk about being Prepared Hams.  BTW, I REALLY appreciate the write up you (Quietus) did on your antenna. 
General class license since 1992, been inactive for about 10 years, just getting back into it, thanks to Going Home.   Edit...AE on 4/29/2012

AD

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Re: Recent shorter-range HF antenna project, it works
« Reply #14 on: April 23, 2012, 10:26:59 PM »
Make dipoles. They are cheap.  Here is the tuner i have http://www.mfjenterprises.com/Product.php?productid=MFJ-941E about $130 ish

The wire you can get here http://www.universal-radio.com/catalog/cable/wire.html
100 feet for $15 bucks

So for <$200 you have the tuner, plenty of wire to make a muliiband fan dipole to us on multiple bands. 

Here is the kit i was talking about earlier http://www.universal-radio.com/catalog/antsup/0297.html
For $30.  It makes it a breeze to build multiple wire lenghts (using the data from the AD page above) and build a fan or single band units that can be changed out very quickly.
The only dumb question is the one that did not get asked!!