Absolutely no argument from me CK.
Just thought I would put it in (after taking the time to load the program) But if the yagi is down and the boom already lengthened those dimensions will work
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Element spacing
- Thread starter spongbob
- Start date
Just thought I would put it in (after taking the time to load the program) But if the yagi is down and the boom already lengthened those dimensions will work
Often it is how one interpertates things...
From my perspective:
It is just the "key" to try them let them work together in a way it was intended.
Im trying to look at it from a different angle:
We are now looking at parameters as individual parameters to make a strong convincing point..but...
If you drive a car...for example a off-the road 4x4 and you insert a drag-race engine the "total" picture would be rubbish.
If you have your normal familly MPV and you insert all racing seats and special racing tires etc...well it still is rubbish.
etc...But for each situation those "individual parameters" will make it strong if the entire "car" was designed for it.
It simply isnt a case if we optimize one aspect all else is lost.
Some small points:
I havnt looked at the figures provided for the antennas...hope i find some time later today to get back to that.
Hope it was of use...
H.
19DX348
From my perspective:
It is just the "key" to try them let them work together in a way it was intended.
Im trying to look at it from a different angle:
We are now looking at parameters as individual parameters to make a strong convincing point..but...
If you drive a car...for example a off-the road 4x4 and you insert a drag-race engine the "total" picture would be rubbish.
If you have your normal familly MPV and you insert all racing seats and special racing tires etc...well it still is rubbish.
etc...But for each situation those "individual parameters" will make it strong if the entire "car" was designed for it.
It simply isnt a case if we optimize one aspect all else is lost.
Some small points:
- Doubling boom-length can increase gain with just below 3dB : correct.
- The maco are not top designs some of them could really be improved on the same boom by just changing spacing and element length.
- Small difference = small changes ...or hugh changes... Well, it depends and on two factors : what does one consider small and hugh ? If had antennas where a fraction of a inch could change several dB's and and SWR going from crazy...to perfect. And im sure most of us recognize that last one. But overall...the OWA is rather forgiving from a "antenna design perspective". But....you have to know what im talking about. Though still...just change a inch on an OWA at the wrong place and you could end up in misery. So ...if it were me....try constructing and designing antennas and you will find out the only thing that matters in the end is...be precise...always.
- Modeling software can help ...and most of them are simple to use, in some cases you can have simple improvements with exciting yagi's Though to get the best...you have to dig in you have to understand what your doing and what the program is capable of to achieve maximum out of it, and that is where many lack. There is a lot of rubbish out there....simple as that.
I havnt looked at the figures provided for the antennas...hope i find some time later today to get back to that.
Hope it was of use...
H.
19DX348
Henry, can you model this antenna for me? It is the base design of my home made 6m yagi. Exact dimensions may have changed slightly since this was drawn but they remain close. The dimensions are in inches with spacings on the left and element lengths on the right. Elements consist of six feet of 5/8 tubing with the remainder of the length 1/2 inch aluminum tubing. The Hairpin has been changed to 10 gauge stainless wire. It works REALLY well and I have wondered just what the specs were on it. The F/B seems exceptionally good but I may be biased. 
View of feedpoint before balun attachment.
Th is picture is several years old and the tower has since been replaced with a much bigger one. The antenna is the second one from the top. I hope to put it back up this summer.
View of feedpoint before balun attachment.
Th is picture is several years old and the tower has since been replaced with a much bigger one. The antenna is the second one from the top. I hope to put it back up this summer.
Hi !
...yes good antenna...roughly were looking at 10,5 dBI (give of take 0,5 dB)
And front to back in the order of 20 dB.
But bare in mind...that "free-space"..
If we situate the antenna at say 30 feet above ground. most signals on the back are above -25 dB (depending on angle arriving) with a "weak" point at really low angle's say 5 degree where its roughly -20 dB again.
I cant escape the feeling it was a "metric" design in the past ?
as some of the spacing's end up in almost "perfect" metric numbers.
could be just lucky though hihi.
I also did a quick switch between the 1st director and radiator as the 1st director is long than the radiator which I dont see that often with "older" designs.
For that reason i had a look ...but isnt of that much interest (besides swr)
Looks to me like its a well known design which still holds up today, cant pin point the origin (yet hihi)..have to go now..meeting this evening.
Picture explains more than words...I know...
But i would like to know how long the center part of each element is (that 5/8 tube)
Then ill insert the hairpin and give a few plots.
enjoy the weekend !
Henry
...yes good antenna...roughly were looking at 10,5 dBI (give of take 0,5 dB)
And front to back in the order of 20 dB.
But bare in mind...that "free-space"..
If we situate the antenna at say 30 feet above ground. most signals on the back are above -25 dB (depending on angle arriving) with a "weak" point at really low angle's say 5 degree where its roughly -20 dB again.
I cant escape the feeling it was a "metric" design in the past ?
as some of the spacing's end up in almost "perfect" metric numbers.
could be just lucky though hihi.
I also did a quick switch between the 1st director and radiator as the 1st director is long than the radiator which I dont see that often with "older" designs.
For that reason i had a look ...but isnt of that much interest (besides swr)
Looks to me like its a well known design which still holds up today, cant pin point the origin (yet hihi)..have to go now..meeting this evening.
Picture explains more than words...I know...
But i would like to know how long the center part of each element is (that 5/8 tube)
Then ill insert the hairpin and give a few plots.
enjoy the weekend !
Henry
Ha ha you caught that part about the driven element being SHORTER than the first director. Yes it is a little shorter which is not often seen, however due to the hairpin as well as the leads from the balun and the close coupling it needed to be shorter to achieve resonance. The center pieces of 5/8 tubing are six feet long (72 inches) with the remainder being 1/2 inch tubing. I forget where I got the basic design from many years ago but I played with it until I had something that worked well. All I had was a signal reference to monitor while adjusting for maximum gain and F/B ratio while watching the impedance. It does however work very well but it seems the pattern is skewed a little bit with a deeper null to the right of the antenna than the left. I worked all over Europe and half of North America as well as the Canary Islands with just 12 watts pep with it on band openings. Within the year I hope to have my Larcan 1Kw amplifier feeding it. It was at 42 feet but will be located at about 71 feet when it goes back up later this year.
Yes it is a little shorter which is not often seen, however due to the hairpin as well as the leads from the balun and the close coupling it needed to be shorter to achieve resonance. The center pieces of 5/8 tubing are six feet long (72 inches) with the remainder being 1/2 inch tubing. I forget where I got the basic design from many years ago but I played with it until I had something that worked well. All I had was a signal reference to monitor while adjusting for maximum gain and F/B ratio while watching the impedance. It does however work very well but it seems the pattern is skewed a little bit with a deeper null to the right of the antenna than the left. I worked all over Europe and half of North America as well as the Canary Islands with just 12 watts pep with it on band openings. Within the year I hope to have my Larcan 1Kw amplifier feeding it. It was at 42 feet but will be located at about 71 feet when it goes back up later this year.owh...cap K. allready forgot about it... Hollidays are up here starting this weekend. Ill put a X on my hand hihi.