Just getting into HF and bought two antennas, MFJ OCF 40-6 which is 66 ft long and MyAntennas 80-10 HWEF which is 130 ft long. Hung some dacron rope in the two support trees. They are about 120 ft apart (maybe a little more) and the rope is 70 ft high. Was going to hang the 40-6 in these trees and hang the 80-10 lower elsewhere for some NVIS work but now thinking that with a 70 ft height, the 80-10 would work well. Concern is that it will put the ends in the tree tops while the 40-6 would be suspended over open space. Thoughts and suggestions welcome.

Don't hang either of them. Sell them on eham and hang this with a DX Engineering 4:1 balun. Don't waste that wonderful 70ft with a shit antenna.

Maybe I missed it, but I could not find a description of the material that he is using for the ladder line insulators. It looks like some kind of tubing.

The concept behind using a single continuous wire for each half of the antenna and feedline is certainly interesting - the point of failure for several of the open-wire-line-fed antennas that I’ve used over the years has often been the connection from the feedline in the center - the soldered joints that I’ve used weaken or corrode over time, and the dissimilarities between the feedline wire size and type and that used in the antenna elements often leads to an awkward connection.

I have no idea what the spacers are made out of but I bet if you email him he'd be happy to tell you.

Ditto this, if you can get the ladder line into the house okay.
Some use 1/2" PVC pipe for laddeer line spreaders. I've never heard of them arcing over unless insects build a nest in them,
"Dog bone insulators will work for the center and end insulators.
"Compression insulators" are stronger, although I've never broken a dog bone -- unless I dropped it onto concrete.

MFJ offers an antenna kit MFJ-2774K with 140' of stranded wire, center and end insulators, wire clamps, and nylon rope. They also have 450 Ohm window line whch is almost as low loss as true ladder line. It's a lot easier to handle than ladder llne.

There's nothing wrong with what you have. That EF-8010 will work great at 70ft, and don't worry if it's in the branches, it won't make a bit of difference. Should work great for long distance and short range/NVIS stuff. I have the MFJ clone of that same antenna and have nothing but good things to say about it. It has nice sharp SWR dips in all the right areas. Proceed with confidence. The 40m-6m antenna probably won't be needed if you put up the other one.

70ft May be a tad high for nvis

I agree for 40 but perhaps not 80. Got a second antenna to play around with heights and directions but this 70ft would be my primary.

The advantage of that W7FG antenna is that when it's fed with a balanced tuner at the end of the ladder line it is extremely efficient, and you lose next to nothing from SWR mismatch losses in your coax cable. With a setup like that you can be sure that every watt you transmit is actually getting out. if your house happens to be towards the middle of the antenna it's even better because then you don't have to run wires very far.

The disadvantage of an antenna like that is if your house is at either end of your planned antenna run you will end up of having a long run of coax from the house to the tuner. Also, unless you can put a tuner at the base of the ladder line you lose every efficiency advantage that antenna has to offer. Maybe you have a tuner, but if you don't there is another expense to consider.

I'm not a dipole hater - I love their efficiency, and for whatever reason I love how they look hanging up up in the air, especially the classic look of the 600ohm open wire feed variety. However, when the rubber meets the road I have had very few instances in my life when the physical layout of my yard or operating area have been conducive to dipoles. Usually my trees are not spaced correctly, or I have other obstacles where the feedline needs to drop down, etc. etc. That's why I have gravitated towards end fed antennas because I can usually get the feed point right up next to my house, and have a short run of coax to my radio. The Par End Fed and EF-8010 (MFJ-1982) varieties are resonant or very close to it so I typically do not need to use a tuner, and even if I do need to use the radio's internal tuner to make up for small mismatches (usually less than 3:1), I at least have the shortest possible run of coax to hopefully offset some of these SWR losses in the coax.

Hope that helps! My opinion is worth what you paid for it, and your mileage may vary

It does help. In the learning stage. First HF (Icom ic-7100) Bought an AT200ProII tuner which tunes to 6m and accepts 2 antennas but does not offer balanced inputs. I'm going to try hanging the endfed with one of the trees next to my house. Run rg213 down the tree to a ground rod and Array Solutions surge arrestor and from there 213 into the house. Just trying to get this right the first time. Thanks.

