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what is the best beam for dx?
- Thread starter 20poundhammer
- Start date
For a BobTail, you'd have to voltage feed it in the center; requires tuner and ground, although some ppl have had success by feeding it with a balun and coax (N4PC for example), but never here.
For a Half Square, the easiest way (although it MILDLY skews the pattern) is current fed in an upper corner with coax. Provides a DIRECT 50 ohm match.
It was a little work getting the spacing and harness correct but it sure was worth it. Back when I was using that setup the band was real crowded and even with the 3 element by itself it was hard to pickup some distant contacts when the ones closer were on the air and causing interference from adjacent channels. They would run power and overmodulate even the stock ones to the point that splatter was horrible.
After getting that rig on the air if I didn't have it pointed at you it was almost like you weren't even on the air. Front to back was very very good and side to side rejection was almost total.
Guess these days with the almost total silence on the band none of that really matters anymore. Plus with the cost of antennas these days a good 4 element would be almost as good, at least as far as gain goes.
After getting that rig on the air if I didn't have it pointed at you it was almost like you weren't even on the air. Front to back was very very good and side to side rejection was almost total.
Guess these days with the almost total silence on the band none of that really matters anymore. Plus with the cost of antennas these days a good 4 element would be almost as good, at least as far as gain goes.
Good point(s). Most of my info either comes from one of the following three sources:
1. 35 years ON-THE-AIR experience (which I can't provide links for you, but I HAVE however uploaded some neat 11 meter verticals I've modeled on EZNEC
2. The late L.B. Cebik - W4RNL, the 'GOD-FATHER' of Antenna Modeling (cebik.com)
3. And here one (of MANY) a source which will show that NOTHING at the SAME height will offer as low of a radiation angle as a Half Square or Bobtail: Bobtail dipole by dxzone.com
"New bobtail owners often report great success with their antenna. It is designed for DXing, not for close-in work where low, horizontally polarized antennas are more appropriate. Mounted at heights of about 25-30 feet for 30 meters and 35-40 feet for 40 meters, these simple antennas deliver DX performance that rivals horizontal antennas in the 100+ foot class. Furthermore, at these heights it is practical to use trees or simple wood or metal masts to support the wires. Metal tubing or pipe masts can also double as the vertical elements. If you have tall trees as I do, 80 meters is not out of the question. Mounted at 70 feet, the tails of a wire 80m half square will be a few feet off the ground. I have used both a 40 meter bobtail and 80 meter half squares and was very pleased with them. I would not hesitate to build some again, under the right circumstances. They are a hard-to-beat combination of DX punch and simplicity."
Please feel free to post contradictory tests; one such example comes to mind: The controversy over YAGI vs QUAD. There is MUCH empirical evidence, modeling, and math to suggest that element-for-element, the QUAD will NOT beat the YAGI for forward gain or F/B. Real-world experience suggests that on bands like 6-20 meters, the advantages of a HORIZONTALLY polarized quad are:
- Increased aperture (capture area) leading to improved S/N ratio
- More resistance to man-made (and atmospheric) noise
Different likes for different tikes I suppose. (Heck, I wish I had the room / budget for EITHER!) That's how / why I began to experiment with antennas like Half Squares.
WOW!!!!! Definitely AWE inspiring. Someday, (land & finances permitting) would LOVE to try a stack like that.
CT,
thanks for the answer on the bobtail.
I was looking at feeding it like a half square on the current null, corner of the array. I reasd it may skew the pattern a tad but it will match to 50 ohm impedance.
The voltage fed presents a cleaner pattern acording to what I read but requires an inductor and a cap to bring the impedance down.
going to play with a 2 meter version and see how it works before I jump into the 40 meter size.
I had a good friend/elmer (sk) who used nothing but stacked three element
yagis, he screamed on signal and as stated rejection was out of sight.
thanks for the answer on the bobtail.
I was looking at feeding it like a half square on the current null, corner of the array. I reasd it may skew the pattern a tad but it will match to 50 ohm impedance.
The voltage fed presents a cleaner pattern acording to what I read but requires an inductor and a cap to bring the impedance down.
going to play with a 2 meter version and see how it works before I jump into the 40 meter size.
I had a good friend/elmer (sk) who used nothing but stacked three element
yagis, he screamed on signal and as stated rejection was out of sight.
Most have saw these pics but heres what im running 20 lb hammer.
Image hosting, free photo sharing & video sharing at Photobucket
Image hosting, free photo sharing & video sharing at Photobucket
Horizontal yagis can sometimes get a little boost from ground gain when they are positioned at the correct height above ground.
They might eek our a little more than a vertical in that case. The horizontal wins hands down for extended surface wave contacts when both sides are similarly polarized.
They might eek our a little more than a vertical in that case. The horizontal wins hands down for extended surface wave contacts when both sides are similarly polarized.
Mr Clean thanks for the pics great looking beam. a friend of mine that has built more beams than anybody i know has tried just about everything. for his money and upkeep and all around performance a 4 element quad is hard to beat. he has stacked 3 , 4, and 5 elements quads and while they do give you some performance over the regular 4 their return is not worth the effort and expense to put them up. guys this is a great post and i thank everybody for chiming in. keep the info coming!
had a 3 el quad, took it down for a 5 el yagi, a month later had a 3 el quad
quad is quiter and better recieve
both were at 55 feet
horizontle always beat verticle for transmiting dx but had to swich back and forth on recieve to keep the signal comming in strong
the stick heard ok but the beam was alot better
quad is quiter and better recieve
both were at 55 feet
horizontle always beat verticle for transmiting dx but had to swich back and forth on recieve to keep the signal comming in strong
the stick heard ok but the beam was alot better
well, i have a neighbor about 1 1/2 miles away, he thinks he is a "big" station on 6 meters. uses an SDR radio, an M squared antenna @ 90 feet, and is always QRO.
one day he asked me HOW i seem to open the band before him, and close it after him. so i invited him to come over and look at my station,...... nothing fancy , just a PROIII , 500 watts (most of the time it's at 100 watts) and a home made 6 element quad @ 60 feet.
if ya can't hear 'em,........ ya can't work 'em,........ quads ARE quietier on RX than yagi's.
I have used a quad.
It is quieter on receive, less noise.
The quad allows you to hear weaker signals due to less noise.
The quad does seem to have less fading than a typical yagi, some say due to both polarization fields being on the quad where as the yagi has one or the other.
The quad does not produce any more notable gain than a similar yagi.
The Quad has less bandwidth than a yagi.
The quad is a mechanical beast and must be engineered from the ground up.
The quad has more wind load than a yagi.
With a quad it is not If it gets destroyed in bad weather but when.
I prefer quads, they are great for DX and local rag chews.
I use yagi's due to lighter weight and ease of construction.
It is quieter on receive, less noise.
The quad allows you to hear weaker signals due to less noise.
The quad does seem to have less fading than a typical yagi, some say due to both polarization fields being on the quad where as the yagi has one or the other.
The quad does not produce any more notable gain than a similar yagi.
The Quad has less bandwidth than a yagi.
The quad is a mechanical beast and must be engineered from the ground up.
The quad has more wind load than a yagi.
With a quad it is not If it gets destroyed in bad weather but when.
I prefer quads, they are great for DX and local rag chews.
I use yagi's due to lighter weight and ease of construction.
I agree with everything except the red text I highlighted above. Quads have a broader bandwidth compared to a yagi of similar gain. A single quad loop has a much lower Q and thus a broader bandwidth than a single dipole element. This carries over to multi-element arrays as well especially as the number of elements exceeds more than three or four.