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K2POP
12-21-2011, 10:55 PM
I have a OCFD wire antenna that is about 66' long. Due to wind, I would like to suspend it from a Dacron line rather than just support it at the ends. (There are no convenient supports between the end points.) Will the Dacron line cause any significant degradation to the signal when receiving or transmitting? How about if it is wet after a rain? Are there other ways to strengthen wire antennas that I should consider?

73, Richard

WB2WIK
12-21-2011, 11:02 PM
I don't see how this makes anything stronger in any way.

All the strain is on the end supports in such a situation, and those would be the same whether you used a messenger rope or not; in fact, the strain would be a bit more with a messenger rope, since the rope will add some weight and definitely some wind loading (more surface area than just wire). As such, you've found a solution but there really isn't any problem it's solving.

Copperweld antenna wire is way stronger than rope. Use strong end insulators, a very strong center insulator, and sufficient end supports, and you're done.

K5RCD
12-21-2011, 11:42 PM
The Dacron rope will have no effect on your signal, but is really not necessary.

If you use 12 ga. copper, stranded, insulated wire, it will withstand almost anything. It's easy to work with, and doesn't kink as badly as almost any other wire. Pre stretch it a bit before putting it up, and it will last almost forever.

My 160 meter loop has been up for over six years, with no maintenance, and is as good as new. It has withstood 90 mph winds, ice storms, and large falling limbs. 12 ga. is much stronger than 14 ga. or smaller wire.

K2POP
12-23-2011, 06:07 AM
Thank you for the replies. The strength question has been answered but the main question, signal interference, has been addressed only in passing. Randy thinks the Dacron line will have no effect. Like trees, I suspect it may at least cause some tuning variations. Does anyone have any experience with this? I also suspect that wet line (after a rain) will have a greater effect. If anyone has tried suspending a wire dipole below a Dacron line (rather than supporting it only at the ends,) please share your experience with it.

73, Richard

AB2T
12-23-2011, 06:23 AM
Copperweld antenna wire is way stronger than rope. Use strong end insulators, a very strong center insulator, and sufficient end supports, and you're done.

Steve's right on, but one more point -- make sure that the insulators you use will not chafe your line. PVC and fiberglas are good electrical insulators for most power levels. However, the risk of chafing is high. Any type of rope will break if the insulator wears through the line. Porcelain or ceramic insulators not only handle voltage well, but also prevent chafes. Your next hamfest will have a vendor selling bunches of these insulators for nearly nothing.

N5AD
12-23-2011, 01:38 PM
my local farm supply carries the ceramic insulators along with other types, all used in electric fencing. Check out a farm supply for inexpensive insulators.

WB2WIK
12-23-2011, 05:13 PM
Thank you for the replies. The strength question has been answered but the main question, signal interference, has been addressed only in passing. Randy thinks the Dacron line will have no effect. Like trees, I suspect it may at least cause some tuning variations. Does anyone have any experience with this? I also suspect that wet line (after a rain) will have a greater effect. If anyone has tried suspending a wire dipole below a Dacron line (rather than supporting it only at the ends,) please share your experience with it.

73, Richard

When dry, it should really have no effect at all. When wet, it will -- not because of the Dacron, but because of the water which has a dielectric constant that's much higher than air.

My biggest concern, though, if you live in a place where you can get snow or ice, would be accumulation of those on the rope. That will make the rope very heavy, you'll have much more strain on everything including the end supports, and the dielectric constant of ice is very high, which will greatly detune the antenna.

Of course that same ice on the antenna wires themselves will do the same thing; however, since wire is skinny and somewhat slippery, ice takes longer to form, and falls off faster, than it would on rope.

Edit: I just looked and it appears you're in Orange County (CA) so the snow and ice part would not apply.

WD5JOY
02-14-2012, 03:30 PM
I'm a couple months late on this 'un - but, have experienced the down-side of using the "support rope". Unlike my usual rambling, I'll try and keep this brief (ya' knows it ain't-a-gonna-happen!):

Moved to Colorado - Four Corners - cold snow country, but we also get an ungawdly amount of "rain" ('unfreezededed' snow or so they tells me). In my glory and wanting to "help the wire" avoid all the forces of nature I could, I hung a 3/16" Dacron "support rope / messenger line" and attached the "wire" to said rope. I just knew it would support most of the weight and lengthen the life of the wire. Not so ......... and it caused problems when the rope was "wet" even though it dumped most water when the rain stopped.

The water IN and ON the line caused the 'tuner' to constantly seek the 'happy spot'. When raining the line was of course saturated and the moisture in the air (as in rain-water) contributed to the 'seeking' of said 'happy spot' and WAS to be expected as in ANY rain. It was AFTER the rain or when there was a light 'mist' the problems were MORE evident. Water was NOT even distributed along the line, it rain down-hil of course, and broadside rain pretty much evenly covered the rope; the end-rainfall might make one end wetter on the North and the opposite end wetter on the South --- it simply was never "even" and the tuner saw this as a need to adjust.

You won't get snow in SoCal - but when I did - the 'weight was at least DOUBLED' thanks to the rope. While it did not stretch - it 'sagged' from the added weight which again was more than double the weight of the WIRE alone. The 'ice' built up ON and ACROSS the two lines effectively increasing the diameter to three or MORE times that of the wire alone. It took an extended time period for the "melting" to take place and the antenna to become stable again. The WEIGHT finally took its toll on antenna nd OPERATOR and I removed the rope and returned to the 'conventional' way of 'hanging' the "V". Problems with RAIN were 90% less and problems with ICE were at least 80% less; WEIGHT issues were reduced and that wire did just fine for a long while.