I homebrewed a 160m doublet using homebrew ~600 ohm ladder line. With a manual boat anchor tuner ( Dentron MT-3000A ) it tunes all bands 160-6 meters and has low loses because it is fed entirely with the ladder line from the tuner.

I used these insulators from tractor supply. they are hollow. I used a black zip ties through the hollow center to hold the line tight. the wire I used was solid core home depot wire.

https://www.tractorsupply.com/tsc/product/zareba-4-in-fin-tube-insulator-pack-of-25

they are 4 inches wide and with 10 gauge wire comes out to just shy of 600 ohms at HF freqs.


Here is a video on how to make it. Note this does not use the Tractor supply insulators, it used some type of tubing, but how you do it is the same.

Damn, I'm going to violently disagree with pretty much everybody posting a follow up to my W7FG antenna recommendation So here goes....

BLUF: W7FG to DX Engineering 4:1 balun at the roof eave, coax from there, use an MFJ-993 tuner at the radio. Yes there will be a little bit of coax mismatch loss, but as long as the coax run is under 25ft it's no big deal. This is essentially my exact setup except that I built a more complex multi-band doublet.


You don't want to bring the ladder line into the house. Yes, that'll be the most hyper-efficient method, but it is a PITA. Screw the 4:1 balun to the eave, then bring in coax from there.


Why are you pointing him to all this stuff? You can't build one any cheaper than you can buy one. Just buy one from W7FG.


Except that truly balanced tuners are all manual and require the ladder line to come into the shack. Both of those things can be a bit of a PITA. Not saying it can't be done, I'm just making the suggestion to go balun-coax-high quality auto tuner. As long as the coax is under 25ft the losses are negligible and operation is automagic.

However, if the OP is really motivated to bring the ladder line into the house and does not mind using a manual tuner, the MFJ-974B is a really good choice. And you don't need a balun, of course.


Please, for all that is holy, stop with the NVIS bullshit. Yes it exists. Rarely. Who cares? Put a dipole at 70ft and you'll hang with all the big dogs on the regional (500 mile) ragchew nets NVIS or no NVIS. Ask ANY of those guys with the big signal what they are running and they will ALL tell you, almost to the last man, that they are either using a dipole above 50ft or an inverted L. Nobody with a big signal is using an end-fed or an OCFD or a Windom. There are reasons for that!

It's funny how bent out of shape you get when people use the word NVIS. Even it's not truly "NVIS", it's a very convenient abbreviated way to say "short range regional contacts that are non-line of sight on the low bands".

It quickly gets the point across when someone says "NVIS" so we don't have to go back forth trying to figure out if they're building a system for long range DX, or a short range "cloud warmer" setup.

I agree with all that. Listen to AA, he is an FR engineer. he knows what he is talking about.

In order to bring open line into the shack, you have to do it right, and you will introduce RF into the shack if the antenna  is not truly balanced especially ( which mine is not ) on bands 20m and above. My doublet is not truly balance because one side is in the trees more and lower to the ground. I just don't have the property to string it all in open air. It does work great on 160m, 60m, 30 meters which is why I made it. The lower bands don't seem to make a difference. I don't know why but I suspect it is frequency dependent because with a longer wavelength and a short run of open line in the shack, the peak of the wave off the feedline ends up further down the feedline away from the shack depending on the feedline length and the antenna length.

I like making antennas, so that is what I do. I get a certain satisfaction from playing with them and being successful making contacts with them, but for most wire antennas if you save money by making them it isn't much at all, unless you already have all the parts from other antennas you made, that may or may not have worked out.

I will say something about NVIS though

On 160, 80, 60 m ( and even 40 ) whether it is NVIS or ground wave, what ever it is, it works when you get the antenna as far away from the ground as possible simply because you have a larger signal all around because of lower ground losses and if you have the ability to get an 160, 80, or 60 m ( or even 40 ) antenna to 1/2 wavelength above the ground then I hate you, but for everybody else like me, the higher the better. This idea that NVIS is great with an antenna 6 feet off the ground is nonsense. The ground losses are huge and the pattern doesn't really change much until you get above 1/3 wavelength.

