Barker & Williamson Folded Dipole
What do you guys think about the B & W folded dipole? I am considering the 90ft model if I can find a way to hang it behind this apt. Reviews are all over the place, from fantastic to it barely radiates. I tend not to put too much confidence in a review if the person cant spell third grade words correctly, so I take most of the bad reviews with a grain of salt. Harold Ort N2RLL, of Popular Communications gave this antenna a pretty good review. Im concerned that the cost is a bit high and was wondering if it was worth it.
Last edited by KD8HMO; 02-18-2008 at 10:53 PM.
It's not only 90' long but must be supported by fairly substantial ropes at each end. This is a heavy wire antenna, since it's really two wires in parallel, with spacers separating them, plus a fairly heavy feedpoint insulator and another heavy terminating resistor opposite the feedpoint, in the other wire.
So before you spend the big bucks on this, make sure you really can install and support it.
Having said that, it does radiate and does so pretty effectively. It's not as good as a 1/2-wave dipole cut for the band you're operating, and performance varies from just a little bit "down" to several dB "down" from a 1/2-wave dipole, depending on the band. But it does load up well and shouldn't require a tuner, or at least not a fancy tuner: The automatic antenna tuner in most modern transceivers can handle it fine.
Based on personal experience, I'd say this "kilowatt rated" dipole really cannot handle a kilowatt, at least not for long (like RTTY or AM). It should handle a kW PEP intermittant duty, like SSB.
The biggest obstacle to installation of this particular antenna is how strong the end supports are! It's pretty heavy, and the "pull" on the end supports can be easily 75-100 lbs...more in a wind.
It is expensive, for what it is. Would it be possible for you to make your own wire antenna ? If people write in and report that they were not satisfied with the antenna why not contact them and ask them why. Its too late when you've bought one.
Originally Posted by KD8HMO
B&W has been producing these for the military for ages. They are a variation of the TTFD (tilted terminated folded dipole), although you don't have to tilt it.
Read W8JI's take on resistively loaded antennas (www.w8ji.com). They are definitely a compromise in efficiency, but they still may do what you want, if what you want is a set-it-and-forget-it installation...as are most of the military deployments.
No problem with quality control with anything from B&W....the stuff us usually built like a brick outhouse.
But just remember the ttfd is not a magic bullet.
"A minute of measurement trumps a decade of debate."
My problem is that I live in a single story ranch apt with no large trees to hang a full size dipole from. I cant have a tower with a gaping beam antenna in it. So I have to be a little more clever and try to hide anything I use as much as possible. I may have to use that 25 ft whip with an automatic tuner.
I had one of these, and was quite pleased with it. It worked better on some bands than on others, and I found it was very quiet on receive, as compared to the G5RV it replaced.
Performance is going to differ from one installation to another. I had the center of mine suspended from a 50 foot tower, with the ends out as close to straight as possible. It was really more of a 'V' in my installation. I'll bet if you visit your local National guard Armory, you'll find one there, along with any U.S. embassy. So, yes, they do work, in some cases very well.
It's not a stealth antenna by any means, and I suspect you could build your own if you could easily fabricate the terminating resistor. But, it looks professional, and not too hideous, if properly installed. I found that mine really shined on 30 and 40 meters. My guess 60 would be good, too. It was OK on 80 and fair on 20. I wasn't impressed on the higher bands, but I'm spoiled there.
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I've been using one for nearly ten years. I put it up once, and despite this being one of the most consistently windy places in the universe (yesterdays' average was 40 mph) it has never come down. Supported with 3/16 nylon rope, 30 feet up at the center, which isn't high enough, but it works. Droops slightly to 25 feet on the ends.
My "review" is that it is a good compromise antenna. But as Steve says, it is not easy to support, and it is very heavy. I have used it with about 1200 watts PEP SSB, and about 800 watts CW, with no problem, but never ran any high power continuous mode with it, like RTTY.
It will not do what a resonant dipole at proper height will do. And it will not fit in a living room, or under the eaves, or behind the TV set, or under the bed. It takes the full 90 feet, straight line (don't bend it) plus support rope length.
It is quieter than many dipoles on receive. I have been happy with mine, aware of its limitations as compared to a dipole. I recommend it to any station with the space as a "one antenna" ham station. Though I now use an LDG autotuner, I ran the 90 foot dipole with no tuner for several years, with a Icom 706, and did have some SWR problems on 30 meters, where it went to 2:1, which the 706 did not like. Boat anchors loved it! No problem, and no tuner.
I use it now with an FT897D and I experience no SWR problems with it.
I have even made a couple of regional contacts on six meters with it, but I don't think I'll get any DX on six!
Yes, it does work very well on 60 meters. At the low height, and poor RF counterpoise I have (desert sand) it doesn't work worth two cents on 160 meters.
Ed, CHOP, W5HTW - Novice 1956, General, 1957, Advanced, 1968, Extra, 1969. Keep the [B][U]amateur[/U][/B] in amateur radio, keep the pros, and Part 90, out of it.
Here are a couple of alternatives you might consider. A bit less obtrusive, performs about the same as the B & W AND less expensive.
Here's a link to a "Build your own" version which was originally used in Botswana for remote studio feeds...
The AR15/M16 - Irritating practically everyone since 1960...
B&W Folded dipole owner
I have the B&W folded dipole because at the time I wanted full range from 160m to 6m. It does work, SWRs are low (below 2:1) across most of the band, and it is quiet. It will make a nice receive antenna.
I have since put up a 270 foot dipole with ladder line and a Palstar AT2K tuner, and the dipole blows the folded dipole out of the water. The dipole with tuner is superior in all respects, except maybe noise.
If you want performance, forget the folded dipole, and go with a full dipole. But if you are space limited, you can get on 160m with the 90' folded.
Interesting observation: On the dipole, I get an occasional impulse noise, which with AGC slow, it will knock the receive down, then slowly come back. It does not happen with the folded dipole. During spring through fall I disconnect the ladder line so not to get zapped by a surprise storm. One evening I kept hearing this occasional zapping sound, got my attention. I found the ladder line close to chassis ground and the ground wire. I moved the ladder line clear from the chassis and it stopped. I am guessing that I am building up a charge, a potential to the point it will avalanche and discharge to the chassis ground. Jumping the gap to the chassis was the zapping sound I would hear. Anyone else experience this?