I suggest ONLY good supports --- good insulators (strength) --- Dacron rope ONLY as end-supports and for the 'apex'; going beyond is (or WAS for ME) unnecessary and counter-productive. Folks have been hanging "V's" for decades and not using "improved methods"; no need to start now IMHO.

Again --- late on commenting --- but hope it helps the OP or someone who might duplicate the question in the future.

AJ4WC
02-14-2012, 05:46 PM
I have two OCF dipoles and so I'm assuming you have a balun at the feedpoint that would need additional support, instead of just a wire dipole. I haven't seen an OCF balun that I would want hanging unsupported from the antenna wire. It's just too heavy and would cause too much sagging. I use support rope, but I have the support rope attached higher from the tree so it doesn't get wrapped around the antenna in the wind. The rope only supports the balun, and is free and clear of the actual antenna wires.

JOEJOENIKK
02-15-2012, 05:04 AM
K2Pop similar situation. For those of you who dont know, Nylon is not intended to be left in the sun for long, most plastics are not. Bear with me, there is an important lesson to this long story.


Where I live, I'm at three feet above sea level, in the middle of a patch of Florida Everglades and the spring and summer thunder storms blast me daily. There is harldy a Plam tree standing in the open without the top burned off, once the lightning finds them, they seem to continue to get hit. But the tropical storms bring flooding problems maiking the radio is somewhat a necessity.

Currently, it's winter, very little weather, which gave metime to experiment. Last month I cast a fishing line over one of the bigger Oak trees and pulled a slip harness and a one pound counter weight and piece of steel wire up, I pulled about 135 feet over the top of the house to a palm tree and tied it off. The weight was there to controlled amount of tension on the line, the slip harness on the oak tree end was held into the tree branch with a spool of the cheepest 50 pound fishing line that I had. I secuedthe fishing line to the base of the oak tree and preceed with my experiment.

I have HUGE problems with propagation and radar QRM's. Like anyone who uses a rig on any island would try to explain, the signals coming off the Gulf of Mexico are of no use to me. My wire was installed on that side of my local vertical ground plane.

I ran another piece of fishing line up and over to the ground plane, tied one end of the line to the MIDDLE of 135 foot "reflecter" that I had just made between the two trees and left the rest of the spool of fishing line still attached but hanging from a nail by my door. I began experimenting with the effects of the distance between the "reflector" and the Vertical concentrating on it's ability to reduce my mid-afternoon QRM.

This experiment provided me with several quick results, most important of them being that there is some effect at Yagi Reflector distances that are greater than the usual standardes that we use but those standards are actualy very good. The reflector must be in the magnetic field of the antenna. For the most part, we can assume that the noise supression provided with the reflector located beyond 1/2 a wave length from the driven element is of little use and the available gain is very lttle and rather unpredictable. My experiment paid off pretty fast, I used by spool by the back door to close the distance nad spent a few days and nights on it.

I didn't mind problems and shortcoming of the effects that I was seeing with the wire about two and a half or three meters from the 10 meter ground plane, it had no effects on my SWR and did seem to provide a little QRM supression. There is noone in Mexico I plan to talk to. So, I used the vertical for a few weeks after having left my wire tied there, with the one pound weight holding tension of it. I didn't want to invest a lot of work into a permentant 80 meter install untill I was certiain I want missing any of my local stations. We all have our prioritys, talking to someone who couldnt be of any help to me even if they wanted to isn't one of them. The Vertical is small, therefore less likely to get hit from flying debris and having the least expensive battery radio also has the greatest number of people that might bring me news and traffic reports. The 80 meters plan might never work.

After about a month in the air, my tenson weighted wire failed during a rather small storm. Althought the weight held even tenson on the wire, the 50 pound fishing line was tied in to the bas of the tree in a solid manner. That fifty ponds of force reduced the flexibility of the live oak branch above it causing the branch to break. Which I suppose, teaches me an important lesson.

You may want to try one of the Yacht places for a better line, Dacron is good stuff. There is a smaller line used by Rock Climbers called Perlon chord, that I really like. When shopping, you have to be careful about how much streach a line has, somtimes it is intentional, Kevlar is more like working with steel wire.

Because it will rain on the rope, use insulators. Supporting a wire by attaching it to a cable is the world's most common way of running a conductor, all that world's power company's use it. They have told me that a fatter dipole diameter is actually desirable, it provides a greater bandwith. The computer tells me is effect seems quite pleasant at about one foot in diameter. You may want to inquire with someone that has experiance at that area and consider making an antenna of that variety.

N8WWM
02-15-2012, 07:13 AM
Hey Randy,
Do you recall where you found the Alfreddy Newham pic on your website? About 5 years ago I copied that pic from a 1966 issue of 73 Magaizine and printed it on photopaper at 11 by 14. It was used on an easel at N8WPH's funeral. What a guy...blind, no legs, no kidneys, and several missing fingers...all due to a savaging attack of diabetes for years. Passed his General, given orally, in his hospital bed 2 days before he died. A good guy and a sadly missed lifelong friend. Seeing the photo there just reminded me of him.

Anyway, I also shot that photo with a digital camera and turned it loose on the web. I see it from time to time on websites, on QRZ, etc. Never fails to remind me of WPH. As far as I know I am the gulity party who unleashed that piece of art. No claim to fame or anything, just neat to see it getting around.

73 Doug

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