Here is the thing though, and it applies to any antenna regardless of how it's fed, or tuners, or whatever.

A 160 meter dipole is going to have a garbage signal pattern (IMO) on any band higher than 80 meters. Sure, you're feeding it with open wire line and a monster tuner and can tune it anywhere, so your transmitter is happy... but where is the signal actually going? 20 meters, yeah, some wonky signal pattern with 10 lobes and a bunch of big nulls. Six meters? Yeah right. I cringe when people try to do 6m from some giant antenna with a tuner.

Here's a diagram I found from a quick search. It says OCFD, but the pattern from a center fed dipole or even an endfed would effectively be the same. If you have a 160 meter dipole, all those patterns would go down an octave.

Attached File


In its defense, a real antenna in a real environment over ground etc would not have a perfect pattern with nulls as deep as predicted, but still...

I recommend fan dipoles a lot, and a good part of the reason why is because they have a more normal dipole signal pattern (the 80m fundamental on that illustration) on higher frequency bands vs using a big antenna with a tuner. I recommend verticals a lot, and much of the reason why is because they have better omnidirectionality and smoother signal patterns in both horizontal as well as vertical planes. Their downside is lack of high angle signal for the short range stuff.

Try some different dipole layouts, like inverted V and crows foot.

Yep, the longer the wire above a 1/2 wavelength, the pattern is broken up into many nodes and nulls.But those nodes do have gain. The same is true for a G5RV or any wire that is operated on a freq so that the wire is multiples of 1/2 wave. The same is true for a HWEF above it's 1/2 wave freq. Even a dipole will have nulls on the ends of the wires.

The only true omni directional antenna is a vertical with a perfect ground or symmetric radial field at the primary 1/4 wave length. Even a multiband vertical will not have a uniform pattern across bands. the primary nodes will be at different take off angles.

An antenna with lots of lobes and nulls doesn't mean it isn't useful. You will make contacts all over with those lobes. And using the grayline kinda doesn't matter much because one of those nodes will intersect the grayline. Other ducting propagation won't matter much either. You can have a universally omni antenna and still not get to where you want because of propagation restrictions with refraction differences and ducting, or get to where you do want to get for the same reasons with lots of nodes. So it isn't all bad and it isn't all good.

My other antenna is a homebrew fan dipole for 80/40/20 with different levels of inverted Vee due to wire lengths.. But for all the other bands, I use the 160m doublet and it is very efficient for a multiband antenna and accept the lobes and nulls on the pattern.

Unless you are going to have a separate resonant wire antenna for every band you have to deal with nodes and nulls. Rotatable yagis and dipoles are different because they are rotatable and you can rotate the nulls and nodes to where you want them.

Every antenna is a compromise of some sort. Nothing is perfect.

This is absolutely true. But the big "but" is: if you can only have a single antenna for every band, what's it going to be? The doublet, and the vertical are the ones to have. The doublet is a lot easier and less expensive to construct if you have the trees to get it up high.

I am living proof of those funny lobing patterns. My main antenna started life as an 80M doublet, 65ft high. On 80 it was pretty much omnidirectional. It wouldn't tune 160. On 40 it was very directional north and south. That was nice because I spend most of my time ragchewing with the "loud" stations up and down the east coast. But 20 and 17 had weird lobes I didn't like. I could only work 17M to the south. So I added 20 and 17M elements to the antenna (after a bunch of time with EZNEC modeling software). Life was good again for a while. Then I wanted to get an antenna that was more omnidirectional on 40M. Again, a little work with EZNEC suggested that a 40M quarterwave vertical element hung from each end of the main 80M element would do that. And it did, but then it screwed up my ability to tune 80M. But that was OK, because by then I had an inverted L I used for 160M and it worked great for 80M, too. So I was happy

The point of all this is that a plain old, 80M doublet is not only a great performer, but maybe more importantly a great foundation and ultimately much more flexible than starting with an end-fed, OCFD or Windom. Get it up high, get it running, and then start adding more elements. Pretty soon you've got a 3 or 4 element fan-doublet and are cooking with gas!

