WELL I CAN SAY ONE THING YOU AND I HAVE DIFFERENT THOUGHTS ON BEAMS THE ONE I DID WAS FOR MYSELF AND IT WORK REALLY GOOD FOR WHAT I USED IT FOR. SO YOU CAN CALL IT JUNK IF YOU WANT TO BUT I LIKE FOR ALL MINE TO COME STRAIGHT OUT THE FRONT OF THE ANTENNA. NOTHING OUT THE BACK. I CHANGED IT FROM A WIDE BAND BEAM TO A NARROW BEAM.
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SKYWAVE BEAMS
- Thread starter youngest man
- Start date
Really? With 3 elements? By re-spacing? Nope! %&* %&*youngest man said:
I won't argue that you can optimize an antenna to work better than stock, but your claims are an insult when you consider all the knowledgeable people on here. Since you claim to have used an antenna modeling program, shoot me the file so I can verify your claims.
youngest man,
If it works for you then it's a good antenna.
There are some things that you really do need to be aware of about HF yagi type directional antennas. A conventional yagi always has some radiation off the sides and back, there's just no way around that. You can minimize those 'non-forward' radiations but you will never get rid of them completely. There certainly are antennas that have no signal off the back (other than 'near field') but they certainly are not typical yagi antennas, different structure.
The less signal off the back means that the radiation pattern to the front is more 'pronounced'/larger, but not particularly 'narrower'. At least not from a typical three element beam. The radiation pattern is something close to about 60 degrees wide, which is considered fairly narrow. A 'wide' pattern is almost anything from around 100 degrees to about 180 degrees. Either narrow or wide is more of a 'flood light' thingy rather than a 'spot light' thingy on HF. That's because to focus a beam narrower than about 60 degrees on HF requires a LOT of room and more structure than just a typical yagi type antenna. Deals with measurements in wave lengths, not in yards. A narrow pattern can also be realized by doing away with the front to back ratio thingy all together, same amount of signal off the back as off the front of the antenna. Not a lot of call for that though.
You know, all this antenna stuff has been around for a very long time. Except for things using very new technology materials, there just are no 'new' antennas that haven't been thought of, or made before. Do some digging in OLD books and I think you might be surprised at what you'll find. Which isn't saying that playing, experimenting with antennas isn't useful or fun, cuz it is! I can only think of one or two things that are as much fun... in the day time... with your clothes on. With or without beer.
- 'Doc
If it works for you then it's a good antenna.
There are some things that you really do need to be aware of about HF yagi type directional antennas. A conventional yagi always has some radiation off the sides and back, there's just no way around that. You can minimize those 'non-forward' radiations but you will never get rid of them completely. There certainly are antennas that have no signal off the back (other than 'near field') but they certainly are not typical yagi antennas, different structure.
The less signal off the back means that the radiation pattern to the front is more 'pronounced'/larger, but not particularly 'narrower'. At least not from a typical three element beam. The radiation pattern is something close to about 60 degrees wide, which is considered fairly narrow. A 'wide' pattern is almost anything from around 100 degrees to about 180 degrees. Either narrow or wide is more of a 'flood light' thingy rather than a 'spot light' thingy on HF. That's because to focus a beam narrower than about 60 degrees on HF requires a LOT of room and more structure than just a typical yagi type antenna. Deals with measurements in wave lengths, not in yards. A narrow pattern can also be realized by doing away with the front to back ratio thingy all together, same amount of signal off the back as off the front of the antenna. Not a lot of call for that though.
You know, all this antenna stuff has been around for a very long time. Except for things using very new technology materials, there just are no 'new' antennas that haven't been thought of, or made before. Do some digging in OLD books and I think you might be surprised at what you'll find. Which isn't saying that playing, experimenting with antennas isn't useful or fun, cuz it is! I can only think of one or two things that are as much fun... in the day time... with your clothes on. With or without beer.
- 'Doc
lords
Active Member
I can believe the forward gain figures but the 50 dB F/B seems a bit much. Maybe that much in a corner null but directly off the rear, I don't think so.Not simply by adjusting spacing and element length. Now if it was a double driven array with two driver elements and the proper phasing similar to what Raibeam did and add an extra reflector then maybe,just maybe.