With knowledge and care that can be exploited. There are people who put up such an antenna oriented in a particular way such that a good signal lobe on 20m is pointing toward Europe, another good lobe pointing toward Australia. Then they think DX is good. But half or more of the US is in the nulls, so trying to make US contacts may be a PITA. And most who are dealing with this aren't pointing their antenna with such precision, they're trying to shoehorn a wire into an existing space somewhere.

If you just want to make a contact, almost anything can work. If you have a goal of say being able to work all over the US the highest percentage of the time, other options are better IMO.

Many things that amateurs do are severe compromises, due to the size of HF antennas, and the fact that even severely degraded systems can still eke out some contacts. It's just a matter of how much performance you are willing to sacrifice and what those sacrifices are.

If people had the room and $ for a giant Spira Cone and some big rotatable log periodics like the real big boys have... well, we'd still be at the mercy of propagation, but it'd be easier.

Looks like he is likely using UV-resistant 1/2-inch polyethylene drip tubing (the unperforated supply tubing, not the perforated drip stuff) for the spreaders as well as for the center and end insulators. The spreaders are 4 inches wide - they use a special punch to notch the tubing edges to permit snapping the wires in place. The wire is #16 ga., insulated.

Here's an interesting video directly from the source showing the construction method up close (it's an annoying vertical-format smartphone video, but it does have good close-ups of the spreaders and other insulators):

It all comes down to what ham radio is all about. Acquiring knowledge and putting it to work for you.

My 80/40/20m fan has 3 dipoles on it in the bands just mentioned at 50 feet. It started life as a 20m inverted Vee on a portable USAVertical tripod at 30 feet. then I kept changing it and adding to it to get the performance I wanted. it was a learning process.

At 50 feet, I knew 20m due to height and less angle down of the inverted Vee would be the most directional, so I put that facing the EU ( via great circle route, not a straight line )and the rest of the US. I also knew the 40m wire would decouple the 20 meter wire and that the 40m wire would be less directional due to lower ends and lower in wavelength to the ground so I oriented that 30 degrees off from the 20m wire. In reality though, I oriented both 15 degrees off the axis I wanted because 15 degrees makes very little difference for an inverted Vee. The came the 80m wire which by height is mostly a cloud burned, so I oriented that 90 degrees away from the desired axis of the other 2 wires.

Then I tuned the 80 to 75 because I knew a higher SWR in the data / CW part of the band meant lower power output but I also knew that those modes had smaller bandwidth and could make up for the power loss in the coax compared to phone,  then tuned the 40, then tuned the 20 because longer wires change the tuning of the shorter wires more than the other way around..

then I wanted 160m so then came the 160m doublet, that I had to orient the only way it would fit, but I also knew that at 45-50 it didn't matter in the least which way the wire was strung.

It all comes down to learning and using knowledge to work this hobby. Too many people thing you can buy an antenna and put it up and it will work the way you want it to. As you said it is much more complicated than that and you use the constraints you have to an advantage and minimize the disadvantages. But to do that takes knowledge and knowledge takes effort.

For fun, find KE5EE on the radio once in a while and listen to one of his QSOs, and he will talk about the design challenges and compromises of his antennas and the decisions he made to work around the issues he had and the compromises he had to make, and why he changed from one antenna to another. Then look at his QRZ page and look at his 5 million dollar antenna field LOL and you come to realize no matter how much space  you have and how much money you spend, decisions have to be made to optimize what you want to do and minimize the disadvantages with your choices of antennas, placement, feedline, and cost and work. Notice the 160m full quarter wave vertical 4 element phased array antenna system he has and the stacked 80m yagis LOL. Nothing is perfect but his farm is as close as anybody is going to get. that is one of the things I love about the hobby. that and talking antennas like this with other hams!!

Could the ladder line be shortened on the recommended antenna if it didn’t fit the available space?    I like the idea about running it to an eave mounted balun and the coax run inside.  

What would the grounding look like in that situation?    Ground the coax at the base and then run it inside?

"NVIS" exists almost all the time. Yes there is a period of time when particular frequencies work at very high efficiency, but it works at lower efficiency over a much larger period of time.

I used to live somewhat nearby to one of those big dog 80 meter nighttime ragchew guys. His antenna was simple - a full size dipole supported at the center and each end on wood power poles removed/surplused by the local electrical co-op, so about 25 or 30 feet high at most. I was told that he had one or more reflector wires on the ground as is a known technique with low height dipoles.

Nobody with a big signal is using OCFDs or Windoms because they'd melt down the tuners and/or transformers required. And it'd be next to impossible to control RFI with the power levels that most of those guys are running.

I love this thread bc I've been looking at something similar. The ladder line posted at the beginning is intriguing. I might actually be able to get it to the peak of my roof and then get the legs of the antenna up to 50ish ft.

My concern is lightning protection. My wife would kill me if I burned the house down.  

Here ya go.

Both really excellent questions!

The answer is a qualified "Yes". With a ladder line fed doublet you need to be careful to not choose a ladder line length that results in bad standing waves on the ladder line, it'll make it impossible to tune. See here for some rough guidance. There used to be a really great Excel spreadsheet you could download that calculated it more precisely, but damn if I can find it online, now.

That's what I do. I have a ground rod right underneath where the balun is, and I put a Morgan lightning arrester right on top of it. Obviously a strike might write off the balun, but I chose to not protect the balun because it was easier for me.

I want to remake my 80m ocfd into an 80 doublet. I don't want to spent $150 for something I have 90% of the parts for already. I have 135ft of copper weld in the air right now and can repurpose, I'll take my Balun Designs 4116 and put it on a fence post outside my shack window and run open ladder line up to the feed point.

I'd like to experiment with adding fan elements for the upper bands.

Only thing holding me back is I want to use the 7300s internal tuner which I think will tune 6:1 if I modify it. I haven't taken the time to look up what the required match is for the various bands. My 939 tuner is in my go box now...

@Nmbmxer you have it nailed, dude. Got to use that 939. W7FG sells just the feedline.

I would not mod the IC7300 tuner, it probably won't stand up the voltages and/ or current that may develop. I may be old fashioned, but I run a big manual tuner because it has lower internal loss'. Highly recommended to get one and at low power learn how to use it.
73,
Rob

I was looking at a cheaper MFJ OCDP but I am only looking at 100w with an internal tuner.  

I do the same thing.

Right now I am using a Dentron MT-3000A boat anchor

Amen! Dentrons have always had a good reputation. At my QTH it's a Palstar AT2K with a Ten Tec 4229 on the side, which was a kit that somebody built and I'm still working out the kinks.
73,
Rob

Modding the tuner just lets it try to tune a larger mismatch before giving up, it doesn't change the fold back circuitry. Based on some swr graphs I looked up it's not going to get anywhere near tuning the mismatch I'd need. I don't even know how the 939 would handle it, some of the charts were more than 32:1.

I dislike my 939 tuner and manual tuning in general. The 939 is busy, I have a 949 too but like it even less. I like how the internal tuner changes tuning without having to transmit first. I like to dial around switching bands looking for something interesting like my father-in-law changes channels on the tv... Someday I'll make a stepper driven link couple tuner that gets the frequency from the ci-v port and compares it to a table, which will end up being 90% of the code I'm writing to do the same basic thing for my homemade screwdriver. Too many irons in the fire...

The issue with modifying the tuner in the 7300 is not damage to the finals due to high SWR. It is damage to the tuner components.  The issue is at higher mismatch higher voltages will develop in the tuner components. Those components can only work a certain high voltage limit. If the high voltage rating of the components are exceeded in finding a match you can arc a capacitor or inductor and blow a tuner component or many.

The IC-7300 will match 10:1 in what is called emergency mode max power out at 50 watts. The power limit is so tuner components dont arc as the less power means less high voltage on the tuner components.

The "big signal" 80m ragchew guys commonly run far more than legal power.


Resonant antennas are so much easier.

The only antenna I've used ladder line on was a ZS6BKW. Very nice antenna, worked well for me. I ended up needing to take it down to do some work in the back yard. The EFHW that I put back up just didn't do as well.

Down here in an apartment, I'm extremely limited in what I can do. So, I have a shorter end-fed that I ran out of the window and over to the balcony. It doesn't perform as well as it did when I ran it straight down the balcony edge at the old apartment. I live with it as this is a temporary living arrangement.

Agreed. I use this one: https://mfjenterprises.com/products/mfj-986
It's easy to tune and with the roller inductor matches just about anything within reason.


If you enjoy kits, this might be interesting: https://mfjenterprises.com/products/mfj-941ek

I have been using something similar from DX Engineering for 14 years. Difference is in the size of ladder line.
When I had my Icon -703 , I made contacts around the world with 5-10 watts.

I hadn’t really thought about guys going over 1500 watts.   I presumed a mostly rule book following in hams.

It might explain why someone in Pensacola is blasting my audio while not so far Ontario Canada is barely audible.   Yea subject to conditions but it makes you wonder.

Listening to 14.207 this morning and hearing some overseas stations, Manchester England was audible but low, Italy at 100 w on a yagi was barely audible through the static.  


ETA I did hear the gent in P cola say he was on a 100 foot tower with a directional beaming toward the N pole.

This is a little (lot ) of thread drift, but...I am personally aware of one Northeastern 80M "personality" that runs 7000W. Not kidding. He shunt feeds his tower so it's a big antenna, too.

A lot of the 80 and 160M guys are broadcaster wannabees.

Back in the AM days, modified broadcast transmitters were often used. A pair of Class C 833As modulated by a pair of class B 833As could put out a crystal clear signal on 75 Meters. The plates glowed a beautiful yellow-orange.

7000w

How would that work about 50' in the air in an inverted v?  I'm looking to get back on the air.  

Better than other alternatives.

How would that work hooked up to a 100’ of coax direct bury (or slipped into a buried plastic conduit)?  

Having a ladder line running in the air back to the basement would be a major nuisance.




I keep looking at options here.  My usable trees are not that big.   25-35 feet to the thin top branches.  

I could do a sloper down my hill maybe.   There always seems to be some dang obstacle midway,....ornamental trees, apple trees etc.  I have considered using the chainsaw but put that off due to the time it takes to replace.  

Then I come back around to a vertical antenna with ground radials at the sandy circle with the old pool ground rod already driven.


arfcom get both someday.

The other antenna I come back to is the Dave Casler reference station MfJ 2010 (or the heavier gage Mfj 2020) OCDP that is already coax adapted.

I got time.   No sit in tests around here.  I just missed one in Rutland vt.  Not set up to do internet testing.  Apparrently my Ipad internet connection isn’t an option.


and the earth is good and frozen.

Poorly, unless you locate a remote tuner at the end of the coax. Because of the way these antennas work, being non-resonant on most bands, fixing the mismatch at the radio end of the coax leads to a lot of losses in the coax. You really don't want to get much above 25ft of coax in these cases without resorting to a remote tuner.

IMHO, anything less than 50ft is a non-starter. Go vertical.

Exactly. But with a remote tuner at the base.

Thank you, I was concerned about mismatching methods and materials of the different styles.  

135' of wire fed with ladder line and tuned with a tuner.  Or 260' or so if you have room.

So I am trying to get up to speed on this. At what height does this have to be hung? I am reading the ladder line should be vertical? How the Hell are you guys getting these 100' plus in the air?

The feed line should come away perpendicular to the antenna.

Height is nice, but the vast majority of the stations I work are around 35' above ground. Some of them are 20' - 25' and still put out a respectable signal.

ETA: My dipole is 35' above ground and I do a lot of QRP work on 40, 20, and 15.
Full Disclosure: I'm a 100% CW OP.

ETA 2: Along with antennas, propagation affects how well your signal gets out.
This book will show you how to take advantage of it.

@Canoeguy
Frank's right, it's best at right angles to the wire but can come away at any angle to the earth. It does need to be kept away from metal by 3 times it's width or so.
73,
Rob